ABSTRACT 
 
 
 
 
Title of Document: PETROGENESIS OF PERALUMINOUS 
GRANITES FROM THE FOSDICK 
MOUNTAINS, MARIE BYRD LAND, WEST 
ANTARCTICA   
  
 Caitlin R. Brown, Master of Science, 2013 
  
Directed By: Professor Michael Brown, Geology 
 
 
 
Granites from the Fosdick Mountains, West Antarctica were analyzed for major and 
trace elements as well as Sr?Nd isotopes ratios in order to investigate the sources and 
processes associated with granite formation at a former convergent margin. U?Pb 
ages from zircon separates are consistent with previous results and yield ages of ~360 
Ma and ~100Ma. Major and trace elements indicate that paragneiss and orthogneiss 
samples are the high-grade equivalents of the Swanson Formation and the Ford 
Granodiorite site. Granites produced from the Devonian?Carboniferous melting event 
are derived primarily from the Ford Granodiorite suite while granites produced from 
the Cretaceous melting event are derived from melting of the Ford Granodiorite suite 
or mixing between the two putative sources. Cretaceous granites show evidence of 
early crystallized minerals. There is no chemical evidence for a source other than the 
Ford Granodiorite suite or the Swanson Formation.   
 
  
 
 
 
 
 
 
 
 
 
 
 
PETROGENESIS OF PERALUMINOUS GRANITES FROM THE FOSDICK 
MOUNTAINS, MARIE BYRD LAND, WEST ANTARCTICA   
 
 
 
By 
 
 
Caitlin R. Brown 
 
 
 
 
 
Thesis submitted to the Faculty of the Graduate School of the  
University of Maryland, College Park, in partial fulfillment 
of the requirements for the degree of 
Master of Science 
2013 
 
 
 
 
 
 
 
 
 
 
Advisory Committee: 
Professor Michael Brown, Chair 
Professor Richard J. Walker 
Senior Research Scientist Philip M. Piccoli 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
? Copyright by 
Caitlin R. Brown 
2013 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ii 
 
Acknowledgements 
I would like to thank my committee, Drs Michael Brown, Rich Walker, and 
Phil Piccoli for their guidance and patience. I would also like to thank Dr Igor Puchtel 
for his assistance in the clean lab and Dr Richard Ash for his assistance in the plasma 
lab. I would like to thank Professor Christine Siddoway and Christopher Yakymchuk 
for their input and collaboration with the project. This study was funded by NSF grant 
ANT0944615 and partially funded from a GSA graduate student grant. 
 
 iii 
 
Table of Contents 
 
 
Acknowledgements ....................................................................................................... ii 
 
Table of Contents ......................................................................................................... iii 
 
List of Tables ................................................................................................................ v 
 
List of Figures .............................................................................................................. vi 
 
Chapter 1: Introduction ................................................................................................. 1 
1.1 Background ......................................................................................................... 1?
  
Chapter 2: Regional Geology........................................................................................ 5 
2.1 Gondwana ........................................................................................................... 5?
 2.2 Marie Byrd Land, West Antarctica ..................................................................... 6?
 2.3 Fosdick migmatite?granite complex ................................................................... 7?
  
Chapter 3: Previous Results and Present Study .......................................................... 13?
 3.1 Previous results ................................................................................................. 13?
 3.2 This study .......................................................................................................... 14?
  
Chapter 4: Sample Descriptions.................................................................................. 16?
 4.1 Swanson Formation .......................................................................................... 16?
 4.2 Ford Granodiorite suite ..................................................................................... 17?
 4.3 Paragneisses ...................................................................................................... 19?
 3.4 Orthogneisses .................................................................................................... 22?
 4.5 Devonian?Carboniferous diatexites .................................................................. 23?
 4.6 Devonian?Carboniferous granites .................................................................... 24?
 4.7 Cretaceous granites ........................................................................................... 24?
 4.8 Cretaceous microgranite ................................................................................... 27?
  
Chapter 5:  Analytical Methods .................................................................................. 28?
 5.1 U?Pb zircon analysis......................................................................................... 28?
 5.2 Major and trace element analysis ...................................................................... 29?
 5.3 Sr?Nd isotope analysis ...................................................................................... 31?
 5.5 Sr and Rb spike calibration ............................................................................... 33?
 5.6 Standard Reproducibility .................................................................................. 34?
  
Chapter 6:  Results and Discussion ............................................................................. 35?
 6.1 U?Pb geochronology results ............................................................................. 35?
 6.2 Major and trace elements results....................................................................... 38?
 6.3 Major and trace element discussion .................................................................. 53?
 6.4 Modeling REE patterns of a Cretaceous granite ............................................... 60?
 
 iv 
 
6.5 Sr?Nd isotope results ........................................................................................ 68?
 6.6 Sr?Nd isotope discussion .................................................................................. 75?
  
Chapter 7: Conclusions ............................................................................................... 78?
  
Appendix A: Sample Analysis and Sample Locations ............................................... 80?
  
Appendix B: Sample Photomicrographs ..................................................................... 87?
  
Appendix C: Zircon U?Pb Radiogenic Ratios and Ages .......................................... 103?
  
Appendix D: Box and Whisker Plots ........................................................................ 124?
  
Appendix E: U?Pb Concordia Plots and Age Histograms........................................ 128?
  
Appendix F: Standard Reproducibility ..................................................................... 136?
  
Bibliography ............................................................................................................. 139?
  
 
 
 
 v 
 
List of Tables 
Table 1: Whole-rock major oxide and trace element composition as determined by 
XRF????????????????????????????50 
Table 2: Rare earth element (REE) compositions as determined by SC-ICP-MS?.57 
Table 3: Modal abundances and Kds of select minerals from sample Y2-HN097 used 
in REE modeling?????????????????????.........68 
Table 4: Sr?Nd isotope composition of source rocks and granites???????.78 
Table A1: List of sample names and analyses completed??????????...87 
Table C1: LA-ICP-MS U?Pb zircon data from sample Y1-AE035??????..109 
Table C2: LA-ICP-MS U?Pb zircon data from sample Y2-GP091??????..110 
Table C3: LA-ICP-MS U?Pb zircon data from sample 51225-1???????..111 
Table C4: LA-ICP-MS U?Pb zircon data from sample 51225-2???????..112 
Table C5: LA-ICP-MS U?Pb zircon data from sample Y2-JU096??????...113 
Table C6: LA-ICP-MS U?Pb zircon data from sample Y1-AW039??????.114 
Table C7: LA-ICP-MS U?Pb zircon data from sample Y1-IG053??????...115 
Table C8: LA-ICP-MS U?Pb zircon data from sample Y1-AW049?????.....116 
Table C9: LA-ICP-MS U?Pb zircon data from sample 10CY-035??????...117 
Table C10: LA-ICP-MS U?Pb zircon data from sample Y1-MJ075??...???.118 
Table C11: LA-ICP-MS U?Pb zircon data from sample Y1-IG073??????.119 
Table C12: LA-ICP-MS U?Pb zircon data from sample Y1-IG071??????.120 
Table C13: LA-ICP-MS U?Pb zircon data from sample Y1-IG062??????.121 
Table C14: LA-ICP-MS U?Pb zircon data from sample Y1-AW038?????...122 
Table C15: LA-ICP-MS U?Pb zircon data from sample Y1-IG070??????.123 
Table C16: LA-ICP-MS U?Pb zircon data from sample Y1-AE033??????124 
Table C17: LA-ICP-MS U?Pb zircon data from sample 10CY-039??????.125 
Table C18: LA-ICP-MS U?Pb zircon data from sample Y1-AE051??????126 
Table C19: LA-ICP-MS U?Pb zircon data from sample Y1-AE064??????127 
Table C20: LA-ICP-MS U?Pb zircon data from sample Y1-IG062??????.128 
Table C21: LA-ICP-MS U?Pb zircon data from sample 10CY-024??????.129 
Table F1: Sr?Nd isotope composition of USGS standard G-2????????.. 144 
 
 
 
 vi 
 
List of Figures 
Figure 1: Regional geology of the Ford Ranges?????????......................19 
Figure 2: Select major and trace element data for samples as determined by XRF?55 
Figure 3: Rare earth element (REE) chondrite-normalized patterns for source rocks 
and granites???????????????????????...?...59 
Figure 4: Ternary (Na+Ca)?(Fe*+Mg+Ti)?K???????????????.62 
Figure 5: Model of batch melting and fractional crystallization with 0% apatite and 
zircon in the source material???????????????????70 
Figure 6: Model of batch melting and fractional crystallization with 0.25% apatite and 
zircon in the source material???????????????????71 
Figure 7: Model of batch melting and fractional crystallization with 0.5% apatite and 
zircon in the source material???????????????????72 
Figure 8: Model of batch melting and fractional crystallization with 1% apatite and 
zircon in the source material???????????????????73 
Figure 9: Sr?Nd isotopic compositions at 360 Ma for source rocks and granites from 
the Ford Ranges???????????????????????...80 
Figure 10: Sr?Nd isotopic compositions at 100 Ma for source rocks and granites from 
the Ford Ranges???????????????????????...81 
Figure A1: Putative source sample locations within the Ford Ranges??????89 
Figure A2: Paragneiss sample locations within the Fosdick migmatite?granite 
complex??????????????????????????...90 
Figure A3: Orthogneiss sample locations within the Fosdick migmatite?granite 
complex??????????????????????????...91 
Figure A4:  Granite sample locations within the Fosdick migmatite?granite  
complex???????????????????????????92 
Figure B1: Photomicrograph of thin section 10CY-001???????????..93 
Figure B2: Photomicrograph of thin section 10CY-002??????????......93 
Figure B3: Photomicrograph of thin section Y2-BR086???????????.93 
Figure B4: Photomicrograph of thin section Y2-MD092???????????94 
Figure B5: Photomicrograph of thin section Y2-MP098???????????94 
Figure B6: Photomicrograph of thin section 51225-1????????????.95 
Figure B7: Photomicrograph of thin section 51225-2????????????.95 
Figure B8: Photomicrograph of thin section Y2-GP091???????????.95 
Figure B9: Photomicrograph of thin section Y2-HN097???????????96 
Figure B10: Photomicrograph of thin section Y2-JU096???????????96 
Figure B11: Photomicrograph of thin section Y2-MS089??????????...97 
Figure B12: Photomicrograph of thin section Y2-SM095??????????...97 
Figure B13: Photomicrograph of thin section Y1-AE035??????????...97 
Figure B14: Photomicrograph of thin section 10CY-010???????????98 
Figure B15: Photomicrograph of thin section 10CY-015???????????98 
Figure B16: Photomicrograph of thin section 10CY-021???????????98  
Figure B17: Photomicrograph of thin section 10CY-023???????????99 
Figure B18: Photomicrograph of thin section 10CY-033???????????99 
Figure B19: Photomicrograph of thin section 10CY-041???????????99 
 
 vii 
 
Figure B20: Photomicrograph of thin section Y1-BB013??????????100 
Figure B21: Photomicrograph of thin section Y1-CB080??????????100 
Figure B22: Photomicrograph of thin section Y1-IG057??????????..100 
Figure B23: Photomicrograph of thin section Y1-IG061??????????..101 
Figure B24: Photomicrograph of thin section Y1-LH077??????????.101 
Figure B25: Photomicrograph of thin section Y1-MJ074??????????.101 
Figure B26: Photomicrograph of thin section 10CY-035??????????..102 
Figure B27: Photomicrograph of thin section Y1-AW039??????????102 
Figure B28: Photomicrograph of thin section Y1-AW049??????????102 
Figure B29: Photomicrograph of thin section Y1-MJ075?????????.....103 
Figure B30: Photomicrograph of thin section Y1-IG071??????????..104 
Figure B31: Photomicrograph of thin section Y1-IG073??????????..104 
Figure B32: Photomicrograph of thin section Y1-IG062??????????..105 
Figure B33: Photomicrograph of thin section Y1-AW038??????????106 
Figure B34: Photomicrograph of thin section 10CY-039??????????..106 
Figure B35: Photomicrograph of thin section Y1-AE051??????????.106 
Figure B36: Photomicrograph of thin section Y1-IG052???????..???107 
Figure B37: Photomicrograph of thin section Y1-IG070??????????..107 
Figure B38: Photomicrograph of thin section Y1-AE064??????????.107 
Figure B39: Photomicrograph of thin section Y1-AE033??????????.108 
Figure D1: Box and whisker plots of zircon ages?????????????..130 
Figure E1: U?Pb Concordia plots and age histograms for Ford Granodiorite  
samples??????????????????????????..134 
Figure E2: U?Pb Concordia plots and age histograms for Devonian orthogneiss 
samples??????????????????????????...136 
Figure E3:  U?Pb Concordia plots and age histograms for Cretaceous orthogneiss 
sample?????????????????????????........137 
Figure E4: U?Pb Concordia plots and age histograms for Devonian diatexite  
Samples??????????????????????????..138 
Figure E5: U?Pb Concordia plots and age histograms for Devonian granite  
Sample???????????????????????????138 
Figure E6: U?Pb Concordia plots and age histograms for Cretaceous granite  
Samples??????????????????????????..139 
Figure E7: U?Pb Concordia plots and age histograms for Cretaceous 
 microgranite samples?????????????????????141 
Figure F1: 390ng load of SRM 987 standard 87Sr/86Sr ratios over 12 month 
 period???????????????????????????142 
Figure F2: 1000ng load of Ames Nd standard 143Nd/144Nd ratios over a 12 month 
period???????????????????????????.142 
Figure F3: 87Sr/86Sr ratios of USGS standard G-2 over a 12 month period???...143 
Figure F4: 143Nd/144Nd ratios of USGS standard G-2 over a 12 month period...?..143
 
1 
 
Chapter 1: Introduction 
 
1.1 Background 
The continental crust comprises about 39% of Earth?s surface (Sawyer et al., 
2011). While the bulk composition of the crust is andesitic, it is highly differentiated 
and stratified, with a mafic lower crust that is depleted in incompatible trace elements 
and a complementary felsic upper crust enriched in incompatible elements (Rudnick 
and Gao, 2003).  There are three dominant processes that can lead to the formation of 
felsic melts. One process is melting of a peridotite. However, melting experiments on 
peridotite produce melts that are less evolved than the bulk continental crust (e.g., 
Jaques and Green, 1980; Hirose, 1997), suggesting that this either is not the dominant 
mechanism, or is not the only mechanism that produces felsic melts. Another option 
is mixing of a mantle component with a crustal component, a process that occurs in 
continental arcs. The third method is reworking of the continental crust by partial 
melting of the lower and middle crust, and melt transfer and emplacement in the 
upper crust (Brown, 1994, 1995, 2007). Partial melting of the lower crust explains 
certain geochemical characteristics of the upper continental crust, including a large 
negative Eu anomaly, and the enrichment in SiO2, K2O and light rare earth elements 
(Rudnick and Gao, 2003). It is this enrichment of the upper crust in incompatible 
elements, water, and heat producing elements such as K, U, and Th, that leads to the 
long term stability of the continental crust. This process of partial melting and 
redistribution of melt occurs predominately in active tectonic settings?mostly in 
 
2 
 
continental arcs associated with subduction and continental collision zones since the 
Early Proterozoic (Brown et al., 1995).  
Anatexis of the deep crust produces granite melts (sensu lato) that may migrate 
and become emplaced in shallower portions of the crust. Therefore, granites provide a 
geochemical window into the processes of partial melting in the deep crust, and the 
chemical differentiation of the continental crust. I-type granites, or granites derived 
from igneous sources, are particularly enigmatic. They are generally metaluminous to 
peraluminous, and are chemically similar to continental arc granitoids. While some 
more mafic I-type granites are thought to contain a mantle component (e.g., Villaseca 
et al., 2009; Collins, 1996; Kemp et al., 2007) and could represent crustal growth, 
generally I-type granites are felsic and could be derived by partial melting of the 
crust, representing crustal reworking rather than growth (Brown, 1994; Sawyer, 1998; 
Annen et al., 2006). The migration and extraction of melt may lead to entrainment of 
peritectic minerals, or leave residual minerals in the source that can affect the 
chemical signature of the melts (Clemens and Stevens, 2012; Clemens et al., 2011). 
By determining how the chemistry of melts relates to entrainment of peritectic 
minerals, the connections between products of partial melting and their sources can 
be better understood.    
 Isotopic tracers are commonly used to identify sources in studies of granite 
petrogenesis (e.g., Vailleros et al., 2011; Clemens and Stevens, 2012; Yang et al., 
2007). Assuming equilibrium melting, the isotope signature of the melt should reflect 
that of the source. However, it is rare that a granite has a similar isotope signature to a 
single source (e.g., Farina and Stevens, 2011; Clemens and Stevens, 2012). Most 
 
3 
 
likely, this could be due to heterogeneous source compositions (Vailleros et al., 2011; 
Farina and Stevens, 2011) such that the granite could be the product of melting of a 
spectrum of lithologies and will yield diverse isotope compositions. Furthermore, 
melt could interact with the crust during transport and/or host rocks during 
emplacement, and, therefore, the granite may represent a mixture of multiple sources 
(Knesel and Davidson, 1996; Yakymchuk et al., 2013a). Also, a granite could 
represent mineral fractionation during melting of the source (e.g., Jung et al., 2000).  
The isotope composition of the melt may also be affected by how quickly the 
melt was extracted from the source and whether chemical equilibrium between melt 
and residue was attained (Harris and Ayres, 1998; Barbero et al., 1995). Accessory 
minerals are commonly hosted along grain boundaries or as inclusions within major 
rock-forming minerals. If the melt does not interact with included accessory minerals, 
then the isotopic signature of the melt may be determined by the accessory minerals 
located along grain boundaries (in addition to major rock-forming minerals such as 
feldspar). Therefore, the isotope signature of melts that have not interacted with all 
minerals present in the source may be strongly influenced by the distribution and 
microstructural location of accessory minerals throughout the rock (Rapp and 
Watson, 1986; Hogan and Sinha, 1991; Zeng et al., 2005a, 2005b, 2005c; Clemens et 
al., 2011; Harrison and Watson, 1983; Evans and Hanson, 1993).  
 This study focuses on characterizing the source rocks of granites produced 
during melting at granulite-facies conditions at the former convergent margin of 
Gondwana, with the intent to better understand the processes associated with granite 
production in a continental arc setting.  In West Antarctica, the Fosdick Mountains 
 
4 
 
expose a migmatite?granite complex in the form of a gneiss dome. The complex 
represents an exposure of the deep crust where melt production, transfer, and loss 
occurred (Korhonen et al., 2010a, 2010b). In addition, the low grade protoliths of the 
migmatites exposed in the Fosdick complex crop out in the surrounding mountain 
ranges. Therefore, the Fosdick complex and surrounding mountain ranges offer an 
ideal location to study the processes associated with granite production in the lower 
continental crust and to test petrogenetic models of granite production along the 
former Gondwanan margin. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5 
 
Chapter 2: Regional Geology 
 
 
2.1 Gondwana 
During the Paleozoic-Mesozoic, the Gondwana active convergent margin 
stretched from East Australia through Antarctica to the tip of South America (Fig 1a). 
West Antarctica and the Western Provinces of New Zealand made up Zealandia, a 
currently submerged continental fragment lying under the Southern Ocean (Tulloch et 
al., 2006). The margin was fragmented during a period of regional extension. Around 
85 Ma, Zealandia separated from the Antarctic margin. A rapid shift from 
convergence to divergence between 110 and 100 Ma, that led to eventual rifting, is 
thought to be due to either ridge?trench interaction (Bradshaw et al., 1983; 
Luyendyk, 1995; Mukasa and Dalziel, 2000), collision of the Hikurangi plateau with 
the trench (Davy and Wood, 1994; Mortimer et al., 2006; Davy et al., 2008), 
horizontal stresses due to buoyancy from the mantle wedge (Rey and M?ller, 2010), 
or the presence of a mantle plume (Weaver et al., 1994). However, among these 
alternatives the presence of a mantle plume seems least likely, based on the rapid shift 
from subduction to extension (Mukasa and Dalziel, 2000), the absence of regional 
uplift in in portions of West Antarctica long the margin at the time of break-up 
(LeMasurier and Landis, 1996), and the geochemistry of mafic rocks emplaced 
around this time (Saito et al., 2013).  
 
6 
 
2.2 Marie Byrd Land, West Antarctica 
Marie Byrd Land lies along the eastern side of the Ross Sea (Fig 1b and 1c) 
and is one of the major crustal blocks of West Antarctica (Dalziel and Elliot, 1982). 
The Ford Ranges of Marie Byrd Land are made up of Paleozoic basement rocks and 
Paleozoic?Mesozoic intrusive rocks. The oldest exposed unit in the Ford Ranges is 
the Swanson Formation, a meta-turbidite sequence that has been correlated with other 
terranes, based on whole rock K?Ar ages and initial Sr isotope values. These terranes 
include the Robertson Bay group in North Victoria Land, the Stawell and Bendigo 
terranes in Australia, and the Greenland Group in New Zealand (Ireland et al., 1998, 
Adams, 1986; Adams, 2004; Bradshaw et al., 1983).  U?Pb ages of 1000?500 Ma 
from detrital zircons derived from granite protoliths suggest sediment provenance 
from the Ross?Delamerian orogen (Pankhurst et al., 1998). Based on K?Ar and 
whole rock Rb?Sr isochrons, the Swanson Formation underwent a period of regional 
metamorphism at c. 450 Ma that resulted in folded and cleaved slates of sub-
 greenschist to greenschist facies (Adams, 1986). These metasedimentary rocks were 
intruded by the Ford Granodiorite suite (FGD), which comprises calc-alkaline, I-type 
granodiorites, emplaced during the interval 375?345 Ma (Adams, 1987; Pankhurst et 
al., 1998; Siddoway and Fanning, 2009; Tulloch et al., 2009; Yakymchuk, 
unpublished) during an episode of magmatism that occurred across the East 
Gondwana margin. The magmatism is attributed to subduction (Borg et al., 1987; 
Weaver et al., 1991) or back-arc extension (Muir et al., 1996; Tulloch et al., 2009). 
Coeval plutonic rocks outside Marie Byrd Land include the Karamea batholith in 
 
7 
 
New Zealand and the Admirality Intrusives in Victoria Land, Antarctica (Allibone et 
al., 2009; Borg, 1987).  
The Byrd Coast granite intrudes both the Swanson Formation and the Ford 
Granodiorite suite, and was emplaced during a period of intracrustal extension and 
back-arc plutonism (Adams, 1987; Weaver et al., 1992; Muir et al., 1994; Storey et 
al., 1999; Mukasa and Danziel, 2000). U?Pb geochronology of zircons from the Byrd 
Coast granite yield ages of 105?99 Ma (Yakymchuk et al., 2013a), which are 
contemporaneous with ages from the Separation Point batholith in the Western 
Province of New Zealand. The age of emplacement of these plutons coincides with 
the transition from wrench deformation to oblique extension (Siddoway 2004; 
McFadden et al., 2010a) that ultimately led to the breakup of the former active 
margin of Gondwana.  
 
2.3 Fosdick migmatite?granite complex 
The Fosdick migmatite?granite complex (Fig 1d), part of the northern Ford 
Ranges, was exhumed in the Cretaceous during a period of regional extension. The 
migmatite?granite complex forms an 80 km by 15 km elongate dome containing 
layered sequences of paragneiss, orthogneiss, granite, and cross-cutting mafic 
intrusions. The paragneisses and orthogneisses are inferred to be the high-grade 
metamorphic equivalents of the Swanson Formation and the Ford Granodiorite suite, 
respectively, based on geochemistry and the distribution of zircon U?Pb ages 
(Korhonen et al., 2010b). The granites were emplaced during the later stages of high 
grade metamorphic events in the Devonian?Carboniferous and the Cretaceous 
 
8 
 
(Siddoway et al., 2004; Korhonen et al., 2010b), and emplacement of the cross-
 cutting mafic intrusions was broadly co-eval with the Cretaceous granites. The dome 
is bounded in the north by the inferred Balchen Glacier fault, a steep dextral strike-
 slip fault (Siddoway et al., 2004, 2005), and in the south by the South Fosdick 
detachment, a south-dipping, dextral oblique detachment zone (McFadden et al., 
2010a).  
The Fosdick complex may be separated into three major plutono?
 metamorphic units: one dominated by migmatitic paragneiss, a layered plutonic 
complex (also referred to as the orthogneiss complex by McFadden et al. (2010a, 
2010b), and a leucogranite sheeted complex (Siddoway and Fanning, 2009; Korhonen 
et al., 2010a, 2010b; McFadden et al., 2010a, 2010b). The migmatitic paragneiss is 
exposed in the central and western portions of the Fosdick complex. It comprises 
stromatic metatexite migmatite with cm- to dm-scale compositional layering 
composed of alternating concordant garnet-bearing leucosomes and biotite?
 silimanite-dominated melanosomes (McFadden et al., 2010; Yakymchuk et al., 
2013b). The layered plutonic complex is also located in central and western portions 
of the complex, and is composed of 10 m- to 100 m-thick sheets of migmatitic 
orthogneiss and m- to dm-thick granite, granodiorite, diorite, and minor m- to 10 m-
 thick paragneiss layers. The migmatitic paragneiss and layered plutonic complex are 
intruded by hornblende-bearing mafic dikes and sills. The leucogranite sheeted 
complex is exposed in the eastern Fosdick Mountains and is composed of 100 m-
 thick subhorizontal leucogranites interlayered with 1?10 m-thick migmatitic 
paragneiss and orthogneiss. Subhorizontal foliation is defined by biotite and 
 
9 
 
sillimanite and is parallel to alternating layers of leucogranite sheets and gneisses. 
Mafic dikes strike NNW-SSE, yield 40Ar/39Ar ages of 143?96 Ma, and are generally 
folded and boudinaged (Siddoway et al., 2005; McFadden et al., 2010b; Saito et al., 
2013).  
The mafic dykes are characterized by enrichment of large-ion lithophile 
elements (LILE) relative to light REEs and high field strength elements (HFSE) and a 
negative Nb anomaly that are consistent with rocks formed in a subduction setting 
(e.g., Pearce and Parkinson, 1993). This suggests that the mafic dykes were not 
formed from a mantle plume, but derived by melting of sub-arc-mantle previously 
metasomatized by fluids from a down-going slab (Saito et al., 2013). The 
deformation of the mafic dikes records the change from transpression to transtension 
(Korhonen et al., 2010b). Zircon and titanite U?Pb ages determined from Cretaceous 
granites collected from steeply foliated domains at Mt Iphigene, as well as ages 
determined from Cretaceous granites collected from subhorizontal granites and 
leucogranites at Marujupu and Mt Ferranto, and ages determined from Cretaceous 
granites collected from diorite dikes at Mt Iphigene suggest that the shift from wrench 
tectonics to extension occurred within 5?10 Ma (Saito et al., 2013; McFadden et al., 
2010a, 2010b; Korhonen et al., 2010a, 2010b). Monazite, titanite, and zircon U?Pb 
ages from syn- and post-tectonic granites intruding the South Fosdick detachment 
constrain dome emplacement to c. 107?96 Ma (Richard et al., 1994; McFadden et al., 
2010). 40Ar/39Ar ages suggest rapid cooling from 105?94 Ma (Richard et al., 1994).  
The Fosdick complex (Fig. 1d) preserves evidence of two high temperature 
metamorphic events, during the Devonian?Carboniferous and the Cretaceous. The 
 
10 
 
Devonian?Carboniferous event is primarily preserved in deeper structural levels of 
the gneiss dome exposed in the western and central Fosdick Mountains. U?Pb ages of 
monazites from the paragneisses date the melting event from 376 to 302 Ma, 
overlapping and slightly post-dating the emplacement of the Ford Granodiorite suite 
(Korhonen et al., 2012).  Granite in shear bands that lack internal foliation, provides a 
minimum age of migmatization of 365?355 Ma (McFadden et al., 2010a). Sr?Nd 
systematics indicate that the Carboniferous granites preferentially preserve melts 
derived from the Ford Granodiorite suite, although one Carboniferous granite has 
chemical and isotopic characteristics that are consistent with derivation from the 
Swanson Formation (Korhonen et al., 2010b). Phase equilibrium modeling of garnet-
 bearing orthogneiss and paragneiss assemblages yield temperatures 820?870?C and 
pressures of 7.5?11.5kbar (Korhonen et al., 2010a). Forward modeling indicates that 
while the Ford Granodiorite suite would be capable of producing 2?3 vol. % melt at 
these P?T conditions, the Swanson Formation would have been a more fertile source, 
capable of producing up to 25 vol. % melt, a minimum of 70% of which must have 
been extracted to preserve the high-grade metamorphic mineral assemblages in the 
paragneisses (Korhonen et al., 2010a). Granites produced from the Swanson 
Formation may have been emplaced at a higher structural level than the melts 
produced from the Ford Granodiorite suite and have been lost to erosion, which could 
explain their rare occurrence in the complex (Korhonen et al., 2010b).  
The Cretaceous event is primarily recorded by granites found in the southern 
and eastern Fosdick Mountains, which are inferred to be shallow crustal levels 
exposed by the domal structure (McFadden et al., 2010). Magmatism during the 
 
11 
 
Cretaceous may have been a two-stage process. The first stage involved the 
production of granites and leucogranites derived from a Ford Granodiorite suite 
source that were emplaced within the Fosdick complex during transpression in the 
interval c. 120?110 Ma (Korhonen et al., 2010b; McFadden et al., 2010; Yakymchuk, 
unpublished data).  The second stage involved the production of granites, including 
the Byrd Coast Granite, by anatexis of the Ford Granodiorite suite and both residual 
and fertile Swanson Formation sources during transtension in the interval c. 109?102 
Ma (Korhonen et al., 2010b; McFadden et al., 2010; Yakymchuk, unpublished data). 
U?Pb ages of zircons from leucosomes and granites yield ages in the range c. 120?
 101 Ma, consistent with monazite U?Pb ages from granites of 106?96 Ma (Richard et 
al., 1994). Phase equilibrium modeling indicates metamorphic temperatures of 830?
 870?C and pressures of 6?7.5kbar (Korhonen et al., 2010a). Forward modeling 
suggests that the metasedimentary protoliths could have produced up to 30 vol. % 
melt, while the paragneisses, depleted of melt during the Devonian?Carboniferous 
melting event, could have only produced up to 12 vol. % melt at the calculated P?T 
conditions during the Cretaceous (Korhonen et al., 2010a). Forward modeling 
indicates the Ford Granodiorite suite would have produced up to 5 vol. % melt and 
would not have been a fertile source at shallower crustal levels. Therefore, Cretaceous 
granites that show Sr?Nd signatures similar to the Ford Granodiorite suite are inferred 
to have a deeper crustal source (Korhonen et al., 2010a, 2010b). Granites and 
leucosomes from the sheeted leucogranite complex below the South Fosdick 
detachment have chemical signatures that suggest derivation from the Swanson 
Formation and its high-grade equivalent. Accumulation of these melts within the 
 
12 
 
complex likely weakened the crust and led to the exhumation and formation of the 
Fosdick dome.  
 
 
Figure 1. Regional geology modified after Yakymchuk et al., 2013a  
(a) Reconstruction of West Antarctica at c. 95Ma (modified from Tulloch et al., 
2006). (b) West Antarctica and Ford Ranges. (c) Geologic map of the Ford Ranges. 
(d) Geologic map of the Fosdick Mountains. 
 
13 
 
Chapter 3: Previous Results and Present Study 
 
3.1 Previous results 
Previous research on the Fosdick complex granites and their source rocks by 
Korhonen et al. (2010b) reported major oxide and trace element, rare earth element, 
and Sr?Nd isotope geochemistry. Results from this study indicated that granites 
produced during the Devonian?Carboniferous melting event were derived primarily 
by anatexis of an I-type granodiorite suite. Based on phase equilibria calculations, 
fluid-absent biotite breakdown melting of the Ford Granodiorite suite would have 
produced <5% melt at the pressures and temperatures within the complex. Therefore, 
Korhonen et al. (2010a) argued that the source of the granites would need to have 
been deeper than the exposed residual migmatites, in order to explain their volume at 
outcrop within the complex. 
Devonian?Carboniferous granites derived from a metasedimentary source are 
not generally exposed in the complex, despite the metasedimentary rocks being a 
fertile source (Korhonen et al., 2010a). The scarcity of these granites may be due to 
melt transfer to shallower crust than is exposed in the Fosdick complex. The 
Devonian?Carboniferous granites generally show high Sr and low Rb concentrations 
that that has been interpreted to reflect fluid-absent, biotite breakdown melting of the 
Ford Granodiorite suite (Korhonen et al 2010a, 2010b). Granites with low Sr and high 
Rb concentrations were interpreted to be derived from the metasedimentary source 
(Korhonen et al., 2010b).  
 
14 
 
Cretaceous granites were derived from both the Ford Granodiorite suite and 
the Swanson Formation. Granites derived from the Swanson Formation show 
evidence of monazite remaining in the source during melting, based on low P2O5 
content and elevated Sm/Nd ratios above the source. Monazite remaining in the 
source during melting and the presence of inherited zircon cores during the 
Cretaceous implies low water content in the melt, suggesting that the 
metasedimentary source may have been dehydrated prior to anatexis. The difference 
between the isotope composition of leucosomes and small-scale granites, and their 
source rocks, suggests that there was disequilibrium partitioning of elements between 
melt and residue, indicating that melt extraction exceeded the rate of accessory 
minerals dissolution.  
3.2 This study 
This study expands on the work done by Korhonen et al., (2010b) to test the 
validity of their petrogenetic models with a larger data set. Ultimately, these results 
could contribute to our understanding of granite petrogenesis and the differentiation 
of the continental crust in active convergent plate margins. In order to test the validity 
of the petrogenetic model set forth by Korhonen et al., (2010b), U?Pb zircon ages of 
selected granites have been determined, and major and trace element concentrations 
and the Sr?Nd isotope composition of both the granites and their putative sources 
have been measured. U?Pb ages of zircons serve a two-fold purpose: (1) to expand 
the dataset of ages for these rocks in order to better constrain the timing of granite 
crystallization during each anatectic event, and (2) to provide age information for 
individual samples to be used to age-correct Sr and Nd isotope ratios to their 
 
15 
 
crystallization ages. Whole-rock major element data and Sr?Nd isotope composition 
were used to characterize and determine the sources of the granites. Trace element 
compositions, including rare earth elements (REE), were used to assess the behavior 
of major rock-forming and accessory minerals during melting. The results from this 
study can be compared to other regions along the former convergent margin of 
Gondwana to determine if similar processes have occurred. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
16 
 
Chapter 4: Sample Descriptions 
 
4.1 Swanson Formation  
Samples 10CY-001 and 10CY-002 are low-grade metasedimentary rocks and 
were collected from two meters apart from each other in the Clark Mountains, within 
the Ford Ranges. 10CY-001 was collected from a layer that contained 1mm sized 
poikiloblasts of cordierite and 10CY-002 was collected from a 2?5 cm thick sandy 
layer. These two samples comprise fined-grained quartz and biotite that is aligned and 
surrounds cordierite poikiloblasts to 1 mm in diameter.  
Thin section photos of this sample and subsequent samples are provided in appendix 
B. 
 Sample Y2-MD092 is low-grade metasedimentary rock collected from Mt 
Dolber, within the Ford Ranges. This sample is composed of contrasting layers of 
fine- and coarse-grained biotite and quartz. Biotite grains are variable in size but are 
less than 0.5 mm long, aligned, and have zircon inclusions.  Fine-grained oxides are 
dispersed throughout the sample but there are higher concentrations of oxides along 
the edges of the fine-grained quartz and biotite layers.  
Sample Y2-BR086 is a low-grade metasedimentary rock collected from 
Bailey Ridge, within the Ford Ranges. It is made up of fine grained biotite and quartz, 
with elongate muscovite and biotite grains, less than 0.5mm long, that surround 
poikiloblasts of cordierite. 
 
17 
 
Sample Y2-MP098 is a low-grade metasedimentary rock collected from Mt 
Passell, within the Ford Ranges. It is made up of fine-grained biotite with larger clasts 
of quartz. Some plagioclase feldspar is present. 
4.2 Ford Granodiorite suite 
Sample Y2-GP091 is a biotite?hornblende granodiorite collected from Greer 
Peak, within in the Ford Ranges. Sporadically distributed, chloritized, pleochroic 
brown to tan biotite grains 1?3 mm long contain inclusions of zircon and oxides, but 
similar-size, green, weakly, pleochroic green to light green hornblende grains only 
contain oxide inclusions. Twinned and zoned plagioclase grains 5?10 mm long are 
sericitized, whereas K-feldspar grains are smaller, up to 3mm long, but heavily 
sericitized. Quartz has undulatory extinction and sutured grain boundaries.  
Sample Y2-SM095 is a biotite?hornblende granodiorite collected from 
Saunders Mountain, within the Ford Ranges. Sporadically distributed, chloritized, 
pleochroic brown to tan biotite grains 1?2 mm long contain inclusions of zircon and 
oxides. Pleochroic green to light green hornblende grains are a similar size. Twinned 
and zoned plagioclase grains 4?5 mm long are sericitized, whereas similar-size K-
 feldspar grains are heavily sericitized. Quartz shows undulatory extinction and 
sutured grain boundaries.  
Sample Y2-HN097 a biotite?hornblende granodiorite collected from Hermann 
Nunatak, within the Ford Ranges. Sporadically distributed, chloritized pleochroic 
brown to tan biotite grains 2?3 mm long contain zircon, apatite, and oxide inclusions. 
Pleochroic green to light green hornblende grains are similar long. Twinned and 
zoned plagioclase grains up to 7 mm long are sericitized. K-feldspar grains are 
 
18 
 
smaller, up to 3 mm long, and are heavily sericitized. Quartz grains have undulatory 
extinction and sutured grain boundaries. 
Samples 51225-1 and 51225-2 are biotite granodiorites collected from the 
Chester Mountains, within the Ford Ranges. Sporadically distributed, pleochroic 
brown to tan biotite grains 1?2 mm long contain inclusions of apatite and zircon. 
Twinned and zoned plagioclase grains up to 3 mm long are sericitized. Potassium 
feldspar is present in the form of microcline grains up to 2 mm long that contain 
sillimanite inclusions. Small grains of muscovite are present. Quartz has undulatory 
extinction, subgrains, and sutured grain boundaries. Myrmekite is present.  
Sample Y2-JU096 is a biotite?hornblende granodiorite collected from Mt 
June, within the Ford Ranges. Pleochroic brown to tan biotite grains are 2?3 mm 
long, and contain inclusions of apatite, zircon, and Fe?Ti oxides. Some grains of 
biotite are chloritized. Hornblende is less than 1 mm long. Twinned and zoned 
plagioclase grains up to 10 mm long are sericitized. Smaller, perthitic K-feldspar 
grains up to 5.5 mm long are also sericitized. Quartz has undulatory extinction and 
sutured grain boundaries. Apatite inclusions in biotite are up to 1 mm long.  
Sample Y2-MS089 is a biotite granodiorite collected from Mt Swan, within 
the Ford Ranges. Pleochroic brown to tan biotite grains are 1?2 mm long, contain 
inclusions of zircon and apatite, and are chloritized.  Plagioclase grains are up to 3 
mm long and are heavily sericitized. Potassium feldspar grains are up to 6 mm long, 
has Carlsbad twinning, and sericitized. Some K-feldspar is present in the form of 
microcline. Quartz has undulatory extinction and sutured grain boundaries. Muscovite 
is present. 
 
19 
 
4.3 Paragneisses 
Sample 10CY-010 was collected from Mt Bitgood, within the Fosdick 
Complex. Garnet is up to 3 mm in diameter and contains rounded inclusions of 
elongate, pleochroic brown to tan biotite grains up to 2 mm long, and zircon and 
monazite. Quartz grain size is variable from less than 1 mm in diameter to 6 mm long. 
Quartz has undulatory extinction and sutured grain boundaries.  
Sample 10CY-015 was collected from Mt Bitgood, within the Fosdick 
Complex. It is a garnet- and biotite-bearing paragneiss. Garnet is anhedral, up to 4 
mm in diameter and contains rounded inclusions of quartz. Elongate, pleochroic 
brown to tan biotite grains are up to 2 mm long and contain inclusions of zircon and 
monazite. Twinned plagioclase and K-feldspar grains up to 3 mm long are sericitized. 
Quartz has undulatory exaction and sutured grain boundaries. 
Sample 10CY-021 was collected from Maigetter Peak, within the Fosdick 
Complex. Elongate, pleochroic brown to tan biotite grains are up to 2 mm long and 
contain inclusions of zircon and monazite. Sillimanite is present as fibrous bundles 
near biotite grain boundaries. Twinned plagioclase grains up to 2 mm long and K-
 feldspar grains up to 1 mm long are sericitized. Quartz has undulatory extinction and 
sutured grain boundaries. Myrmekite is present.  
Sample 10CY-023 was collected from Maigetter Peak, within the Fosdick 
Complex. Elongate, pleochroic brown to tan biotite grains up to 2 mm long contain 
inclusions of zircon and monazite. Sillimanite is present as fibrous bundles near 
biotite grain boundaries. Twinned plagioclase grains up to 2 mm long and K-feldspar 
 
20 
 
grains up to 1 mm long are sericitized. Quartz has undulatory exaction and sutured 
grain boundaries. 
Sample 10CY-033 was collected from east Mt Avers, within the Fosdick 
Complex. Anhedral garnet up to 3 mm long is associated with biotite. Irregularly 
shaped pinitized cordierite is present. Elongate, pleochroic brown to tan biotite up to 
2 mm long contains inclusions of zircon and monazite. Sillimanite is present in 
fibrous bundles near biotite grain boundaries. Twinned plagioclase up to 2 mm long 
and K-feldspar up to 1 mm long are sericitized. Quartz has undulatory extinction and 
sutured grain boundaries  
Sample 10CY-041 was collected from east Mt Avers, within the Fosdick 
Complex. Anhedral garnet up to 2 mm in diameter has rounded quartz inclusions. 
Elongate biotite grains up to 3 mm long contains inclusions of zircon and monazite. 
Twinned plagioclase grains up to 5 mm long and K-feldspar grains up to 4 mm long 
are sericitized. Quartz has undulatory extinction and sutured grain boundaries. 
Myrmekite is present. 
Sample Y1-BB013 was collected from Bird Bluff, within the Fosdick 
Complex. Generally unaltered cordierite grains 0.5?1.5 mm long contain inclusions 
of sillimanite and zircon, the latter with characteristic pleochroic halos. Elongate, 
pleochroic brown to tan biotite grains up to 2 mm long include zircon and monazite. 
Twinned plagioclase up to 5 mm long and K-feldspar grains up to 4 mm long are 
sericitized. Quartz has undulatory extinction and sutured grain boundaries. 
Myrmekite is present. 
 
21 
 
Sample Y1-CB080 was collected from Colombo, within the Fosdick 
Complex. Anhedral garnet up to7 mm in diameter contains rounded quartz inclusions. 
Anhedral cordierite is up to 3 mm in diameter. Elongate, pleochroic brown to tan 
biotite grains are up to 3 mm long and contain inclusions of zircon and oxides. 
Twinned plagioclase grains up to 5 mm in diameter are weakly sericitized. Quartz has 
undulatory extinction and sutured grain boundaries. 
Sample Y1-IG057 was collected from Mt Iphigene, within the Fosdick 
Complex. Garnet is elongate, up to 6 mm long, and contains inclusions of sillimanite 
and quartz. Elongate, pleochroic brown to tan biotite up to 7 mm long is the dominant 
mineral, making up ~80% of the rock, defining a foliation; biotite contains inclusions 
of zircon and monazite. Sparsely distributed quartz grains are less than 1 mm in 
diameter.  
 Sample Y1-IG061 was collected from Mt Iphigene, within the Fosdick 
Complex. Garnet is up to 3 mm in diameter. Elongate, pleochroic brown to tan biotite 
grains are up 2 mm long and contain inclusions of zircons and monazite. Twinned 
plagioclase is sericitized. Quartz shows undulatory extinction and sutured grain 
boundaries. 
Y1-LH077 was collected from Mt Lockhart, within the Fosdick Complex. 
Garnet up to 3 mm across is associated with pinitized cordierite. The foliation is 
defined by elongate, pleochroic brown to tan biotite grains up to 2 mm long that 
contain inclusions of zircon. Twinned plagioclase less than 1 mm in diameter and K-
 feldspar grains up to 2 mm long with rounded quartz inclusions are weakly 
 
22 
 
sericitized. Quartz grains have undulatory extinction and sutured grain boundaries. 
Myrmekite is present.  
Y1-MJ074 was collected from Marujupu, within the Fosdick Complex. 
Pinitized cordierite up to 4 mm long contains rounded inclusions of quartz. Elongate, 
pleochroic brown to tan biotite grains up to 2 mm long with zircon inclusions define a 
foliation. Twinned plagioclase grains up to 4 mm long and K-feldspar grains up to 7 
mm long with rounded inclusions of quartz are sericitized. Quartz has undulatory 
exaction, sutured grain boundaries, and ranges in size from less than 1 mm in 
diameter to 3 mm in diameter.  
 
3.4 Orthogneisses 
Sample 10CY-035 was collected from Mt Avers, within the Fosdick Complex. 
Although a coarsely-spaced foliation is seen in hand sample, it is not apparent in thin 
section. Elongate, pleochroic brown to tan biotite up to 2 mm long contains zircon 
inclusions. Tabular twinned plagioclase grains up to 6 mm long contain rounded 
quartz inclusions and are weakly sericitized. Simply twinned perthitic K-feldspar up 
to 10 mm long has rounded quartz inclusions. Quartz grains show undulatory 
exaction and grain boundary migration. Myrmekite is present.  
Sample Y1-AW039 was collected from west Mt Avers, within the Fosdick 
Complex. Elongate pleochroic brown to tan biotite grains up to 3 mm long define a 
weak foliation in thin section and contain inclusions of zircon and apatite. Twinned 
plagioclase and twinned K-feldspar grains are up to 5 mm long but are irregularly 
shaped. Quartz has undulatory extinction and sutured grain boundaries. 
 
23 
 
Sample Y1-AW049 was collected from west Mt Avers, within the Fosdick 
Complex. Elongate, pleochroic brown to tan biotite grains up to 2 mm long define a 
weak foliation and contain inclusions of zircon. Irregularly-shaped twinned 
plagioclase and K-feldspar grains are up to 4 mm long. Quartz has undulatory 
extinction and sutured grain boundaries. 
 
4.5 Devonian?Carboniferous diatexites 
Sample Y1-IG071 is a heterogeneous diatexite collected from Mt Iphigene, 
within the Fosdick Complex. Elongate, pleochroic brown to tan biotite grains are up 
to 2.5 mm long and contain zircon inclusions. Twinned plagioclase and twinned K-
 feldspar grains are up to 8 mm long and sericitized. Elongate grains of muscovite up 
to 1 mm long contain inclusions of plagioclase. Quartz has undulatory extinction and 
sutured grain boundaries.  
Sample Y1-IG073 is a homogeneous diatexite collected from Mt Iphigene, 
within the Fosdick Complex. Elongate, pleochroic brown to tan biotite grains up to 2 
mm long and contains zircon inclusions. Subhedral to anhedral twinned tabular 
plagioclase grains up to 5 mm long, have inclusions of rounded quartz, and are 
weakly sericitized. Anhedral K-feldspar grains are up to 4 mm long, have inclusions 
of rounded quartz, and are weakly sericitized. Quartz grains show undulatory 
exaction and have sutured grain boundaries.  
 
 
24 
 
4.6 Devonian?Carboniferous granites 
 Sample Y1-IG062 is a garnet?biotite granite from Mt Iphigene, within the 
Fosdick Complex. Garnet is euhedral, up to 1 mm in diameter and is associated with 
pleochroic green to light green biotite. Chloritized biotite grains up to 2 mm long 
contain zircon inclusions. Tabular twinned plagioclase up to 3 mm long with small 
inclusions of rounded quartz is sericitized. Tabular perthitic K-feldspar grains up to 
10 mm long also contain small round inclusions of quartz and are sericitized. Quartz 
shows undulatory extinction and sutured grain boundaries. Myrmekite is present.  
 Sample C5-I26 is a cordierite?K-feldspar granite collected from Mt Iphigene, 
within the Fosdick Complex. Cordierite and cm-size K-feldspar are subhedral to 
euhedral. Quartz is optically uniform along grain boundaries (Siddoway and Fanning, 
2009). 
 Sample C6-AW86-1 was collected from Mt Avers, within the Fosdick 
Complex. It is a K-feldspar granite with weak foliation defined by sparsely 
distributed biotite (Siddoway and Fanning, 2009).  
Sample M5-G175 is a dark, medium-grained, equigranular biotite granodiorite 
collected from Mt Getz, within the Fosdick Complex (Siddoway and Fanning, 2009). 
 
4.7 Cretaceous granites 
Sample 10CY-039 is a biotite granite collected from east Mt Avers, within the 
Fosdick Complex. Pleochroic brown to tan biotite grains are up to 4 mm long, contain 
inclusions of rounded quartz, and are chloritized. Plagioclase grains are up to 5 mm 
long and strongly sericitized, K-feldspar grains are tabular, up to 7 mm long, twinned, 
 
25 
 
and oriented. Quartz has undulatory exaction and sutured grain boundaries. 
Muscovite is present between grain boundaries.  
Sample Y1-AE051 is a garnet?cordierite?biotite granite collected from east 
Mt Avers, within the Fosdick Complex. Anhedral garnet grains 5?11 mm in diameter 
contain inclusions of anhedral chloritized biotite and chlorite, and rounded quartz. 
Cordierite is 3?6 mm in diameter, occasionally associated with biotite, and frequently 
contains inclusions of rounded quartz and anhedral garnet. Elongate, pleochroic 
brown to tan grains of biotite up to 2 mm long contain inclusions of zircon. Tabular 
twinned plagioclase grains up to 7 mm long with inclusions of sillimanite are 
sericitized. K-feldspar grains up to 1 mm long are sericitized. Quartz grains show 
undulatory extinction and grain boundary migration. Muscovite occurs interstitially 
and myrmekite is present.  
Sample Y1-AE064 is a garnet?biotite granite collected from east Mt Avers, 
within the Fosdick Complex. Garnet grains are anhedral to subhedral, are 2?5 mm in 
diameter, and contain inclusions of anhedral biotite and chlorite, and rounded quartz. 
Biotite is green pleochroic green to light green, up to 2 mm long, and is associated 
with garnet and chloritized when present as inclusions in garnet. Twinned plagioclase 
grains are 1?2 mm long. K-feldspar grains are up to 7 mm long, perthitic, sericitized, 
and have rounded quartz inclusions. Quartz has undulatory extinction and sutured 
grain boundaries. Muscovite is found interstitially. Myrmekite is present.  
Sample Y1-AE033 is a garnet?cordierite granite collected from east Mt 
Avers, within the Fosdick Complex. Subhedral, garnet up to 3 mm in diameter 
contains inclusions of biotite, sillimanite, and rounded quartz. Irregularly shaped 
 
26 
 
cordierite grains contain inclusions of quartz. Elongate, pleochroic brown to tan 
biotite grains up to 2 mm long are associated with garnet. Sillimanite is present in 
bundles along grain boundaries and included in garnet and feldspars. Anhedral 
twinned plagioclase grains up to 5 mm long contain inclusions of rounded quartz and 
sillimanite. Perthitic K-feldspar grains up to 8 mm long contain inclusions of rounded 
quartz and are sericitized. Quartz have undulatory extinction, have sutured grain 
boundaries, and are present as inclusions in feldspars and garnet. Muscovite is present 
as along grain boundaries and near cordierite grains. Myrmekite is present.  
Sample Y1-AW038 It is a garnet-biotite bearing granite was collected from 
west Mt Avers, within the Fosdick Complex. Garnet grains are subhedral to euhedral, 
up to 5 mm in diameter, and contains inclusions of anhedral biotite and chlorite, and 
rounded quartz and frequently associated with biotite and chlorite grains. Pleochroic 
brown to tan biotite and chlorite are present both as elongate grains that are up to 3 
mm long and contain zircon inclusions, and as anhedral grains infilling space between 
plagioclase grains and garnet. Tabular twinned plagioclase grains up to 4 mm long K-
 feldspar grains up to 5 mm long are both sericitized. Quartz has undulatory extinction 
and have sutured grain boundaries. Muscovite is present along grain boundaries. 
Myrmekite is present.  
Sample Y1- IG052 is a garnet?cordierite?biotite granite collected from Mt 
Iphigene, within the Fosdick Complex. Anhedral garnet up to 7 mm in diameter 
contains inclusions of anhedral biotite and chlorite, and rounded quartz. Cordierite is 
anhedral and up to 2 mm long. Elongate grains of biotite up to 4 mm long are 
chloritized; they contain inclusions of zircon. Tabular twined plagioclase grains up to 
 
27 
 
4 mm long are sericitized. Tabular K-feldspar up to 6mm long is sericitized. Quartz 
has undulatory extinction and has sutured grain boundaries. Muscovite occurs 
interstitially. Myrmekite is present.  
Sample Y1-IG070 is a garnet?biotite granite collected from Mt Iphigene, 
within the Fosdick Complex. Garnet grains are between 1 mm and 7mm in diameter. 
The larger, anhedral garnets contain inclusions of euhedral biotite and chlorite, and 
rounded quartz, whereas the smaller, euhedral garnets are surrounded by chloritized 
biotite. Chloritized biotite grains up 2 mm long contain zircon inclusions. Tabular 
twinned plagioclase grains and perthitic K-feldspar grains are up to 7 mm long and 
sericitized. Quartz grains have sutured grain boundaries and have undulatory 
extinction.    
 
4.8 Cretaceous microgranite 
Sample 10CY-024 is a biotite microgranite collected from Maigetter Peak, 
within the Fosdick Complex. Chloritized biotite grains up to 1 mm long contain 
zircon inclusions. Strongly sericitized, twinned plagioclase grains are up to 3 mm 
long. Perthitic K-feldspar grains have Carlsbad twinning and contain inclusions of 
plagioclase. Quartz has sutured grain boundaries and has undulatory extinction. 
Muscovite is present interstitially.  
 
 
 
 
 
28 
 
Chapter 5:  Analytical Methods 
 
 
5.1 U?Pb zircon analysis 
Zircon grains were separated from whole rock samples using the rock 
crushing and mineral separation facilities at the University of Maryland. Samples 
were crushed using a steel mortar and pestle, passed through a 400 ?m nylon mesh 
sieve, and run through a Franz Magnetic Separator. The non-magnetic fraction was 
subjected to a heavy liquid treatment of methylene iodide to separate quartz and 
feldspars from the heavy mineral fraction, then zircon grains were hand-picked to 
>90% purity. Separates were sent to the University of Arizona to be mounted 
following in-house procedures. To determine where to take the analyses, mounts were 
imaged at the University of Maryland NanoCenter using electron backscatter and 
cathodeluminescence (CL) imaging. U?Pb analysis was conducted at the University 
of Arizona LaserChron center using a Nu Plasma inductively coupled mass 
spectrometer (ICP-MS) with an Analyte G2 excimer laser, equipped with a HeLex 
ablation chamber, following procedures described by Gehrels et al. (2008). 
Preference was given to grains that were large and did not contain any inclusions or 
cracks.   
Ages were calculated and U?Pb Terra-Wasserburg concordia graphs and 
probability histograms were constructed using Isoplot 4.1 (Ludwig, 2010). Terra-
 Wasserburg concordia diagrams were used because the curvature of the concordia 
plots that use 207Pb/235U and 206Pb/238U make determining ages younger than 1 Ga 
 
29 
 
years less accurate than the Terra-Wasserburg concordia plot. Ages were corrected 
for elemental and isotopic fractionation using an in-house Sri Lankan zircon standard 
that yielded an average isotope dilution?thermal ionization mass spectrometer (ID?
 TIMS) age of 563.5 ? 3.2 Ma (Gehrels et al., 2008). Final ages and systematic errors 
were propagated separately and added to the uncertainty of the weighted mean. Spot 
ages that were more than 10% discordant were discarded. Samples that showed a 
bimodal distribution of ages were re-assessed by creating unmixing plots using 
Isoplot (Ludwig, 2010; Sambridge and Compston, 1994), which determines the 
number of age components and the fraction of each age component. Box and whisker 
plots were created for all samples to determine which ages were within 2? error. 
Those that fell outside of the whisker were determined to be outliers and were not 
considered in age calculations.  
 
5.2 Major and trace element analysis 
Major oxide and select trace elements were analyzed by X-ray fluorescence 
spectrometry (XRF) at Franklin and Marshall College. A PANanalytical 2404 X-ray 
fluorescence vacuum spectrometer equipped with a PW2540 X-Y sample handler was 
used following the procedures described by Boyd and Mertzman (1987). 
Rare earth elements were analyzed by inductively coupled plasma mass 
spectrometry (ICP-MS) at the University of Maryland following sample preparation. 
USGS standards G-2, a granite standard, and MAG-1, a marine sediment standard, 
were used to calculate sample concentrations. Twenty milligrams of powdered 
sample, both unknowns and USGS standards G-2 and MAG-1, were dissolved in 
 
30 
 
closed Savillex? Teflon beakers using 0.5 ml of 14M HNO3 and 3mls of 29M HF. 
Samples were digested for 24 hours, dried down, and subjected to a second 
dissolution in 0.25 ml 12M HClO4, 0.5 ml of 14M HNO3 and 3 ml of 29M HF for 72 
hours. The solution was dried down and then brought up in 6M HCl and dissolved for 
a further 24 hours. The dissolution in 6M HCl was repeated until the sample was fully 
dissolved, as evidenced by a clear solution. Samples were diluted by a factor of 100. 
One ml of a 20 ppb 115In solution was added to the diluted sample to enable 
correction for instrumental drift. Indium was used due to its low abundance in 
samples and standards and negligible isobaric interferences.   
Samples were analyzed for REE using a Finnigan Element 2 single collector 
ICP-MS; solutions were introduced into the plasma using an APEX desolvating 
nebulizer. Isotopes measured were 115In, 139La, 140Ce, 141Pr, 143Nd, 147Sm, 153Eu, 
158Gd, 159Tb, 163Dy, 165Ho, 167Er, 169Tm, 173Yb, and 175Lu. 
Signals for samples and standards were corrected for instrumental drift by 
normalizing all data to the 115In signal in the G-2 standard. Signals from the blank 
were subtracted from the In-normalized signal. Concentrations of each element in 
each sample were calculated based on the signal response of each isotope in a 
standard with well-established concentrations and a similar matrix to that of the 
samples. Granites, granodiorites and orthogneisses were corrected using USGS 
standard G-2, while metasedimentary and paragneiss samples were corrected using 
USGS standard MAG-1.  
Uncertainties from counting statistics for samples and standards ranged from 
1% to 6% with an average of 3.5%. Propagated uncertainties for concentrations 
 
31 
 
ranged from 4% to 12%, with an average of 5%. Blanks were less than 0.1% of the 
signal for standards and less than 0.7% of the signal for samples.  
For graphical representation, sample concentrations were normalized using 
the CI chondrite values from McDonough and Sun (1995).  
 
5.3 Sr?Nd isotope analysis 
To investigate granite petrogenesis, the Sr and Nd isotope systematics of 38 
samples from varying locations from the Ford Ranges were determined. The rocks 
were prepared in a similar manner to Korhonen et al. (2010b). Samples were crushed 
in a steel mortar and pestle and powdered using a shatterbox with a ceramic insert. 
The resulting powders were dissolved as follows. Fifty milligrams of powder were 
dissolved in Savillex? Teflon beakers using 3 ml 29M HF, 0.5 ml 14M HNO3 
together with isotopic spikes enriched in 87Rb, 84Sr, 149Sm, and 150Nd using a closed 
digestion at 180?190?C for 24 hours. Samples were dried and re-dissolved in 3 ml 
29M HF, 0.5 ml 14M HNO3, and 0.25 ml of 12M HClO4 and digested for a further 72 
hours at 180?190?C, then dried. Finally, 2 ml of 6M HCl was added to the samples 
and digested at 180?C for 24 hours and dried down. The digestion in 6M HCl was 
repeated until the resulting solution was clear. The samples were then dried and 
brought up in 2 ml of 2.5M HCl.  
Rubidium, Sr and REEs were separated from each other using a primary 
cation exchange column filled with AG50Wx4 (200?400 mesh) resin. Samples were 
loaded in chloride form. Rubidium and Sr were eluted in 2.5M HCl while the REE 
were eluted from the column in 6M HCl. Rubidium cuts were dried and diluted in 2% 
 
32 
 
HNO3. Strontium cuts were passed through a clean-up column filled with Eichrom? 
Sr-spec resin and eluted in 0.05M HNO3. The REE cuts from the primary column 
were passed through a second column filled with 0.225M 2-Methyllactic acid (MLA). 
Samarium and Nd were eluted in 0.225M MLA (pH = 4.67). 
Strontium, Nd and Sm ratios were analyzed using a VG Sector 54 TIMS.  
Strontium cuts were loaded onto a single Re filament with a Ta-oxide activator, and 
analyzed in a multi-dynamic mode. Strontium isotopes were corrected for mass 
fractionation by normalizing the measured 87Sr/86Sr ratio to an 86Sr/88Sr ratio = 
0.1194. The mass fractionation corrected and spike corrected 87Sr/86Sr ratio was 
normalized to an average SRM 987 87Sr/86Sr = 0.710238 (n = 30; appendix F) to 
correct for instrumental bias. Strontium blanks concentrations averaged 14.0 ng (n = 
4) were less than 1% of the samples? Sr concentration.  
Rubidium ratios were measured using a Nu Plasma multi-collector 
inductively-coupled mass spectrometer (MC-ICP-MS). Samples were diluted by a 
factor of 100 and were introduced into the plasma using an Aridus I desolvating 
nebulizer. A 50 ppb Rb SpecPure? plasma standard was introduced after every three 
sample analyses and was used to correct for instrumental fractionation and drift. 
Rubidium blanks averaged 8.04 ppm (n = 4) and were less than 1% of the Rb 
concentrations found in the samples. 87Sr/86Sr ratios were age corrected to 360 Ma 
and 100 Ma using the formula 
 
where ?=1.3968x10-11 yr-1 (Rotenberg et al., 2012).  
 
33 
 
Neodymium and Sm were loaded on two Re filaments with phosphoric acid 
and loaded into the machine in a triple filament arrangement. Neodymium ratios were 
measured in dynamic mode and corrected for mass fractionation by normalizing the 
measured 143Nd/144Nd ratio to 146Nd/144Nd = 0.7219. The fractionation and spiked 
corrected 143Nd/144Nd ratio was normalized to an average Ames 143Nd/144Nd = 
0.512126 (n = 33; appendix F) value to correct for instrumental bias. Samarium cuts 
were run in a static mode. Neodymium isotope ratios were age corrected to 360 Ma or 
100 Ma using the formula 
 
where ?= 6.54 x 10-12 yr-1 (Lugmair and Marti, 1978). Samarium blanks averaged 
0.311 ng (n = 3) while Nd blanks averaged 2.28 ng (n = 3). Both Sm and Nd blanks 
were less than 1% of sample Sm and Nd abundances. 
 
5.5 Sr and Rb spike calibration 
Strontium and Rb spike concentrations were re-calibrated prior to use. Ten 
mixtures of SpecPure Rb plasma standard and Rb isotopic spike (97.99% 87Rb) in 
spike:standard ratios of 2:1, 2:2, 2:3, 2:4, and 2:5 were analyzed using the Nu Plasma 
MC-ICP-MS. Repeated analyses yielded an average Rb concentration of 106.0 ? 0.4 
ppm. This spike was then diluted twice by mass. The first dilution was to 10.52 ppm 
and was used for sample analysis. The second dilution was to 0.148ppm and was used 
for blank analysis. Five mixtures of SpecPure? Sr plasma standard and SRM 988 
(99.89% 84Sr) in spike:standard ratios of 1:1, 1:1.5, 1:2, 1:2.5 and 1:3 were made. 
 
34 
 
Spike:standard mixtures were analyzed using a VG Sector 54 TIMS. Repeated 
analyses yielded an average Sr concentration of 8.085 ? 0.007 ppm that was also 
diluted twice by mass. The first dilution was to 0.9152 ppm that was used for sample 
analysis and the second dilution was to 0.00733 ppm and was used for blank analysis. 
 
5.6 Standard Reproducibility 
USGS G-2 granite standard was analyzed 7 times over a period of 12 months 
using ID-TIMS and ID-ICP-MS (appendix F). Repeat analyses yielded an average 
87Sr/86Sr= 0.709767 ? 0.000038 (n = 7) and an average 143Nd/144Nd = 0.512243 ? 
0.000010 (n = 7).  Rubidium concentrations for G-2 average 167.6 ppm and range 
from 162.9?174.2 ppm. Strontium concentrations average 488.8 ppm and range from 
482.1?496.2 ppm. Rb/Sr ratios range from 0.3367?0.3511. Samarium concentrations 
for G-2 average 7.1 ppm and range from 7.0?7.3 ppm. Neodymium concentrations 
average 52.6 ppm and range from 52.2?53.2 ppm. Sm/Nd ratios range from 0.1344?
 0.1372.  
 
 
 
 
 
 
 
 
 
35 
 
Chapter 6:  Results and Discussion  
 
6.1 U?Pb geochronology results 
In order to investigate the timing of melt crystallization, U?Pb isotopes were used 
to date zircon separates from granites and orthogneisses. These ages were used to 
correct Sr and Nd isotope ratios to their ages of crystallization. Of the 21 samples for 
which zircon was separated, 5 samples are from the Ford Granodiorite suite, 7 
samples are granites, 5 samples are orthogneisses, 1 sample is a homogenous diatexite 
and 1 sample is a heterogeneous diatexite, and 1 sample is a microgranite. Ford 
Granodiorite locations are from both within and outside of the Fosdick complex. 
Orthogneisses, granites and diatexites were taken from locations on the west side of 
the mountain range, predominately from Mt Avers and Mt Iphigene, but also from 
Marujupu Peak. Locations of granite samples are provided in appendix A, individual 
spot U?Pb ratios and associated ages are given for each sample in appendix C, box 
and whisker plots are provided in appendix D, and concordia plots for each sample 
are provided in appendix E.  
Four samples from the Ford Granodiorite suite (51225-1, 51225-2, Y2-GP091, 
and Y2-JU096) were collected from outside of the complex. One sample, Y1-AE035, 
was collected from Mt Avers, inside the Fosdick complex. These samples were 
chosen to increase the geographic distribution of zircon ages for the Ford 
Granodiorite suite. Zircons from the Ford Granodiorite suite are generally euhedral, 
prismatic and elongate.  Samples 51225-1 and 51225-2 have oscillatory-zoned 
magmatic zircons with zoned magmatic cores. Zircons from Y2-JU096 and Y2-
 
36 
 
GP091 are oscillatory zoned with cores that show mild evidence of recrystallization 
as evidenced by irregularly shaped zonation. Samples from Y1-AE035 are zoned and 
comprise a mix of euhedral, prismatic and elongate grains, and euhedral, stubby 
grains. Mean ages from this study for the Ford Granodiorite Suite range from 372.3 to 
364.5 Ma and are consistent with published ages of 375?345 Ma (Adams, 1987; 
Pankhurst et al., 1998; Siddoway and Fanning, 2009; Tulloch et al., 2009; 
Yakymchuk, unpublished). 
Orthogneiss samples are from Mt Iphigene (Y1-IG053), Mt Avers (Y1-
 AW039, Y1-AW049, 10CY-035, and Marujupu Peak (Y1-MJ075). Magmatic zircons 
from Y1-IG053 and from Y1-AW049 are stubby to elongate, prismatic, zoned, with a 
few grains showing bright cores that show evidence of recrystallization. Y1-IG053 
and Y1-AW049 yield Devonian ages of 366.8 ? 6.2Ma and 361.2 ? 6.2, respectively. 
Zircons from sample 10CY-035 are elongate and prismatic, but have cores that show 
evidence of recrystallization that is surrounded by a darker zoned area which is then 
surrounded by very thin bright rim as seen in cathodoluminescence. Zircons from this 
sample also yield Devonian ages, but are characterized by a larger range of ages from 
380?100 Ma, with three dominant populations at 360 Ma, 320 Ma and 100 Ma. The 
darker zoned areas from this sample give Devonian?Carboniferous ages while the 
brighter rims give Cretaceous ages, suggesting that this sample has a crystallization 
age of c. 100 Ma, but an inherited core that crystallized c. 360 Ma.  Zircons from Y1-
 MJ075 are stubby to elongate and show evidence of recrystallization. These zircons 
have ages that range from 1520 to 100 Ma with a dominant population at 115.5 ? 3.7 
(n = 7; MSWD = 2.2). Zircons from sample from Y1-AW039 are zoned, euhedral to 
 
37 
 
anhedral and are a mix of elongate and stubby grains. Sample Y1-AW039 yields a 
generally uniform age of 368.5 ? 5.3 (n = 15; MSWD = 1.1). Generally the 
orthogneiss yields consistent Devonian ages with one sample yielding a Cretaceous 
age. 
Samples Y1-IG071 and Y1-IG073 are from Mt Iphigene. The zircons from the 
homogeneous diatexite sample Y1-IG073, are euhedral to subhedral, prismatic, 
elongate with zoned cores that show evidence of recrystallization. The homogenous 
diatexite yields an age of 362.4 ? 5.7 Ma (n = 21; MSWD = 2.1). The zircons from 
the heterogeneous diatexite sample Y1-IG071, are euhedral to anhedral, prismatic, 
and elongate to stubby. Zoned inherited cores show evidence of recrystallization. The 
cores are surrounded by a darker zoned rim, which is surrounded by a thin, bright rim. 
The darker zoned rim is interpreted to be the age of protolith crystallization while the 
bright rim is interpreted to reflect the age the granite crystallized.  Zircons from 
sample Y1-IG071 yield a range of ages from 800 to 100 Ma, with a dominant age 
population between 300 and 400 Ma.  
The granites yielded two age populations at c. 360 Ma and c. 100 Ma. One 
granite from Mt Iphigene, sample Y1-IG062, has zircons that are zoned, 
predominantly prismatic and euhedral with a few that have bright zoned cores that 
show evidence of recrystallization. This granite was the only sample analyzed to yield 
a Devonian age of 363.2 ? 5.0 Ma (n = 12; MSWD = 1.7).  
Other granites from Mt Iphigene (Y1-IG070 and Y1-IG052) and from Mt 
Avers (Y1-AW038, 10CY-039, Y1-AE051, and Y1-AE064) yielded zircons that are 
euhedral and prismatic with dark cores. Ages were obtained from bright overgrowths. 
 
38 
 
The dark cores could not be analyzed due to high concentrations of 204Pb. Zircons 
from these samples yielded ages from 108 to 102 Ma, with two samples that showed 
evidence of two age populations. Sample Y1-AW038 has a zircon population at 113.6 
? 2.9 Ma and another at 105.1 ? 2 Ma. Sample Y1-AE051 also shows evidence of 
two zircon populations at 107.2 ? 1.3 Ma and 100.0 ? 1.8 Ma. Zircons from the 
microgranite sample, 10CY-024, from Maigetter Peak yield a Cretaceous age of 
104.3 ? 1.8 Ma (n = 19; MSWD = 1.05). 
Given that zircons from the first metamorphic event yielded Devonian ages, 
contrasting with ages from the Korhonen et al., (2010b), Sr and Nd from this study 
are age-corrected to 360 Ma instead of 350 Ma. Data from the Korhonen et al., 
(2010b) study have been recalculated to 360 Ma so that the full range of data now 
available for the Devonian?Carboniferous samples may be discussed below.   
 
6.2 Major and trace elements results 
Whole rock major oxide and trace element compositions determined by XRF 
are given in Table 1 and presented in Figure 2. Rare earth element concentration 
results, as determined by ICP-MS, are presented in Table 2, and chondrite-normalized 
patterns are presented in Figure 3.  
Putative sources  
Samples from the Swanson Formation have SiO2 content ranging from 61 to 
74 wt %; they are peraluminous with aluminum saturation indices (ASI= Molar 
[Al2O3/(CaO+Na2O+K2O)]) of 1.24?2.08. For this suite of samples, TiO2, 
(MgO+FeO*), CaO and Na2O remain relatively constant with increasing SiO2 
 
39 
 
content, while Al2O3 and K2O are negatively correlated with increasing SiO2 content 
(Fig. 2). Rubidium and Rb/Sr are also negatively correlated with increasing SiO2. 
Barium and Th remain constant with increasing SiO2, whereas Sr and Zr are 
positively correlated with increasing SiO2.  Samples from the Swanson Formation 
have a limited range of absolute and relative abundances of REE and are 
characterized by smooth to concave down patterns for the LREE (La?Gd) and smooth 
HREE (Tb?Lu) patterns (Fig. 3). The La to Lu slopes of the Swanson Formation 
samples are relatively consistent (La/Lu = 1.5?2.8); all samples have a negative Eu 
anomaly (Eu/Eu* = 0.55?0.70).   
Samples from the Ford Granodiorite suite from within the Fosdick complex, 
and from the surrounding area, have SiO2 contents ranging from 66 to 70 wt%, except 
one sample that has SiO2 of 76 wt % (Fig. 2). The samples are metaluminous to 
peraluminous (ASI = 0.98?1.12). For this suite of samples, (CaO, Na2O, K2O, ASI, 
Rb, Sr, Rb/Sr, Ba, Zr and Th are all have positive correlation with increasing SiO2 
content. TiO2 (MgO+FeO*), Al2O3, and ASI have a negative correlation with SiO2. 
Samples from the Ford Granodiorite suite have smooth to concave down patterns for 
the LREE and smooth to concave up HREE patterns (Fig. 3). All samples have 
negative Eu anomalies (Eu/Eu*=0.31?0.85).   
Paragneisses have major oxide and trace element abundances and trends that 
are similar to the Swanson Formation rocks. Paragneisses generally have SiO2 content 
ranging from 60 to 75 wt %; these samples are peraluminous (ASI = 1.25?2.19). One 
biotite-rich paragneiss sample, Y1-IG057, has 42 wt % SiO2 and an ASI value of 
3.13. For these samples, TiO2, Al2O3, CaO, Ba, and Zr correlate negatively with 
 
40 
 
increasing SiO2, while (MgO+FeO*), ASI, Na2O, Rb, Sr, Rb/Sr and Th are relatively 
constant (Fig. 2). Sample Y1-IG057 has higher TiO2, Al2O3, Rb, Rb/Sr, and Th, and 
lower CaO, Na2O, and Sr than the rest of the paragneiss samples. These results are 
consistent with the predominance of biotite in this sample. Chondrite-normalized 
REE patterns for the paragneisses show a wider range of LREE concentrations than 
those for the Swanson Formation, but otherwise show a similar pattern of chondrite-
 normalized abundances (Fig. 3). All paragneiss samples have negative Eu anomalies 
that varies in magnitude (Eu/Eu* = 0.17?0.90). Sample Y1-IG057 has the smallest Eu 
anomaly (Eu/Eu* = 0.17) as well as elevated HREE compared with the other 
paragneiss and Swanson Formation samples.  
Orthogneisses have major oxide and trace element abundances and trends that 
are consistent with a Ford Granodiorite suite parentage. Orthogneisses have SiO2 
content ranging from 64 to 74 wt %; the range of ASI values is small (ASI = 1.05?
 1.10). With increasing SiO2, the orthogneisses have decreasing TiO2 and 
(MgO+FeO*), constant Al2O3, ASI, Na2O, CaO, Sr, and Zr, and increasing K2O and 
Ba, and slightly increasing Rb, Rb/Sr and Th (Fig. 2). Orthogneisses have LREE 
concentrations that broadly overlap the LREE concentrations of the Ford Granodiorite 
suite, except sample Y1-MJ075, which has higher LREE concentrations (Fig. 3). 
There is some variability in the abundances of HREE and the overall HREE 
chondrite-normalized patterns that reflects the presence or absence of garnet. The 
orthogneisses have negative Eu anomalies (Eu/Eu* = 0.44?0.87), except sample 
10CY-035, which has a positive Eu anomaly (Eu/Eu* = 1.48).  
Diatexites and Granites 
 
41 
 
Two Devonian-Carboniferous diatexites have SiO2 of 71 and 73 wt%; they are 
both metaluminous (ASI = 1.13 and 1.16). Both samples have Rb/Sr ratios <1 (Table 
1). Sample Y1-IG073 has twice as much Ba (Ba = 1109 ppm) as sample Y1-IG071 
(Ba = 551 ppm). With the exception of Ba, the other major and trace element 
abundances are comparable to each other. The REE abundances and the steep 
chondrite-normalized patterns (La/Lu = 21.5?57.1) of the diatexites are similar to 
those of the Ford Granodiorite suite or the Swanson Formation (Fig. 3). They have 
negative Eu anomalies (Eu/Eu* = 0.52 and 0.64).  
Devonian?Carboniferous granites have SiO2 contents ranging from 65 to 76 
wt %; they are metaluminous to peraluminous (ASI = 0.99?1.20).  The granites show 
decreasing TiO2, Al2O3, (MgO+FeO*), CaO, Ba, Zr, Th, and Rb with increasing SiO2 
(Fig. 2). The samples have ASI, Na2O, K2O, Sr and Rb/Sr that remain relatively 
constant with increasing SiO2; Rb/Sr ratios are <1 (Table 1).  
Devonian?Carboniferous granites have varied LREE and HREE abundances 
as well as both positive and negative Eu anomalies (Eu/Eu* = 0.4?1.1). Sample C6-
 AW86-1 from Mt Avers has the steepest La/Lu slope (La/Lu = 82.6), the steepest 
Tb/Lu slope (Tb/Lu = 6.79), and is depleted in HREE compared to the Swanson 
Formation and the Ford Granodiorite suite (Fig. 3). Sample Y1-IG062 has the lowest 
LREE concentrations of the Devonian?Carboniferous granites and also has the lowest 
Tb/Lu and La/Lu slopes (Tb/Lu = 0.42; La/Lu = 1.77). The HREE concave upward 
pattern is likely due to the presence of garnet in the sample. Sample C5-I26 has 
concentrations of LREE and HREE that are almost twice as high as the Ford 
Granodiorite suite. This sample also has P2O5 of 1.2 wt % that is an order of 
 
42 
 
magnitude higher than all of the other samples analyzed. Only one sample, M5-G175, 
has REE abundances and a REE pattern comparable to the Ford Granodiorite suite.  
Cretaceous granites have silica contents ranging from 71 to 78 wt % and have 
a higher and more limited range of SiO2 contents than the Devonian?Carboniferous 
granites. Cretaceous granites have TiO2, Al2O3, (FeO*+MgO) and Zr content that are 
negatively correlated with increasing SiO2 content (Fig. 2). Rb, Rb/Sr and Th show 
slight decreasing trends with increasing SiO2. The Cretaceous granites have CaO, 
Na2O, ASI, Ba, and Sr contents that show no obvious trend with increasing SiO2 
content.  Sr and K2O content is positively correlated with increasing SiO2 content 
with one outlier, sample Y1-AW038, which has a greater K2O weight percent than 
would be expected for its SiO2 content. The Cretaceous microgranite has oxide and 
trace element abundances similar to the other Cretaceous granites, except for TiO2, 
Zr, and Th, which are significantly elevated over other Cretaceous granites.  
The Cretaceous granites are generally depleted in REE compared with the 
potential sources (Fig. 3). All show moderate to strong positive Eu anomalies 
(Eu/Eu* = 1.17?7.91). HREE patterns are not flat and have TbN/LuN values that range 
from 0.17?4.01. Samples Y1-IG052, Y1-AE051 and Y1-AW038 have increasing, 
concave downward HREE patterns that are consistent with the presence of garnet. 
The Cretaceous microgranite, 10CY-024, has REE abundances that are greater than 
the other Cretaceous granites, with a negative, concave downward chondrite-
 normalized LREE slope and a negative, concave upward chondrite-normalized HREE 
pattern. This sample also has a negative Eu anomaly (Eu/Eu* = 0.37). 
 
 
43 
 
Table 1: Whole-rock major oxide and trace element composition as determined by 
XRF 
Rock Type: Swanson Formation Ford Granodiorite  Suite
 Sample Name: 10CY-001 10CY-002 Y2-BR086 Y2-MD092 Y2-MP098 51225-1 51225-2 Y2-GP091 Y2-HN097
 wt %
 SiO2 64.33 63.92 71.59 73.92 74.06 68.24 66.43 67.50 69.08
 TiO2 0.68 0.70 0.73 0.57 0.68 0.70 0.78 0.59 0.53
 Al2O3 15.86 16.52 14.02 11.54 12.00 15.13 15.37 15.35 14.98
 Fe2O3 0.70 0.74 0.58 0.21 0.57 0.39 0.56 0.89 0.83
 FeO 5.70 5.82 4.08 4.03 4.06 3.61 4.01 2.47 2.43
 MnO 0.11 0.11 0.08 0.11 0.11 0.07 0.07 0.06 0.06
 MgO 3.69 3.76 2.41 2.97 2.78 1.42 1.62 2.02 1.77
 CaO 3.01 1.25 0.94 2.31 1.47 2.67 2.59 3.20 3.15
 Na2O 2.20 2.44 1.70 1.57 1.93 3.19 3.03 3.83 3.97
 K2O 3.02 4.24 3.36 2.33 2.15 3.7 4.19 3.05 2.52
 P2O5 0.18 0.17 0.19 0.17 0.18 0.22 0.24 0.18 0.17
 LOI 1.50 1.86 2.05 0.98 1.97 1.06 1.05 1.62 0.94
 Total 100.11 100.32 100.13 100.18 100.44 99.74 99.34 99.42 99.76
 ASI 1.28 1.52 1.52 1.24 1.47 1.07 1.08 1.00 1.00
 (FeO+MgO) 9.38 9.55 6.48 6.99 6.81 5.04 5.67 4.52 4.21
 ppm
 Rb 140 196 163 99 96 189 209 144 88
 Sr 207 149 137 196 155 223 218 378 354
 Rb/Sr 0.7 1.3 1.2 0.5 0.6 0.8 1.0 0.4 0.2
 Y 32 34 39 33 39 32 35 23 24
 Zr 123 121 172 166 233 228 240 146 143
 V 131 112 89 80 84 73 82 77 72
 Ni 110 118 43 106 112 9 10 37 35
 Cr 110 118 84 123 151 33 36 60 80
 Nb 12 13 15 12 14 20 21 13 15
 Ga 21 21 19 16 17 22 22 19 20
 Cu 39 41 6 8.0 30 12 23 9 9
 Zn 120 152 85 74 78 66 73 48 46
 Co 26 28 18 17 17 11 14 12 11
 Ba 483 658 727 426 438 514 565 483 472
 La 26 29 32 30 37 34 44 24 23
 Ce 69 75 82 65 83 75 105 51 44
 U 3.1 1.4 3.8 1.9 3.8 5.1 5.3 2.1 4.9
 Th 14 17 14 14 13 15 25 15 5
 Sc 18 16 12 12 12 11 12 11 9
 Pb 8 12 15 11 3 15 28 <1 10   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
44 
 
Table 1: Continued
  
Rock Type: Ford Granodiorite  Suite O rthogneiss
 Sample Name: Y2-JU096 Y2-MS089 Y2-SM095 Y1-AE035 10CY-035 Y1-AW049 Y1-AW039 Y1-IG053 Y1-MJ075
 wt %
 SiO2 69.10 76.00 67.38 66.59 74.19 64.19 67.82 65.51 72.84
 TiO2 0.54 0.15 0.68 0.87 0.08 0.92 0.76 0.89 0.29
 Al2O3 15.00 13.76 15.29 16.04 14.29 16.48 15.85 16.60 14.80
 Fe2O3 0.53 0.27 1.06 1.15 0.06 1.65 0.91 1.03 0.28
 FeO 2.68 0.77 3.14 3.71 0.50 3.70 3.42 3.86 1.49
 MnO 0.05 0.04 0.07 0.06 0.01 0.07 0.08 0.07 0.03
 MgO 1.66 0.27 2.35 1.63 0.23 1.95 1.71 2.02 0.63
 CaO 2.74 0.88 3.92 3.52 0.89 3.62 2.86 3.95 1.30
 Na2O 3.48 3.29 3.40 3.68 2.43 4.09 4.17 3.40 3.44
 K2O 3.35 4.88 2.63 2.26 7.22 2.17 2.23 2.20 5.03
 P2O5 0.16 0.06 0.17 0.27 0.08 0.29 0.31 0.30 0.16
 LOI 1.71 1.32 1.36 1.05 0.43 1.08 1.18 1.01 0.69
 Total 99.59 100.46 100.44 100.19 100.04 99.54 100.50 100.26 100.46
 ASI 1.05 1.12 0.98 1.08 1.06 1.05 1.10 1.10 1.10
 (FeO+MgO) 4.36 1.04 5.47 5.33 0.73 5.68 5.13 5.86 2.11
 ppm
 Rb 117 381 99 146 201 131 149 128 236
 Sr 418 90 346 281 264 291 186 280 158
 Rb/Sr 0.3 4.2 0.3 0.5 0.8 0.5 0.8 0.5 1.5
 Y 35 35 27 23 6 16 31 25 13
 Zr 173 89 155 256 93 260 198 191 261
 V 73 14 97 100 15 101 93 102 26
 Ni 34 3 35 10 4 12 14 12 6
 Cr 64 14 78 58 24 61 59 65 28
 Nb 15 23 10 17 3 17 20 14 17
 Ga 19 20 19 22 15 23 24 23 21
 Cu 9 3 9 8 3.0 5.0 10 17 4.0
 Zn 53 34 59 80 14 88 74 78 41
 Co 11 <1 15 14 <1 17 14 16 1
 Ba 628 209 525 690 963 388 267 486 945
 La 38 23 29 23 19 28 23 18 51
 Ce 80 46 55 50 32 60 49 38 122
 U 4.7 3.5 2.3 2.2 1.9 2.1 3.9 2.9 8.4
 Th 16 14 9 6 6.8 6.7 8.0 1.5 17
 Sc 11 3 11 16 <1 16 14 16 5
 Pb 189 26 22 21 47 14 2 15 38   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
45 
 
 
Table 1: Continued 
Rock Type: Paragneiss
 Sample Name: 10CY-010 10CY-015 10CY-021 10CY-023 10CY-033 10CY-041 Y1-BB013 Y1-CB080 Y1-IG057 Y1-IG061
 wt %
 SiO2 61.55 68.82 67.40 66.51 67.85 67.32 60.89 70.39 42.01 71.00
 TiO2 0.94 0.81 0.94 1.05 0.76 0.77 0.85 0.76 1.57 0.68
 Al2O3 17.54 14.67 14.56 14.76 14.39 14.26 19.04 13.15 23.10 14.34
 Fe2O3 1.32 1.24 0.76 1.06 1.36 1.08 1.21 0.67 3.89 0.94
 FeO 6.05 4.55 5.50 5.87 4.21 4.61 5.87 5.04 12.78 4.34
 MnO 0.09 0.05 0.07 0.08 0.08 0.05 0.07 0.08 0.44 0.09
 MgO 3.71 2.76 3.26 3.59 2.74 2.89 3.90 3.00 7.74 2.45
 CaO 0.91 0.82 1.31 0.71 1.37 1.75 0.93 1.75 0.43 1.17
 Na2O 1.91 1.64 1.81 0.99 2.03 2.55 1.33 1.85 0.37 1.43
 K2O 3.98 3.05 3.31 3.52 3.60 3.69 5.23 2.61 5.54 3.42
 P2O5 0.13 0.06 0.14 0.08 0.13 0.14 0.15 0.19 0.15 0.19
 LOI 2.21 1.77 1.50 1.90 1.85 1.18 2.65 1.69 3.49 2.22
 Total 100.34 100.24 100.56 100.12 100.37 100.29 100.12 100.05 99.44 100.53
 ASI 1.93 1.96 1.63 2.19 1.48 1.25 2.00 1.45 3.13 1.75
 (FeO+MgO) 9.73 7.29 8.71 9.45 6.92 7.48 9.76 8.04 20.64 6.75
 ppm
 Rb 276 247 198 228 201 188 299 141 394 176
 Sr 106 66 133 80 126 161 135 152 18 157
 Rb/Sr 2.6 3.7 1.5 2.9 1.6 1.2 2.2 0.9 21.9 1.1
 Y 40 29 34 37 33 33 35 29 91 38
 Zr 218 245 253 232 200 193 140 214 155 177
 V 138 113 127 135 110 110 121 115 222 95
 Ni 76 50 51 61 51 51 54 53 90 55
 Cr 188 139 141 159 141 129 120 118 166 98
 Nb 22 32 19 28 22 15 22 17 39 13
 Ga 26 28 22 27 23 20 29 20 39 19
 Cu 43 15 13 5 18 10 11 14 69 16
 Zn 138 141 114 138 107 110 129 100 296 81
 Co 28 21 22 27 20 20 23 22 51 18
 Ba 682 306 399 373 428 456 901 427 262 822
 La 28 28 28 32 22 26 28 26 16 25
 Ce 74 57 65 75 54 54 72 68 53 60
 U 3.4 5.6 1.2 2.6 3.8 2.3 2.3 2.1 1.2 2.6
 Th 21 25 19 24 16 15 14 18 34 14
 Sc 18 15 17 13 16 14 16 15 41 11
 Pb <1 <1 <1 <1 <1 <1 18 14 <1 14   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
46 
 
 
Table 1: Continued 
Devonian-Carboniferous
 Rock Type: Paragneiss Diatexite Granite
 Sample Name: Y1-LH077 Y1-MJ074 Y1-IG071 Y1-IG073 Y1-IG062 C5-I26 C6-AW86-1 M5-G175
 wt %
 SiO2 69.59 68.37 72.88 71.63 75.60 65.27 75.85 67.54
 TiO2 0.76 0.74 0.46 0.48 0.01 0.55 0.08 0.70
 Al2O3 13.58 15.71 13.91 14.62 13.97 16.07 13.47 15.23
 Fe2O3 1.06 1.00 0.49 0.26 0.03 0.27 0.05 0.92
 FeO 4.17 4.53 2.51 2.39 0.76 2.67 0.43 3.76
 MnO 0.04 0.09 0.04 0.02 0.06 0.05 0.01 0.06
 MgO 2.90 2.75 1.36 1.04 0.17 1.07 0.22 1.96
 CaO 2.22 0.85 1.63 2.08 1.05 2.65 1.02 1.72
 Na2O 2.21 1.69 2.72 2.96 2.77 2.47 2.60 3.11
 K2O 2.89 3.92 4.16 4.00 5.80 6.85 5.93 4.14
 P2O5 0.18 0.14 0.08 0.17 0.09 1.20 0.05 0.09
 LOI 1.42 2.30 1.06 0.98 0.58 0.91 0.39 1.10
 Total 100.06 100.29 100.52 99.92 100.39 99.42 99.76 99.65
 ASI 1.26 1.83 1.16 1.13 1.10 0.99 1.07 1.20
 (FeO+MgO) 6.75 6.75 3.85 3.43 0.93 3.75 0.65 5.73
 ppm
 Rb 158 201 173 151 167 222 183 201
 Sr 147 151 191 259 225 269 321 249
 Rb/Sr 1.1 1.3 0.9 0.6 0.7 0.8 0.6 0.8
 Y 32 31 26 22 27 89 3 39
 Zr 215 166 169 255 76 295 122 233
 V 103 105 57 51 <1 59 12 85
 Ni 49 55 15 10 2 12 2 23
 Cr 128 107 75 34 21 66 11 77
 Nb 15 17 14 12 1 12 2 19
 Ga 19 22 19 19 14 19 15 22
 Cu 5.0 7.0 7 7 7 12 3 23
 Zn 102 100 58 50 11 51 13 81
 Co 18 19 8 6 <1 5 <1 15
 Ba 459 875 551 1109 632 1533 803 1119
 La 23 26 24 40 19 37 25 36
 Ce 59 63 53 100 37 106 53 87
 U 2.2 4.3 3.7 3.6 3.1 8.7 2.0 6.2
 Th 17 11 12 22 3 11 7 17
 Sc 14 14 8 8 4 10 <1 12
 Pb 20 22 28 33 52 58 36 27   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
47 
 
 
Table 1: Continued 
Cretaceous 
Rock Type: Granites Microgranite
 Sample Name: 10CY-039 Y1-AE051 Y1-IG052 Y1-IG070 Y1-AW038 Y1-AE033 Y1-AE064 10CY-024
 wt %
 SiO2 73.95 76.08 75.33 77.50 71.16 74.06 75.01 74.25
 TiO2 0.04 0.02 0.02 0.01 0.03 0.10 0.04 0.28
 Al2O3 14.85 14.62 14.17 13.85 16.02 15.58 14.64 13.99
 Fe2O3 0.08 0.11 0.11 0.03 0.04 0.09 0.22 0.12
 FeO 0.22 0.39 0.83 0.08 0.54 0.14 0.40 1.31
 MnO 0.01 0.03 0.07 0.01 0.08 0.01 0.05 0.03
 MgO 0.15 0.14 0.20 0.004 0.11 0.10 0.18 0.31
 CaO 0.89 2.50 1.22 1.98 0.44 1.37 1.65 1.20
 Na2O 2.80 3.60 2.74 3.66 2.80 2.74 3.13 2.82
 K2O 6.81 2.84 5.43 3.21 8.89 5.91 5.15 5.34
 P2O5 0.11 0.10 0.09 0.08 0.07 0.11 0.06 0.07
 LOI 0.61 0.65 0.48 0.33 0.47 0.62 0.48 0.78
 Total 99.93 100.47 100.30 100.42 100.24 100.23 100.57 99.87
 ASI 1.09 1.08 1.12 1.06 1.07 1.16 1.07 1.11
 (FeO+MgO) 0.37 0.53 1.03 0.08 0.65 0.24 0.58 1.62
 ppm
 Rb 182 80 137 92 284 178 147 195
 Sr 236 209 250 224 167 194 210 222
 Rb/Sr 0.8 0.4 0.5 0.4 1.7 0.9 0.7 0.9
 Y 5 15 16 4 15 9 10 34
 Zr 39 56 57 28 76 23 73 227
 V 5 1 6 1 5 8 6 23
 Ni 6 2 2 1 1 1 3 1
 Cr 35 33 18 19 14 8 21 4
 Nb 2 1 1 1 2 2 2 15
 Ga 15 17 14 16 15 19 16 20
 Cu 4 2 7 25 4 3 4 7
 Zn 11 9 10 7 13 10 13 27
 Co <1 <1 <1 <1 <1 <1 <1 2
 Ba 895 402 1073 434 457 640 515 834
 La 11 19 17 13 15 21 26 48
 Ce 13 23 20 17 13 28 39 108
 U 1.1 3.0 <0.5 1.1 1.4 1.4 1.7 2.4
 Th <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 6 36
 Sc <1 4 3 1 3 1 2 3
 Pb 65 46 62 43 64 58 47 29   
 
48 
 
  
Figure 2: Select major and trace element data for samples as determined by XRF. 
Ford Granodiorite samples include data from Korhonen et al. (2010b), Weaver et al. 
(1992), and Pankhurst et al. (1998). FeO* represents total ferrous iron. Aluminum 
saturation index (ASI) = molar [Al2O3 / CaO + Na2O + K2O]. Graphs of oxides are 
plotted as weight percent while trace elements are plotted as parts per million (ppm).  
 
49 
 
Figure 2: Continued 
 
 
 
 
 
 
 
 
 
50 
 
Table 2: Rare earth element (REE) compositions as determined by SC-ICP-MS 
Rock Type: Swanson Formation Ford Granodiorite  Suite
 Sample  Name: 10CY-001 10CY-002 Y2-BR086 Y2-MD092 Y2-MP098 51225-1 51225-2 Y2-GP091 Y2-HN097
 Sc 18.2 17.3 11.2 9.8 10.4 10.9 11.3 8.64 8.72
 Y 28.6 30.4 38.9 27.0 31.3 34.5 33.8 20.9 19.0
 La 32.3 37.3 42.9 32.7 36.7 48.0 53.2 25.0 21.0
 Ce 66.6 76.4 90.1 66.7 75.0 103 114 50.1 41.6
 Pr 7.83 8.84 10.60 7.92 8.97 12.8 14.1 6.16 5.04
 Nd 30.0 34.2 40.3 30.3 34.2 48.3 52.7 23.3 19.3
 Sm 6.25 6.96 8.43 6.10 6.92 8.97 9.47 4.65 3.93
 Eu 1.34 1.44 1.65 1.18 1.29 1.38 1.34 1.06 0.94
 Gd 5.05 5.52 6.95 4.89 5.47 7.53 7.59 4.21 3.65
 Tb 0.85 0.91 1.20 0.81 0.93 1.17 1.18 0.69 0.61
 Dy 5.03 5.26 7.03 4.75 5.50 6.31 6.48 3.90 3.45
 Ho 1.03 1.07 1.41 0.96 1.14 1.19 1.22 0.74 0.67
 Er 2.89 3.01 3.83 2.65 3.17 3.51 3.63 2.21 1.99
 Tm 0.43 0.43 0.55 0.39 0.47 0.55 0.58 0.36 0.32
 Yb 2.81 2.86 3.45 2.43 3.03 3.39 3.59 2.38 2.03
 Lu 0.39 0.40 0.45 0.33 0.42 0.52 0.56 0.39 0.32
 Eu/Eu* 0.70 0.68 0.64 0.64 0.62 0.50 0.47 0.72 0.74
 TbN/LuN 1.50 1.54 1.82 1.67 1.53 1.53 1.44 1.22 1.29
 LaN/LuN 8.64 9.61 9.94 10.2 9.18 8.64 9.61 9.94 10.2
 Rock Type: Ford Granodiorite  Suite O rthogneiss
 Sample  Name: Y2-JU096 Y2-MS089 Y2-SM095 Y1-AE035 10CY-035 Y1-AW049 Y1-AW039 Y1-IG053 Y1-MJ075
 Sc 9.59 3.83 11.4 15.8 1.46 14.8 13.9 14.8 5.0
 Y 30.7 33.5 22.4 25.8 7.83 15.7 33.7 26.0 14.4
 La 40.5 16.8 22.4 43.7 14.7 43.5 33.4 24.5 93.4
 Ce 82.6 37.4 49.0 91.8 30.1 89.2 70.3 52.5 169
 Pr 10.0 4.83 6.05 11.3 3.74 10.6 8.94 6.89 18.2
 Nd 37.4 17.5 23.1 44.5 13.8 38.3 34.8 27.7 60.3
 Sm 6.91 4.12 4.63 8.37 2.95 6.55 7.56 5.82 8.73
 Eu 1.39 0.42 1.16 1.76 1.35 1.28 1.28 1.63 1.10
 Gd 6.02 4.09 4.30 6.83 2.45 5.44 7.09 5.52 5.97
 Tb 0.97 0.82 0.70 1.05 0.37 0.77 1.23 0.95 0.83
 Dy 5.34 5.10 3.94 5.38 1.71 3.67 6.76 5.33 3.61
 Ho 1.03 1.05 0.77 0.95 0.28 0.61 1.22 0.98 0.50
 Er 3.06 3.47 2.27 2.54 0.73 1.46 3.38 2.63 1.04
 Tm 0.49 0.63 0.36 0.37 0.11 0.19 0.52 0.36 0.12
 Yb 3.09 4.54 2.29 2.19 0.73 1.07 3.10 2.01 0.63
 Lu 0.49 0.77 0.37 0.33 0.12 0.17 0.45 0.29 0.08
 Eu/Eu* 0.64 0.31 0.78 0.69 1.48 0.63 0.52 0.52 0.44
 TbN/LuN 1.35 0.73 1.30 2.19 2.04 3.17 1.86 1.86 6.84
 LaN/LuN 8.60 2.27 6.34 13.9 12.4 27.3 7.68 7.68 117
 Rock Type: Paragneiss
 Sample  Name: 10CY-010 10CY-015 10CY-023 10CY-033 10CY-041 Y1-BB013 Y1-CB080 Y1-IG057 Y1-IG061
 Sc 18.4 13.8 16.7 13.6 14.2 16.6 13.4 58.2 12.6
 Y 40.5 34.4 45.2 28.0 34.4 23.9 25.9 99.2 34.3
 La 57.1 47.8 68.7 43.9 35.6 41.5 48.6 68.0 28.1
 Ce 114 97.0 140 91.1 72.74 83.7 98.4 138 57.9
 Pr 13.4 11.3 16.5 10.7 8.72 9.58 11.45 16.23 6.87
 Nd 51.6 43.1 63.2 40.6 33.1 37.5 44.0 60.7 26.6
 Sm 10.3 8.72 12.8 7.96 6.89 7.61 8.56 11.96 5.54
 Eu 1.60 0.98 1.09 1.13 1.22 1.41 1.31 0.63 1.53
 Gd 8.07 6.66 9.31 5.79 5.65 5.75 6.35 10.06 4.62
 Tb 1.33 1.11 1.45 0.94 0.99 0.90 0.98 2.16 0.84
 Dy 7.36 6.11 8.19 5.21 5.90 4.76 5.19 16.04 5.41
 Ho 1.47 1.17 1.66 0.99 1.23 0.87 0.93 3.58 1.20
 Er 3.90 3.07 4.70 2.56 3.43 2.12 2.24 9.84 3.55
 Tm 0.55 0.43 0.70 0.36 0.50 0.27 0.29 1.40 0.54
 Yb 3.31 2.64 4.47 2.17 3.14 1.56 1.73 8.36 3.48
 Lu 0.43 0.35 0.62 0.28 0.43 0.20 0.23 1.09 0.46
 Eu/Eu* 0.51 0.38 0.29 0.48 0.58 0.62 0.52 0.17 0.90
 TbN/LuN 2.09 2.17 1.60 2.30 1.58 3.07 2.94 1.35 1.24
 LaN/LuN 13.7 14.3 11.5 16.3 8.66 21.5 22.2 6.48 6.31   
 
 
 
 
51 
 
Table 2: Continued  
Devonian-Carboniferous
 Rock Type: Paragneiss Diatexite Granite
 Sample  Name: Y1-LH077 Y1-MJ074 Y1-IG071 Y1-IG073 Y1-IG062 C5-I26 C6-AW86-1 M5-G175
 Sc 12.5 10.9 10.3 7.97 7.32 9.78 1.11 14.0
 Y 31.5 21.8 17.7 22.5 24.9 103 3.50 35.9
 La 45.0 35.9 31.5 63.8 14.3 61.4 27.6 58.0
 Ce 91.9 72.7 65.7 132 30.0 137 55.4 115
 Pr 10.8 8.57 8.16 16.0 3.79 18.1 6.87 13.7
 Nd 41.6 33.2 29.8 61.0 13.8 72.7 24.9 50.1
 Sm 8.38 6.66 6.0 11.1 3.20 17.1 4.54 8.94
 Eu 1.58 1.34 1.18 1.74 1.13 2.25 0.98 1.53
 Gd 6.54 4.97 4.92 8.65 2.77 18.1 3.25 7.82
 Tb 1.06 0.78 0.79 1.24 0.52 3.48 0.34 1.19
 Dy 5.84 4.21 3.88 5.83 3.51 20.3 1.12 6.25
 Ho 1.11 0.79 0.64 0.87 0.86 3.61 0.13 1.19
 Er 2.82 2.04 1.56 1.91 3.31 9.57 0.26 3.50
 Tm 0.37 0.29 0.20 0.21 0.65 1.35 0.03 0.53
 Yb 2.18 1.74 1.10 0.96 4.95 7.07 0.21 3.10
 Lu 0.28 0.23 0.15 0.12 0.84 0.94 0.03 0.48
 Eu/Eu* 0.63 0.68 0.64 0.52 1.13 0.39 0.74 0.54
 TbN/LuN 2.54 2.29 3.52 7.27 0.42 2.51 6.79 1.69
 LaN/LuN 16.5 16.0 21.5 57.1 1.77 6.76 82.6 12.5
 Cretaceous 
Rock Type: Granites Microgranite
 Sample  Name: 10CY-039 Y1-AE051 Y1-IG052 Y1-IG070 Y1-AW038 Y1-AE033 Y1-AE064 10CY-024
 Sc 0.79 4.51 6.40 0.51 3.57 1.04 3.96 3.80
 Y 5.63 12.7 17.8 2.95 10.9 9.77 11.9 35.4
 La 6.12 7.79 11.1 4.34 1.87 15.2 20.1 66.2
 Ce 11.1 13.2 20.1 7.14 2.45 31.3 40.7 141
 Pr 1.28 1.48 2.32 0.76 0.24 3.90 4.86 17.1
 Nd 4.54 5.06 8.13 2.43 0.75 14.4 17.3 62.7
 Sm 0.99 1.04 1.48 0.45 0.23 3.26 3.33 11.0
 Eu 1.32 1.44 1.58 1.13 0.60 1.49 1.16 1.22
 Gd 0.94 0.99 1.33 0.41 0.41 2.93 2.54 8.33
 Tb 0.18 0.22 0.31 0.08 0.13 0.47 0.39 1.25
 Dy 1.00 1.70 2.51 0.47 1.21 2.17 2.10 6.65
 Ho 0.19 0.45 0.61 0.10 0.35 0.33 0.41 1.26
 Er 0.52 1.73 2.30 0.33 1.51 0.79 1.43 3.68
 Tm 0.08 0.33 0.48 0.06 0.34 0.10 0.30 0.56
 Yb 0.45 2.36 3.80 0.45 2.87 0.57 2.51 3.38
 Lu 0.07 0.39 0.62 0.08 0.53 0.08 0.46 0.52
 Eu/Eu* 4.10 4.24 3.35 7.91 5.88 1.44 1.17 0.37
 TbN/LuN 1.73 0.37 0.33 0.68 0.17 4.01 0.58 1.63
 LaN/LuN 9.14 2.05 1.85 5.88 0.36 19.9 4.56 13.1   
 
 
 
 
 
 
 
 
52 
 
 Figure 3: Rare earth element (REE) chondrite-normalized patterns for source rocks 
and granites. Data from Korhonen et al. (2010b) are given as black symbols for 
comparison. 
 
 
53 
 
6.3 Major and trace element discussion 
Granite may not represent direct melts of their sources, which could account 
for differences in their chemical compositions when compared with their putative 
sources. In order to determine whether or not the granites analyzed represent direct 
melts of the Swanson Formation or the Ford Granodiorite suite, the compositional 
variability  of Carboniferous and Cretaceous granites was investigated using the 
ternary system (Na+Ca)?(Fe*+Mg+Ti)?K (after Solar and Brown, 2001). Because 
there have been no melting experiments done on the either the Swanson Formation or 
the Ford Granodiorite suite, experimental melt compositions from Skjerlie et al. 
(1993), Pati?o-Douce and Harris (1998) and Koester et al., (2002) were used based 
on similarity of the chemical composition of their starting material to the putative 
sources. The starting material and melt compositions from Skjerlie et al. (1993), 
Pati?o-Douce and Harris (1998) and Koester et al., (2002)  are plotted along with 
samples from the Swanson Formation, Ford Granodiorite suite, their high-grade 
equivalents, and Devonian?Carboniferous and Cretaceous granites in Figure 4. The 
experimental melts from Skjerlie et al. (1993) were used as proxies for the Ford 
Granodiorite suite melt composition while the experimental results of Pati?o-Douce 
and Harris (1998) and Koester et al. (2002) were used to infer melt compositions of 
the Swanson Formation and the paragneiss samples, respectively. Select mineral 
composition are also plotted on the ternary diagram. 
 Paragneiss samples generally fall within the same major and trace element 
compositional field as the Swanson Formation with sample Y1-IG057 plotting close 
to the biotite (Fig. 4), consistent with this sample h as indicated by the elevated Rb/Sr 
 
54 
 
ratio and biotite-rich mineral assemblage. Paragneisses have major and trace element 
compositions and REE patterns that are very similar to the Swanson Formation. 
Orthogneiss samples generally fall within the compositional field as the Ford 
Granodiorite suite (Fig. 4) and have major and trace element compositions and REE 
patterns that are very similar to the Ford Granodiorite suite (Figs 2 and 3). Samples 
10CY-035 and Y1-MJ075 are exceptions. Both samples are displaced toward the 
potassium apex indicating slightly more evolved compositions (Fig. 4). Samples Y1-
 MJ075 and 10CY-035 have higher K and Ba content than the Ford Granodiorite suite, 
consistent with the accumulation of plagioclase and potassium feldspar during 
crystallization. Sample 10CY-035 also has a positive Eu anomaly, consistent with the 
sample being a cumulate. 
 
55 
 
 
Figure 4: Ternary (Na+Ca)?(Fe*+Mg+Ti)?K (after Solar and Brown, 2001). The 
arrow from glass (Skjerlie et al., 1993) through M5-G175 tracks model cumulate and 
fractionated melt trend. This granite would represent ~65% cumulate composed of 
63% biotite and 37% plagioclase 
 
 
 
 
 
56 
 
Devonian?Carboniferous granites Y1-IG062, C6-AW86-1, C5-I26, M5-G175 
and diatexites Y1-IG073 and Y1-IG071 have major and trace element compositions 
that are consistent with them being derived from or having a component of the Ford 
Granodiorite suite (Figs 2 and 3). However, none of these samples fall within the field 
defined by experimental melt compositions resulting from melting of the Ford 
Granodiorite suite (Fig. 4). Instead, they can be described as cumulates. By projecting 
from the melt composition through the granite composition, it is possible to determine 
the amount of cumulate material and the proportion of minerals needed to produce a 
granite of that composition (e.g., Solar and Brown, 2001; Korhonen et al., 2010b). 
Sample M5-G175 could reflect a Ford Granodiorite suite melt with ~65% cumulate 
composed of ~63% biotite and ~37% plagioclase (Fig. 4). Sample C5-I26 can be 
modeled as a ~15% cumulate derived from the Ford Granodiorite suite composed of 
~87% biotite and ~13% plagioclase. Sample Y1-IG073 can be modeled as ~45% 
cumulate composed of ~35% biotite and ~65% plagioclase while sample Y1-IG071 
as ~50% cumulate composed of ~60% biotite and ~40% plagioclase. Samples Y1-
 IG062 and C6-AW086-1 plot closer to the Na?Ca and K tie line than the melt 
composition, which suggests that they have either lost residual ferromagnesian 
minerals (biotite or garnet) or that they contain early crystallized (cumulate) feldspar. 
Sample Y1-IG062 could represent a cumulate composed of 25% biotite and 60% K-
 feldspar and 40% plagioclase, which could account for the slight positive Eu 
anomaly. Sample C6-AW086-1 could represent 25% cumulate composed of 70% K-
 feldspar and 30% plagioclase. Because samples Y1-IG062 and C6-AW86-1 lie close 
 
57 
 
to the K-feldspar?plagioclase feldspar tie line, there is more uncertainty in estimating 
the proportion of cumulate minerals. 
Cretaceous granites also do not fall within the melt compositions of the 
Swanson Formation or the Ford Granodiorite suite. They all have positive Eu 
anomalies, indicating that they could be cumulates of early crystallizing feldspars. 
Samples 10CY-039, Y1-AW038, Y1-IG052 and Y1-AE064 are have major and trace 
element compositions similar to the Ford Granodiorite suite. The major element 
compositions of these samples are displaced towards the K-feldspar?plagioclase tie 
line relative to the experimental melt compositions. Projecting from the melt 
composition through each sample to the K-feldspar?plagioclase join (Fig. 4), the 
amount and composition of cumulate can be calculated. 10CY-039 can be modeled as 
~60% cumulate composed of ~87% K-feldspar and ~13% plagioclase. Y1-AW038 
can be modeled as ~70% cumulate composed of ~75% K-feldspar and ~25% 
plagioclase. Y1-IG052 could represent the lowest amount of cumulate at ~50% 
cumulate composed of ~52% K-feldspar and ~48% plagioclase. Y1-AE064 could 
represent ~50% cumulate composed of ~50% K-feldspar and ~50% plagioclase. Y1-
 AE033 can be modeled as ~80% cumulate composed of ~64% K-feldspar and ~36% 
plagioclase. Y1-IG070 lies closest to the plagioclase and K-feldspar tie line It can be 
modeled as >80% cumulate composed of ~65% plagioclase and ~35% K-feldspar. 
This sample also has the strongest positive Eu anomaly, consistent with containing a 
lot of cumulate feldspar. As with two of the Devonian?Carboniferous granites, there 
is large uncertainty on estimating the proportion of cumulate in the Cretaceous 
samples as they lie so close the feldspar tie-line.   
 
58 
 
Because these granites aren?t melt compositions, the behavior of major and 
accessory minerals during partial melting may have a strong impact on the chemical 
and isotope composition of the granite. Certain minerals are more likely to affect the 
chemical and isotopic composition of a melt more strongly than others. Trace 
elements such as Rb and Sr are controlled primarily major rock-forming minerals. 
Strontium ratios are controlled by the growth or breakdown of major rock-forming 
minerals rich in Rb and Sr (e.g., micas and plagioclase); the stability of these minerals 
is primarily controlled by temperature, pressure, water content during melting. Rb is 
incorporated into the K site in biotite while Sr can be found in the Ca site of 
plagioclases. Therefore, melting reactions that involve micas will increase the 
87Sr/86Sr ratio of the melt, while the breakdown of plagioclase during melting will 
decrease the 87Sr/86Sr ratio (Farina and Stevens, 2011). In the Fosdick complex, >10 
vol. % melt is expected to be generated at temperatures above biotite stability for 
Ford Granodiorite suite compositions (>850?C; Korhonen et al., 2010a). Melt derived 
from this source generally has low Rb/Sr, consistent with the breakdown of 
plagioclase and hornblende. Melts derived from the Swanson Formation would be 
expected to have high Rb/Sr and high 87Sr/86Sr due to the prevalence of biotite in the 
source and melting conditions that involve the break-down of biotite (Korhonen et al., 
2010a). 
Unlike Sr isotope signatures, which are controlled by the growth and 
breakdown of major minerals, REEs and Nd isotope ratios are mainly controlled by 
the behavior of accessory minerals during partial melting. Minerals such as zircon, 
apatite, monazite and xenotime contain more than 80?90% of the REE, Zr Y, U, and 
 
59 
 
Th budget in granites and migmatites (Ayres and Harris, 1997). Zircon and xenotime 
have negligible amounts of Sm and Nd when compared with monazite and apatite. 
The REE-rich minerals will have a large influence on the REE budget of a melt and, 
therefore, will have a large effect on the Nd isotopic signature of the melt.  Their 
dissolution into the melt is largely controlled by water content and composition of the 
melt, temperature and pressure at which melt is produced, and whether the minerals 
are sequestered from melt in other minerals. If the melt is saturated in REE and P2O5, 
dissolution of apatite and monazite is inhibited (Pati?o-Douce and Harris, 1998; Rapp 
and Watson, 1986). Hot and dry conditions promote apatite dissolution whereas 
wetter and lower temperature conditions favor the dissolution of monazite. Apatite 
will generally contribute ~10% of LREE, 50% of MREE, and >90% HREE to the 
melt (Ayres and Harris, 1997). Therefore melt with a large contribution of apatite 
relative to monazite will show an increase in P2O5, a large Sm/Nd fractionation 
signature, a more radiogenic ?Nd value, and a depleted LREE signature compared 
with the putative source (Zeng et al., 2005a, 2005b). However, because apatite and 
monazite can occur as inclusions in other minerals, such as biotite, the availability of 
these minerals can be strongly dependent on the breakdown of the host mineral, 
which is frequently biotite. Wetter conditions will promote biotite stability, so even 
though the conditions may be favorable for monazite dissolution, biotite stability may 
prevent the inclusions from reacting with the melt and affecting the Nd signature. If 
biotite is residual, and accessory minerals are sequestered away in biotite, then the 
melt will be depleted in REE compared with the source (Bea, 1996; Watt and Harley, 
1993; Rapp and Watson, 1986).  Understanding the behavior major rock forming 
 
60 
 
minerals and accessory minerals is necessary in understanding the REE patterns and 
isotope compositions of the granites. 
 
6.4 Modeling REE patterns of a Cretaceous granite 
Although the REE patterns of the granites are consistent with crustal source, it 
is necessary to determine if one of the putative sources could produce a REE pattern 
that matches one of the granites. To determine if the Ford Granodiorite suite could 
produce one of the granites, batch melting and fractional crystallization of the Ford 
Granodiorite suite was modeled. Sample Y1-IG070, a Cretaceous granite, was used to 
compare against the model. This sample has the largest positive Eu anomaly (Eu/Eu* 
= 7.91) of the Cretaceous granites and can be used to determine if melting of the Ford 
Granodiorite suite and subsequent crystallization can produce a REE pattern with a 
positive Eu anomaly of similar magnitude. This sample also has no visible accessory 
phases, so uncertainties in estimating modal abundances of accessory minerals can be 
minimized to estimates of accessory minerals in the source.  
Melting of the Ford Granodiorite was modeled using the modal abundance of 
Y2-HN097 (Table ___) because it has the most plagioclase and could add enough Eu 
to the melt to produce a large Eu anomaly in a granite if the Eu is sequestered in early 
crystallizing feldspars. The model uses average REE concentrations from all Ford 
Granodiorite samples. Batch melting was modeled first using the batch melting 
equation: 
CL/CO = 1/(F + (1-F)*D) where CL is the concentration of a given element in the melt, 
CO is the concentration of a given element in the whole system, D is the bulk 
 
61 
 
distribution coefficient, and F is the fraction of melt produced. Minerals that were 
used to calculate the bulk distribution coefficient were limited by available mineral 
partition coefficients for peraluminous granites. Minerals used to calculate the bulk 
distribution coefficients were biotite, plagioclase, K-feldspar, apatite and zircon. 
Partition coefficients (Kds) that were used are listed in Table ____. Fractional 
crystallization of the melt was modeled second. The fractional crystallization model 
used the 5% melt composition determined by the batch melting model. This is 
approximately the same amount of melt that the Ford Granodiorite suite would have 
produce at the P?T conditions during the Cretaceous melting event (Korhonen et al., 
2010a). Fractional crystallization of this melt was modeled using the equation: CL/CO 
= F(D-1).  
 
Table 3: Modal abundances and Kds of select minerals from sample Y2-HN097 used 
in REE modeling 
Biotite Plagioclase K-feldspar Quartz Hornblende Apatite Zircon
 Modal Abundances 0.17 0.5 0.11 0.16 0.05 0.005 0.005
 Kd*
 La 0.06 4.61 1.01 456 1.3
 Ce 0.05 3.87 0.86 569 2.04
 Pr 0.07 4.22 0.87 764 2.54
 Nd 0.08 2.56 0.51 855 3.35
 Sm 0.06 1.45 0.42 1105 3.79
 Eu 0.05 2.99 2.32 23.8 0.45
 Gd 0.1 2.05 0.6 2133 9.21
 Tb 0.18 2.93 0.92 3643 24.8
 Dy 0.17 1.94 0.77 3257 38.8
 Ho 0.16 1.8 0.88 3143 74.5
 Er 0.22 1.94 1.14 4231 165
 Tm 0.22 1.63 1.12 3769 282
 Yb 0.12 0.82 0.64 2216 278
 Lu 0.2 1.32 0.96 2981 923  *Bea, 1994 
 
 
62 
 
If the modal proportions of apatite and zircon are not considered, different 
proportions of melting do not change the REE pattern relative to the average Ford 
Granodiorite patterns. The REE pattern only changes when accessory phases are 
considered. Figures 5?8 presents the REE pattern of melting the Ford Granodiorite 
with 5%, 10%, 20%, 50% and 90% melt when apatite and zircon modal abundances 
in the source are 0%, 0.25%, 0.5%, and 1%. Figures 5?8 also presents the REE 
patterns of 10%, 30%, 50%, and 80% fractional crystallization of 5% batch melting of 
Ford Granodiorite suite. Results indicate that it is possible to produce a Eu anomaly 
of similar magnitude to Y1-IG070 from melting of the Ford Granodiorite suite that 
has 0.5% modal abundance of apatite and zircon and 80% fractional crystallization. 
This percentage of crystallization is similar to the proportion of cumulate determined 
from Figure 4. The closest match to the Eu anomaly in Y1-IG070 comes from a 
source that has 1% modal abundance of apatite and zircon and 80% cumulate. 
However, this is an unrealistic modal abundance of apatite and zircon for the Ford 
Granodiorite suite.  
 
 
 
 
 
 
 
 
 
63 
 
 
 
Figure 5: Model of batch melting and fractional crystallization with 0% apatite and 
zircon in the source material 
 
64 
 
 
  Figure 6: Model of batch melting and fractional crystallization with 0.25% apatite 
and zircon in the source material  
 
65 
 
 
 Figure 7: Model of batch melting and fractional crystallization with 0.5% apatite and 
zircon in the source material 
 
66 
 
 
Figure 8: Model of batch melting and fractional crystallization with 1% apatite and 
zircon in the source material 
 
67 
 
Although the model closely match the positive Eu anomaly seen in sample 
Y1-IG070, there are differences in the modeled REE pattern when compared with the 
REE pattern of sample Y1-IG070. The LREE concentrations are lower in the sample 
than in the model and the HREE are higher in the sample than in the model. This 
could be due to basic assumptions of the model, such as equilibrium melting. 
However, for melt abundances less than 7%, equilibrium melting may be a reasonable 
assumption. The model also does not account for monazite in the source because 
REEs are essential structural elements. Their behavior is non-Henrian and therefore, 
partition coefficients are not constant. This makes modeling the behavior of monazite 
during melting difficult. It is possible that monazite remained in the source during 
melting, causing a depletion in LREE seen in the sample, but, because monazite was 
not considered in bulk distribution coefficients, the LREE depletion is not seen in the 
model. It is also possible that this sample has a component of Swanson Formation 
that is affecting the REE pattern of the sample that is not accounted for in the model.   
However, even with some differences between the model and the sample, the 
model suggests that it is possible to melt the Ford Granodiorite suite to produce one 
of the Cretaceous granites with positive Eu anomalies.  
 
 
 
 
 
 
 
68 
 
6.5 Sr?Nd isotope results  
Thirty-eight samples were analyzed for Sr and Nd isotopic compositions and 
Rb and Sr and Sm and Nd concentrations. Samples include 5 metasedimentary 
samples from the Swanson Formation, 8 samples from the Ford Granodiorite Suite, 7 
paragneiss samples, 5 orthogneiss samples, 2 diatexite samples, 4 Devonian?
 Carboniferous granites, 6 Cretaceous granites, and 1 microgranite.  
Isotopic ratios of granites have been age-corrected to either 360 Ma or 100 Ma 
depending on the U?Pb age of the granite. Potential sources have been corrected to 
360 Ma and 100 Ma to compare their isotope signatures at time of crystallization of 
either the Devonian?Carboniferous granites or Cretaceous granites. Mixing lines 
between the two putative sources were calculated using the average Rb, Sr, Nd and 
Sm compositions of each source and the end-member isotope compositions for each 
source. The Swanson Formation has 87Sr/86Sr360Ma values between 0.711890?
 0.759472 and has ?Nd360Ma values ranging from -9.3 to -6.3 (Table 4). Samples from 
the Ford Granodiorite suite collected from outside of the Fosdick complex have 
87Sr/86Sr360Ma values of 0.705231?0.709237 and have ?Nd360Ma values ranging from -
 3.1 to -0.2 (Table 4). The Ford Granodiorite suite sample collected from within the 
Fosdick complex, Y1-AW039, has 87Sr/86Sr360Ma value of 0.709056 and has an 
?Nd360Ma value of -3.8 (Table 4). At 100 Ma, the Swanson formation has 
87Sr/86Sr100Ma values of 0.723375?0.766167 and has ?Nd100Ma values ranging from -
 11.9 to -9.1 (Table 4).  The Ford Granodiorite suite samples from outside the Fosdick 
complex have 87Sr/86Sr100Ma values of 0.709028?0.751809 and have ?Nd100Ma values 
ranging from -6.0 to -3.0 (Table 4). The Ford Granodiorite suite sample collected 
 
69 
 
from within the Fosdick complex, Y1-AW039, has an 87Sr/86Sr100Ma value of 
0.714059 and has an ?Nd360Ma values of -6.5.  
Paragneiss samples have 87Sr/86Sr360Ma values that range from 0.695066 to 
0.720852 and ?Nd360Ma values that range from -8.3 to -4.0 (Table 4). Sample Y1-
 IG057 yields a calculated 87Sr/86Sr360Ma ratio of 0.313076.  87Sr/86Sr100Ma values that 
range from 0.719704 to 0.733346 and ?Nd100Ma values that range from -10.9 to -7.5. 
Cretaceous age corrected isotope ratios for the paragneiss are consistent with the 
Swanson Formation. Devonian?Carboniferous age corrected isotope ratios produce a 
wider spread of Sr and Nd isotope ratios compared with isotope composition of the 
Swanson Formation. Three of the paragneiss samples have 87Sr/86Sr360 Ma that are less 
than the initial solar system (Fig. 9). If the paragneiss formed during the Cretaceous, 
they would give a false age if corrected back to 360 Ma. It is also possible that those 
paragneiss samples had Sr rich melt extracted from them between the Devonian?
 Carboniferous and the Cretaceous, producing a higher 87Sr/86Sr than would be 
expected had the system remained closed. If the residue remaining is rich in biotite, 
then the resulting 87Sr/86Sr ratio could increase if enough time has passed for the 87Rb 
to decay to 87Sr.  
Orthogneiss samples have 87Sr/86Sr360Ma values of 0.707423?0.710255 and 
?Nd360Ma values ranging from -4.5 to -0.2 (Table 4). At 100 Ma, 87Sr/86Sr100Ma values 
range from 0.712295 to 0.724913 and ?Nd100Ma values range from -6.8 to -3.7. The 
age corrected isotope ratios of the orthogneiss are consistent with the age corrected 
isotope ratios of the Ford Granodiorite suite (Fig. 9 and 10), which supports the 
 
70 
 
hypothesis that the orthogneiss is the high grade equivalent of the Ford Granodiorite 
suite.  
The Devonian?Carboniferous homogenous diatexite, Y1-IG073, has an 
87Sr/86Sr360Ma of 0.709360 and an ?Nd360Ma of -4.3. At 100 Ma, the 87Sr/86Sr100Ma = 
0.715431 and the ?Nd100Ma =  
-7.1. This sample is consistent with isotope composition of the Ford Granodiorite 
suite and the orthogneisses (Fig. 9). The Devonian?Carboniferous heterogeneous 
diatexite, Y1-IGO71, has an 87Sr/86Sr360Ma = 0.704513 and an ?Nd360Ma of -5.7. It has 
a similar ?Nd360Ma to C5-I26, although has a slightly less radiogenic Sr signature. At 
100 Ma, the 87Sr/86Sr100Ma ratio is 0.713997 and the ?Nd100Ma is -8.1 (Table 4).  
Devonian?Carboniferous granites have 87Sr/86Sr360Ma values of 0.707423?
 0.710255 and ?Nd360Ma values that range from -6.0 to -3.3. The isotope compositions 
for samples Y1-IG062, C6-AW86-1 and M5-G175 are comparable to the Ford 
Granodiorite suite and the orthogneiss (Fig. 9), suggesting that the granites were 
derived from the Ford Granodiorite suite. Sample C5-I26 lies between the Ford 
Granodiorite suite and the Swanson Formation, close to the mixing line between the 
two potential sources at about 45% Swanson Formation (Fig. 9).  
Cretaceous granites have 87Sr/86Sr100Ma ratios that range from 0.718598to 
0.725792 and ?Nd100Ma values of -8.2 to -5.1. Garnet-bearing Cretaceous granites, 
Y1-IG052 and Y1- AE064, have 87Sr/86Sr100Ma of 0.723376 and 0.718598, 
respectively and have ?Nd100Ma of -6.3 and -6.5, respectively. The microgranite, 
10CY-024, has an 87Sr/86Sr100Ma ratio of 0.708989 and an ?Nd100Ma of -10 (Table 4). 
 
71 
 
Table 4: Sr?Nd isotope composition of source rocks and granites   
Rock Type: Swanson Formation Ford Granodiorite  Suite
 Sample Name: 10CY-001 10CY-002 Y2-BR086 Y2-MD092 Y2-MP098 51225-1 51225-2 Y2-GP091 Y2-HN097
 Rb (ppm) 131.3 205.5 155.2 99.95 95.55 194.2 220.7 142.5 85.33
 Sr (ppm) 201.1 147.6 128.7 194.8 150.7 223.0 220.4 375.9 357.2
 Rb/Sr 0.65 1.39 1.21 0.51 0.63 0.87 1.00 0.38 0.24
 87Rb/86Sr 2.086 4.037 0.000 1.487 1.838 2.288 2.901 1.097 0.6911
 87Sr/86Sr 0.726291 0.732242 0.738139 0.727782 0.768736 0.720773 0.721630 0.710770 0.708715
 87Sr/86Sr100Ma 0.723375 0.726599 0.738139 0.725704 0.766167 0.717575 0.717575 0.709237 0.707749
 87Sr/86Sr360Ma 0.715775 0.711890 0.738139 0.720285 0.759472 0.709237 0.707005 0.705241 0.705231
 Sm (ppm) 6.612 6.652 7.977 6.022 6.856 9.190 11.179 4.315 3.823
 Nd (ppm) 35.29 32.76 38.80 30.32 34.32 45.89 59.61 21.54 18.21
 Sm/Nd 0.19 0.20 0.21 0.20 0.20 0.20 0.19 0.20 0.21
 147Sm/144Nd 0.1133 0.1227 0.1243 0.1200 0.1208 0.0904 0.1134 0.1211 0.1109
 143Nd/144Nd 0.512117 0.512084 0.512079 0.511979 0.512061 0.512378 0.512292 0.512432 0.512276
 ?Nd100Ma -9.1 -9.9 -10.0 -11.9 -10.3 -3.7 -5.7 -3.1 -6.0
 ?Nd360Ma -6.3 -7.4 -7.6 -9.3 -7.8 -0.2 -2.9 -0.5 -3.1
 Rock Type: Ford Granodiorite  Suite O rthogneiss
 Sample Name: Y2-JU096 Y2-MS089 Y2-SM095 Y1-AE035 10CY-035 Y1-AW049 Y1-AW039 Y1-IG053 Y1-MJ075
 Rb (ppm) 122.2 339.13 100.45 128.6 196.2 133.2 131.3 114.4 224.8
 Sr (ppm) 422.8 81.49 345.6 271.1 269.8 288.3 181.0 285.9 156.5
 Rb/Sr 0.29 4.16 0.29 0.47 0.73 0.46 0.73 0.40 1.44
 87Rb/86Sr 0.8362 12.11 0.8408 1.373 2.105 1.337 2.101 1.159 4.164
 87Sr/86Sr 0.710850 0.768736 0.710204 0.715979 0.718183 0.714164 0.721511 0.716095 0.730733
 87Sr/86Sr100Ma 0.709681 0.751809 0.709028 0.714059 0.715240 0.712295 0.718575 0.716091 0.724913
 87Sr/86Sr360Ma 0.706634 0.707688 0.705965 0.709056 0.707570 0.707423 0.710921 0.716079 0.709743
 Sm (ppm) 8.560 4.328 4.828 6.072 2.494 6.532 6.301 6.469 6.997
 Nd (ppm) 46.65 17.31 22.98 31.43 11.52 38.37 28.79 34.52 46.79
 Sm/Nd 0.18 0.25 0.21 0.19 0.22 0.17 0.22 0.19 0.15
 147Sm/144Nd 0.1269 0.1511 0.1270 0.1168 0.1309 0.1029 0.1323 0.1133 0.0904
 143Nd/144Nd 0.512438 0.512385 0.512368 0.512254 0.512253 0.512229 0.511900 0.512252 0.512378
 ?Nd100Ma -3.0 -4.4 -4.4 -6.5 -6.7 -6.8 -13.6 -6.5 -3.7
 ?Nd360Ma -0.7 -2.8 -2.1 -3.8 -4.5 -3.7 -11.4 -3.7 -0.2
 Rock Type: Paragneiss
 Sample Name: 10CY-010 10CY-015 10CY-023 10CY-033 Y1-CB080 Y1-IG057 Y1-LH077
 Rb (ppm) 205.5 284.9 232.4 206.5 147.3 453.1 164.7
 Sr (ppm) 147.6 104.4 99.59 98.35 144.3 11.92 139.3
 Rb/Sr 1.39 2.73 2.33 2.10 1.02 38.02 1.18
 87Rb/86Sr 4.037 7.919 6.762 6.090 2.960 111.8 3.429
 87Sr/86Sr 0.732242 0.739512 0.729157 0.734120 0.731493 0.876604 0.738139
 87Sr/86Sr100Ma 0.726599 0.728444 0.719704 0.725607 0.727356 0.720353 0.733346
 87Sr/86Sr360Ma 0.711890 0.699593 0.695066 0.703418 0.716573 0.313076 0.720852
 Sm (ppm) 13.23 9.802 10.50 7.233 7.593 12.45 7.506
 Nd (ppm) 69.90 51.43 46.59 35.57 38.56 65.74 38.24
 Sm/Nd 0.19 0.19 0.23 0.20 0.20 0.19 0.20
 147Sm/144Nd 0.1144 0.1152 0.1210 0.1229 0.1190 0.1145 0.1186
 143Nd/144Nd 0.512098 0.512203 0.512253 0.512090 0.512187 0.512044 0.512027
 ?Nd100Ma -9.5 -7.5 -6.6 -9.8 -7.8 -10.5 -10.9
 ?Nd360Ma -6.8 -4.7 -4.0 -7.3 -5.2 -7.8 -8.3  
 
 
 
 
72 
 
 Table 4: Continued 
Devonian-Carboniferous
 Rock Type: Diatexite Granite
 Sample Name: Y1-IG071 Y1-IG073 Y1-IG062 C5-I26 C6-AW86-1 M5-G175
 Rb (ppm) 171.2 146.6 154.4 225.6 167.2 213.8
 Sr (ppm) 190.5 279.7 225.8 280.4 328.8 248.5
 Rb/Sr 0.90 0.52 0.68 0.80 0.51 0.86
 87Rb/86Sr 2.603 1.642 1.987 2.330 1.472 2.492
 87Sr/86Sr 0.717636 0.717636 0.719813 0.719497 0.713661 0.720081
 87Sr/86Sr100Ma 0.713997 0.715341 0.717036 0.716241 0.711604 0.716597
 87Sr/86Sr360Ma 0.704513 0.709360 0.709795 0.707752 0.706242 0.707518
 Sm (ppm) 8.463 11.48 3.471 16.61 4.972 10.15
 Nd (ppm) 41.30 61.65 15.02 65.96 25.77 53.60
 Sm/Nd 0.20 0.19 0.23 0.25 0.19 0.19
 147Sm/144Nd 0.123871 0.112547 0.1361 0.1522 0.1166 0.1145
 143Nd/144Nd 0.512175 0.512217 0.512256 0.512227 0.512281 0.512225
 ?Nd100Ma -8.1 -7.1 -6.7 -7.4 -5.9 -7.0
 ?Nd360Ma -5.7 -4.3 -4.7 -6.0 -3.3 -4.3
 Cretaceous 
Rock Type: Granites Microgranite
 Sample Name: 10CY-039 Y1-IG052 Y1-IG070 Y1-AW038 Y1-AE033 Y1-AE064 10CY-024
 Rb (ppm) 164.9 131.0 84.58 255.2 130.7 154.9 192.1
 Sr (ppm) 240.1 252.9 219.1 172.3 210.7 195.2 225.6
 Rb/Sr 0.69 0.52 0.39 1.48 0.62 0.79 0.85
 87Rb/86Sr 1.901 1.532 1.118 4.244 1.736 2.125 2.303
 87Sr/86Sr 0.723183 0.725517 0.721505 0.725957 0.721024 0.728763 0.712208
 87Sr/86Sr100Ma 0.720526 0.723376 0.719943 0.720025 0.718598 0.725792 0.708989
 87Sr/86Sr360Ma 0.713598 0.717794 0.715869 0.704562 0.712273 0.718048 0.700600
 Sm (ppm) 0.4368 1.073 0.4497 0.3425 2.625 2.927 10.08
 Nd (ppm) 1.975 5.652 2.956 1.120 13.39 12.29 54.93
 Sm/Nd 0.22 0.19 0.15 0.31 0.20 0.24 0.18
 147Sm/144Nd 0.1337 0.1400 0.0919 0.1848 0.1440 0.1133 0.1243
 143Nd/144Nd 0.512338 0.512277 0.512151 0.512346 0.512251 0.512190 0.512079
 ?Nd100Ma -5.1 -6.3 -8.2 -5.5 -6.5 -8.1 -10.0
 ?Nd360Ma -3.0 -4.4 -4.7 -5.2 -3.7 -6.3 -7.6  
 
 
73 
 
 Figure 9: Sr?Nd isotopic compositions at 360 Ma for source rocks and granites from 
the Ford Ranges. Tick marks along mixing curve are 10% increments of melting 
between sources.  
 
 
 
 
 
74 
 
 Figure 10: Sr?Nd isotopic compositions at 100 Ma for source rocks and granites from 
the Ford Ranges. Tick marks along mixing curve are 10% increments of melting 
between sources. 
 
 
75 
 
6.6 Sr?Nd isotope discussion 
Paragneiss sample have isotope compositions that generally overlap with the 
isotope composition of the Swanson Formation. The agreement between the 
paragneiss and the Swanson Formation is strongest when the samples are age 
corrected to 100Ma. When corrected to 360Ma, 3 paragneiss samples have 87Sr/86Sr 
ratios that are lower than the initial solar system 87Sr/86Sr ratio (Fig. 9). Either these 
samples were not formed during the Devonian?Carboniferous and the age correct 
ratios are spurious, or the samples have had Sr-rich melt extracted from them at some 
point after 360 Ma, leaving behind a Rb rich residue. This would falsely increase the 
87Sr/86Sr ratio when age corrected to 360 Ma. Despite the isotopic irregularities 
during the Devonian?Carboniferous, the paragneiss generally have major and trace 
element compositions as well as isotope compositions that are similar to the Swanson 
Formation, consistent with the conclusions of Korhonen et al., (2010b) that the 
paragneisses are the high-grade equivalents of the Swanson Formation. 
 Orthogneiss samples have isotope compositions that generally overlap with 
the isotope composition for the Ford Granodiorite suite (Fig. 9 and 10). The 
orthogneiss also have similar major and trace element compositions as the Ford 
Granodiorite suite (Fig 2 and 3). Sample Y1-AW039 has a less radiogenic Nd 
signature than the rest of the orthogneisses. This may reflect the entrapment of melt 
derived from the less radiogenic Swanson Formation in the sample or an analytical 
issue. The isotope data from this study support the conclusions of Korhonen et al. 
(2010b) that the orthogneisses are genetically related to the Ford Granodiorite suite. 
 
76 
 
Devonian?Carboniferous granites and diatexites generally have similar 
isotope compositions as the Ford Granodiorite suite and the orthogneiss samples (Fig. 
9), suggesting that they were either derived from that source or has a mixed source 
with larger contribution from the Ford Granodiorite than from the Swanson 
Formation. Sample Y1-IG071 does not fall on a mixing line between the Swanson 
Formation and the Ford Granodiorite suite (Fig. 9). It is possible that the Swanson 
Formation can have lower 87Sr/86Sr but no samples with those compositions have 
been sampled and analyzed. This sample also has a mixed zircon population. If the 
sample crystallized in the Cretaceous, then age correcting back to 360 Ma could yield 
a lower than expected 87Sr/86Sr ratio. Sample C5-I26 has an isotope composition that 
reflects a mix of the Ford Granodiorite source and the Swanson Formation source 
(Fig. 9). This sample also has a phosphorus content that is an order of magnitude 
greater than the other granites, as well as elevated Sm/Nd values compared with 
values from the potential sources (Tables 1 and 2). The elevated Sm/Nd ratios and the 
elevated phosphorous content are consistent with the presence of apatite either 
precipitated from the melt or entrained from the source. This sample may reflect a 
filter zone where apatite or monazite remained after melt was removed.  
Cretaceous granites generally have isotope compositions that are consistent 
with the Ford Granodiorite suite with two samples, Y1-IG070 and Y1-AE033, which 
could represent mixing between the two sources. Sample Y1-IG070 does not have 
elevated Sm/Nd ratios compared with either source and likely represents a mix of the 
two sources (Table 2). Sample Y1-AE033 has elevated Sm/Nd and low phosphorous 
content compared with the source. It is possible that this sample represents a mixture 
 
77 
 
of the two sources and has an accessory phase that is controlling the Sm/Nd ratio and 
possibly the ?Nd value.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
78 
 
Chapter 7: Conclusions  
 
 
Based on the major and trace elements as well as the isotope compositions of 
the granites analyzed in the study, Devonian?Carboniferous granites are derived 
primarily from the Ford Granodiorite Suite, consistent with results from Korhonen et 
al. (2010b). Because the Ford Granodiorite suite was not a fertile source at the P?T 
conditions of metamorphism during the Devonian?Carboniferous at the level of the 
Fosdick complex, it is likely that these granites were sourced from deeper in the crust. 
The elevated Sr and low Rb would indicate melting at P?T conditions above biotite 
stability, involving the breakdown of plagioclase and hornblende at higher 
temperatures than recorded in the Fosdick complex. These minerals would contribute 
more Sr to the melt and produce melts with lower Rb/Sr ratios. The major and trace 
element concentrations of these granites are consistent with them being mixtures of 
melt and either cumulate biotite and plagioclase or, for two samples, cumulate 
plagioclase and K-feldspar.  
 The chemical compositions and isotope composition of the Cretaceous 
granites are consistent with them being derived from mixtures of both the Ford 
Granodiorite suite and the Swanson Formation. Because the Ford Granodiorite suite 
is not a fertile source at the P?T conditions during the Cretaceous, it is likely that 
these melts were sourced from deeper in the crust, much like the Devonian?
 Carboniferous granites. Devonian?Carboniferous granites tend to show oscillatory-
 zoned zircons whereas zircons from Cretaceous granites show dark metamict cores 
surrounded by a thin bright rim in CL. The presence of inherited zircon cores may 
indicate lower water content during melting in the Cretaceous. These findings are 
 
79 
 
consistent with findings of Korhonen et al., (2010b). Previous results noted a 
temporal and spatial difference between Cretaceous granites derived from the Ford 
Granodiorite and granites from the Swanson Formation, where Ford Granodiorite 
suite-derived granites are older than those derived from the Swanson (Korhonen et 
al., 2010b). In contrast to previous results, all Cretaceous granites in this study yield 
ages younger than 110 Ma and granites with a Swanson Formation component are not 
limited spatially to the leucogranite sheeted complex, but were emplaced throughout 
the Fosdick complex.  
In summary, the results of this study have determined that the Devonian?
 Carboniferous granites from the Fosdick migmatite?granite complex crystallized 
c.360 Ma and are primarily derived from the Ford Granodiorite suite. Samples that 
fall between the two sources can be ascribed to mixing. The Cretaceous samples 
crystallized c.100 Ma and are prevalent thought out the Fosdick complex. The 
Cretaceous granites are also primarily derived from the Ford Granodiorite suite. 
Samples that fall in between the two sources represent mixing or possibly represent a 
melt where an accessory phase is controlling the ?Nd value. There is no evidence for 
source other than the two crustal sources previous mentioned, indicating that is 
possible to differentiate the continental crust a convergent margin without the 
addition of a more juvenile source.  
 
 
 
80 
 
Appendix A: Sample Analysis and Sample Locations 
 
 Table A1: List of sample names and analyses completed 
      ?? ?? ?? ??
 Swanson 
Formation     ?? ?? ?? ??
 Sample Name Location    U?Pb  XRF REE Sr?Nd 
10CY-001 Clark Mts   ?? ?? ?? ??
 10CY-002 Clark Mts   ?? ?? ?? ??
 Y2-BR086 Bailey Ridge   ?? ?? ?? ??
 Y2-MD092 Mt. Dolber   ?? ?? ?? ??
 Y2-MP098 Mt. Passell   ?? ?? ?? ??
      ??  ?  ?  ?
 Ford Granodiorite suite   ??  ?  ?  ?
 Sample Name Location    U?Pb  XRF REE Sr?Nd 
51225-1 Chester Mts   ?? ?? ?? ??
 51225-2 Chester Mts   ?? ?? ?? ??
 Y2-GP091 Greer Peak   ?? ?? ?? ??
 Y2-HN097 
Hermann 
Nunatak   ?? ?? ?? ??
 Y2-JU096 Mt June   ?? ?? ?? ??
 Y2-MS089 Mt Swan   ?? ?? ?? ??
 Y2-SM095 
Saunders 
Mountain   ?? ?? ?? ??
 Y1-AE035 Mt Avers East   ?? ?? ?? ??
       ?  ?  ?  ?
 Paragneiss     ?? ?? ?? ??
 Sample Name Location    U?Pb  XRF REE Sr?Nd 
10CY-010 Mt Bitgood   ?? ?? ?? ??
 10CY-015 Mt Bitgood   ?? ?? ?? ??
 10CY-021 Maigetter Peak   ?? ??  ? ??
 10CY-023 Maigetter Peak   ?? ?? ?? ??
 10CY-033 Mt Avers East   ?? ?? ?? ??
 10CY-041 Mt Avers East   ?? ?? ?? ??
 Y1-BB013 Bird Bluff   ?? ?? ?? ??
 Y1-CB080 Colombo   ?? ?? ?? ??
 Y1-IG057 Mt Iphigene   ?? ?? ?? ??
 Y1-IG061 Mt Iphigene   ?? ?? ?? ??
 Y1-LH077 Lochart   ?? ?? ?? ??
 
81 
 
Swanson Formation
 Sample Name Location U?Pb XRF REE Sr?Nd
 10CY-001 Clark Mts ? ? ?
 10CY-002 Clark Mts ? ? ?
 Y2-BR086 Bailey Ridge ? ? ?
 Y2-MD092 Mt. Dolber ? ? ?
 Y2-MP098 Mt. Passell ? ? ?
 Ford Granodiorite suite
 Sample Name Location U?Pb XRF REE Sr?Nd
 51225-1 Chester Mts ? ? ? ?
 51225-2 Chester Mts ? ? ? ?
 Y2-GP091 Greer Peak ? ? ? ?
 Y2-HN097 Hermann Nunatak ? ? ?
 Y2-JU096 Mt June ? ? ? ?
 Y2-MS089 Mt Swan ? ? ?
 Y2-SM095 Saunders Mountain ? ? ?
 Y1-AE035 Mt Avers East ? ? ? ?
 Paragneiss
 Sample Name Location U?Pb XRF REE Sr?Nd
 10CY-010 Mt Bitgood ? ? ?
 10CY-015 Mt Bitgood ? ? ?
 10CY-021 Maigetter Peak ?
 10CY-023 Maigetter Peak ? ? ?
 10CY-033 Mt Avers East ? ? ?
 10CY-041 Mt Avers East ? ?
 Y1-BB013 Bird Bluff ? ? ?
 Y1-CB080 Colombo ? ? ?
 Y1-IG057 Mt Iphigene ? ?
 Y1-IG061 Mt Iphigene ? ? ?
 Y1-LH077 Lochart ? ?   
Table A1: Continued 
 
82 
 
Orthogneiss
 Sample Name Location U?Pb XRF REE Sr?Nd
 10CY-035  Mt Avers East ? ? ? ?
 Y1-AW039 Mt Avers West ? ? ? ?
 Y1-AW049  Mt Avers West ? ? ? ?
 Y1-IG053 Mt Iphigene ? ? ? ?
 Y1-MJ075 Marujupu ? ? ? ?
 Diatexite (Devonian-Carboniferous)
 Sample Name Location U?Pb XRF REE Sr?Nd
 Y1-IG071  Mt Iphigene ? ? ? ?
 Y1-IG073  Mt Iphigene ? ? ? ?
 Carboniferous high-Sr granite
 Sample Name Location U?Pb XRF REE Sr?Nd
 Y1-IG062 Mt Iphigene ? ? ? ?
 C5-I26 Mt Iphigene ? ? ?
 C6-AW86-1 Mt Avers West ? ? ?
 M5-G175 Mt Getz ? ? ?
 Cretaceous Granites
 Sample Name Location U?Pb XRF REE Sr?Nd
 Y1-AW038 Avers West ? ? ? ?
 10CY-039 Avers East ? ? ? ?
 Y1-AE051 Avers East ? ? ?
 Y1-IG052 Iphigene ? ? ? ?
 Y1-IG070 Iphigene ? ? ? ?
 Y1-AE064 Avers East ? ? ? ?
 Y1-AE033 Avers East ? ? ? ?
 Microgranite
 Sample Name Location U?Pb XRF REE Sr?Nd
 10CY-024 Maigetter Peak ? ? ? ?   
 
 
83 
 
 Figure A1: Putative source sample locations within the Ford Ranges 
 
 
 
 
 
 
 
 
 
84 
 
 Figure A2: Paragneiss sample locations within the Fosdick migmatite?granite complex 
 
 
 
85 
 
  Figure A3: Orthogneiss sample locations within the Fosdick migmatite?granite complex 
 
86 
 
 Figure A4:  Granite sample locations within the Fosdick migmatite?granite complex 
 
87 
 
Appendix B: Sample Photomicrographs 
Swanson Formation  
 Figure B1: Photomicrograph of thin section 10CY-001 
 
 Figure B2: Photomicrograph of thin section 10CY-002 
 
 Figure B3: Photomicrograph of thin section Y2-BR086 
 
88 
 
 Figure B4: Photomicrograph of thin section Y2-MD092 
 
 Figure B5: Photomicrograph of thin section Y2-MP098 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
89 
 
Ford Granodiorite suite 
 
 Figure B6: Photomicrograph of thin section 51225-1 
 
  
 Figure B7: Photomicrograph of thin section 51225-2 
 
 
 Figure B8: Photomicrograph of thin section Y2-GP091 
 
90 
 
 
 Figure B9: Photomicrograph of thin section Y2-HN097 
 
 Figure B10: Photomicrograph of thin section Y2-JU096 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
91 
 
 Figure B11: Photomicrograph of thin section Y2-MS089 
 
 
 Figure B12: Photomicrograph of thin section Y2-SM095 
 
 
 
 Figure B13: Photomicrograph of thin section Y1-AE035 
 
92 
 
Paragneisses  
 
 Figure B14: Photomicrograph of thin section 10CY-010 
 
 Figure B15: Photomicrograph of thin section 10CY-015 
 
 Figure B16: Photomicrograph of thin section 10CY-021 
 
 
93 
 
 
 Figure B17: Photomicrograph of thin section 10CY-023 
 
 
 Figure B18: Photomicrograph of thin section 10CY-033 
 
  
Figure B19: Photomicrograph of thin section 10CY-041 
 
94 
 
Y1-BB013 
 Figure B20: Photomicrograph of thin section Y1-BB013 
 
 Figure B21: Photomicrograph of thin section Y1-CB080 
 
 Figure B22: Photomicrograph of thin section Y1-IG057 
 
 
 
95 
 
 Figure B23: Photomicrograph of thin section Y1-IG061 
 
 Figure B24: Photomicrograph of thin section Y1-LH077 
 
 Figure B25: Photomicrograph of thin section Y1-MJ074 
 
 
 
 
96 
 
Orthogneisses 
 
 Figure B26: Photomicrograph of thin section 10CY-035 
 
 Figure B27: Photomicrograph of thin section Y1-AW039 
 
 Figure B28: Photomicrograph of thin section Y1-AW049 
 
97 
 
 Figure B29: Photomicrograph of thin section Y1-MJ075 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
98 
 
Devonian?Carboniferous diatexites 
 
 Figure B30: Photomicrograph of thin section Y1-IG071 
 
 Figure B31: Photomicrograph of thin section Y1-IG073 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
99 
 
Devonian?Carboniferous granite 
 
 Figure B32: Photomicrograph of thin section Y1-IG062 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
100 
 
Cretaceous granites 
 
 Figure B33: Photomicrograph of thin section Y1-AW038 
 
 Figure B34: Photomicrograph of thin section 10CY-039 
 
 Figure B35: Photomicrograph of thin section Y1-AE051 
 
 
101 
 
 Figure B36: Photomicrograph of thin section Y1-IG052 
 
 Figure B37: Photomicrograph of thin section Y1-IG070 
 
 Figure B38: Photomicrograph of thin section Y1-AE064 
 
 
 
 
 
102 
 
 Figure B39: Photomicrograph of thin section Y1-AE033 
 
 
 
103 
 
Appendix C: Zircon U?Pb Radiogenic Ratios and Ages  
 
 
Table C1: LA-ICP-MS U?Pb zircon data from sample Y1-AE035 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-AE035
 Y1-AE035_16 30 114 52 2.2 0.0537 0.0030 0.4022 0.093 337.2 62.3 337.2 18.4
 Y1-AE035_1 30 180 93 1.9 0.0623 0.0018 0.4659 0.049 389.3 42.6 389.3 11.0
 Y1-AE035_2 30 261 172 1.5 0.0567 0.0020 0.4182 0.026 355.8 43.1 355.8 12.2
 Y1-AE035_3 30 258 119 2.2 0.0578 0.0035 0.4223 0.035 362.4 76.2 362.4 21.0
 Y1-AE035_3 30 242 114 2.1 0.0588 0.0009 0.4397 0.036 368.3 20.3 368.3 5.6
 Y1-AE035_5 30 207 167 1.2 0.0585 0.0013 0.4453 0.025 366.4 28.1 366.4 7.6
 Y1-AE035_6 30 251 84 3.0 0.0572 0.0021 0.4187 0.039 358.6 46.0 358.6 12.8
 Y1-AE035_7 30 472 481 1.0 0.0598 0.0012 0.4414 0.014 374.5 27.9 374.5 7.4
 Y1-AE035_8 30 135 56 2.4 0.0599 0.0025 0.4365 0.046 374.7 57.3 374.7 15.2
 Y1-AE035_9 30 310 115 2.7 0.0597 0.0022 0.4427 0.032 374.0 49.7 374.0 13.2
 Y1-AE035_9 30 385 200 1.9 0.0583 0.0030 0.4402 0.033 365.1 66.3 365.1 18.2
 Y1-AE035_11 30 368 99 3.7 0.0592 0.0027 0.4372 0.026 370.5 60.0 370.5 16.2
 Y1-AE035_12 30 259 105 2.5 0.0613 0.0016 0.4546 0.026 383.5 37.4 383.5 9.8
 Y1-AE035_13 30 149 60 2.5 0.0605 0.0031 0.4456 0.032 378.8 70.8 378.8 18.6
 Y1-AE035_14 30 138 61 2.3 0.0575 0.0018 0.4334 0.046 360.6 40.2 360.6 11.2
 Y1-AE035_17 30 145 63 2.3 0.0601 0.0016 0.4342 0.045 376.0 37.6 376.0 10.0
 Y1-AE035_18 30 206 127 1.6 0.0593 0.0015 0.4441 0.032 371.4 34.4 371.4 9.2
 Y1-AE035_19 30 137 62 2.2 0.0583 0.0020 0.4276 0.046 365.1 43.8 365.1 12.0
 Y1-AE035_20 30 140 53 2.7 0.0606 0.0037 0.4395 0.062 379.4 84.9 379.4 22.4
 Y1-AE035_21 30 227 107 2.1 0.0609 0.0009 0.4469 0.023 381.1 21.7 381.1 5.6
 Y1-AE035_22 30 106 44 2.4 0.0584 0.0021 0.4411 0.063 365.9 46.4 365.9 12.6
 Y1-AE035_23 30 240 101 2.4 0.0608 0.0020 0.4415 0.036 380.2 47.3 380.2 12.4
 Y1-AE035_24 30 138 64 2.1 0.0598 0.0019 0.4446 0.064 374.2 43.3 374.2 11.6
 Y1-AE035_25 30 207 168 1.2 0.0586 0.0017 0.4294 0.035 367.1 37.9 367.1 10.4
 *1.3=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
104 
 
 
Table C2: LA-ICP-MS U?Pb zircon data from sample Y2-GP091 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y2-GP091
 Y2-GP091_23 30 156 96 1.6 0.0573 0.0016 0.4297 0.038 359.4 35.5 373.6 15.4
 Y2-GP091_13 30 326 260 1.3 0.0576 0.0025 0.4309 0.023 361.2 56.0 461.6 27.7
 Y2-GP091_15 30 195 93 2.1 0.0579 0.0018 0.4247 0.020 363.0 39.6 375.6 16.8
 Y2-GP091_4 30 109 57 1.9 0.0580 0.0058 0.4297 0.045 363.7 127.6 363.7 35.1
 Y2-GP091_14 30 100 76 1.3 0.0581 0.0017 0.4139 0.054 363.8 37.0 373.2 10.8
 Y2-GP091_11 30 193 54 3.6 0.0581 0.0020 0.4225 0.033 364.0 43.3 377.1 10.9
 Y2-GP091_20 30 104 69 1.5 0.0583 0.0030 0.4363 0.037 365.0 65.9 369.5 14.5
 Y2-GP091_18 30 65 45 1.4 0.0584 0.0031 0.4333 0.090 366.0 68.2 367.7 23.3
 Y2-GP091_19 30 105 39 2.7 0.0586 0.0043 0.4580 0.060 367.1 95.7 391.4 21.7
 Y2-GP091_12 30 96 76 1.3 0.0587 0.0019 0.4475 0.047 367.6 43.2 372.7 10.4
 Y2-GP091_8 30 125 126 1.0 0.0587 0.0038 0.4356 0.038 367.7 85.8 364.0 11.9
 Y2-GP091_7 30 344 110 3.1 0.0590 0.0024 0.4377 0.022 369.5 53.7 367.6 11.7
 Y2-GP091_17 30 110 78 1.4 0.0591 0.0035 0.4488 0.051 370.4 78.4 361.2 15.5
 Y2-GP091_10 30 480 183 2.6 0.0595 0.0017 0.4466 0.016 372.7 38.9 363.8 10.2
 Y2-GP091_5 30 329 364 0.91 0.0596 0.0018 0.4423 0.019 373.2 40.4 363.0 10.9
 Y2-GP091_1 30 126 59 2.1 0.0597 0.0025 0.4499 0.043 373.6 57.5 380.8 24.3
 Y2-GP091_22 30 225 163 1.4 0.0598 0.0043 0.4488 0.033 374.1 97.8 370.4 21.2
 Y2-GP091_3 30 265 78 3.4 0.0600 0.0028 0.4425 0.025 375.6 63.1 366.0 18.6
 Y2-GP091_21 30 102 68 1.5 0.0600 0.0044 0.4575 0.046 375.9 101.3 367.1 26.1
 Y2-GP091_6 30 229 76 3.0 0.0602 0.0018 0.4472 0.020 377.1 41.1 365.0 18.1
 Y2-GP091_16 30 233 111 2.1 0.0608 0.0040 0.4447 0.037 380.8 92.7 375.9 27.0
 Y2-GP091_25 30 648 127 5.1 0.0610 0.0013 0.4549 0.010 381.8 29.4 374.1 26.2
 Y2-GP091_24 30 460 120 3.8 0.0611 0.0035 0.4571 0.030 382.5 81.4 359.4 9.9
 Y2-GP091_9 30 147 50 2.9 0.0626 0.0036 0.4793 0.045 391.4 85.1 382.5 21.3
 Y2-GP091_2 30 160 39 4.1 0.0742 0.0046 0.6055 0.050 461.6 128.0 381.8 7.7
 *1.0=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
105 
 
 
Table C3: LA-ICP-MS U?Pb zircon data from sample 51225-1 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 51225-1
 51225-1_2 30 337 218 1.5 0.0562 0.0046 0.4205 0.040 352.5 98.9 352.5 28.1
 51225-1_6 30 1295 265 4.9 0.0563 0.0013 0.4209 0.010 352.8 28.7 352.8 8.1
 51225-1_7 30 693 192 3.6 0.0573 0.0029 0.4276 0.022 359.3 63.5 359.3 17.7
 51225-1_4 30 381 147 2.6 0.0575 0.0034 0.4315 0.027 360.2 75.7 360.2 21.0
 51225-1_10 30 279 173 1.6 0.0581 0.0017 0.4346 0.022 363.9 37.8 363.9 10.4
 51225-1_1 30 520 123 4.2 0.0581 0.0024 0.4333 0.022 364.0 53.8 364.0 14.8
 51225-1_17 30 158 150 1.0 0.0581 0.0013 0.4298 0.037 364.2 28.0 364.2 7.7
 51225-1_22 30 430 258 1.7 0.0582 0.0019 0.4340 0.018 364.7 42.8 364.7 11.7
 51225-1_9 30 330 121 2.7 0.0589 0.0021 0.4398 0.020 368.9 46.6 368.9 12.6
 51225-1_12 30 482 166 2.9 0.0590 0.0016 0.4375 0.018 369.6 36.1 369.6 9.8
 51225-1_13 30 487 204 2.4 0.0593 0.0036 0.4427 0.029 371.1 82.2 371.1 22.2
 51225-1_8 30 339 150 2.3 0.0596 0.0038 0.4412 0.031 373.3 86.9 373.3 23.3
 51225-1_11 30 810 260 3.1 0.0597 0.0014 0.4473 0.011 373.6 32.6 373.6 8.7
 51225-1_24 30 497 196 2.5 0.0597 0.0032 0.4435 0.025 373.8 71.8 373.8 19.2
 51225-1_18 30 400 203 2.0 0.0600 0.0011 0.4426 0.012 375.5 24.0 375.5 6.4
 51225-1_25 30 423 158 2.7 0.0602 0.0017 0.4452 0.016 377.1 39.2 377.1 10.4
 51225-1_14 30 1045 158 6.6 0.0603 0.0016 0.4489 0.013 377.4 36.4 377.4 9.7
 51225-1_21 30 278 112 2.5 0.0604 0.0015 0.4514 0.025 378.2 33.6 378.2 8.9
 51225-1_19 30 324 111 2.9 0.0605 0.0016 0.4489 0.021 378.6 37.4 378.6 9.9
 51225-1_20 30 768 194 4.0 0.0612 0.0023 0.4562 0.019 382.6 53.6 382.6 14.0
 51225-1_15 30 263 94 2.8 0.0634 0.0054 0.4738 0.046 396.4 128.9 396.4 32.5
 51225-1_23 30 443 124 3.6 0.0665 0.0024 0.4984 0.025 415.0 60.4 415.0 14.5
 51225-1_16 30 224 166 1.4 0.0667 0.0086 0.5213 0.092 416.2 216.8 416.2 52.1
 51225-1_3 30 78 53 1.5 0.1810 0.0060 1.8772 0.074 1072.4 350.2 1074.4 42.8
 *1.3=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
106 
 
 
Table C4: LA-ICP-MS U?Pb zircon data from sample 51225-2 
Radiogenic Ratios Age (Ma)
 Spot Size (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 51225-2
 51225-2_2 30 778 163 4.8 0.0559 0.0032 0.4158 0.024 350.7 67.9 358.6 12.7
 51225-2_4 30 641 125 5.1 0.0572 0.0011 0.4286 0.011 358.4 24.4 350.7 19.4
 51225-2_1 30 505 147 3.4 0.0572 0.0021 0.4270 0.019 358.6 45.5 371.9 7.2
 51225-2_5 30 537 129 4.2 0.0577 0.0013 0.4253 0.014 361.6 28.3 358.4 6.8
 51225-2_6 30 452 318 1.4 0.0579 0.0016 0.4304 0.015 362.9 36.2 361.6 7.8
 51225-2_18 30 645 159 4.1 0.0580 0.0011 0.4323 0.012 363.2 24.9 362.9 10.0
 51225-2_21 30 766 133 5.8 0.0580 0.0015 0.4309 0.014 363.4 32.6 380.2 13.4
 51225-2_13 30 368 115 3.2 0.0580 0.0018 0.4345 0.019 363.7 40.6 369.8 7.5
 51225-2_11 30 639 105 6.1 0.0584 0.0012 0.4365 0.011 366.0 27.4 373.5 10.0
 51225-2_19 30 1143 174 6.6 0.0585 0.0007 0.4343 0.008 366.2 16.2 368.9 10.0
 51225-2_10 30 792 96 8.2 0.0589 0.0016 0.4378 0.013 368.9 36.9 366.0 7.5
 51225-2_8 30 401 124 3.2 0.0590 0.0012 0.4374 0.017 369.8 27.6 378.7 7.9
 51225-2_15 30 209 71 2.9 0.0594 0.0011 0.4399 0.025 371.7 24.8 363.7 11.2
 51225-2_3 30 589 217 2.7 0.0594 0.0012 0.4444 0.012 371.9 26.8 383.3 25.9
 51225-2_9 30 161 135 1.2 0.0597 0.0016 0.4456 0.028 373.5 37.3 371.7 6.7
 51225-2_17 30 683 140 4.9 0.0597 0.0014 0.4441 0.015 374.1 32.3 377.1 7.9
 51225-2_24 30 561 206 2.7 0.0602 0.0019 0.4485 0.015 376.7 42.7 374.1 8.6
 51225-2_16 30 484 137 3.5 0.0602 0.0013 0.4494 0.014 377.1 29.8 363.2 6.9
 51225-2_12 30 572 157 3.6 0.0605 0.0013 0.4466 0.016 378.7 29.8 366.2 4.4
 51225-2_23 30 676 208 3.2 0.0606 0.0012 0.4529 0.013 379.0 28.0 385.4 25.5
 51225-2_7 30 472 169 2.8 0.0608 0.0022 0.4533 0.023 380.2 50.9 363.4 9.0
 51225-2_14 30 213 140 1.5 0.0613 0.0043 0.4529 0.044 383.3 99.2 379.0 7.4
 51225-2_20 30 911 244 3.7 0.0616 0.0042 0.4615 0.032 385.4 98.3 376.7 11.3
 51225-2_22 30 326 167 2.0 0.0818 0.0036 0.6462 0.031 506.6 109.1 506.6 21.5
 51225-2_25 30 547 131 4.2 0.1254 0.0058 1.2081 0.057 761.6 253.0 761.6 33.2   
 
 
 
 
 
 
 
 
 
 
107 
 
 
Table C5: LA-ICP-MS U?Pb zircon data from sample Y2-JU096 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y2-JU096
 Y2-JU096_14 30 771 428 1.8 0.0499 0.0039 0.3737 0.032 313.9 75.7 364.7 15.8
 Y2-JU096_7 30 582 315 1.8 0.0523 0.0048 0.3917 0.039 328.8 96.2 354.1 16.8
 Y2-JU096_8 30 626 303 2.1 0.0530 0.0017 0.3967 0.016 332.7 35.1 370.2 10.6
 Y2-JU096_11 30 391 264 1.5 0.0532 0.0084 0.4034 0.066 334.2 172.7 362.1 10.6
 Y2-JU096_13 30 297 137 2.2 0.0542 0.0036 0.4004 0.029 340.3 74.7 369.5 12.9
 Y2-JU096_24 30 264 159 1.7 0.0563 0.0051 0.4253 0.041 353.1 110.3 328.8 29.2
 Y2-JU096_2 30 467 218 2.1 0.0565 0.0028 0.4234 0.026 354.1 59.5 332.7 10.6
 Y2-JU096_10 30 721 444 1.6 0.0575 0.0017 0.4263 0.014 360.1 37.4 366.7 6.6
 Y2-JU096_25 30 382 320 1.2 0.0577 0.0043 0.4314 0.036 361.7 94.2 360.1 10.4
 Y2-JU096_22 30 475 315 1.5 0.0577 0.0019 0.4295 0.019 361.8 42.2 334.2 51.7
 Y2-JU096_23 30 472 271 1.7 0.0578 0.0011 0.4284 0.012 362.0 25.2 371.2 17.8
 Y2-JU096_4 30 360 205 1.8 0.0578 0.0017 0.4370 0.021 362.1 38.2 340.3 21.9
 Y2-JU096_15 30 335 187 1.8 0.0581 0.0020 0.4318 0.018 364.2 45.4 313.9 24.1
 Y2-JU096_21 30 650 372 1.8 0.0582 0.0032 0.4320 0.025 364.7 70.2 364.2 12.5
 Y2-JU096_1 30 617 414 1.5 0.0582 0.0026 0.4310 0.023 364.7 57.7 368.1 9.9
 Y2-JU096_9 30 407 190 2.1 0.0585 0.0011 0.4327 0.015 366.7 24.2 389.0 15.5
 Y2-JU096_16 30 209 145 1.4 0.0588 0.0016 0.4381 0.024 368.1 36.6 364.7 19.2
 Y2-JU096_6 30 258 98 2.6 0.0590 0.0021 0.4412 0.020 369.5 47.8 361.8 11.7
 Y2-JU096_3 30 342 186 1.8 0.0591 0.0017 0.4466 0.021 370.2 39.3 362.0 7.0
 Y2-JU096_12 30 288 131 2.2 0.0593 0.0029 0.4346 0.025 371.2 66.2 353.1 31.2
 Y2-JU096_20 30 394 187 2.1 0.0622 0.0026 0.4836 0.029 389.0 60.3 361.7 26.1
 *1.0=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
108 
 
 
Table C6: LA-ICP-MS U?Pb zircon data from sample Y1-AW039 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-AW039
 Y1-AW039_11 30 171.969 61.19063 2.8104 0.0429 0.0024 0.3158 0.027 270.7 40.6 350.5 22.9
 Y1-AW039_14 30 616.761 58.70103 10.507 0.0441 0.0073 0.3162 0.055 278.3 125.2 351.3 20.8
 Y1-AW039_25 30 508.902 109.7093 4.6386 0.0512 0.0026 0.3801 0.021 322.2 51.8 395.4 29.1
 Y1-AW039_1 30 403.55 84.76941 4.7606 0.0559 0.0037 0.4180 0.030 350.5 80.2 363.5 9.9
 Y1-AW039_2 30 139.42 82.12934 1.6976 0.0560 0.0034 0.4179 0.039 351.3 73.2 377.0 8.9
 Y1-AW039_10 30 350.907 97.519 3.5983 0.0577 0.0025 0.4326 0.022 361.5 55.5 370.5 13.0
 Y1-AW039_24 30 154.451 127.1083 1.2151 0.0579 0.0019 0.4337 0.026 363.0 42.8 365.2 13.6
 Y1-AW039_4 30 396.191 95.67819 4.1409 0.0580 0.0016 0.4328 0.017 363.5 36.0 372.6 10.0
 Y1-AW039_18 30 282.262 117.0235 2.412 0.0581 0.0029 0.4377 0.037 364.1 64.1 382.0 17.7
 Y1-AW039_7 30 107.181 65.46837 1.6371 0.0583 0.0022 0.4353 0.039 365.2 49.5 361.5 15.3
 Y1-AW039_21 30 163.014 64.3179 2.5345 0.0587 0.0028 0.4389 0.033 367.4 62.4 270.7 15.0
 Y1-AW039_23 30 459.21 119.5613 3.8408 0.0587 0.0026 0.4372 0.021 367.6 58.5 429.9 49.8
 Y1-AW039_13 30 112.775 76.05766 1.4828 0.0591 0.0019 0.4361 0.044 370.0 41.8 370.0 11.3
 Y1-AW039_6 30 441.756 159.7709 2.7649 0.0592 0.0021 0.4431 0.018 370.5 48.2 415.3 62.0
 Y1-AW039_8 30 425.782 233.7478 1.8215 0.0595 0.0016 0.4453 0.021 372.6 37.1 278.3 45.0
 Y1-AW039_17 30 174.381 122.5009 1.4235 0.0597 0.0031 0.4450 0.037 373.7 71.2 373.7 19.0
 Y1-AW039_5 30 443.732 105.4176 4.2093 0.0602 0.0015 0.4506 0.014 377.0 33.5 364.1 17.6
 Y1-AW039_9 30 83.8121 55.15553 1.5196 0.0611 0.0029 0.4440 0.064 382.0 67.7 367.4 17.0
 Y1-AW039_22 30 260.262 107.2714 2.4262 0.0630 0.0038 0.4650 0.036 393.6 90.9 393.6 23.1
 Y1-AW039_3 30 197.892 84.02775 2.3551 0.0633 0.0048 0.4738 0.042 395.4 115.1 367.6 15.9
 Y1-AW039_14 30 293.144 101.0806 2.9001 0.0665 0.0103 0.4892 0.077 415.3 257.4 363.0 11.8
 Y1-AW039_12 30 355.994 93.1319 3.8225 0.0690 0.0083 0.5126 0.062 429.9 214.0 322.2 16.1
 *1.1=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
109 
 
 
Table C7: LA-ICP-MS U?Pb zircon data from sample Y1-IG053 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-IG053
 Y1-IG053_23 30 214 92 2.3 0.0536 0.0088 0.3982 0.095 336.8 180.8 349.7 16.9
 Y1-IG053_17 30 246 180 1.4 0.0547 0.0023 0.4122 0.034 343.1 47.4 368.1 9.2
 Y1-IG053_20 30 170 67 2.5 0.0548 0.0041 0.4364 0.061 343.8 85.6 365.5 11.9
 Y1-IG053_22 30 293 151 1.9 0.0556 0.0031 0.4232 0.041 348.9 65.5 391.2 15.4
 Y1-IG053_1 30 170 76 2.2 0.0557 0.0028 0.4107 0.042 349.7 58.9 382.7 8.8
 Y1-IG053_10 30 152 127 1.2 0.0562 0.0048 0.4250 0.053 352.5 103.2 367.1 7.2
 Y1-IG053_18 30 189 118 1.6 0.0568 0.0022 0.4258 0.034 356.3 48.1 373.8 28.8
 Y1-IG053_21 30 235 184 1.3 0.0570 0.0022 0.4254 0.038 357.4 47.2 382.4 21.7
 Y1-IG053_14 30 242 126 1.9 0.0570 0.0025 0.4184 0.022 357.6 54.0 358.6 30.9
 Y1-IG053_9 30 353 196 1.8 0.0572 0.0051 0.4247 0.039 358.6 110.7 352.5 29.3
 Y1-IG053_12 30 110 56 2.0 0.0577 0.0025 0.4069 0.087 361.4 55.9 375.3 15.1
 Y1-IG053_16 30 329 159 2.1 0.0581 0.0044 0.4384 0.044 364.1 97.2 361.4 15.5
 Y1-IG053_3 30 473 291 1.6 0.0583 0.0020 0.4330 0.020 365.5 43.5 427.9 17.6
 Y1-IG053_6 30 367 333 1.1 0.0586 0.0012 0.4226 0.025 367.1 26.6 357.6 15.1
 Y1-IG053_15 30 245 160 1.5 0.0586 0.0029 0.4366 0.030 367.1 65.4 367.1 17.8
 Y1-IG053_2 30 241 213 1.1 0.0588 0.0015 0.4311 0.022 368.1 33.8 364.1 26.7
 Y1-IG053_19 30 271 103 2.6 0.0588 0.0017 0.4338 0.024 368.5 38.2 343.1 13.8
 Y1-IG053_7 30 489 323 1.5 0.0597 0.0047 0.4482 0.038 373.8 107.8 356.3 13.5
 Y1-IG053_11 30 136 74 1.8 0.0599 0.0025 0.4518 0.052 375.3 56.7 368.5 10.4
 Y1-IG053_8 30 428 268 1.6 0.0611 0.0036 0.4554 0.035 382.4 83.0 343.8 24.9
 Y1-IG053_5 30 282 130 2.2 0.0612 0.0015 0.4632 0.034 382.7 33.8 357.4 13.2
 Y1-IG053_24 30 378 273 1.4 0.0615 0.0025 0.4475 0.029 385.0 59.6 348.9 18.8
 Y1-IG053_4 30 374 148 2.5 0.0626 0.0025 0.4636 0.024 391.2 60.2 336.8 53.7
 Y1-IG053_13 30 249 140 1.8 0.0686 0.0029 0.5066 0.036 427.9 75.4 385.0 15.5
 *0.9=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
110 
 
 
Table C8: LA-ICP-MS U?Pb zircon data from sample Y1-AW049 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-AW049
 Y1-AW049_8 30 441 272 1.6 0.0550 0.0049 0.4191 0.050 344.9 103.2 371.6 12.0
 Y1-AW049_15 30 721 421 1.7 0.0556 0.0014 0.4140 0.013 348.5 29.0 367.6 15.0
 Y1-AW049_23 30 436 277 1.6 0.0556 0.0022 0.4126 0.024 349.1 47.7 371.6 32.7
 Y1-AW049_18 30 171 114 1.5 0.0558 0.0035 0.3980 0.042 349.8 75.1 369.3 8.4
 Y1-AW049_12 30 247 238 1.0 0.0562 0.0046 0.4158 0.046 352.3 98.0 392.9 44.0
 Y1-AW049_9 30 241 120 2.0 0.0569 0.0036 0.4254 0.038 357.0 78.8 344.9 29.9
 Y1-AW049_11 30 183 95 1.9 0.0570 0.0028 0.4308 0.045 357.2 61.0 357.0 22.1
 Y1-AW049_13 30 682 221 3.1 0.0571 0.0025 0.4284 0.021 358.0 54.2 360.1 22.5
 Y1-AW049_25 30 254 111 2.3 0.0572 0.0060 0.4173 0.068 358.5 132.2 357.2 17.1
 Y1-AW049_10 30 549 164 3.4 0.0575 0.0037 0.4239 0.029 360.1 81.0 352.3 27.8
 Y1-AW049_4 30 182 130 1.4 0.0587 0.0025 0.4345 0.052 367.6 55.2 358.0 15.1
 Y1-AW049_6 30 637 199 3.2 0.0590 0.0014 0.4392 0.012 369.3 31.1 348.5 8.3
 Y1-AW049_5 30 310 127 2.4 0.0593 0.0054 0.4409 0.050 371.6 121.6 374.6 21.8
 Y1-AW049_1 30 243 182 1.3 0.0593 0.0020 0.4382 0.027 371.6 44.5 349.8 21.5
 Y1-AW049_17 30 753 290 2.6 0.0598 0.0036 0.4459 0.030 374.6 81.5 411.5 30.1
 Y1-AW049_24 30 159 92 1.7 0.0602 0.0033 0.4484 0.049 376.6 75.9 378.0 25.6
 Y1-AW049_20 30 85 51 1.7 0.0604 0.0042 0.4612 0.077 378.0 96.6 382.7 48.9
 Y1-AW049_21 30 830 153 5.4 0.0612 0.0081 0.4421 0.061 382.7 187.2 349.1 13.7
 Y1-AW049_7 30 208 90 2.3 0.0628 0.0073 0.4835 0.074 392.9 172.8 376.6 20.2
 Y1-AW049_19 30 164 128 1.3 0.0659 0.0050 0.5000 0.064 411.5 124.0 358.5 36.9
 *0.9=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
111 
 
 
Table C9: LA-ICP-MS U?Pb zircon data from sample 10CY-035 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 10CY035
 10CY-035_23 30 917 63 14.6 0.0174 0.0011 0.1158 0.009 111.2 7.9 296.4 9.1
 10CY-035_14 30 1948 191 10.2 0.0177 0.0006 0.1193 0.004 113.1 4.0 294.0 10.3
 10CY-035_10 30 1205 107 11.3 0.0183 0.0005 0.1224 0.005 117.0 3.9 287.5 17.9
 10CY-035_20 30 582 8 70.9 0.0183 0.0008 0.1214 0.007 117.0 6.1 366.6 16.4
 10CY-035_21 30 771 17 46.7 0.0281 0.0012 0.1950 0.010 178.6 13.6 367.3 23.8
 10CY-035_4 30 647 204 3.2 0.0456 0.0029 0.3354 0.023 287.5 51.5 348.5 16.6
 10CY-035_3 30 483 109 4.4 0.0467 0.0017 0.3440 0.018 294.0 30.2 304.0 12.2
 10CY-035_1 30 929 111 8.4 0.0470 0.0015 0.3430 0.011 296.4 26.8 117.0 3.3
 10CY-035_9 30 851 114 7.5 0.0483 0.0020 0.3553 0.016 304.0 37.0 386.4 33.3
 10CY-035_25 30 841 18 46.5 0.0484 0.0041 0.3590 0.030 304.9 76.7 359.2 39.0
 10CY-035_19 30 544 55 10.0 0.0495 0.0013 0.3670 0.018 311.5 24.7 363.2 14.4
 10CY-035_8 30 152 77 2.0 0.0555 0.0027 0.4078 0.046 348.5 57.9 113.1 3.5
 10CY-035_12 30 635 310 2.0 0.0573 0.0064 0.4286 0.049 359.2 140.0 379.9 8.6
 10CY-035_24 30 2518 437 5.8 0.0574 0.0011 0.4311 0.011 360.0 24.6 311.5 7.9
 10CY-035_13 30 92 66 1.4 0.0580 0.0024 0.4252 0.047 363.2 52.2 117.0 5.2
 10CY-035_5 30 530 249 2.1 0.0585 0.0027 0.4371 0.022 366.6 60.0 178.6 7.6
 10CY-035_7 30 1210 391 3.1 0.0586 0.0039 0.4340 0.029 367.3 87.6 111.2 7.1
 10CY-035_18 30 1513 514 2.9 0.0607 0.0014 0.4522 0.011 379.9 32.7 360.0 6.8
 10CY-035_11 30 527 289 1.8 0.0618 0.0055 0.4625 0.043 386.4 128.6 304.9 25.2
 *1.1=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
112 
 
 
Table C10: LA-ICP-MS U?Pb zircon data from sample Y1-MJ075 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-MJ075
 Y1-MJ075_15 30 388 319 1.2 0.0172 0.0012 0.1177 0.013 110.0 8.2 110.0 7.5
 Y1-MJ075_9 30 712 665 1.1 0.0176 0.0006 0.1159 0.007 112.4 4.6 112.4 4.1
 Y1-MJ075_7 30 587 351 1.7 0.0177 0.0015 0.1227 0.019 112.8 10.7 112.8 9.5
 Y1-MJ075_5 30 555 346 1.6 0.0180 0.0005 0.1280 0.015 114.9 3.5 114.9 3.0
 Y1-MJ075_18 30 668 789 0.8 0.0180 0.0019 0.1227 0.020 115.2 13.9 115.2 12.1
 Y1-MJ075_13 30 472 307 1.5 0.0189 0.0007 0.1268 0.014 120.9 5.1 120.9 4.2
 Y1-MJ075_20 30 475 190 2.5 0.0191 0.0015 0.1303 0.014 122.1 11.6 122.1 9.5
 Y1-MJ075_12 30 574 342 1.7 0.0233 0.0013 0.1575 0.012 148.4 11.9 148.4 8.0
 Y1-MJ075_19 30 1088 90 12.1 0.0375 0.0042 0.2756 0.032 237.2 61.5 237.2 25.9
 Y1-MJ075_6 30 491 68 7.2 0.0509 0.0060 0.4132 0.050 320.2 117.5 320.2 36.7
 Y1-MJ075_1 30 306 183 1.7 0.0561 0.0018 0.4229 0.021 351.6 39.3 351.6 11.2
 Y1-MJ075_14 30 163 99 1.6 0.0565 0.0024 0.4133 0.029 354.0 50.2 354.0 14.2
 Y1-MJ075_17 30 295 128 2.3 0.0576 0.0045 0.4275 0.045 361.2 99.8 361.2 27.6
 Y1-MJ075_8 30 211 121 1.7 0.0751 0.0020 0.5913 0.038 466.7 54.7 466.7 11.7
 Y1-MJ075_2 30 384 38 10.1 0.2401 0.0149 3.1317 0.208 1387.2 1066.6 1520.1 46.1
 *1.0=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
113 
 
 
Table C11: LA-ICP-MS U?Pb zircon data from sample Y1-IG073 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-IG073
 Y1-IG073_20 30 268 20 13.1 0.0516 0.0094 0.3865 0.077 324.5 187.6 376.2 13.9
 Y1-IG073_09 30 375 36 10.4 0.0534 0.0027 0.3994 0.029 335.2 54.3 359.3 20.4
 Y1-IG073_05 30 128 64 2.0 0.0554 0.0034 0.3979 0.046 347.7 73.7 379.4 12.1
 Y1-IG073_11 30 249 59 4.2 0.0558 0.0029 0.4122 0.036 350.3 62.4 369.9 12.0
 Y1-IG073_08 30 317 38 8.3 0.0559 0.0048 0.4062 0.040 350.5 101.6 347.7 21.2
 Y1-IG073_24 30 77 48 1.6 0.0565 0.0041 0.4045 0.085 354.1 87.1 371.5 15.4
 Y1-IG073_14 30 276 197 1.4 0.0566 0.0025 0.4232 0.028 354.7 53.2 356.4 13.6
 Y1-IG073_13 30 525 81 6.5 0.0566 0.0010 0.4208 0.015 355.1 22.7 350.5 29.0
 Y1-IG073_07 30 274 53 5.2 0.0568 0.0023 0.4197 0.028 356.4 48.5 335.2 16.3
 Y1-IG073_22 30 242 65 3.7 0.0571 0.0010 0.4242 0.039 358.0 22.2 371.3 19.8
 Y1-IG073_02 30 127 49 2.6 0.0573 0.0033 0.4208 0.065 359.3 73.3 350.3 17.7
 Y1-IG073_12 30 197 42 4.7 0.0574 0.0018 0.4236 0.034 359.7 40.3 359.7 11.2
 Y1-IG073_19 30 311 58 5.4 0.0574 0.0011 0.4267 0.023 360.0 25.2 355.1 6.3
 Y1-IG073_18 30 112 70 1.6 0.0580 0.0020 0.4361 0.072 363.6 42.9 354.7 15.0
 Y1-IG073_16 30 115 88 1.3 0.0581 0.0023 0.4271 0.044 364.3 52.5 365.7 7.7
 Y1-IG073_15 30 525 75 7.0 0.0584 0.0013 0.4331 0.016 365.7 28.5 364.3 14.4
 Y1-IG073_04 30 173 192 0.9 0.0591 0.0020 0.4532 0.035 369.9 44.4 413.7 38.1
 Y1-IG073_10 30 168 40 4.2 0.0593 0.0032 0.4324 0.053 371.3 73.5 363.6 11.7
 Y1-IG073_06 30 180 39 4.6 0.0593 0.0025 0.4334 0.032 371.5 57.2 360.0 6.9
 Y1-IG073_23 30 111 69 1.6 0.0599 0.0018 0.4276 0.063 374.8 39.7 324.5 57.8
 Y1-IG073_01 30 332 63 5.3 0.0601 0.0023 0.4508 0.032 376.2 51.9 358.0 6.3
 Y1-IG073_03 30 331 24 13.6 0.0606 0.0019 0.4456 0.022 379.4 45.5 374.8 10.6
 Y1-IG073_25 30 818 210 3.9 0.0614 0.0033 0.4581 0.026 383.9 76.8 354.1 24.6
 Y1-IG073_17 30 226 61 3.7 0.0663 0.0064 0.4891 0.059 413.7 158.0 383.9 20.0
 *1.2=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
114 
 
 
Table C12: LA-ICP-MS U?Pb zircon data from sample Y1-IG071 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-IG071
 Y1-IG071_11 30 1032 42 24 0.0165 0.0003 0.1106 0.005 105.5 2.3 425.7 18.2
 Y1-IG071_11 30 1491 57 26 0.0165 0.0004 0.1096 0.004 105.8 2.5 766.1 19.8
 Y1-IG071_3 30 756 17 44 0.0223 0.0024 0.1528 0.020 142.3 21.9 142.3 15.4
 Y1-IG071_9 30 765 7 108 0.0233 0.0009 0.1632 0.008 148.7 8.3 439.2 9.6
 Y1-IG071_25 30 1084 31 35 0.0275 0.0006 0.1918 0.007 175.0 6.7 212.0 9.0
 Y1-IG071_5 30 1142 28 41 0.0334 0.0014 0.2377 0.011 212.0 19.1 358.4 15.9
 Y1-IG071_17 30 624 5 123 0.0410 0.0016 0.2980 0.013 259.3 24.9 321.6 7.2
 Y1-IG071_14 30 673 243 2.8 0.0442 0.0035 0.3238 0.027 279.1 61.4 411.9 19.2
 Y1-IG071_19 30 951 5 194 0.0502 0.0015 0.3686 0.012 315.5 28.4 148.7 5.5
 Y1-IG071_7 30 1068 7 151 0.0512 0.0012 0.3831 0.010 321.6 23.2 334.5 7.7
 Y1-IG071_12 30 933 8 113 0.0514 0.0018 0.3838 0.015 323.1 34.9 105.5 2.2
 Y1-IG071_10 30 1123 12 93 0.0533 0.0013 0.3944 0.010 334.5 25.4 105.8 2.3
 Y1-IG071_16 30 1225 5 272 0.0552 0.0016 0.4084 0.013 346.5 34.7 323.1 10.8
 Y1-IG071_21 30 1139 4 308 0.0556 0.0016 0.4124 0.013 349.1 32.8 364.1 10.8
 Y1-IG071_18 30 911 231 3.9 0.0564 0.0016 0.4248 0.015 353.9 34.7 279.1 21.9
 Y1-IG071_6 30 1032 24 44 0.0572 0.0026 0.4227 0.020 358.4 57.3 579.6 29.2
 Y1-IG071_20 30 406 40 10 0.0580 0.0015 0.4368 0.018 363.4 34.2 346.5 10.0
 Y1-IG071_13 30 421 149 2.8 0.0581 0.0018 0.4269 0.016 364.1 39.3 259.3 9.7
 Y1-IG071_23 30 216 183 1.2 0.0618 0.0027 0.4583 0.031 386.8 64.2 353.9 9.8
 Y1-IG071_8 30 573 13 45 0.0660 0.0032 0.5206 0.026 411.9 79.1 315.5 9.0
 Y1-IG071_1 30 629 59 11 0.0683 0.0030 0.5345 0.024 425.7 77.5 363.4 9.4
 Y1-IG071_4 30 693 45 15 0.0705 0.0016 0.5528 0.015 439.2 42.2 349.1 9.5
 Y1-IG071_15 30 685 143 4.8 0.0941 0.0050 0.7802 0.042 579.6 169.2 386.8 16.6
 Y1-IG071_2 30 235 14 17 0.1262 0.0035 1.1937 0.041 766.1 151.7 175.0 3.7
 *1.0=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
115 
 
 
Table C13: LA-ICP-MS U?Pb zircon data from sample Y1-IG062 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-IG062
 Y1-IG062_1 30 643 7.3 88 0.0159 0.0014 0.1060 0.014 102.0 8.9 102.0 8.8
 Y1-IG062_16 30 1213 6.9 175 0.0205 0.0017 0.1389 0.012 130.6 13.7 352.8 7.2
 Y1-IG062_11 30 1074 10 103 0.0229 0.0008 0.1566 0.008 145.7 7.4 356.8 14.6
 Y1-IG062_24 30 1184 8 144 0.0476 0.0023 0.3482 0.019 299.5 41.5 386.1 23.1
 Y1-IG062_14 30 167 48 3.5 0.0479 0.0046 0.3462 0.049 301.9 84.9 369.1 6.5
 Y1-IG062_4 30 130 27 4.8 0.0563 0.0012 0.4223 0.058 352.8 25.4 369.5 20.7
 Y1-IG062_5 30 788 61 13 0.0569 0.0024 0.4246 0.019 356.8 51.9 359.7 13.8
 Y1-IG062_15 30 1054 41 25 0.0571 0.0012 0.4220 0.011 357.8 26.5 145.7 5.0
 Y1-IG062_10 30 1284 67 19 0.0574 0.0023 0.4244 0.017 359.7 49.5 371.1 11.4
 Y1-IG062_23 30 1865 119 16 0.0580 0.0014 0.4331 0.011 363.3 31.1 365.3 6.6
 Y1-IG062_25 30 1221 52 24 0.0582 0.0011 0.4321 0.012 364.4 25.0 301.9 28.1
 Y1-IG062_13 30 1635 97 17 0.0583 0.0011 0.4340 0.011 365.3 24.3 357.8 7.4
 Y1-IG062_21 30 122 31 3.9 0.0584 0.0031 0.4308 0.067 365.6 69.1 130.6 10.5
 Y1-IG062_7 30 1382 67 21 0.0589 0.0011 0.4390 0.009 369.1 23.9 370.9 12.2
 Y1-IG062_9 30 113 52 2.2 0.0590 0.0034 0.4434 0.059 369.5 76.4 365.6 18.9
 Y1-IG062_17 30 1219 54 23 0.0592 0.0020 0.4398 0.017 370.9 45.4 363.3 8.5
 Y1-IG062_12 30 1395 63 22 0.0593 0.0019 0.4426 0.017 371.1 42.4 299.5 13.9
 Y1-IG062_6 30 240 51 4.7 0.0617 0.0038 0.4628 0.039 386.1 89.4 364.4 6.9
 *0.9=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
116 
 
 
Table C14: LA-ICP-MS U?Pb zircon data from sample Y1-AW038 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-AW038
 Y1-AW038_14 10 1386 29 48 0.0163 0.0005 0.1085 0.004 104.4 3.4 104.4 3.2
 Y1-AW038_6 10 933 27 34 0.0174 0.0009 0.1169 0.006 111.1 6.3 111.1 5.6
 Y1-AW038_2 10 1014 28 36 0.0158 0.0009 0.1051 0.006 100.8 6.0 100.8 5.9
 Y1-AW038_8 10 923 24 39 0.0164 0.0009 0.1090 0.006 104.8 6.3 104.8 6.0
 Y1-AW038_24 10 1091 29 38 0.0181 0.0010 0.1211 0.007 115.5 7.0 115.5 6.1
 Y1-AW038_21 10 526 23 23 0.0161 0.0010 0.1083 0.007 102.7 6.6 102.7 6.4
 Y1-AW038_26 10 1342 31 43 0.0174 0.0011 0.1165 0.007 111.0 7.5 111.0 6.8
 Y1-AW038_22 10 1340 23 59 0.0185 0.0011 0.1234 0.008 117.9 7.9 117.9 6.7
 Y1-AW038_23 10 929 23 40 0.0176 0.0011 0.1176 0.007 112.2 7.8 112.2 6.9
 Y1-AW038_13 10 1013 23 45 0.0180 0.0011 0.1200 0.008 114.7 7.9 114.7 6.9
 Y1-AW038_17 10 1259 30 42 0.0180 0.0012 0.1206 0.008 114.7 8.8 114.7 7.7
 Y1-AW038_9 10 662 15 44 0.0171 0.0015 0.1145 0.010 109.2 10.2 109.2 9.3
 Y1-AW038_1 10 587 28 21 0.0156 0.0022 0.1061 0.015 99.8 14.2 99.8 14.2
 Y1-AW038_25 10 987 28 36 0.0165 0.0007 0.1219 0.036 105.3 4.7 105.3 4.5
 Y1-AW038_12 10 635 27 24 0.0168 0.0006 0.1247 0.038 107.6 4.2 107.6 3.9
 Y1-AW038_18 10 1117 39 28 0.0158 0.0022 0.1450 0.134 100.9 13.9 100.9 13.8
 *1.3=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
117 
 
 
Table C15: LA-ICP-MS U?Pb zircon data from sample Y1-IG070 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-IG070
 Y1-IG070_25 30 711 8 91 0.0160 0.0006 0.1052 0.010 102.4 3.7 108.0 4.0
 Y1-IG070_2 30 1868 81 23 0.0164 0.0005 0.1099 0.004 104.9 3.5 104.9 3.4
 Y1-IG070_22 30 483 17 28 0.0165 0.0008 0.1054 0.011 105.5 5.6 107.0 3.3
 Y1-IG070_7 30 795 17 48 0.0165 0.0004 0.1154 0.011 105.8 2.9 108.3 2.3
 Y1-IG070_24 30 1091 38 29 0.0166 0.0005 0.1111 0.007 105.9 3.6 111.5 3.5
 Y1-IG070_8 30 1089 44 25 0.0166 0.0007 0.1085 0.010 106.0 4.9 105.8 2.7
 Y1-IG070_16 30 553 16 34 0.0166 0.0006 0.1079 0.009 106.1 4.2 106.0 4.6
 Y1-IG070_9 30 440 17 26 0.0166 0.0004 0.1131 0.016 106.2 2.6 106.2 2.4
 Y1-IG070_18 30 1119 45 25 0.0167 0.0005 0.1105 0.006 106.5 3.5 108.8 3.1
 Y1-IG070_15 30 849 22 39 0.0167 0.0005 0.1099 0.009 106.5 3.3 106.5 3.1
 Y1-IG070_21 30 1900 83 23 0.0167 0.0005 0.1130 0.006 106.7 3.5 106.1 3.9
 Y1-IG070_3 30 976 37 27 0.0167 0.0005 0.1120 0.006 107.0 3.5 106.5 3.3
 Y1-IG070_1 30 1306 40 33 0.0169 0.0006 0.1131 0.007 108.0 4.3 108.1 4.1
 Y1-IG070_20 30 684 25 27 0.0169 0.0007 0.1115 0.009 108.1 4.5 106.7 3.3
 Y1-IG070_5 30 1425 23 62 0.0169 0.0004 0.1190 0.009 108.3 2.4 105.5 5.3
 Y1-IG070_23 30 1167 33 35 0.0169 0.0008 0.1136 0.008 108.3 5.6 108.3 5.2
 Y1-IG070_11 30 1232 41 30 0.0170 0.0005 0.1157 0.005 108.8 3.4 105.9 3.4
 Y1-IG070_6 30 1224 16 76 0.0174 0.0006 0.1159 0.006 111.5 3.9 102.4 3.6
 *0.9=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
118 
 
 
Table C16: LA-ICP-MS U?Pb zircon data from sample Y1-AE033 
Radiogenic Ratios Age (Ma)
 Spot Size (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-AE033
 Y1-AEO33-5R 10 2050 16 129 0.0157 0.0007 0.1048 0.005 20.7 0.6 100.5 4.3
 Y1-AEO33-10R 10 1922 14 136 0.0159 0.0003 0.1059 0.004 20.7 0.7 101.7 1.8
 Y1-AEO33-11C 10 832 8 100 0.0159 0.0014 0.1065 0.010 20.6 0.4 101.8 8.9
 Y1-AEO33-12R 10 1869 12 154 0.0160 0.0005 0.1063 0.004 20.7 0.5 102.2 3.4
 Y1-AEO33-3C 10 1423 10 142 0.0160 0.0006 0.1054 0.005 20.9 0.5 102.3 4.0
 Y1-AEO33-15R 10 2121 11 189 0.0160 0.0005 0.1068 0.005 20.7 0.6 102.3 2.9
 Y1-AEO33-2R 10 1865 11 166 0.0161 0.0008 0.1066 0.006 20.8 0.5 102.8 4.8
 Y1-AEO33-13R 10 1940 11 180 0.0162 0.0005 0.1087 0.005 20.5 0.6 103.5 3.2
 Y1-AEO33-3R 10 1803 14 127 0.0162 0.0006 0.1076 0.004 20.7 0.5 103.6 3.5
 Y1-AEO33-16R 10 2128 10 204 0.0162 0.0006 0.1071 0.006 20.9 0.8 103.7 3.6
 Y1-AEO33-8R 10 810 27 30 0.0162 0.0003 0.1068 0.003 20.9 0.4 103.8 2.0
 Y1-AEO33-22R 10 515 10 53 0.0168 0.0006 0.1139 0.006 20.3 0.7 107.3 3.6
 Y1-AEO33-7C 10 550 12 44 0.0171 0.0002 0.1134 0.002 20.7 0.4 109.1 1.1
 Y1-AEO33-4R 10 572 5 126 0.0172 0.0009 0.1252 0.019 18.9 2.8 110.0 5.5
 Y1-AEO33-18R 10 851 6 148 0.0173 0.0012 0.1468 0.080 16.3 8.8 110.8 7.7
 Y1-AEO33-19R 10 640 7 90 0.0174 0.0005 0.1746 0.009 13.7 0.6 111.1 3.3
 Y1-AEO33-21R 10 710 5 134 0.0176 0.0006 0.1187 0.007 20.4 1.0 112.2 4.0
 Y1-AEO33-14R 10 857 14 61 0.0179 0.0019 0.1488 0.043 16.6 4.5 114.3 12.2
 Y1-AEO33-17R 10 1463 39 38 0.0185 0.0008 0.2745 0.048 9.3 1.6 118.1 5.3
 *0.9=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
119 
 
 
Table C17: LA-ICP-MS U?Pb zircon data from sample 10CY-039 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 10CY-039
 10CY039_120 10 1028 14 71 0.0160 0.0004 0.1066 0.003 102.0 2.5 106.2 4.9
 10CY039_18 10 575 12 49 0.0163 0.0007 0.1084 0.005 104.2 4.8 104.4 3.4
 10CY039_2 10 568 25 23 0.0163 0.0005 0.1091 0.004 104.4 3.5 106.3 7.1
 10CY039_8 10 500 7.4 67 0.0164 0.0007 0.1100 0.005 105.0 4.5 108.7 11.5
 10CY039_15 10 1500 11 135 0.0165 0.0008 0.1095 0.006 105.2 5.4 106.5 9.1
 10CY039_13 10 582 16 36 0.0165 0.0009 0.1109 0.006 105.8 5.9 107.5 4.2
 10CY039_25 10 521 10 54 0.0166 0.0008 0.1124 0.006 106.1 5.2 106.5 4.9
 10CY039_1 10 541 8.9 61 0.0166 0.0008 0.1105 0.006 106.2 5.2 105.0 4.3
 10CY039_3 10 397 7.6 52 0.0166 0.0011 0.1121 0.008 106.3 7.5 106.7 7.7
 10CY039_5 10 724 16 44 0.0167 0.0014 0.1112 0.010 106.5 9.6 110.0 5.5
 10CY039_7 10 748 11 69 0.0167 0.0008 0.1111 0.006 106.5 5.2 107.9 4.0
 10CY039_9 10 611 15 41 0.0167 0.0012 0.1118 0.008 106.7 8.2 114.5 4.4
 10CY039_6 10 671 14 47 0.0168 0.0007 0.1125 0.005 107.5 4.5 105.8 5.6
 10CY039_11 10 727 17 42 0.0169 0.0006 0.1126 0.005 107.9 4.3 110.5 5.8
 10CY039_4 10 498 14 37 0.0170 0.0018 0.1133 0.012 108.7 12.5 105.2 5.1
 10CY039_19 10 510 19 26 0.0170 0.0008 0.1177 0.009 109.0 5.5 104.2 4.6
 10CY039_23 10 482 20 24 0.0172 0.0010 0.1153 0.007 110.0 6.9 109.0 5.0
 10CY039_10 10 446 6 77 0.0172 0.0009 0.1151 0.006 110.0 6.1 102.0 2.5
 10CY039_14 10 651 14 45 0.0173 0.0009 0.1641 0.025 110.5 6.4 110.8 6.6
 10CY039_24 10 458 9 53 0.0173 0.0010 0.1156 0.007 110.7 7.2 110.0 6.3
 10CY039_22 10 554 10 55 0.0173 0.0010 0.1161 0.007 110.8 7.4 110.7 6.5
 10CY039_12 10 586 10 61 0.0179 0.0007 0.1196 0.005 114.5 5.1 106.1 4.9
 *2.2= Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
120 
 
 
Table C18: LA-ICP-MS U?Pb zircon data from sample Y1-AE051 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-AE051
 Y1AE051_14 10 703 25 28 0.0149 0.0006 0.0998 0.004 95.6 3.5 106.4 1.6
 Y1AE051_1 10 946 52 18 0.0155 0.0006 0.1182 0.006 99.3 3.5 95.6 3.7
 Y1AE051_12 10 913 57 16 0.0156 0.0007 0.1037 0.005 100.0 4.7 110.7 4.0
 Y1AE051_18 10 718 23 31 0.0157 0.0009 0.1052 0.006 100.4 5.5 108.6 4.4
 Y1AE051_8 10 375 7 51 0.0157 0.0009 0.1205 0.058 100.6 5.7 100.0 4.7
 Y1AE051_13 10 961 56 17 0.0159 0.0009 0.1062 0.006 101.5 5.9 101.8 4.6
 Y1AE051_16 10 1113 43 26 0.0159 0.0007 0.1066 0.005 101.8 4.7 101.9 5.1
 Y1AE051_10 10 612 17 35 0.0159 0.0008 0.1082 0.006 101.9 5.2 110.3 5.2
 Y1AE051_25 10 583 25 23 0.0160 0.0013 0.1094 0.010 102.1 8.4 100.4 5.5
 Y1AE051_4 10 843 50 17 0.0162 0.0008 0.1117 0.008 103.7 5.6 108.4 5.4
 Y1AE051_11 10 548 17 32 0.0163 0.0011 0.1081 0.008 104.4 7.2 104.8 5.0
 Y1AE051_5 10 983 51 19 0.0164 0.0008 0.1091 0.006 104.8 5.2 99.3 3.6
 Y1AE051_21 10 424 12 36 0.0164 0.0009 0.1086 0.007 104.9 6.2 101.5 5.8
 Y1AE051_24 10 755 34 22 0.0166 0.0003 0.1115 0.003 106.4 1.7 104.9 6.0
 Y1AE051_19 10 604 5 131 0.0169 0.0022 0.1132 0.015 107.7 14.7 103.7 5.4
 Y1AE051_3 10 1170 68 17 0.0170 0.0009 0.1140 0.006 108.4 5.9 104.4 6.9
 Y1AE051_22 10 557 10 58 0.0170 0.0007 0.1129 0.005 108.6 4.8 102.1 8.2
 Y1AE051_7 10 746 37 20 0.0171 0.0010 0.1290 0.037 109.1 6.6 112.7 12.3
 Y1AE051_23 10 691 30 23 0.0172 0.0007 0.1210 0.019 109.9 5.2 107.7 13.6
 Y1AE051_15 10 1102 7 168 0.0173 0.0011 0.1221 0.020 110.3 7.7 109.9 4.7
 Y1AE051_20 10 563 18 32 0.0173 0.0008 0.1146 0.006 110.3 5.8 110.3 7.0
 Y1AE051_2 10 1033 44 23 0.0173 0.0006 0.1157 0.004 110.7 4.4 109.1 6.1
 Y1AE051_17 10 1150 9 125 0.0176 0.0019 0.1181 0.013 112.7 13.9 100.6 5.7
 *1.2=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
121 
 
Table C19: LA-ICP-MS U?Pb zircon data from sample Y1-AE064 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-AE064
 Y1-AE064_25 10 649 19 35 0.0147 0.0007 0.0983 0.005 94.3 4.3 94.3 4.6
 Y1-AE064_22 10 548 24 23 0.0151 0.0017 0.1017 0.012 96.9 10.5 96.9 10.9
 Y1-AE064_3 10 717 28 26 0.0157 0.0006 0.1054 0.005 100.4 4.1 100.4 4.1
 Y1-AE064_13 10 976 30 32 0.0157 0.0011 0.1041 0.007 100.6 6.9 100.6 6.8
 Y1-AE064_7 10 441 21 21 0.0158 0.0006 0.1048 0.005 100.8 4.1 100.8 4.0
 Y1-AE064_2 10 680 25 27 0.0159 0.0008 0.1056 0.005 101.9 4.9 101.9 4.8
 Y1-AE064_1 10 692 26 26 0.0160 0.0008 0.1056 0.006 102.0 5.4 102.0 5.3
 Y1-AE064_14 10 599 31 19 0.0161 0.0009 0.1072 0.006 103.2 5.9 103.2 5.7
 Y1-AE064_4 10 354 25 14 0.0161 0.0006 0.1078 0.006 103.2 3.8 103.2 3.7
 Y1-AE064_16 10 411 18 23 0.0162 0.0012 0.1085 0.009 103.7 8.0 103.7 7.8
 Y1-AE064_19 10 497 22 23 0.0162 0.0010 0.1070 0.007 103.7 6.9 103.7 6.6
 Y1-AE064_24 10 680 33 20 0.0163 0.0007 0.1122 0.009 104.2 4.4 104.2 4.3
 Y1-AE064_6 10 814 33 25 0.0163 0.0008 0.1089 0.006 104.5 5.4 104.5 5.2
 Y1-AE064_18 10 423 35 12 0.0164 0.0010 0.1221 0.008 105.1 6.7 105.1 6.3
 Y1-AE064_21 10 601 32 19 0.0165 0.0008 0.1102 0.006 105.2 5.4 105.2 5.2
 Y1-AE064_15 10 803 33 25 0.0165 0.0006 0.1100 0.004 105.6 4.1 105.6 3.9
 Y1-AE064_8 10 610 12 52 0.0165 0.0008 0.1108 0.006 105.6 5.5 105.6 5.2
 Y1-AE064_10 10 428 32 13 0.0165 0.0009 0.1124 0.013 105.7 6.3 105.7 6.0
 Y1-AE064_5 10 449 28 16 0.0165 0.0004 0.1101 0.004 105.8 3.0 105.8 2.8
 Y1-AE064_12 10 359 23 16 0.0168 0.0009 0.1117 0.007 107.2 6.3 107.2 5.9
 Y1-AE064_23 10 942 16 58 0.0177 0.0020 0.1467 0.096 113.3 14.6 113.3 12.9
 Y1-AE064_9 10 625 34 18 0.0164 0.0023 0.1518 0.100 104.9 15.2 104.9 14.5
 Y1-AE064_20 10 900 12 78 0.0191 0.0007 0.1287 0.005 122.1 5.2 122.1 4.2
 Y1-AE064_17 10 1338 30 45 0.0453 0.0018 0.4035 0.285 285.9 32.6 285.9 11.4
 *0.7=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
122 
 
Table C20: LA-ICP-MS U?Pb zircon data from sample Y1-IG062 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 Y1-IG052
 Y1-IG052_24 10 495.585 19.86456 24.948 0.0149 0.0009 0.0986 0.006 95.5 5.2 95.5 5.4
 Y1-IG052_13 10 488.597 16.55435 29.515 0.0153 0.0007 0.1031 0.006 97.8 4.3 97.8 4.4
 Y1-IG052_20 10 298.438 9.073079 32.893 0.0155 0.0007 0.1032 0.005 99.1 4.6 99.1 4.7
 Y1-IG052_23 10 448.381 21.70993 20.653 0.0156 0.0011 0.1134 0.029 100.0 7.3 100.0 7.3
 Y1-IG052_9 10 432.231 16.44661 26.281 0.0158 0.0011 0.1057 0.007 101.2 6.8 101.2 6.7
 Y1-IG052_16 10 409.409 23.18697 17.657 0.0158 0.0005 0.1054 0.004 101.3 3.4 101.3 3.4
 Y1-IG052_4 10 387.278 16.96091 22.834 0.0159 0.0006 0.1077 0.004 101.6 3.8 101.6 3.7
 Y1-IG052_6 10 401.374 19.13053 20.981 0.0159 0.0009 0.1049 0.006 101.6 5.8 101.6 5.7
 Y1-IG052_10 10 402.287 16.70144 24.087 0.0161 0.0010 0.1065 0.007 102.9 6.5 102.9 6.3
 Y1-IG052_7 10 613.899 10.74514 57.133 0.0162 0.0006 0.1146 0.006 103.7 4.0 103.7 3.9
 Y1-IG052_5 10 434.494 19.09688 22.752 0.0163 0.0007 0.1093 0.006 104.0 4.7 104.0 4.5
 Y1-IG052_18 10 359.288 16.72064 21.488 0.0164 0.0011 0.1093 0.008 104.8 7.2 104.8 6.9
 Y1-IG052_19 10 537.838 10.92955 49.21 0.0167 0.0005 0.1105 0.005 106.5 3.6 106.5 3.4
 Y1-IG052_11 10 240.487 7.289655 32.99 0.0167 0.0010 0.1135 0.007 106.6 6.5 106.6 6.1
 Y1-IG052_1 10 594.762 12.68342 46.893 0.0181 0.0006 0.1210 0.004 115.9 4.4 115.9 3.8
 Y1-IG052_2 10 965.646 6.397825 150.93 0.0224 0.0044 0.1555 0.030 143.0 39.3 143.0 27.5
 Y1-IG052_21 10 327.6 117.994 2.7764 0.0865 0.0046 0.7025 0.039 534.9 146.5 534.9 27.4
 *1.1=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
123 
 
Table C21: LA-ICP-MS U?Pb zircon data from sample 10CY-024 
Radiogenic Ratios Age (Ma)
 Spot S ize (?m) U (ppm) Th (ppm) U/Th 206Pb/238U 2? 207Pb/235U 2? 206/207 Pb 2? 206Pb/238U 2?
 10CY024
 10CY024_4 30 416 517 0.81 0.0143 0.0010 0.1032 0.035 19.3 5.1 101.9 5.6
 10CY024_6 30 321 431 0.75 0.0158 0.0005 0.1020 0.024 21.4 2.9 102.0 3.9
 10CY024_1 30 339 415 0.82 0.0159 0.0009 0.1141 0.031 21.3 2.7 105.6 8.1
 10CY024_2 30 351 458 0.77 0.0159 0.0006 0.1026 0.014 19.1 6.3 91.3 6.3
 10CY024_7 30 510 350 1.46 0.0159 0.0006 0.1171 0.026 21.4 4.3 108.3 4.4
 10CY024_17 30 106 159 0.67 0.0160 0.0013 0.1080 0.055 21.3 4.9 100.9 3.4
 10CY024_25 30 282 790 0.36 0.0163 0.0010 0.1080 0.021 18.8 4.1 102.0 3.8
 10CY024_15 30 157 248 0.63 0.0164 0.0016 0.1273 0.042 20.9 4.6 106.2 4.0
 10CY024_3 30 337 496 0.68 0.0165 0.0013 0.1070 0.016 19.0 4.7 106.1 4.7
 10CY024_14 30 391 537 0.73 0.0166 0.0009 0.1072 0.020 24.1 18.2 107.2 12.8
 10CY024_24 30 155 179 0.87 0.0166 0.0019 0.0947 0.051 19.4 3.1 117.2 21.0
 10CY024_9 30 257 371 0.69 0.0166 0.0007 0.1203 0.030 18.4 13.7 108.0 12.5
 10CY024_8 30 403 537 0.75 0.0166 0.0006 0.1095 0.025 18.6 5.2 110.7 7.1
 10CY024_10 30 137 114 1.20 0.0168 0.0020 0.0957 0.073 21.3 3.9 105.9 5.8
 10CY024_18 30 153 369 0.42 0.0168 0.0018 0.0879 0.041 17.8 5.6 104.9 9.9
 10CY024_12 30 105 35 2.99 0.0169 0.0020 0.1263 0.095 20.5 3.2 108.1 8.9
 10CY024_16 30 238 655 0.36 0.0169 0.0014 0.1138 0.020 20.5 10.3 102.6 8.2
 10CY024_5 30 372 823 0.45 0.0169 0.0007 0.1091 0.023 26.3 12.0 107.2 11.2
 10CY024_13 30 214 141 1.52 0.0173 0.0011 0.1281 0.037 20.9 8.6 120.4 11.0
 10CY024_11 30 437 516 0.85 0.0183 0.0033 0.1307 0.032 24.2 12.6 106.1 11.8
 10CY024_22 30 109 167 0.65 0.0189 0.0017 0.1245 0.052 20.8 3.8 104.1 6.2
 *1.2=Systematic error of 206Pb/238U age based on Sri Lankan standard   
 
 
 
 
 
 
 
 
 
 
 
 
124 
 
Appendix D: Box and Whisker Plots 
 
 Figure D1: Box and whisker plots of zircon ages  
 
 
 
 
 
 
 
 
 
125 
 
 
 Figure D1: Continued 
 
 
 
 
 
 
 
 
 
 
 
 
126 
 
 
 Figure D1: Continued 
 
 
 
 
 
 
 
 
 
 
 
 
127 
 
 
 Figure D1: Continued 
 
 
 
 
 
 
 
 
 
 
 
 
128 
 
Appendix E: U?Pb Concordia Plots and Age Histograms 
 Figure E1:  U?Pb Concordia plots and age histograms for Ford Granodiorite samples 
 
129 
 
 Figure E1:  Continued 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
130 
 
 Figure E2:  U?Pb Concordia plots and age histograms for Devonian orthogneiss 
samples 
 
 
 
 
131 
 
 
  
Figure E2: Continued 
 
 
 
  
Figure E3:  U?Pb Concordia plots and age histograms for Cretaceous orthogneiss 
sample 
 
 
 
 
 
 
132 
 
  
Figure E4: U?Pb Concordia plots and age histograms for Devonian diatexite samples 
 
 Figure E5: U?Pb Concordia plots and age histograms for Devonian granite sample 
 
133 
 
 Figure E6: U?Pb Concordia plots and age histograms for Cretaceous granite samples 
 
134 
 
  
Figure E6: Continued 
 
 
 
 
 
135 
 
 Figure E6: Continued 
 
 
 
 Figure E7: U?Pb Concordia plots and age histograms for Cretaceous microgranite 
samples 
 
 
 
 
 
 
 
 
 
 
136 
 
Appendix F: Standard Reproducibility 
 Figure F1: 390ng load of SRM 987 standard 87Sr/86Sr ratios over 12 month period. 
Error bars are 2? analytical uncertainty.  
 Figure F2: 1000ng load of Ames Nd standard 143Nd/144Nd ratios over a 12 month 
period. Error bars are 2? analytical uncertainty.  
 
137 
 
 Figure F3: 87Sr/86Sr ratios of USGS standard G-2 over a period of 12 months. Solid 
black line is the average 87Sr/86Sr and the dashed black lines are 2 sigma standard 
error of the average.  
 
 Figure F4: 143Nd/144Nd ratios of USGS standard G-2 over a period of 12 months. 
Solid black line is the average 143Nd/144Nd and the dashed black lines are 2 sigma 
standard error of the average.  
 
138 
 
Table F1: Sr?Nd isotope composition of USGS standard G-2 
Date Rb?(ppm) 2? Sr?(ppm) 2? Rb/Sr 87Rb/86Rb
 87Sr/86Sr 2? Sm?(ppm) 2? Nd?(ppm) 2? Sm/Nd
 147Sm/144Nd 143Nd/144Nd 2? ?Nd
 G?2 1701 4781 0.3556 0.7097702 0.0000162 7.21 551 0.1309 0.5122282 0.0000062 ?8.0
 G?2_1 12/22/2012 171.0 493.7 0.3463 1.002 0.709762 0.000017 7.102 52.19 0.1361 0.08226 0.512230 0.000007 ?8.0
 G?2_2 3/20/2013 174.2 496.2 0.3511 1.016 0.709772 0.000018 7.279 53.18 0.1369 0.08275 0.512263 0.000028 ?7.3
 G?2_3 3/21/2013 166.7 492.1 0.3387 0.9799 0.709821 0.000017 7.133 52.62 0.1356 0.08195 0.512249 0.000006 ?7.6
 G?2_4 3/21/2013 168.1 491.5 0.3419 0.9893 0.709747 0.000016 7.192 52.43 0.1372 0.08292 0.512244 0.000009 ?7.7
 G?2_5 6/5/2013 162.9 483.9 0.3367 0.9740 0.709803 0.000026 7.048 52.46 0.1344 0.08122 0.512250 0.000032 ?7.6
 G?2_6 6/27/2013 163.6 482.1 0.3394 0.9820 0.709797 0.000017 7.124 52.84 0.1348 0.08150 0.512226 0.000010 ?8.0
 G?2_7 9/18/2013 166.6 482.3 0.3455 0.9995 0.709670 0.000021 7.106 52.78 0.1346 0.08094 0.512237 0.000007 ?7.8
 Average 9/18/2013 167.6 3.0 488.8 4.4 0.3428 0.992 0.709767 0.000038 7.141 0.056 52.64 0.24 0.1356 0.08193 0.512243 0.000010 ?7.7  1Gladney et al., 1998 
2Weis et al., 2006 
 
139 
 
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