Appendix 1 Analytical Methods

Appendix 1 – Analytical Methods Major elements Major elements for whole rock powders were obtained by electron microprobe at the Cornell University Center for Materials Research (CCMR) and by Atomic Absorption at SERNAGEOMIN. Rock samples were cut into ~ 1 cm thick slabs and then polished (300 and 450 grit) to remove any metallic residue from the saw blades. Slabs were crushed into small chips and later ground using a corundum-lined (Al2O3) vessel in a shatterbox. Major elements were obtained following methods in Kay et al. (1987) using a three-spectrometer JEOL-733 Superprobe© in WDS mode with a beam diameter of 30 μm, a 15 kV accelerating voltage, and a 20 nA incident current. Microprobe data was reduced using a Tracor-Northern system and Bence-Albee matrix corrections (Albee and Ray 1970). For each sample, an average of five spot analyses were obtained and normalized using correction factors calculated by secondary standard analyses. Smithsonian standards A-99 and JDF (Juan de Fuca glass) and internal standard RHA- Z were each analyzed at the beginning, middle, and end of each session. Only fluxed whole rock glasses were normalized to 100.0 wt %. Error is 2-5 % for major elements with concentrations > 1 wt % and ± 10-20 % for elements with < 1 wt %. The Fe2+/Fe3+ ratio was determined on selected samples by wet chemistry techniques at SERNAGEOMIN.

Trace elements

Trace element data were obtained using Instrumental Neutron Activation Analysis (INAA) at Cornell University and Atomic Absorption Spectroscopy (AAS) at the Chilean Geological Survey (SERNAGEOMIN). Methodology and standard concentration data for selected trace element analyses using INAA are published in Kay et al. (1987). Sample powder (~ 0.5 g) was packed into ultrapure Suprasil® quartz tubing that was pre-cleaned in 6N nitric acid

(HNO3). Eleven samples and 3 internal standards (PAL, SIT, and WBD-2) were irradiated at Ward Laboratory TRIGA reactor at Cornell University. All irradiated samples were counted at Cornell University on an Ortec intrinsic Ge detector both 6 and ~ 40 days post-irradiation. Acceptable in-run statistics were achieved by counting for ~ 3-4 hours per sample with standards counted for ~ 12 hours. Replicate analyses of internal standards yield analytical precision (2σ) of ± 2-7 % for most elements (Kay, et al. 1987).

Isotopic ratios Sr and Nd isotopes were analyzed with a VG Sector 54 Thermal Ionization Mass Spectrometer (TIMS) in the Keck Isotope Lab at Cornell University. Sample preparation and analytical methodology is described by White and Duncan (1996). A ~ 50 mg aliquot of sample powder was leached with 1 mL of hot 6N 2QD HCl for one hour in 15 mL Savillex teflon vessels and subsequently dissolved overnight using 2 ml of HF and ~ 0.1 ml of concentrated perchloric acid (HClO4). Digestions were dried down to liberate SiF6 and twice re-dissolved in 6N HCl to breakdown polyatomic fluorides before being dissolved in 1.15 mL of 2.5N HCl and centrifuged for 10 minutes. Sr and the REE were separated by elution with 2.5N and 6N HCl through AG50W-x12 resin cation exchange columns. Nd elution was accomplished using HDHEP-coated resin and with a 0.16N HCl eluent. Sr and Nd isotopic ratios were normalized to 88Sr/86Sr = 0.1194 and 146Nd/144Nd = 0.7219 respectively. Average isotopic values for Sr standard NBS 987 and Nd standards Ames and La Jolla are given in Table 5. Pb separations were obtained using the technique outlined by White and Dupré (1986) at Cornell University and analyzed at the University of Florida Nu-Plasma multi collector (MC) ICP-MS using the Tl mass-bias normalization technique by Kamenov et al. (2004). A procedural blank spiked with 2.3 mg of 208Pb/206Pb solution yielded 0.654 ng of excess Pb. Sr and Nd isotopic ratios for Incapillo ignimbrite pumices were analyzed by MC-ICPMS at the University of Florida following the methods described by Kamenov et al (2008). Oxygen isotopes were analyzed by ArF laser fluorination on select olivine and quartz mineral grains at the Universität Göttingen following the procedures of Fiebig et al. (1999). Measured values for unknowns were corrected to the average measured value for the Gore Mountain garnet standard (UWG-2, δ18O = 5.7). In run error (2σ) is estimated at ± 0.2 ‰. External precision from repeat analyses averaged ± 0.2-0.5 per mil.

Appendix 2

Represenative major element mineral analyses from Incapillo dome xenoliths and Pircas Negras amphiboles

------am phibole analyses------biotit e analyses------plagioclase analyses------P ircas Negras am phiboles analysis # 29 73 90 85 31 61 44 48 77 97 83 85 type CO512b CO512b CO512b CO512b CO512b CO512b CO512b CO512b CO512b CO512b CO 309-1CO 309-1 sam ple r c r r c c c c c c c r

SiO2 45.24 44.17 47.98 45.64 38.29 38.48 55.38 58.91 56.30 60.91 40.98 42.29

T iO2 1.48 1.74 1.31 1.53 3.15 2.92 0.01 0.00 0.01 0.02 2.92 2.74

Al2O3 9.47 11.56 7.35 9.14 14.65 14.83 28.31 26.32 28.35 24.96 13.36 12.04 FeO 14.05 12.39 14.11 14.75 14.24 11.81 0.21 0.16 0.17 0.23 13.08 10.96 MnO 0.38 0.31 0.39 0.37 0.20 0.16 0.00 0.00 0.00 0.01 0.13 0.10 MgO 13.56 13.93 14.28 13.37 17.50 17.91 0.00 0.02 0.01 0.00 12.60 14.85 CaO 12.09 12.25 12.05 11.96 0.06 0.04 10.25 7.53 10.08 6.03 11.15 11.41

Na2O 1.68 2.01 1.36 1.69 0.72 0.64 5.35 6.60 5.37 7.18 2.70 2.60

K2O 0.82 0.78 0.68 0.75 9.26 9.36 0.34 0.55 0.33 0.82 0.78 0.78

Cr2O3 ------0.01 0.03 Total 98.77 99.14 99.50 99.20 98.07 96.15 99.85 100.10 100.61 100.16 97.72 97.80

Si 6.549 6.345 6.851 6.582 2.790 2.840 2.497 2.628 2.515 2.705 6.001 6.112 T i 0.161 0.188 0.141 0.166 0.173 0.162 0.000 0.000 0.000 0.001 0.322 0.297 1.451 1.655 1.149 1.418 0.210 0.160 1.504 1.384 1.492 1.306 1.999 1.888 Al (iv) 0.165 0.302 0.089 0.136 1.048 1.129 - - - - 0.307 0.162 Al (vi) Fe2+ 1.112 0.988 1.095 1.139 0.867 0.728 0.008 0.006 0.006 0.009 0.966 0.606 Fe3+ 0.589 0.501 0.589 0.640 ------0.635 0.719 Mn 0.046 0.037 0.047 0.045 0.012 0.010 0.000 0.000 0.000 0.000 0.016 0.012 Mg 2.926 2.983 3.039 2.874 1.900 1.970 0.000 0.001 0.001 0.000 2.752 3.200 Ca 1.876 1.887 1.845 1.849 0.004 0.003 0.496 0.360 0.483 0.287 1.750 1.768 0.124 0.113 0.155 0.151 0.102 0.091 0.468 0.571 0.465 0.618 0.250 0.232 Na(B) 0.346 0.446 0.221 0.323 ------0.515 0.497 Na(A) K 0.152 0.142 0.124 0.138 0.861 0.881 0.019 0.032 0.019 0.046 0.146 0.144 Cr ------0.002 0.004 Total 15.699 15.76 15.54 15.68 7.967 7.975 4.993 4.982 4.981 4.973 15.874 15.889 0.498 0.588 0.344 0.461 - - 50.5 37.4 49.9 30.2 (Na + K)A An 0.661 0.641 2.000 2.000 2.000 2.000 - - 47.6 59.3 48.1 64.9 (Ca + Na)B Ab 2.000 2.000 2+ 2+ 0.632 0.667 0.643 0.618 0.69 0.73 2.0 3.3 1.9 4.9 Mg /(Mg +Fe T) Or 0.632 0.707 All unknown mineral analyses were corrected by deviation from Smithsonian standards JDF and A99 and in-house standard RHA. Methods and replicated analyses of USGS secondary standards are reported Goss (2008) relative to published values by Jarosewich et al. (1980). Amphiboles, biotites, and plagioclase phenocrysts were calculated on the basis of 23, 11, and 32 oxygens respectively. An = Anorthite Ab = Albite Or = Orthoclase Appendix 3 Endmember compositions used in Incapillo mixing models source magm a ------crustal assim ilant s------Pircas Negras Average Paleozoic Average UC CO 309 P z G UC

SiO2 61.7 68.8 66.0

T iO2 0.95 0.41 0.50

Al2O3 16.2 14.6 15.2

FeOt 4.83 3.82 4.50 MnO 0.08 0.08 0.08 MgO 2.61 1.29 2.20 CaO 6.46 3.02 4.20

Na2O 4.52 3.60 3.90

K2O 2.51 2.83 3.40

P 2O5 0.36 0.12 0.40 T otal 100.3 98.6 100.4

Sr 899 189 350 Rb 60 113 112 P b 10.5 16.0 20.0 Ba 1057 525 550 La 39.1 23.1 30.0 Nd 38.2 20.1 26.0 Sm 6.7 4.4 4.5 Eu 1.6 1.1 0.9 Yb 0.83 2.31 2.20 Hf 5.8 5.0 5.8 T a 0.69 0.80 2.20 T h 4.9 11.0 10.7 Pircas Negras composition is from Goss and Kay (2009). Major and trace element data for Paleozoic is from Lucassen (2001) and bulk upper crust from Rudnick and Fountain (1995). Ta concentrations for average Paleozoic are calculated from the Nb concentration (15 ppm) using a Nb/Ta ratio of 17.5. Appendix 4 Partition coefficients used in Incapillo EC-AFC mixing models xenolith1 plag-rich2 Paleozoic3 Av. Upper Crust4 plag am ph biot ite m ag K-spar qz zircon crystal/m elt crystal/m elt assim ilant /m e assimilant/m elt Sr 3.40 0.01 0.52 0.01 5.40 - - 0.73 1.43 2.20 2.17 Rb 0.30 0.40 4.20 0.01 1.75 0.011 - 0.52 0.50 0.77 0.96 Pb 0.27 0.30 5.36 0.10 11.45 - - 0.52 0.52 0.55 0.54 Ba 0.53 0.53 0.10 0.71 2.44 0.011 - 0.50 0.49 2.04 2.22 La 0.18 0.31 3.18 0.66 0.08 0.013 16.9 0.41 0.39 0.45 0.60 Nd 0.09 1.20 2.23 0.93 0.04 0.011 13.3 1.01 0.78 0.32 0.43 Sm 0.06 2.00 1.55 1.20 0.025 0.01 14.1 1.56 1.16 0.25 0.32 Eu 0.75 1.90 0.87 0.91 4.45 0.038 16 1.59 1.35 0.99 1.00 Yb 0.10 2.10 0.54 0.44 0.03 0.011 527 1.57 1.15 0.66 0.68 Hf 0.03 0.54 0.60 0.24 0.03 0.017 3193 0.43 0.32 3.33 3.36 Ta 0.3 0.59 1.34 1.2 0.01 0.006 47 0.52 0.41 0.29 0.343 Th 0.01 0.16 1.22 0.01 0.02 0.006 76.8 0.17 0.14 0.28 0.33 Modal abundances: 1Xenolith: amph (70 %), plag (20 %), biotite (4 %), magnetite (3 %), glass (2 %); 2Plag-rich assemblage: amph (50 %), plag (40 %), biotite (4 %), magnetite (3 %), glass (2 %); 3Paleozoic crust: plag (44%), quartz (30 %), biotite (10%), K-spar (13 %), magnetite (2.4 %), zircon (0.1 %); 4Average upper crust: plag (44 %), quartz (27 %), biotite (15 %), K-spar (12 %), magnetite (2.2 %), zircon (0.1 %). Partition coefficients are from Mahood and Hildreth (1983), Bacon and Druitt (1988), Ewart and Griffin (1994), and Nash and Crecraft (1985).

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