Table S1. Compositions of experimental glasses and secondary glass standards (in wt%)

Run / SiO2 / TiO2 / Al2O3 / FeO* / MnO / MgO / CaO / Na2O / K2O / P2O5 / ZrO2 / BaO / H2O / Sum
MMG1-1 / 70.8(5) / 2.03(7) / 14.1(4) / 1.66(6) / - / 0.33(2) / 1.40(7) / 3.13(9) / 5.22(5) / - / 0.49(6) / - / n.a. / 99.19
MMG2-1 / 69.1(2) / 5.01(11) / 13.93(15) / 1.53(4) / - / 0.31(2) / 1.35(4) / 2.98(19) / 4.83(3) / - / 0.92(8) / - / 0.39 / 100.32
MMG2-2 / 68.6(4) / 4.99(12) / 13.82(10) / 1.51(5) / - / 0.31(2) / 1.34(4) / 2.97(9) / 4.83(5) / - / 0.91(8) / - / 0.49 / 99.82
MMG3-1 / 69.0(3) / 2.75(6) / 15.20(11) / 1.64(5) / - / 0.35(2) / 1.45(4) / 3.23(8) / 5.25(5) / - / 0.85(8) / - / 0.49 / 100.17
MMG4-1 / 69.4(4) / 2.75(7) / 14.89(14) / 1.44(4) / - / 0.33(2) / 1.44(2) / 3.16(8) / 5.14(5) / - / 0.42(10) / - / 0.74 / 99.74
MMG5-1 / 71.8(4) / 1.91(7) / 13.97(12) / 1.57(4) / - / 0.33(1) / 1.42(3) / 3.12(4) / 5.07(6) / - / 0.41(4) / - / 0.40 / 100.03
MMGh1-1 / 66.0(3) / 3.44(8) / 15.41(9) / 1.14(4) / - / 0.33(3) / 1.40(4) / 3.06(18) / 4.98(4) / - / 0.57(7) / - / 3.22 / 99.52
MMGh1-2 / 64.4(4) / 3.50(7) / 14.75(14) / 0.97(5) / - / 0.31(2) / 1.35(5) / 2.98(8) / 4.84(6) / - / 0.67(7) / - / 6.11 / 99.88
MMGh2-1 / 68.2(3) / 1.89(5) / 14.71(15) / 1.02(6) / - / 0.33(2) / 1.41(4) / 3.08(7) / 5.01(4) / - / 0.53(8) / - / 3.57 / 99.69
MMGh3-1 / 66.2(4) / 2.32(4) / 13.75(12) / 0.92(4) / - / 0.32(2) / 1.36(4) / 2.98(8) / 4.84(4) / - / 0.34(6) / - / 6.89 / 99.91
MMGh4-1 / 67.8(5) / 1.88(5) / 13.37(15) / 0.43(4) / - / 0.28(2) / 1.28(4) / 2.87(9) / 4.67(5) / - / 0.28(6) / - / 6.97 / 99.87
MMGh4-2 / 70.6(3) / 1.69(5) / 15.16(11) / 0.61(3) / - / 0.31(1) / 1.38(4) / 3.00(4) / 4.88(4) / - / 0.20(8) / - / 1.50 / 99.33
GO1-1 / 69.8(6) / 4.75(11) / 12.72(11) / 1.53(6) / 0.02(2) / 0.47(2) / 1.23(4) / 2.61(7) / 5.22(6) / 0.08(3) / 0.88(9) / 0.15(6) / 0.44 / 99.90
GO1-2 / 69.3(5) / 4.97(13) / 12.56(8) / 1.35(5) / 0.03(2) / 0.46(2) / 1.18(4) / 2.60(8) / 5.20(5) / 0.07(2) / 0.97(10) / 0.15(8) / 0.66 / 99.54
GO2-1 / 68.9(2) / 1.92(5) / 13.47(11) / 1.40(4) / 0.02(2) / 0.51(2) / 1.29(4) / 2.76(6) / 5.52(4) / 0.08(4) / 1.14(5) / 0.15(5) / 2.56 / 99.70
GO3-1 / 69.1(2) / 3.10(6) / 13.99(8) / 1.21(5) / 0.02(2) / 0.48(2) / 1.34(3) / 2.86(9) / 5.56(3) / 0.09(3) / 0.49(9) / 0.16(6) / 1.50 / 99.88
GO4-1 / 68.0(4) / 1.79(6) / 12.44(14) / 0.95(5) / 0.02(2) / 0.42(2) / 1.18(4) / 2.56(13) / 4.95(6) / 0.05(3) / 0.67(6) / 0.09(6) / 6.68 / 99.82
GO5-1 / 70.7(4) / 1.90(8) / 14.11(10) / 1.15(19) / 0.02(2) / 0.45(2) / 1.36(4) / 2.93(6) / 5.50(6) / 0.07(2) / 0.28(11) / 0.11(6) / 1.58 / 100.17
GO5-2 / 70.0(2) / 1.86(5) / 14.00(9) / 1.45(5) / 0.03(2) / 0.46(3) / 1.36(3) / 2.91(6) / 5.46(4) / 0.06(2) / 0.24(6) / 0.11(7) / 1.93 / 99.87
GO6-1 / 68.3(3) / 0.86(4) / 14.24(8) / 1.19(5) / 0.02(2) / 0.43(2) / 1.31(4) / 2.85(6) / 5.30(5) / 0.05(2) / 0.35(6) / 0.09(5) / 5.25 / 100.25
QS2b-2 / 77.1(3) / 4.02(7) / 10.41(14) / 0.72(2) / - / 0.19(2) / 0.88(3) / 1.80(4) / 3.02(3) / - / 0.61(9) / - / n.a. / 98.80
QS2c-3 / 78.9(3) / 3.93(6) / 9.13(11) / 0.62(3) / - / 0.17(2) / 0.74(2) / 1.70(6) / 2.76(2) / - / 0.62(6) / - / 1.91 / 100.42
QS2d-1 / 80.5(4) / 3.88(7) / 8.63(9) / 0.58(4) / - / 0.16(2) / 0.71(3) / 1.33(4) / 2.41(3) / - / 0.64(8) / - / n.a. / 98.81
QS2d-2 / 80.2(5) / 3.81(6) / 8.00(11) / 0.55(4) / - / 0.17(1) / 0.67(3) / 1.21(4) / 2.25(3) / - / 0.63(6) / - / n.a. / 97.50
QS1a-1 / 75.2(4) / 2.68(7) / 11.95(9) / 1.36(7) / 0.02(1) / 0.41(2) / 1.09(3) / 2.24(15) / 4.66(9) / 0.07(2) / 0.39(7) / 0.15(4) / n.a. / 100.21
QS1c-1 / 74.2(3) / 2.83(8) / 12.26(11) / 1.33(5) / 0.02(2) / 0.40(5) / 1.09(2) / 2.27(8) / 4.54(3) / 0.09(1) / 0.36(5) / 0.13(5) / 0.40 / 99.88
QS2a-1 / 77.3(3) / 2.60(7) / 11.22(11) / 0.80(3) / - / 0.22(1) / 0.98(3) / 1.97(6) / 3.39(4) / - / 0.33(9) / - / n.a. / 98.79
QS2b-1 / 77.5(2) / 2.66(8) / 10.57(11) / 0.72(5) / - / 0.20(6) / 0.87(2) / 1.93(11) / 3.13(2) / - / 0.36(6) / - / 2.09 / 100.03
QS4a-1 / 74.5(4) / 1.78(6) / 12.31(12) / 1.27(4) / 0.01(1) / 0.36(1) / 1.10(3) / 2.36(4) / 4.51(3) / 0.06(3) / 0.26(10) / 0.08(4) / n.a. / 98.61
QS4a-2 / 74.0(3) / 1.78(4) / 12.45(9) / 1.23(4) / 0.01(1) / 0.36(2) / 1.09(3) / 2.35(8) / 4.42(8) / 0.05(2) / 0.23(9) / 0.10(5) / 1.55 / 99.62
QLO-1-1 / 64.5(5) / 2.07(7) / 15.19(14) / 3.50(7) / 0.08(2) / 0.90(3) / 2.86(5) / 3.8(2) / 3.21(4) / 0.23(3) / 1.91(10) / 0.15(6) / 0.31 / 98.37
normalized / 65.2(2) / 2.10(7) / 15.36(11) / 3.54(7) / 0.08(2) / 0.91(3) / 2.89(6) / 3.8(2) / 3.25(4) / 0.23(3) / 1.94(11) / 0.15(6) / 99.48
accepted / 65.47 / 2.14 / 14.86 / 3.57 / 0.08 / 0.92 / 2.91 / 3.86 / 3.31 / 0.23 / 1.99 / 0.14 / 99.48
QLO-1-2 / 65.8(5) / 0.62(4) / 16.11(16) / 3.92(8) / 0.09(3) / 0.98(3) / 3.18(6) / 4.22(18) / 3.56(4) / 0.25(3) / 0.03(3) / 0.17(6) / 0.07 / 98.98
normalized / 66.33(19) / 0.62(3) / 16.23(10) / 3.96(8) / 0.09(3) / 0.99(3) / 3.21(6) / 4.26(18) / 3.59(4) / 0.26(3) / 0.03(3) / 0.17(6) / 99.73
accepted / 66.21 / 0.63 / 16.34 / 3.93 / 0.09 / 1.01 / 3.20 / 4.24 / 3.64 / 0.26 / 0.02 / 0.16 / 99.73

Average experimental glass compositions based on 10 to 20 analyses; values in parentheses represent one standard deviation in terms of the least units cited, e.g., 70.8(5) represents 70.8 ± 0.5; FeO* indicates all Fe as FeO; dashes indicate that the oxide was not explicitly added to the starting mix and was not detected; n.a. indicates that the element was not analyzed; sodium and potassium values in bold italics are based on mass balance, i.e., corrected for alkali migration under the electron microprobe beam (see Supplementary Material for a detailed discussion of the mass balance procedure). On-peak counting times were 20 s for each element (Si through Ba); high- and low-backgrounds were counted for 10 s each. Glass in run QS1b-1 (Table 2, main text) was not analyzed. The average secondary standard glass compositions are based on 164 analyses of QLO-1-1 and 166 analyses of QLO-1-2 collected over the course of this study; the normalized compositions represent the raw oxide values renormalized to the oxide sum of each accepted bulk composition; accepted composition of QLO-1-2 is based on the reported composition of USGS rock powder QLO-1 (Potts et al. 1992) with trace elements converted to oxides and with the sum normalized to 100 wt% and including 0.07 wt% H2O and 0.03 wt% CO2 (volatile content of QLO-1-2 measured by FTIR); the powder was fused in a graphite-Pt capsule at 1 GPa and 1450°C for 4 h. The accepted composition of QLO-1-1 is based on the accepted composition of QLO-1 and the weight fractions of QLO-1, SiO2, TiO2, and ZrO2 that were mixed and fused in a graphite-Pt capsule in the piston cylinder (1 GPa, 1450°C, 4 h); the volatile content of QLO-1-1 is 0.31 wt% H2O and 0.06 wt% CO2 measured by FTIR.