SiO2 & CaO-SiO2
The new end-members in this subsystem are high tridymite, high cristobalite, stishovite and larnite--bredigite. High cristobalite and high tridymite are fitted to the experiments of Ostrovsky (1966) and Jackson (1976), while data for stishovite are derived from the experiments of Zheng et al. (1996) and constrained by the calorimetry of Liu et al. (1996). Data for larnite--bredigite have been retrieved from the experiments of Zharikov & Shmulovich (1969).
Coesite enthalpy is now fitted to the experiments of Bose & Ganguly (1995), which lie at slightly higher pressure than those of Bohlen & Boettcher (1982), but are similar to the new experimental data of Theye et al. (1997).
Quartz is now treated with a pressure-dependent Landau tricritical model and so explicit use of alpha and beta quartz, as in HP90, is no longer required.
The calcite--aragonite equilibrium is now fitted over an extended temperature range (80--1100°C), using the experiments of Johannes & Puhan (1971) and Irving & Wyllie (1975). A Landau model for carbonate group rotational disordering was used for calcite, following Redfern et al. (1989); to prevent extreme curvature on the PT boundary, a similar Landau excess had to be added to the free energy of aragonite.
All equilibria involving wollastonite, pseudowollastonite, tilleyite, spurrite and rankinite are well fitted by the data set, with the exception of the cc + q = wo + CO2 experiments of Greenwood (1967) and Harker & Tuttle (1956). The calculated curve marginally misses the brackets of Zhu, Newton & Kleppa (1994) for this same reaction by 0.1 kbar.
1) diam = gph (Kennedy & Kennedy, 1976)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 47.0 46.0 1100 -2.10 -1.95 46.83 0.98 3 (-2.24 <-> -1.90)
0 - 50.0 49.0 1200 -2.13 -1.98 49.61 1.00 cH = -2.07 (sd 0.07)
0 - 53.0 52.0 1300 -2.17 -2.03 52.31 1.01 within bracket
0 - 56.0 54.0 1400 -2.23 -1.95 54.88 1.02 uH = 0.14, d/s = 0.2, h = 1.00
0 - 58.0 57.0 1500 -2.17 -2.03 57.32 1.03
0 - 60.0 59.0 1600 -2.13 -1.99 59.60 1.05
2) q = trd (Ostrovsky, 1966)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 0.0 864 870 4.14 4.15 867 12 2 (4.14 <-> 4.16)
0 - 1.0 1040 1090 4.10 4.18 1070 12 cH = 4.15 (sd 0.01)
within bracket
uH = 0.01, d/s = 0.6, h = 0.98
3) trd = crst (Ostrovsky, 1966)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 0.0 1465 1475 0.70 0.70 1468 12 2 (0.69 <-> 0.70)
0 - 1.0 1220 1260 0.68 0.70 1257 12 cH = 0.70 (sd 0.00)
within bracket
uH = 0.00, d/s = 0.5, h = 1.00
4) q = crst (Ostrovsky, 1966; Jackson, 1976)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 2.2 1.6 1300 4.90 5.05 0.24 2.44 0.06 2 (4.85 <-> 4.91)
0 - 7.0 1730 4.43 2040 16 cH = 4.84 (sd 0.01)
0 - 5.0 1690 4.85 1684 14 too low but OK
uH = 0.02, d/s = -1.3, h = 0.02
5) coe = q (Bose & Ganguly, 1995)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 27.6 26.9 500 -5.37 -5.24 27.55 0.58 3 (-5.51 <-> -5.24)
0 - 28.4 27.6 600 -5.46 -5.30 27.93 0.58 cH = -5.37 (sd 0.05)
0 - 29.0 28.3 700 -5.48 -5.34 28.41 0.59 within bracket
0 - 29.8 29.0 800 -5.53 -5.37 -0.00 29.00 0.60 uH = 0.11, d/s = 0.0, h = 0.95
0 - 30.3 29.6 900 -5.49 -5.34 29.70 0.61
0 - 31.1 29.9 1000 -5.48 -5.24 30.52 0.62
0 - 31.7 30.9 1100 -5.41 -5.25 31.46 0.63
0 - 32.6 31.8 1200 -5.38 -5.21 32.53 0.64
* coe = q (Bohlen & Boettcher, 1982; Gasparik, 1984)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 24.9 24.5 400 -4.90 -4.82 2.37 27.27 0.57 ** NOT USED **
0 - 25.7 25.3 500 -5.00 -4.92 1.85 27.55 0.58 cH = -5.37 (sd 0.05)
0 - 26.6 26.1 600 -5.10 -5.00 1.33 27.93 0.58
0 - 27.3 26.7 700 -5.14 -5.02 1.11 28.41 0.59
0 - 28.1 27.7 800 -5.18 -5.10 0.90 29.00 0.60
0 - 28.8 28.4 900 -5.18 -5.10 0.90 29.70 0.61
0 - 29.9 29.4 1000 -5.24 -5.13 0.62 30.52 0.62
0 - 31.1 30.6 1100 -5.29 -5.18 0.36 31.46 0.63
6) stv = coe (Zheng et al., 1996)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 90.6 87.0 1100 -31.14 -29.22 88.15 2.13 3 (-30.99 <-> -28.67)
0 - 93.2 90.4 1200 -30.76 -29.28 91.45 2.15 cH = -29.84 (sd 0.57)
0 - 96.3 93.0 1300 -30.61 -28.89 94.82 2.17 within bracket
0 - 97.6 1430 -28.97 1381 64 uH = 0.98, d/s = 0.7, h = 0.61
0 - 100.4 1530 -28.61 1462 64
7) arag = cc (Johannes & Puhan, 1971; Crawford & Hoersch, 1972)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 4.1 70 90 -0.08 -0.00 31 121 14 5 (0.04 <-> 0.19)
0 - 5.0 160 200 0.04 0.21 178 12 cH = 0.11 (sd 0.03)
0 - 7.0 280 320 0.07 0.26 289 12 within bracket
0 - 9.0 380 420 0.08 0.28 387 12 uH = 0.04, d/s = -1.0, h = 0.95
0 - 11.0 460 500 0.03 0.23 477 10
0 - 13.0 540 580 -0.00 0.20 562 10
0 - 15.0 600 640 -0.11 0.10 3 643 10
8) arag = cc (Irving & Wyllie, 1973)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 20.0 19.0 800 -0.02 0.16 19.25 0.31 3 (-0.04 <-> 0.16)
0 - 25.6 24.7 950 -0.15 -0.01 -0.80 23.90 0.35 cH = 0.11 (sd 0.03) 2
0 - 30.5 29.5 1100 -0.00 0.13 29.64 0.41 within bracket
uH = 0.09, d/s = -0.1, h = 0.05
9) wo = pswo (Osborne & Shairer, 1941; Huang & Wyllie, 1975)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 0.0 1115 1135 6.34 6.41 1124 16 1 (6.34 <-> 6.40)
0 - 22.0 21.0 1550 6.32 6.40 21.37 0.69 cH = 6.37 (sd 0.03)
within bracket
uH = 0.03, d/s = 1.1, h = 0.99
10) cc = lime + CO2 (Smyth & Adams, 1923; Baker, 1962)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 0.0 930 950 176.81 179.51 947 6 3 (178.92 <-> 180.81)
0 1 0.0 1035 1065 178.91 182.62 1036 6 cH = 179.09 (sd 0.37)
0 1 0.0 1065 1095 179.42 183.05 -3 1062 6 within bracket
0 1 0.0 1140 1160 178.30 180.57 1147 6 uH = 0.68, d/s = 0.1, h = 0.54
0 1 0.0 1210 1230 178.66 180.81 1214 6
0 1 0.0 1230 1250 179.13 181.26 1230 6
11) cc + q = wo + CO2 (Zhu, Newton & Kleppa, 1993)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 2.3 1.9 700 88.66 90.51 -0.07 1.83 0.08 3 (89.49 <-> 90.50)
0 1 3.1 2.7 750 89.25 90.77 -0.02 2.68 0.10 cH = 90.86 (sd 0.20)
0 1 4.1 3.8 800 89.45 90.41 -0.14 3.66 0.12 too high but OK
0 1 5.2 4.9 850 89.63 90.46 -0.14 4.76 0.13 uH = 0.43, d/s = 0.9, h = 0.36
12) cc + q = wo + CO2 (Jacobs & Kerrick, 1981)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 0.86 6.0 870 890 90.30 91.61 879 6 1 (90.34 <-> 91.56)
0 1 6.0 890 915 90.18 91.77 901 6 cH = 90.86 (sd 0.20)
within bracket
uH = 0.44, d/s = 1.5, h = 0.15
* cc + q = wo + CO2 (Ziegenbein & Johannes, 1974)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 2.0 690 710 89.24 90.80 1 711 6 ** NOT USED **
0 1 4.0 790 810 89.07 90.46 6 816 6 cH = 90.86 (sd 0.20)
0 1 6.0 895 915 90.50 91.77 901 6
* cc + q = wo + CO2 (Greenwood, 1967; Harker & Tuttle, 1955)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 1.0 662 685 93.05 95.02 -26 636 4 ** NOT USED **
0 0.69 1.0 640 93.82 -33 607 4 cH = 90.86 (sd 0.20)
0 0.72 1.0 660 95.31 610 4
0 1 2.0 725 750 91.97 93.91 -14 711 6
0 0.80 2.0 700 711 91.77 92.65 -11 689 6
0 0.50 2.0 658 679 91.38 93.16 -6 652 4
0 1 1.0 650 690 92.03 95.45 -14 636 4
0 1 2.0 730 750 92.36 93.91 -19 711 6
0 1 2.7 780 800 92.99 94.46 -29 751 6
13) cc + q = wo + CO2 (Haselton et al., 1978)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 9.3 1000 1015 89.84 90.68 3 1018 8 3 (89.84 <-> 90.99)
0 1 15.0 1175 1200 89.92 91.16 1194 8 cH = 90.86 (sd 0.20) 2
0 1 19.0 1300 1325 90.59 91.75 1306 8 within bracket
0 1 10.2 9.3 1015 89.05 90.68 -0.10 9.20 0.20 uH = 0.49, d/s = 0.1, h = 0.08
14) 3cc + 2wo = ty + CO2 (Zharikov & Shmulovich, 1969)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 0.1 800 830 125.67 128.82 830 6 3 (127.91 <-> 129.11)
0 1 0.2 880 890 127.27 128.23 7 897 6 cH = 128.86 (sd 0.31)
0 1 0.3 950 960 128.34 129.21 956 8 within bracket
0 1 0.4 960 980 128.02 129.69 970 8 uH = 0.51, d/s = -0.1, h = 0.90
0 1 0.5 990 1000 128.17 128.98 998 8
15) ty = spu + CO2 (Zharikov & Shmulovich, 1968)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 0.1 850 860 123.40 124.40 7 867 6 3 (124.17 <-> 125.36)
0 1 0.2 930 940 124.32 125.24 939 6 cH = 125.13 (sd 0.32)
0 1 0.2 950 980 124.28 126.98 959 6 within bracket
0 1 0.3 990 1000 124.14 125.00 1 1001 8 uH = 0.51, d/s = -0.4, h = 0.89
0 1 0.5 1040 1060 124.79 126.44 1044 8
16) spu + 4wo = 3rnk + CO2 (Zharikov & Shmulovich, 1968)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 0.1 850 870 156.80 159.34 867 14 2 (158.07 <-> 159.89)
0 1 0.2 920 940 158.62 161.00 923 14 cH = 158.98 (sd 0.84)
within bracket
uH = 0.65, d/s = 0.6, h = 1.00
17) spu + rnk = 4lrn + CO2 (Zharikov & Shmulovich, 1968)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 0.1 900 910 170.46 171.93 908 10 3 (170.77 <-> 172.50)
0 1 0.1 935 960 170.51 174.10 943 10 cH = 171.64 (sd 0.67)
0 1 0.2 980 1000 169.83 172.60 993 10 within bracket
0 1 0.3 1020 1050 171.08 175.17 1024 10 uH = 0.74, d/s = 0.6, h = 1.00
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