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用电子显微探针和多元线性回归技术研究了蒙大拿西南部 Ruby 地区二个小区各种岩性变质岩中共存石榴石和辉石之间 Fe—Mg 分配的热——成分关系。通过对二个地区的独立变质 P—T 的确定和十三个矿物的分析结果推测共存石榴石——单斜辉石的热——成分关系归纳为下式RT|nKD=(2482±845)+(1509±1392)(X_(Fe)-X_(Mg))~(Ga)+(2810±954)(X_(Ca)~(Gar))+(2855±792)(X_(Mn)~(Gar))式中 K_D=(X_(Fe)/X_(Mg))~(Gar)/(X_(Fe)/X_(Mg))~(Cpx) X=分子数;对于石榴石——单斜辉石的 Fe—Mg 交换反应。2482=2324+0.029=-△G(卡).其系数代表石榴石混合参数回归值(Wy~(Gar))。Ca 和 m_n的回归参数与 Ganguly(1979)的计算值比较一致;可是,W_(Fe)Mg~(Gar)的回归值则界于 Ganguly(1979)与 O′Neill 和 Wood(1979)的计算值之间.对于九个石榴石——斜方辉石来说最适于使用上述公式,则求得石榴石——斜方辉石的 Fe—Mg 交换反应为-△Grp=1391±288卡。根据 Ganguly(1979)和 Saxena(1979)提供的石榴石——单斜辉石地温计。获得 Ruby 地区的变质温度异常地高。如果这一结果是在其它的高级角闪岩相到低级麻粒岩相中观察到的,那么.按照在此提供的石榴石——单斜辉石公式.可以获得比较符合实际的温度。该石榴石——斜方辉石公式能够做为相对的(但不是绝对的)地质温度计应用。
The thermal-component relationships of Fe-Mg distribution between coexisting garnet and pyroxene in various lithologic metamorphic rocks in two plots in Ruby region, southwestern Montana, were studied using electron microprobe and multivariate linear regression techniques. Based on the determination of the independent metamorphic P-T and the analysis results of thirteen minerals in two areas, the thermal-component relationship of coexisting garnet-clinopyroxene is summarized as follows: RT | nKD = (2482 ± 845) + + 1509 ± 1392 X - Fe Mg - Ga + 2810 ± 954 X - Ca + Gar 2855 ± 792 X Mn - Gar) where K_D = (Gar) / (X_ (Fe) / X_ (Mg)) ~ (Cpx) X = number of molecules; for garnet-monoclinic Pyroxene Fe-Mg exchange reaction. 2482 = 2324 + 0.029 = - ΔG (card) The coefficients represent the regression values for garnet mixing parameters (Wy ~ (Gar)). The regression coefficients of Ca and m_n are consistent with those of Ganguly (1979); however, the regression values of W_ (Fe) Mg ~ (Gar) are in the range of the calculated values of Ganguly (1979) and O’Neill and Wood (1979) For the nine garnets - orthopyroxene is the most suitable for the use of the above formula, the obtained garnet - orthopyroxene Fe-Mg exchange reaction - △ Grp = 1391 ± 288 card. Based on the garnet-clinopyroxen thermometers provided by Ganguly (1979) and Saxena (1979). The metamorphic temperature in the Ruby region was abnormally high. If this result is observed in other high amphibolite to low-grade granulite facies, a more realistic temperature can be obtained according to the garnet-clinopyroxene formula provided herein. The garnet-orthopyroxene formula can be used as a relative (but not absolute) geothermometer.