一种新的地质压力计——单斜辉石-石英-斜长石-钠钙质角闪石地质压力计  

A New Geobarometer Established on Coexisting Clinopyroxene-Quartz-Plagioglase-Taramite Assemblage

作　　者：王朴[1] 刘嵘[2] 王国灿[2] 

机构地区：[1]中国地质大学研究生院,武汉430074 [2]中国地质大学地球科学学院,武汉430074

出　　处：《地质科技情报》2007年第1期28-32,共5页Geological Science and Technology Information

基　　金：中国地质大学(武汉)地质学理科基地专项基金项目(40334037)

摘　　要：根据超高压岩石的退变质反应20Jd+3Di+H2O=12Ab+2An+Tar+3Na2O和18Jd+3Di+2Aeg+H2O=12Ab+2An+Fe-Tar+3Na2O,利用拟合的绿闪石和铁质绿闪石的热力学数据,在平衡热力学原理的基础上,建立了两个反应的压力计表达式:p=0.001 6(t+273)-0.028lnK+0.321K=(aPlNaAlSi3O8)12·(aPlCaAl2Si2O8)2·aTarNa2CaMg3Al2[Si6Al2O22](OH)2·(aSodNa2O)3(aCNpaxAlSi2O6)20·(aCpxCaMgSi2O6)3·aWatH2O经中国安徽省潜山县双河和西阿尔卑斯高压超高压变质带的验证及与角闪石-斜长石温度计的对比,其计算结果基本合理,表明这一新的压力计具有较好的应用价值。A new geobarometer is established on the two reactions： 20Jd＋3Di＋H2O=12Ab＋2An＋Tar＋3Na2O and 18Jd＋3Di＋2Aeg＋H2O=12Ab＋2An＋Fe-Tar＋3Na2O, which are designed from the corona developing in Jadeite-Quartzite. According to the method of structural estimation, the problem that a series of minerals do not have published experimental thermodynamic properties is solved. The geobaromet- ric formulae for the mineralogic assemblage are presented as well. By comparing the ultrahigh pressure zones between Shuanghe in Qianshan and Western Alps using Am-PI geothermometer and the present geobarometer,the new geobarometer is of potential application.

关 键 词：Cox-Q-Pl-Tar压力计 硬玉石英岩 冠状体 结构拟合法 

分 类 号：P588.34[天文地球—岩石学]