河北平山阜平群两种岩石熔融过程中的矿物相变及成分变化  

Phase Transition and Composition Change of Minerals from Melting Experiment of Two Kinds of Metamorphics in Fuping Group, Pingshan, Hebei Province, China

作　　者：贺义兴[1] 宋书林[1] 

机构地区：[1]长春科技大学,130026

出　　处：《地质学报》1999年第4期315-319,T001,共6页Acta Geologica Sinica

基　　金：国家自然科学基金(编号49872024)

摘　　要：河北平山阜平群浅粒岩和黑云变粒岩-片麻岩熔融高温高压实验结果表明,在开放体系条件下两类岩石深熔作用性质有一定的独特性。主要表现为SiO_2不饱和的非均一局部熔融-再结晶效应。当实验温度为680C时,黑云母与斜长石发生脱水熔融和部分熔融,转换成白云母、绿帘石、铁尖晶石、石英等物质成分;当温度为750～800 C时,上述中间产物和残留黑云母及新生熔体进一步转变为夕线石、铁尖晶石、橄榄石、富Ca斜长石和钛铁晶石组合;而当温度高于830 C时,残留黑云母与斜长石进一步发生深熔作用,形成含单斜辉石新的矿物组合,并出现再结晶产物的分带现象。新生的矿物相Mg、Fe、Ca等随实验温度的升高显示出规律性的变化。该项实验对深入探讨开放体系条件下岩石的熔融行为和矿物相转变机制有着重要的科学意义。A high-T/high-P experiment of melting of leuco-granulitite(lcuco-leptite) and biotite gran-ulitite-gneiss of the Fuping Group in Pingshan, Hebei Province shows that in an open system, the two types of rocks have some unique features of anatexis. They are mainly manifested by SiO2-unsaturated and inhomogeneous local melting-recrystallization. At the temperature of 680 ℃, biotite and plagioclase became dehydrated-melted and partially melted , transformed into muscovite, epidote, hercynite, quartz,etc. ; when t=750-800℃, the above intermediate products as well as the residual biotite and new-born melts were transformed into sillimanite, her-cynite, olivine, Ca-rich plagioclase and ulvospinel assemblages; and when the temperature exceeded 830℃, the residual biotite and plagioclase were further melted to form new assemblages containing clinopyroxene. with the occurrence of zoning of the recrystallized products. The content of Mg,Fe and Ca in the neogenic mineral facies displayed regular variations with rising of the temperature. This experiment is of important scientific significance in further exploring into the melting behaviours of rocks and the transformation mechanism of mineral facies in an open system.

关 键 词：浅粒岩 黑云变粒岩 片麻岩 橄榄石 矿物相变 

分 类 号：P588.345[天文地球—岩石学] P588.346[天文地球—地质学]