胶北荆山群富铝片麻岩的脱水熔融实验研究

STUDY ON THE DEHYDRATION-MELTING EXPERIMENT OF Al-RICH GENISS FROM THE JINGSHAN GROUP IN THE NORTH JIAODONG

通过对胶北荆山群富铝片麻岩块状样品的脱水熔融实验研究表明 ,半开放体系下富铝岩石熔融作用的发生首先表现为含水矿物黑云母的暗化脱水 ,并诱发其他矿物熔融 ,各矿物组分参与熔融的顺序为 :Bi→ Kf→ Pl→ Gt→ Cord→ Sil→ Q。研究发现石榴石这种原认为比较难熔的矿物 ,当其被大量黑云母包围时极易熔融 ,而黑云母脱水并生成一种强腐蚀性流体物质 ,是导致矿物及岩石发生熔融的主要原因。熔体的成分既依附于其周边的矿物相 ,但又有所差异 ,具有多相混熔的特点。实验过程中某些新生结晶矿物的出现表明熔融变质反应的发生可能未必需要很长的时间 ,也未必是在宏观平衡状态下。

The studies on the dehydration melting experiment of Al rich geniss from the Jingshan Group under semi opened system suggest that the melting action begin with dehydrating and darkening of biotites of mineral bearing H 2O, and bring on melting of other minerals.The melting sequence of minerals is: Bi→Kf→Pl→Gt→Cord→Sil→Q .Garnet which usually be considered as hard to melt would become easily melted while they were surrounded by large quantitie of biotite. The composition of melted object is controlled by minerals nearby and shows the characteristics of multiphase melting.It is thought that the strong corrosive fluid induced by biotite dehydration melting is responsible for the melting of rocks and minerals.The forming of some new minerals during the experiment indicates that the melting reaction may neither need a long time nor macroscopic equilibrium state .