摘要
山西中条山下元古界正变质的基性岩,尤其是胡家峪-上玉坡背斜核部变基性岩,并不象人们一直所认定的完全都是绝县群变基性火山岩,而是具有不同岩石化学及成因矿物学特征的两类不同的变基性岩(变基性火山岩与变基性侵入岩)。岩石的CaO含量、K/Na值、氧化度等,可作为两类岩石的区分标志。基性侵入岩变形变质改造系列中化学元素的变化规律,与变形分解作用有关。其寄主岩石为正变质的基性(偏中性)岩浆岩或辉长岩。变质条件为:温度450～540℃,压力200～500MPa,变质相为高绿片岩相或绿帘角闪岩相。
This paper mainly discusses the aspects of petrochemistry and geneticmineralogy of the Zhongtiaoshan Lower-Proterozoic metabasic pyrolith.By the comparison of petrochemistry, it is found that there are really twodifferent metabasic series-metabasic intrusive series and metabasic vol-canic series. rhe petrochemical elements and parameters such as CaO wt%,K/Na ratio and Fe_2O_3/(Fe_2O_3+FeO) can be considered as the distingui-shing features. The changes of chemical elements of deformational andmetamorphic reworked series have a very close relationship with thepartitioning deformation field. The host rock belongs to metabasic intrusionor metagabbro. The metamorphic condition is: T is 450～540℃, P is 200～500 MPa. Metamorphic facies are high greenschist facies or epidote amphibo-lite facies.
关键词
火成岩
基性岩
变质作用
岩石化学
igneous rock
basic rock
metamorphism
petrochemistry
genetic mineralogy
Shanxi
Zhongtiaoshan
