摘要
胶东南部沿海中生代断裂花岗质岩浆带包含了五个岩石系列。根据各岩石系列的Rb-Sr全岩和矿物等吋线年龄(122—220Ma)可将它们划分为三个岩浆亚旋回(三叠纪、晚侏罗世和早白垩世)。利用锶同位素提供的信息与华北地区太古代变质岩系进行对比,并结合地球物理研究成果讨论各岩石系列的源区,强调岩浆是分别来自上地幔顶部和地壳深部麻粒岩相及角闪岩相岩石的部分熔融。
Developed in the southeast coast of the East Shandong peninsula, the Mesozoic fault-granitic magma belt consists of five rock series: the syenite series; the monzonite series; the megaporph-yritic monzonitic-granitic series; the biotite-granite series; and the alkali granite series. Based on their Rb-Sr isochron ages (122-220Ma), these rock series may be divided into three magma su-bcycles dated at Triassic, Late Jurassic and Early Cretaceous.The initial 87Sr/86Sr ratios in these rock eries range from 0.70436 to 0.7155. The starting points of the Rb-Sr isochrons exhibit four different distribution trends on the (87Sr/86Sr)i-87Rb/86Sr diagram. These characteristics show that the multiple granitic rock series are different in genesis and derivation. The syenite series might be derived from the combination of mantle-derived magma and crustal material, and the oners could be derived from granulite-facies and amphibolite-facies rocks in the deep crust.
出处
《地球化学》
CAS
CSCD
北大核心
1992年第3期265-272,共8页
Geochimica
基金
国家自然科学基金
