摘要:
本文根据黄陵地体、神农架地体和武当地体在沉积建造、岩石组合、变质作用、岩浆活动特点,现有同位素地质年龄及古地磁资料,进行了详细分析与区域性对比。并运用板块构造理论,对上述三个地体从元古代到中生代时期,在中国二个古板块运移过程中,它们发生离散和拼合的演化历史。还指出本区的地震活动带的分布,是受地体之间的沉陷带或地体内部深断裂的控制。
Abstract:
1.The characteristics of three outliers in western Hubei The Huangling terrane,dated at 1981 Ma,is an Archean-Proterozoic upper amphibolite-facies terrane,which has a superposition relationship with the Shennong terrane.The Shennong terrane,dated at 1332 Ma.is represented by a sequence of neritic sedimentary rocks,dominated by Proterozoic magnesian carbonate rocks which have been slightly metamorphosed.The Wudang terrane, dated at 1336 Ma,is a lower-upper greenschist-facies terrane consisting mainly of basic-acid volcanic-sedimentary rocks. 2.The convergence of terranes By the end of the Proterozoic,the Huangling terrane,Shennong terrane and Wudang terrane drifted and converged along the Sichuan old land,covered by Sinian and lower Archean. 3.Continental dispersion Continental dispersion resulted in the formation of fractured depressions such as the Nanyang-Xiaugfan-Dongting fractured depression.The three above- mentioned terranes were split and dispersed,causing the blocks of various sizes to move eastwards,forming the Yangpo terrane,Dagu terrane and Tong- bai terrane. 4.The contact zones and juncture zones of the terranes are composed of migmatites and late Proterozoic,Paleozoic,Mesozoic and Cenozoic sediments. The fractured depressions and faults within the terranes are closely related to seismie activity.
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