琼西戈枕侵入体的地质特征及其发现意义

通过详细的地质调查和综合研究,笔者在海南西部中元古界抱板混合岩中划分出古老的戈枕侵入体,它由花岗闪长岩单元和二长花岗岩单元组成,并以锆石Pb-Pb法测得其中的花岗闪长岩的结晶年龄为1397±46Ma,从而肯定了海南岛存在长城纪变质地层,它应是华夏古陆的一部分。长城纪末的大规模钙碱性花岗岩侵入是一次造山作用的记录,并使抱板群基本固结定型。因而提出了海南克拉通的概念。

THE GEOLOGICAL CHARACTERISTICS OF GEZHEN INTRUSIVE MASS IN WESTERN HAINAN AND ITS SIGNIFICANCE

Investigating regional geology, the author discovered Gezhen old intrusive mass in middle proterozoic Baoban migmatite of western Hainan, which is composed of mon-zonitic granite and granodiorite, and discussed the geological occurence, petrography, accessory minerals and geochemistry of the intrusive mass. The zircon Pb-Pb isochron age of 1397**46 Ma from the- gcanodiorite indicates that in Hainan there exist changcheng metamorphic rocks as a part of Cathaysia. The intrusion of Lime-alkali magma in the end of Changcheng is a record of orogenic movement. Therefore the author Proposed the concept of Hainan Craton.