西伯利亚碱性花岗岩的等级体制研究——赴原苏联考察报告

AN INTRODUCTION TO THE HIERACHICAL SYSTEM OF ALKALINE GRANITOIDS IN SIBERIA鈥斺€擜 REPORT OF A VISITING RUSSIAN GEOLOGIST

作者于1990年赴苏考察。本文着重介绍苏联地质学家对外贝加尔色楞格—维季姆地区碱性花岚岩的研究情况。该区的碱性岩浆活动分成两个岩套:早二叠世偏碱性花岗岩和正长岩岩套及晚二叠世至三叠纪初碱性花岗岩和正长岩岩套。每一个岩套又包括早期的正长岩韵律和晚期的花岗岩韵律。每一个韵律内部按照岩石的结构特点至少可以分出2～3个顺序的侵入阶段,最后以脉岩活动结束。在每一个岩套内正长岩总是同基性岩在时间上和空间上密切共生。

This paper mainly introduces the study of alkaline granite in the Selenga-Vitim area of Transbaikalia, Siberia, by Russian geoloists. Two suites of alkaline rnagmatism are distinguished: the Early Permian subalkaline granite and syenite suite and the Late Permian to initial Triassic alkaline granite and syenite suite. Each suite includes the carly-stage syenite rhythm and the late-stage granite rhythm. According to the rock textures each rhythm can be subdivided into at least 2-3 sequential intrusion stages. The magmatism ended with the activity of dike rocks. In each suite syenite is always intimately associated with basic rocks in time and space.