摘要
以四川和云南晚二叠世—早三叠世形成的峨嵋山玄武岩和同期形成的龙门山、墨江辉绿玢岩为主要研究对象，结合与勉略、三江蛇绿岩套内的玄武岩的对比，从岩石的化学成分、稀土元素和微量元素的含量和特征比值分析，提出晚古生代扬子陆块西缘的基性岩浆活动经历了由特提斯洋壳俯冲诱发陆块内玄武岩浆的发生、洋壳消减和陆块内大规模玄武岩浆喷发及局部小规模岩浆活动的萎缩消亡３个发展演化阶段．扬子陆块内玄武岩浆主要来源于正常或富集型地幔，在发生和萎缩阶段部分岩浆源自亏损型地幔．扬子陆块西缘晚古生代时期的基性岩浆活动是全球岩石圈构造活动的局域表现，与特提斯洋的俯冲—封闭有直接联系．
Emeishan basalt, Longmenshan diabase_prophyrite, and Mojiang diabase_prophyrite in the Late Permian-Early Triassic are important objects of the present paper. A correlation between the basalt in the Mianlüe ophiolite suite and that in the Sanjiang ophiolite suite can be used to suggest, on the bases of the chemical compositions of the rocks, the contents of the REE and trace elements, and the ratio of special elements in these rocks, that the Late Paleozoic basic magmatic activity in the western margin of Yangtze craton can be divided into three evolutionary stages: (1) basaltic magma in Yangtze continent was induced by the subduction of Tethyan oceanic crust; (2) the basaltic magma erupted on a large scale within the Yangtze craton with the subduction of Tethyan oceanic crust, and (3) the magmatic activity turned weaker and weaker until it was extinct within a limited region. The basaltic magma within the Yangtze craton mainly originated from the normal or concentrated mantle. During the initial and final evolutionary stages, part of magma originated from the depleted mantle. The Late Paleozoic basic magma activity in the western margin of the Yangtze craton must have been part of the tectonic changes of the global lithosphere and, therefore, must have been directly correlated with the subduction of Tethyan oceanic plate.
出处
《地球科学（中国地质大学学报）》
EI
CSCD
北大核心
1999年第3期234-239,共6页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金
关键词
晚古生代
玄武岩浆
稀土元素
微量元素
玢岩
western margin of Yangtze craton
Late Paleozoic
basaltic magma
rare earth element
trace element
Tethys.
