滇西古特提斯造山带的威尔逊旋回：岩浆活动记录和深部过程讨论  

Wilson Cycle of the Paleo-Tethyan Orogenic Belt in Western Yunnan:Record of Magmatism and Discussion on Mantle Processes

作　　者：张旗[1] 周德进[1] 赵大升[1] 彭兴阶 罗万林 刘祥品 

机构地区：[1]中国科学院地质研究所,云南省地质矿产局第三地质大队

出　　处：《岩石学报》1996年第1期17-28,共12页Acta Petrologica Sinica

基　　金：国家自然科学基金

摘　　要：滇西古特提斯造山带威尔逊旋回的岩浆活动记录保存在昌宁－孟连带和金沙江－哀牢山带及其周围地区。在大陆拉张阶段，思茅地块之下的大陆岩石圈地幔是明显亏损的，指示它已经历过一次或几次部分熔融事件。洋盆阶段的ＭＯＲＢ源于强烈亏损的大洋岩石圈地幔源区，但与地幔柱发生广泛的混合作用，与现代印度洋脊下的大洋岩石圈地幔相似。从俯冲阶段到碰撞阶段，大陆地幔则变得越来越富集。文中还讨论了滇西古特提斯大陆岩石圈地幔和大洋岩石圈地幔的性质以及大陆岩石圈地幔转化为大洋岩石圈地幔的过程，推测板块扩张的起因可能与下地幔的活动有关。It is discovered that the magmatic activity records on Wilson cycle from Plaeo-Tethyan orogenic in western Yunnan are well preserved in Changning - Menglian and Jinshajiang-Ailaoshan suture zonesand their surrounding areas. In continental extensional stage, the continental lithospheric mantle (CLM) under Simao Massif was distinctly depleted in εNd, showing that the CLM has undergone one or more events of partial melting. It may indicate that there is not old crystalline basement under Simao Massif during the PaleoTethyan. The MORB was derived from strongly depleted oceanic lithospheric mantle (OLM) in the oceanic basin stage here, but the mixing of plume with depleted asthenospheric mantle was extensive and similar to that of recent OLM under the Indian Ocean ridge. The mantle became more enriched in Nd isotopes from subduction stage to collision one. In the paper the authors also discuss the characteristics of CLM and OLM and trasform process from CLM to OLM in Paleo-Tethyan orogenic belt in western Yunnan and suggest that the spreading of plate is probably caused by action of the lower mantle material at first.

关 键 词：岩浆活动 深部过程 威尔逊旋回 古特提斯 

分 类 号：P542.2[天文地球—构造地质学] P588.11[天文地球—地质学]