Characteristics of Paleoproterozoic Subduction System in Western Margin of Yangtze Plate  

作　　者：Zhang Hongxiang Liu Congqiang Xu Zhifang Geology and Geophysics Institute, Chinese Academy of Sciences, Beijing 100101 Huang Zhilong Geochemistry Institute, Chinese Academy of Sciences, Guiyang 550002 

出　　处：《Journal of Earth Science》2000年第1期58-67,共10页地球科学学刊（英文版）

基　　金：Chinese Technology Ministry!95-pre-39program

摘　　要：Paleoproterozoic subduction strongly occurred in the western margin of Yangtze plate. The basalticandesite volcanics of Ailaoshan Group and Dibadu Formation had been formed during paleo QinghaiTibet oceanic plate subduction under the paleoYangtze plate. Their trace element geochemistry suggests that their forming environments are continentalmarginarc and back arcbasin respectively. Consequently, the Paleoproterozoic subduction system in the western margin of Yangtze plate was established. Ailaoshan Group and Dibadu Formation came from an enriched mantle source that was contaminated by crustal sediments carried by subducted slab, and formed the Paleoroterozoic metamorphic basement of western margin of Yangtze plate. Ailaoshan Group is actually western boundary of Yangtze plate.Paleoproterozoic subduction strongly occurred in the western margin of Yangtze plate. The basalticandesite volcanics of Ailaoshan Group and Dibadu Formation had been formed during paleo QinghaiTibet oceanic plate subduction under the paleoYangtze plate. Their trace element geochemistry suggests that their forming environments are continentalmarginarc and back arcbasin respectively. Consequently, the Paleoproterozoic subduction system in the western margin of Yangtze plate was established. Ailaoshan Group and Dibadu Formation came from an enriched mantle source that was contaminated by crustal sediments carried by subducted slab, and formed the Paleoroterozoic metamorphic basement of western margin of Yangtze plate. Ailaoshan Group is actually western boundary of Yangtze plate.

关 键 词：western margin of Yangtze plate Paleoproterozoic subduction system Ailaoshan Group (AG) Dibadu Formation (DF) incompatible element (IE) large ion lithospheric element (LILE) high field strengthen element (HFSE). 

分 类 号：P59[天文地球—地球化学]