Geochemical Features and Tectonic Significances of Weiya Ophiolitic Mélange and Mafic Granulite, Xinjiang
详细信息
- 责任者：Chen Xijie (State Key Laboratory of Mineral Deposits Research ; School of Earth Sciences and Engineering ; Nanjing University ; Nanjing 210093 ; China) ; Shu Liangshu
- 刊名：Geological Journal of China Universities
- 出版年：2012
- 卷期：18(4)
- 关键词：蛇绿混杂堆积 ; ophiolite complexes ; 麻粒岩 ; granulite ; 新疆 ; Xinjiang
- 页码：p.661-675
- 图表：7 illus., 2 tables, 45 refs.
- 分类号：0802
- issnNo：ISSN1006-7493
- isbnNo：CN32-1440/P
摘要
The ophiolitic mélange and mafic granulites are outcropped in the Weiya segment which is near to the northern boundary fault of the Central Tianshan belt. The petrological and geochemical data suggest that the geochemical features of the diabase and gabbro of the ophiolitic mélange are similar, characterized by high MgO contents (6.78%), low Na2O+K2O (0.52%) contents and Na2O > K2O. Combining with previous research results on the regional geology, petrology and geochemistry, the authors conclude that the mafic-ultramafic blocks in the eastern Weiya belong to the dismembered EMORB-type ophiolite, formed in mid-oceanic ridge and represents fragments of ancient Tianshan oceanic basin. The protolith of mafic granulites was formed in an immature island-arc setting. The ophiolitic melange and mafic granulites may be related to the subduction of oceanic plate along the northern boundary fault of the Central Tianshan and represents the relics of the Tianshan Ocean.