Zircon U-Pb Chronology and Geochemistry of Carboniferous Volcanic Rocks in Awulale Area, Western Tianshan Mountains
详细信息
- 责任者：Li Dapeng (Institute of Geological Science ; China University of Geosciences ; Beijing 100083 ; China) ; Du Yangsong
- 刊名：Acta Geoscientica Sinica
- 出版年：2013
- 卷期：34(2)
- 关键词：火山岩 ; volcanic rocks ; 岩石地球化学 ; lithogeochemistry ; 天山 ; Tianshan Mountains
- 页码：p.176-192
- 图表：illus., 2 tables, 80 refs.
- 分类号：0801
- issnNo：ISSN1006-3021
- isbnNo：CN11-3474/P
摘要
Carboniferous volcanic rocks are widespread in Awulale rift zone area. Geochemical data suggest that they belong to calc-alkalic series, and consist of basalt, trachybasalt, basaltic trachyandesite, basaltic andesite, trachyte and rhyolite. LA-ICP-MS zircon dating of the rocks yielded an isotopic age of (316.1±2.2) Ma, which represents the late Early Carboniferous. Their major and trace element geochemistry shows that these volcanic rocks are characterized by the enrichment of large ion lithophile elements, suggesting that they had a very intimate relationship with volcanic-arc rocks and probably resulted from the northward sudbuction of the Junggar Ocean beneath the Ili-Middle Tianshan Plate. They might have been formed from a partially melted (about 1%~5%) lithospheric mantle (probably spinel-lherzolite) source that had been enriched with subduction fluids, and experienced extensive fractional crystallization and crustal contamination before eruption.