Compositions of Carboniferous-Triassic Clastic Rocks in the Southern Margin of the Tianshan, Northwest China: Implications for the Evolution of the Provenance Tectonic Attributes
详细信息
- 责任者：Wang Song(School of Resources and Environmental Engineering ; Hefei University of Technology ; Hefei 230009 ; China) ; Li ShuangYing
- 刊名：Acta Petrologica Sinica
- 出版年：2012
- 卷期：28(8)
- 关键词：碎屑岩 ; clastic rocks ; 物源分析 ; provenance analysis ; 天山 ; Tianshan Mountains
- 页码：p.2453-2465
- 图表：illus.,8 tables,31 refs.
- 分类号：0803
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
Our research focuses on the composition and provenance tectonic evolution of the Carboniferous-Triassic clastic rocks in the southern margin of the Tianshan. Analysis of petrology and geochemistry of detrital rocks shows that the Carboniferous and Triassic sandstones have a low compositional, textural maturity and high matrix content. The unstable component of sandstones increases from the Carboniferous to the Triassic. The Carboniferous and Permian have a similar characteristic of REE abundances, which is obviously higher than that in the Triassic. The fractionation degree of light and heavy rare earth elements and the ratios of La/Th and La/Y descend from the Carboniferous to the Triassic and the Th/U ratio increases, which implicate the increase of recycled sediments. According to the distinction of detrital composition, major elements, rare earth elements and trace elements, the provenance tectonic settings of the Carboniferous were continental island arcs, active continental margin and passive continental margin, and the Permian’s was continental island arcs and the provenance of the Triassic was more similar to continental island arcs and ancient sedimentary geological bodies. The carboniferous has a more complex provenance compared with Permian and Triassic provenances, which may be related to the collision between the Central Tianshan-Yili block and the Tarim block.