Geochemistry, Geochronology and Petrogenesis of East Kunlun High Nb-Ta Rhyolites
详细信息
- 责任者：Ding Shuo (State Key Laboratory of Geological Processes and Mineral Resources ; School of Earth Science and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Huang Hui
- 刊名：Acta Petrologica Sinica
- 出版年：2011
- 卷期：27(12)
- 关键词：流纹岩 ; rhyolites ; 铀—铅计时 ; U-Pb dating ; 昆仑山 ; Kunlun Mountains
- 页码：p.3603-3614
- 图表：9 illus., 4 tables, 56 refs.
- 分类号：0801
- 出版序号：20122295
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The East Kunlun high Nb-Ta rhyolite is located at the eastern end of the Kunlun orogenic belt. Zircon U-Pb analysis gives a magmatic age of about 213 Ma, corresponding to the subduction/collision stage of the Kunlun Orogeny. Compared to the felsic volcanic rocks of similar ages in the region and rhyolites associated with subduction and collision zones worldwide. The authors propose that the East Kunlun high Nb-Ta rhyolites may be generated as follows: mantle-derived alkali basaltic melts (with inherited high Nb-Ta and εNd(t)>0) intruded the crust and developed a magma chamber, where the melt evolved through fractional crystallization with significant plagioclase separation (strongly depleted Sr and Eu) while assimilating the crustal material characterized by εNd(t)<0 and relatively low Nb and Ta before eruption.