The Petrogenesis of Postcollisional Potassic-Ultrapotassic Rocks in Xungba Basin , Western Lhasa Terrane: Constraints from Zircon U-Pb Geochronology and Geochemistry
详细信息
- 责任者：Liu Dong (State Key Laboratory of Geological Processes and Mineral Resources ; and School of Earth Science and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Zhao Zhidan
- 刊名：Acta Petrologica Sinica
- 出版年：2011
- 卷期：27(7)
- 关键词：火山岩 ; volcanic rocks ; 铀—铅计时 ; U-Pb dating ; 岩石地球化学 ; lithogeochemistry ; 青藏高原 ; Qinghai-Tibetan Plateau
- 页码：p.2045-2059
- 图表：5 illus., 2 tables, 49 refs.
- 分类号：0801
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
This paper present a series of zircon LA-ICP-MS U-Pb dating and element geochemical studies on the new-recognized potassic and ultrapotassic rocks from Xungba basin. The volcanic rocks are named as latite (23.9±0.6 Ma), trachydacite (23.3±0.4 Ma) and rhyolite (24.1±0.3 Ma). The geochemical data of these rocks show that different magma sources should have been responsible for their petrogenesis. The crustal-derived rhyolite show three groups (~150 Ma, ~90 Ma and ~50 Ma), the potassic trachydacite have the major populations of ~90 Ma and 2 zircon grains with Neoproterozoic ages representing the basement beneath cental Lhasa subterrane. The inherited zircons of the mantle-derived latite mainly record the ages of late Cretaceous (110~80 Ma) and Paleogene (62~30 Ma) peaks.