Discovery of Pyroxenite Xenoliths in the Ceuozoic Basalt from Xikeer, Tarim, Northwest China and Its Geological Implications
详细信息
- 责任者：Wang Yuhua (Key Laboratory of Orogenic Belts and Crustal Evolution ; MOE ; School of Earth and Space Sciences ; Peking University ; Beijing 100871 ; China) ; Tian Wei
- 刊名：Acta Petrologica Sinica
- 出版年：2012
- 卷期：28(4)
- 关键词：碧玄岩 ; basanite ; 辉石岩 ; pyroxenite ; 捕虏体 ; xenoliths ; 塔里木盆地 ; Tarim Basin
- 页码：p.1139-1147
- 图表：illus., 1 table, 41 refs.
- 分类号：0801
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
A suite of newly discovered pyroxenite xenoliths in the Cenozoic basanite from Xikeer, Tarim Block have the primary mineral assemblage of ol+opx+cpx+pl+sp and the secondary mineral assemblage of amp+phl. Exsolved texture is common in clinopyroxenes and orthopyroxenes. Two generations of spinels occur, among which, the later euhedral small spinel grains are enclosed in metamorphic plagioclases. After recalling the exsolved components, the primary plagioclase-bearing mineral assemblage record temperature and pressure of 1 100～1 200 ℃ and 1.5 GPa. This process may imply that the crust-mantle transition zone of the Tarim Block have once been greatly uplifted, due to mantle upwelling and consequent stretch of the subcontinental lithospheric mantle.