LA-ICP-MS U-Pb Dating of the Zircon from Muztagata Pluton in Western Kunlun Orogenic Belt： Constraints on the Time of Paleotethys’ Collision

详细信息   

• 责任者：Kang Lei (Xi’an Institute of Geology and Mineral Resources ; Xi’an 710054 ; China) ; Xiao Peixi
• 刊名：Geological Review
• 出版年：2012
• 卷期：58(4)
• 关键词：黑云母花岗岩 ; biotite granite ; 二长花岗岩 ; monzogranite ; 铀—铅计时 ; U-Pb dating ; 昆仑山 ; Kunlun Mountains
• 页码：p.763-774
• 图表：illus., 2 tables, 47 refs.
• 分类号：0801
• issnNo：ISSN0371-5736
• isbnNo：CN11-1952/P

摘要

The Muztagata pluton is the largest granitic intrusion in Western Kunlun orogenic belt, which is composed of biotite monzonitie granite, porphyritic-like biotite monzonitic granite and granodiorite with a mass of widely developed dark microgranular enclaves and basaltic magmatie stripes. Noticed that the zircons of the rocks are typically magmatie zircon according to their cathodoluminescence （CL） image and characteristics of Th, U and REE. And the weighted mean age of ^206Pb/^238U to the western and eastern plutons are (229.6± 0.8 Ma) （MSWD = 0.44） and (232.8 ±1.5 Ma) （MSWD =0.21 ） respectively measured by LA-ICP-MS zircon U-Pb dating, which are consistent in error range. Accordingly, the Muztagata pluton is formed in (231.4 ± 0.7 Ma) （MSWD = 1.5）, representing an emplacement time of the Muztagata pluton in late Middle Triassic. Furthermore, the rocks are interpreted to have derived from magma mixing between crust and mantle by the proofs of petrology characteristics, internal structure and REE patterns of zircons, geochemistry data of predecessors. From the above and based on the regional geological data, Muztagata pluton was formed in the transitional period from primary collision to post- collision, indicating that the primary collision of Paleotethys in Western Kunlun occurred before late Middle Triassic, and entered post-collisional period from then on.