地质论评2012，Vol.58Issue(4)：763-774,12.
西昆仑慕士塔格岩体的LA-ICP-MS锆石U-Pb定年:对古特提斯碰撞时限的制约
LA-ICP-MS U-Pb Dating of the Zircon from Muztagata Pluton in Western Kunlun Orogenic Belt: Constraints on the Time of Paleotethys' Collision
摘要
Abstract
The Muztagata pluton is the largest granitic intrusion in Western Kunlun orogenic belt, which is composed of biotite monzonitic granite, porphyritic-like biotite monzonitic granite and granodiorite with a mass of widely developed dark microgranular enclaves and basaltic magmatic stripes. Noticed that the zircons of the rocks are typically magmatic 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 ±0.8Ma ( MSWD = 0.44) and 232. 8 ± 1. 5Ma ( 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. 7Ma ( 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.关键词
LA-ICP-MS锆石U-Pb测年/慕士塔格岩体/西昆仑/古特提斯Key words
LA-ICP-MS zircon U-Pb geochronology/ Muztagata pluton/ Western Kunlun/ Paleotethys引用本文复制引用
康磊,校培喜,高晓峰,董增产,过磊,奚仁刚..西昆仑慕士塔格岩体的LA-ICP-MS锆石U-Pb定年:对古特提斯碰撞时限的制约[J].地质论评,2012,58(4):763-774,12.基金项目
本文为中国地质调查局国土资源大调查研究项目(编号1212011085034)和陕西省自然科学基金资助项目(编号2012JM5004)的成果. （编号1212011085034）
