西北地质2018，Vol.51Issue(1)：144-158,15.
东昆仑巴音呼都森晚三叠世中酸性侵入岩锆石LA-ICP-MS U-Pb定年及地质意义
LA-ICP-MS Zircon U-Pb Age of Late Triassic Intrusive Rocks in Bayinhudousen Area, East Kunlun and Its Tectonic Significance
摘要
Abstract
The Bayinhudousen intrusive rocks are located at Qimantage Mountain in the western part of East Kunlun Mountains,and they are occurred in the North Kunlun magmatic arc.They are composed of gray white fine granite granodiorite,gray medium-fine grained monzonitic granite,flesh red fine-medium grained porphyritic monzogranite and light grey monzonitic granite porphyry.In this paper,the LA-ICP-MS Zircon U-Pb method has been used to date the samples of porphyritic monzogranite in Duodeng area and monzonitic granite porphyry in Jingren area.The obtained ages are (217.0±2.0) Ma and (212.0±1.0) Ma,respectively,suggesting that these plutons were formed in Late Triassic epoch.The geochemical results show that these rocks have highSiO2 (67.01％～76.61％),K20 (3.47％～5.52％) andNa2O (1.55％～4.52％) contents,but havelow MgO (0.12％～1.37％),TiO2 (0.06％～0.84％) and P2O5 (0.01％～0.36％) contents.Their rare earth elements have weak negative Eu anomaly (δEu values are 0.17～0.72),and their A/CNK ratios are less than 1.1,showing the features of peraluminous high-k calc-alkaline series.After analyzing the characteristics mentioned above,it's believed that these granites were formed in post orogenic extensional environment.Therefore,the existence of Bayinhudousen late triassic intrusive rocks has proved that the collision orogenesis was existed in Qimantage tectonic belt before Late Triassic epoch.关键词
东昆仑/晚三叠世中酸性侵入岩/LA-ICP-MS锆石微区定年/构造意义Key words
East Kunlun/Late Triassic intrusive rocks/LA-ICP-MS zircon U-Pb ages/tectonic significance分类
天文与地球科学引用本文复制引用
韩海臣,王国良,丁玉进,张小永,许海全,王钦元..东昆仑巴音呼都森晚三叠世中酸性侵入岩锆石LA-ICP-MS U-Pb定年及地质意义[J].西北地质,2018,51(1):144-158,15.基金项目
中国地质调查局地质专项项目“青海省1∶5万喀雅克登塔格地区五幅区调”(1212010710321) （1212010710321）
