西北地质Issue(2)：99-108,10.
北祁连甘禅口基性辉绿岩脉 LA-ICP-MS锆石 U-Pb 定年及其地质意义
LA-ICP-MS Zircon U-Pb Dating of Ganchankou Basite Diabase in Northern Qilian and Its Geological Significance
摘要
Abstract
Located in Qilian orogenic belt,Ganchankou basite diabase emplaces in Tuolai terrain of Paleoproterozoic Era,and its lithology is dark grey diabase.In this paper,LA-ICP-MS zircon U-Pb dating method is adopted to date the diabase,and 293.0 ±1.8Ma is obtained which indi-cates that a stretch event happened in early Permian Epoch.This paper finds that the diabase be-longs to tholeiite series,with the ratio of chemical A/CNK changing from 0.60 to 0.76,the value of A/NK varying from 2.40 to 4.35,the content of Al2 O3 ranging from 1 1.60% to 18.36%,and the content of TiO2 fluctuating between 0.66% and 2.85%.Meanwhile,trace elements such as K,Rb,Ba and Th have strong enrichment,but Hf and Zr are apparently depleted while Y and Yb are characterized by slight depletion.The study also shows that light rare earth elements after weak fractionation are enriched while the fractionation of heavy rare earth elements is not obvious in the diabase.At the same time there is a weak negative Eu anomaly.According to the regional tectonic background and the petrological and geochemical characteristics,it can be concluded that Ganchankou diabase dyke is formed by the post-tectonic crust thickening underplating of Qilian o-rogenic belt and the magma intermingling effect.关键词
北祁连/基性辉绿岩脉/锆石 U-Pb 定年/陆壳加厚Key words
Northern Qilian/basite diabase/zircon U-Pb dating/continental crust thickening分类
天文与地球科学引用本文复制引用
王国良,叶占福,赵洪菊,韩海臣,严玉峰..北祁连甘禅口基性辉绿岩脉 LA-ICP-MS锆石 U-Pb 定年及其地质意义[J].西北地质,2014,(2):99-108,10.基金项目
中国地质调查局地质调查项目“青海省1∶5万玉龙滩、抓什究、贺尔、桥头幅区域地质调查”(1212011121192) （1212011121192）
