中国地质2011，Vol.38Issue(5)：1150-1167,18.
东昆仑南缘布青山构造混杂岩带早古生代白日切特中酸性岩浆活动:来自锆石U-Pb测年及岩石地球化学证据
Early Paleozoic intermediate-acid magmatic activity in Bairiqiete area along the Buqingshan tectonic melange belt on the southern margin of East Kunlun:Constraints from zircon U-Pb dating and geochemistry
摘要
Abstract
Based on 1:50000 regional geological mapping on the southern margin of the East Kunlun Mountains and using methods of detailed field section measurement and petrologic analysis as well as LA-ICP-MS zircon U -Pb dating and geochemical investigation, the authors studied the intermediate -acid magmatic rocks in Bairiqiete area of the Buqingshan tectonic melange belt. The results show that the rocks are mainly granodiorite with 206Pb/238U average weighted age of 441 ±6 Ma (MSWD=0.75)and intermediate-acid volcanic rock such as rhyolite-porphyry with 206Pb/238U average weighted age of 438+3 Ma (MSWD=2.0). Geochemically, the former is characterized by high content of Si, Al and Na and should belong to the Na-enriched calc- alkali series, whereas the latter is of Si-saturated, aluminous and calc-alkali series. These two kinds of rocks are characterized by low H REE content and relatively enriched LREE and depleted HREE, with LRJEE differentiated more evidently than HREE, and show right-inclination pattern in REE patterns, without or with weak Eu anomalies. All of these features are similar to features of the island -arc calc -alkali series in relation to subduction, representing the volcanic-arc products of the subduction of east proto-Tethys crust in Early Silurian. The results obtained by the authors provide new evidence for the study of the evolution of east proto-Tethys Ocean. Southern margin of east Kunlun region;Bairiqiete; tectonic melange; intermediate-acid volcanic;关键词
东昆仑南缘/白日切特/构造混杂岩/中酸性火山岩/花岗闪长岩/LA-ICP-MS铬石U-Pb测年/岩石地球化学Key words
granodiorite/LA-ICP-MS zircon U-Pb geochronology/lithogeochemistry分类
天文与地球科学引用本文复制引用
刘战庆,王学良,张刚,裴先治,李瑞保,李佐臣,陈国超,陈有炘,高景民,刘成军,魏方辉..东昆仑南缘布青山构造混杂岩带早古生代白日切特中酸性岩浆活动:来自锆石U-Pb测年及岩石地球化学证据[J].中国地质,2011,38(5):1150-1167,18.基金项目
国家自然科学基金项目(41172186、40972136、40572121)、中央高校基本科研业务费专项资金(CHD2009JC053、CHD2009JC046、 CHD2009JC070)及青海省国土资源厅-中国铝业公司公益性区域地质矿产调查基金项目(中铝基金200801)联合资助. （41172186、40972136、40572121）
