| 东昆仑祁漫塔格地区乌兰乌珠尔早古生代花岗岩锆石U-Pb年代学、地球化学及其地质意义 |
| |
| 引用本文： | 韩志辉,孙丰月,田楠,高宏昶,李良,赵拓飞.东昆仑祁漫塔格地区乌兰乌珠尔早古生代花岗岩锆石U-Pb年代学、地球化学及其地质意义[J].地球科学,2021,46(1):13-30. |
| |
| 作者姓名： | 韩志辉 孙丰月 田楠 高宏昶 李良 赵拓飞 |
| |
| 作者单位： | 吉林大学地球科学学院,吉林长春 130061;云南大学资源环境与地球科学学院,云南昆明 650000 |
| |
| 摘 要： | 为确定东昆仑祁漫塔格乌兰乌珠尔地区片麻状黑云母花岗岩和二长花岗岩的形成时代、岩石成因、源区性质和构造背景，对该岩石样品进行了锆石U-Pb年代学、地球化学和锆石Hf同位素研究.结果显示:片麻状黑云母花岗岩加权平均年龄为457.5±2.3 Ma，铝饱和指数A/CNK介于0.98~1.02，属准铝质岩石，Na2O/K2O比值为0.440~0.625，属于高钾钙碱性系列.二长花岗岩加权平均年龄为422.5±1.6 Ma，铝饱和指数A/CNK介于1.03~1.05，属弱过铝质岩石.二者均具有高硅(SiO2介于68.93%~74.72%)、高碱(全碱ALK介于6.83%~9.40%)、低磷(P2O5小于0.12%)等特征.富集轻稀土元素，亏损重稀土元素，δEu值为0.29~0.70，显示Eu中度负异常.富集Rb、K等大离子亲石元素，亏损Nb、Ta、P、Ti等高场强元素，属于I型花岗岩.二长花岗岩样品的εHf(t)值为-2.2~+1.4，二阶段模式年龄为1 320~1 546 Ma.结合岩石成岩年龄、地球化学特征及区域构造演化认为片麻状黑云母花岗岩(457.5±2.3 Ma)为下地壳部分熔融产物，形成于原特提斯洋向北俯冲导致的局部拉张环境.二长花岗岩(422.5±1.6 Ma)岩浆来源于中元古代新增生的下部地壳熔融产物，形成于碰撞拼贴后的伸展构造环境.
|
| 关 键 词： | 花岗岩 地球化学 锆石U-Pb定年 Hf同位素 祁漫塔格 |
| 收稿时间： | 2020-02-11 |
Zircon U-Pb Geochronology,Geochemistry and Geological Implications of the Early Paleozoic Wulanwuzhuer Granites in the Qimantag,East Kunlun,China |
| |
| Han Zhihui,Sun Fengyue,Tian Nan,Gao Hongchang,Li Liang,Zhao Tuofei.Zircon U-Pb Geochronology,Geochemistry and Geological Implications of the Early Paleozoic Wulanwuzhuer Granites in the Qimantag,East Kunlun,China[J].Earth Science-Journal of China University of Geosciences,2021,46(1):13-30. |
| |
| Authors: | Han Zhihui Sun Fengyue Tian Nan Gao Hongchang Li Liang Zhao Tuofei |
| |
| Affiliation: | (College of Earth Sciences,Jilin University,Changchun 130061,China;School of Resource Environment and Earth Science,Yunnan University,Kunming 650000,China) |
| |
| Abstract: | In order to determine the formation time,petrogenesis,magma source and tectonic setting of gneissic biotite granites and the monzonotic granites in the wulanwuzhuer area of Qimantag,East Kunlun.Zircon U-Pb geochronology,geochemistry and HF isotopes of the rocks have been studied.The results show that:The weighted mean age of gneissic biotite granites is 457.5±2.3 Ma,and the A/CNK is between 0.98-1.02,belonging to sub-aluminous rocks.The ratio of Na2O/K2O is between 0.440-0.625,which belongs to high-K calc-alkaline series.The weighted mean age of the Monzonotic granites is 422.5±1.6 Ma,and the A/CNK is between 1.03-1.05,belonging to the weakly peraluminous rocks.Both of them have the characteristics of high SiO2 (SiO2 between 68.93% and 74.72%),high alkali (all alkali ALK between 6.83% and 9.40%),low P2O5 (P2O5 less than 0.12%).Enrichment of LREE and depletion of HREE,and δEu is between 0.29-0.70,indicating that Eu is moderately negative.These samples are enriched in LILE (such as Rb、K) and depleted in HFSE (such as Nb、Ta、P、Ti),belongs to I-type granites.The εHf(t) values of zircon from the monzonotic granites range from -2.2 to +1.4,their Hf two-stage model ages vary from 1.32 Ga to 1.54 Ga.Combined with the geochronological data,geochemical characteristics and regional tectonic evolution,the gneissic biotite granite (457.5±2.3 Ma) is a partial melting product of the lower crust,which was formed in the local tensional environment of the North subduction of the Proto-Tethys.The monzonotic granitic (422.5±1.6 Ma) magma is derived from the partial melting products of the juvenile lower crust in Mesoproterozoic.it is considered that the rocks should be formed in the post-collisional extension setting. |
| |
| Keywords: | granite geochemistry zircon U?Pb diating Hf istope Qimantag |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《地球科学》浏览原始摘要信息 |
|
点击此处可从《地球科学》下载全文 |
|
