阿拉套山南缘岩浆岩锆石SHRIMP年代学研究  

SHRIMP U-Pb zircon geochronology of igneous rocks from southern margin of the Alataw mountains, Xinjiang, China.

作　　者：陈必河[1] 罗照华[1] 贾宝华 刘伟 魏阳[1] 韩以贵[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]湖南省地质调查院,长沙410007

出　　处：《岩石学报》2007年第7期1756-1764,共9页Acta Petrologica Sinica

基　　金：中国地质调查局地质调查项目'新疆博乐市纯库根一带1:5万区域地质矿产调查'(XJQDZ2004-07)部分成果

摘　　要：位于中国与哈萨克什坦国边境的阿拉套山南缘,火山岩及花岗岩十分发育。其中流纹岩分布广泛,仅研究区内面积达370.8km^2,与下伏早石炭世阿克沙克组及晚石炭世东图津河组呈角度不整合或假整合,SHRIMP 锆石 U-Pb 年龄300±5Ma。乌拉斯台花岗岩体是研究区内规模最大的岩体,出露面积约82km^2,侵入于早石炭统阿克沙克组及至晚石炭统东图津河组以及早二叠统乌郎组火山岩内,与围岩界线清楚。岩体形态不规则,由4个侵入次岩体组成。第4次侵入的花岗闪长岩体 HRIMP 锆石 U-Pb 年龄为294±4Ma。夏尔敖腊岩体为由4个侵入次组成的岩体,侵入于早石炭统内,平面上呈不规则椭圆形,出露面积近10km^2,主要岩性为二长花岗岩。出露规模较大的第6次侵入岩体的 SHRIMP 锆石 U-Pb 年龄为299±6Ma。研究表明,新疆阿拉套山南缘岩浆岩,SHRIMP 锆石 U-Pb 同位素年龄300Ma 左右,主要形成于晚石炭世末至早二叠世初,为同一构造-岩浆作用下的产物。Volcanic and granitic rocks occur widespread on the southern margin of the Alataw Mountains near the border of China and Kazakstan. Rhyolites are widely distributed and outcrop up to 370.8km^2 in study area. The rhyolites have zircon U-Pb SHRIMP age of 300 - 5Ma, and are underlain unconformably by the Early Carboniferous Akeshake Formation and the Late Carboniferous Dongtujinhe Formation. The Wulasitai granite, the largest pluton in study area, outcrops about 82km^2 and intruded into the Akeshake Formation Dongtujinhe Formation and Early Permian volcanic rocks of the Wulang Formation with clear contact relationships. This pluton is irregular in shape and consists of four intrusive bodies. The fourth-intrusion granodioritic body has zircon U-Pb SHRIMP age of 294 ± 4Ma. The Xiaer＇aola pluton is elliptical in shape and composed mainly of monzogranite with outcrop area about 10km^2. This pluton consists of four bodies, which intruded into Early Carboniferous strata. The sixth-intrusion body is the largest one and has zircon U-Pb SHRIMP age of 299 - 6Ma. Our investigations suggest that the igneous rocks on the southern margin of the Alataw Mountains have zircon U-Pb SHRIMP ages around 300Ma （Late Carboniferous Early Permian）; these rocks formed in the same tectono-magmatic environment.

关 键 词：岩浆岩 锆石 SHRIMP定年 阿拉套山 新疆 

分 类 号：P597.3[天文地球—地球化学]