新疆东部卡瓦布拉克地区古生代岩浆活动对中天山地块构造归属的指示意义  

Paleozoic magmatic activity in the Kawabulake area,eastern Xinjiang and its indicative significance for tectonic affinity to the Central Tianshan block

作　　者：木扎帕尔·木合塔尔 尼加提·阿布都逊 郭瑞清[1,2] 宫相宽 崔涛[1,2] 宋志豪 MUZHAPAER•Muhetaer;NIJIATI•Abuduxun;GUO Ruiqing;Gong Xiangkuan;CUI Tao;SONG Zhihao(College of Geology and Mining Engineering Xinjiang University Urumqi,830046;Xinjiang Key Laboratory for Geodynamic Processes and Metallogenic Prognosis of the Cet Ural Asian Orogenic Belt,Xinjiang University,Urumqi 830046;Xinjiang Institute of Ecology and Geography Chinses Academy of Sciences,Urumqi,830011)

机构地区：[1]新疆大学地质与矿业工程学院,乌鲁木齐830046 [2]新疆大学中亚造山带大陆动力学与成矿预测自治区重点实验室,乌鲁木齐830046 [3]中国科学院新疆生态与地理研究所,乌鲁木齐830011

出　　处：《地质学报》2020年第5期1450-1461,共12页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号41962013,41502213,41562010);新疆维吾尔自治区自然科学基金项目(编号2016D01C082)联合资助成果。

摘　　要：卡瓦布拉克地区位于中天山地块南缘。该区古生代侵入岩类广泛发育,是探究中天山构造演化及地壳生长历史的重要窗口。本文获得该区两件二长花岗岩样品的LA-ICP-MS锆石U-Pb定年结果分别为447.4±4.9Ma、422.6±5Ma。LA-MC-ICP-MS锆石Hf同位素原位分析结果显示,其εHf(t)值分别为7.1~11.9、5.8~11.8,对应的二阶段模式年龄为674~963 Ma、514~1043 Ma。侵入于晚古生代花岗岩中的中-基性岩脉携带多期捕获锆石,其εHf(t)介于-7.4~4.8,对应的模式年龄变化范围为1.47~2.54Ga。卡瓦布拉克地区古生代花岗岩及中-基性岩脉中捕获锆石所反映的基底信息表明,中天山与塔里木在中元古代(~1.4Ga)、新元古代(~800Ma)以及古生代(~400Ma)期间岩浆活动具有截然不同的源区特征。结合前人研究成果,认为中天山与塔里木不具有构造亲缘性。Paleozoic intrusions,which are widely exposed in the Kawabulake area,provide valuable clues about the tectonic evolution and crustal growth of the Central Tianshan.LA-ICP-MS U-Pb zircon ages of 447.4±4.9 Ma and 422.6±5 Ma were obtained for two monzogranites,both of which are characterized by positiveεHf(t)values ranging from 7.1 to 11.9,and 5.8 to 11.8 with relative young crustal model(TDM2)ages of 674~963 Ma and 514~1043 Ma,respectively.The inherited zircons captured by an intermediate basic dyke that intruded a Late Paleozoic granite yielded various old ages,theεHf(t)values of which range between-7.4 and+4.8 with corresponding TDM2 ages of 1.47~2.54 Ga.Hf isotopic compositions of the Paleozoic granites and coexisting intermediate basic dikes in the Kawabulake area show that the magmatic activities during the Mesoproterozoic(~1.4 Ga),Neoproterozoic(~800 Ma)and Paleozoic(~400 Ma)display completely different source characteristics from northern Tarim.After integrating with the previous published data,we propose that the Central Tianshan has no close tectonic affinity to the Tarim Craton.

关 键 词：HF同位素 卡瓦布拉克 中天山地块 塔里木 构造归属 

分 类 号：P588.11[天文地球—岩石学] P548[天文地球—地质学]