| 塔里木盆地东南缘(阿尔金山)"变质基底"记录的多期构造热事件:锆石U-Pb年代学的制约 |
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| 引用本文： | 张建新,李怀坤,孟繁聪,相振群,于胜尧,李金平.塔里木盆地东南缘(阿尔金山)"变质基底"记录的多期构造热事件:锆石U-Pb年代学的制约[J].岩石学报,2011,27(1):23-46. |
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| 作者姓名： | 张建新 李怀坤 孟繁聪 相振群 于胜尧 李金平 |
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| 作者单位： | 中国地质科学院地质研究所,北京 100037;中国地质调查局天津地质矿产研究所,天津 300170;中国地质科学院地质研究所,北京 100037;中国地质调查局天津地质矿产研究所,天津 300170;中国地质科学院地质研究所,北京 100037;中国地质科学院地质研究所,北京 100037 |
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| 基金项目： | 本文受中国石化股份有限公司科技开发部项目 (YPH08110)、国家自然科学基金创新群体项目(40921001)和中国地质科学院地质研究所基本科研业务费项目联合资助. |
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| 摘 要： | 塔里木盆地东南缘的阿尔金山被认为是塔里木克拉通变质基底的主要出露地区之一。 本文通过阿尔金山北坡不整合在太古代-古元古代变质基底之上的安南坝群中的碎屑岩和中南阿尔金中深变质岩石(原定为阿尔金岩群)的锆石U-Pb年代学研究,来确定塔里木盆地东南缘变质基底的性质及所经历的多期构造热历史。研究结果显示,塔里木盆地东南缘的安南坝群中含砾砂岩的碎屑锆石年龄集中在1.92Ga左右,少量在2.0~2.4Ga,表明其碎屑物质主要来源于下伏的太古代-早元古代米兰岩群和相关的深成侵入体。在中阿尔金地块和南阿尔金俯冲碰撞杂岩带的深变质岩石中,锆石U-Pb年代学数据表明其记录有新元古代早期(920~940Ma)、新元古代晚期(760Ma左右)和早古生代(450~500Ma)三期构造热事件,新元古代早期的构造热事件与塔里木(或晋宁)造山作用有关,它普遍存在于塔里木盆地周缘的和南中国地块(扬子克拉通)的变质基底岩石中,与Rodinia超级大陆汇聚相关;新元古代晚期的构造热事件也同样广泛存在于塔里木盆地周缘和扬子克拉通之中,被认为与Rodinia超大陆的裂解作用有关。因此,在新元古代时期,阿尔金的地质演化历史与扬子克拉通非常相似,而与华北则有很大的不同,锆石U-Pb测定还表明中南阿尔金的深变质岩石普遍遭受了早古生代的变质作用的改造,显示它们普遍卷入了早古生代的碰撞造山事件之中,成为早古生代碰撞造山带的组成部分。
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| 关 键 词： | 塔里木盆地 阿尔金山 变质基底 锆石定年 构造热事件 |
| 收稿时间： | 4/9/2010 12:00:00 AM |
| 修稿时间： | 2010/4/30 0:00:00 |
0Polyphase tectonothermal events recorded in "metamorphic basement" from the Altyn Tagh, the southeastern margin of the Tarim basin, western China: Constraint from U-Pb zircon geochronology |
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| ZHANG JianXin,LI HuaiKun,MENG FanCong,XIANG ZhenQun,YU ShengYao and LI JinPing.0Polyphase tectonothermal events recorded in "metamorphic basement" from the Altyn Tagh, the southeastern margin of the Tarim basin, western China: Constraint from U-Pb zircon geochronology[J].Acta Petrologica Sinica,2011,27(1):23-46. |
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| Authors: | ZHANG JianXin LI HuaiKun MENG FanCong XIANG ZhenQun YU ShengYao and LI JinPing |
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| Institution: | Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Tianjin Institute of Geology and Mineral Resources, China Geological Survey, Tianjin 300170, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Tianjin Institute of Geology and Mineral Resources, China Geological Survey, Tianjin 300170, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China |
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| Abstract: | The Altyn Tagh, located on the southeastern margin of the Tarim basin, is a main region where metamorphic basement of the Tarim craton is exposed. In this paper, zircon U-Pb isotopic data of sedimentary rocks unconformably overlying on Archaean-Early Paleoproterozoic metamorphic basement and high grade metamorphic rocks from the Cental-South Altyn Tagh are used to investigate the nature and ployphase tectonothermal events of the metamorphic basement in the southeastern margin of the Tarim basin. Detrital zircons from Neoproterozoic Annanba Group overlying on the Tarim basement yield mainly an age at ca. 1.92Ga, with a few grains between 2.0Ga and 2.4Ga, suggesting that detrital material of the Annanban Group shed from the underlying Milan Group and associated plutonic rocks. In the Central Altyn Tagh massif and South Altyn Tagh subduction-collision complex belt, zircon U-Pb chronological data show that high grade metamorphic rocks recorded three phase tectonothermal events: Early Neoproterozoic event (900~940Ma), Late Neoproterozoic event (760Ma) and Early Paleozoic event. Early Neoproterozoic tectonothermal event can be linked to the Tarim (or Jinning) orogeny, which was commonly recognized in the metamorphic basement around the Tarim basin and the South China block (or Yangtze craton), and was related to the formation of the Rodinia supercontinent. Late Neoproterozoic tectonothermal event has been also commonly recognized around the Tarim basin and Yangtze craton and was related to the breakup of Rodinia supercontinent. Therefore, in Neoproterozoic era, the Altyn Tagh has a similar evolution history to the Yangtze craton, differing from the North China craton. Zircon U-Pb chronological data also indicate that the high grade metamorphic rocks from the Central-South Altyn Tagh commonly experienced Early Paleozoic metamorphic overprint related to subduction and collision. |
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| Keywords: | Tarim basin Altyn Tagh Metamorphic basement Zircon U-Pb dating Tectonic thermal event |
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