| 中天山基底与塔里木克拉通的构造亲缘性 |
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| 引用本文： | 舒良树,邓兴梁,马绪宣.中天山基底与塔里木克拉通的构造亲缘性[J].地球科学,2019,44(5):1584-1601. |
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| 作者姓名： | 舒良树 邓兴梁 马绪宣 |
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| 作者单位： | 1.南京大学成矿作用国家重点实验室, 江苏南京 210023 |
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| 基金项目： | 国家自然基金委青年项目41502198 |
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| 摘 要： | 中天山基底与塔里木克拉通的构造亲缘性问题涉及中亚大地构造单元的划分,倍受学术界关注.在诸多学者的研究基础上,特别是塔里木北缘物质成分和年代学成果基础上,通过区域地质调查,对托克逊县干沟与和静县阿拉沟两地的前南华纪地层序列及其岩石组合进行了专门研究,并筛选出4件浅变质砂岩样品做碎屑锆石U-Pb测年研究,获得165组年龄数据.结果表明,发育在中天山地区的前南华纪地层序列、岩石组合、地层接触关系、沉积环境与塔里木北缘的基本一致,可比性好,揭示了二者之间密切的构造亲缘性.其Th/U比值密集分布在0.4～4.0,表明岩浆锆石占绝大多数.锆石U-Pb测年产生了4个年龄峰值,分别为950Ma、1 550Ma、1 920Ma和2 480Ma,表明中天山较好地保存了元古代的4次重大构造-岩浆活动信息.这些年龄峰值在塔里木陆块均有对应岩浆体的发育,也与塔里木周缘的前寒武纪年龄谱吻合,进一步佐证了中天山基底与塔里木克拉通曾经是一个统一块体的认识.结合区域构造分析,认为中天山陆块是在南华纪以来,逐渐从塔里木克拉通拉张裂离出来的;伴随早古生代天山洋的俯冲,一个奥陶纪-志留纪火山弧发育在这个裂离的中天山陆块之上.
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| 关 键 词： | 地层序列 碎屑锆石 U-Pb年龄谱 构造亲缘性 中天山基底 塔里木克拉通 构造地质 |
| 收稿时间： | 2019-01-06 |
Tectonic Affinity between Central Tianshan Basement and Tarim Block Craton |
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| Shu Liangshu,Deng Xingliang,Ma Xuxuan.Tectonic Affinity between Central Tianshan Basement and Tarim Block Craton[J].Earth Science-Journal of China University of Geosciences,2019,44(5):1584-1601. |
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| Authors: | Shu Liangshu Deng Xingliang Ma Xuxuan |
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| Institution: | (State Key Laboratory for Mineral Deposits Research,Nanjing University,Nanjing 210023,China;Tarim Petroleum Field Prospect Headquarter,Korla 841000,China;Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China) |
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| Abstract: | The tectonic affinity between the Chinese Central Tianshan basement and the Tarim craton is pivotal for us to understand the tectonic framework of the Central Asian orogenic belt. Based on analyses of field investigation and stratigraphic sequences, it performed detrital zircon U-Pb dating analysis on the four Neoproterozoic meta-sandstone samples from the Gangou region of Hejing County and Alagou region of Baluntai Town, Chinese Central Tianshan. Stratigraphically, the Precambrian strata, rock assemblages, stratigraphical contacts, sedimentary environment in the Chinese Central Tianshan are very similar to those in the northern margin of the Tarim craton, revealing close tectonic affinity between them. All analyzed detrital zircons show oscillatory zoning and have Th/U ratios >0.1 (mainly ranging from 0.4 to 4.0), suggesting that they were mainly derived from igneous rocks. A total of about 165 detrital zircon analyses yielded four age peaks, namely, 950 Ma, 1 550 Ma, 1 920 Ma and 2 480 Ma, respectively, corresponding to four prominent tectonomagmatic events that occurred in the Tarim craton. In addition, these peak ages are remarkably consistent with age populations of detrital zircons in the Tarim craton and its neighbouring areas, and further corroborate that the Chinese Central Tianshan terrane has close tectonic affinity with the Tarim craton. Furthermore, some Proterozoic zircons have been found, showing ages of 2 600-3 260 Ma. Therefore, it is argued that the Chinese Central Tianshan belonged to the Tarim craton in the Precambrian time. Owing to the southward subduction of the Paleo-Tianshan oceanic lithosphere beneath the northern margin of the Tarim craton during the Neoproterozoic period, the remarkable arc-type magmatism occurred in the Chinese Central Tianshan terrane, which rifted away from the Tarim craton. |
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| Keywords: | stratigraphic sequence detrital zircon U-Pb age population tectonic affinity basement of Chinese Central Tianshan Tarim craton tectonics |
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