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http://www.igeodata.org/handle/20.500.11758/236
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DC 字段 | 值 | 语种 |
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所有者 | Zhen-Yu He | - |
所有者 | Ze-Ming Zhang | - |
所有者 | Ke-Qing Zong | - |
所有者 | Hua Xiang | - |
所有者 | Xi-Jie Chen | - |
所有者 | Ming-Jun Xia | - |
获取日期 | 2017-03-06T06:27:29Z | - |
获取日期 | 2017-03-06T06:27:29Z | - |
首次发表日期 | 2014-07 | - |
引用地址 | http://www.igeodata.org/handle/20.500.11758/236 | - |
摘要 | The Chinese Tianshan occupies the southernmost part of the Central Asian Orogenic Belt (CAOB). High-grade metamorphic rocks are widely distributed in its central uplift zones, composing the crustal basement of the Central Tianshan Block of the Chinese Tianshan. However, the origin of the crustal basement and whether the high-grade metamorphism was associated with the Paleozoic orogeny are still unresolved. Here, we present precise LA-ICP-(MC)-MS zircon U–Pb dating and Hf isotopic data for three meta-sedimentary rocks and one orthogneiss from the XingxingxiaComplex,which representsthe Precambrian basement of theCentral Tianshan Block. Zircon U–Pb dating results show that the protolith age of the orthogneiss is ca. 880 Ma and that the meta- sedimentary rocks consist dominantly of 0.8–1.0 Ga and 1.3–2.0 Ga materials with minor early Paleoproterozoic components. In combination with the zircon Hf isotopic data, it is suggested that the crustal basement of the Central Tianshan Block was formed in the early Mesoproterozoic, which is evidently different from the Archean basementformationoftheTarimCraton.WesuggestthattheCentralTianshanBlockmayhaveformedthrougha magmaticarcaccretionaryorogenalongthecontinentalmarginofBalticaduringtheMesoproterozoic.Moreover, both the meta-sedimentary rocks and the orthogneiss of the Xingxingxia Complex simultaneously suffered a metamorphic overprint at ca. 380 Ma. Zircon REE and Hf isotopic data indicate that the metamorphic zircon rims were formed by new zircon overgrowths in partial melts. Geothermobarometry and average P–T calculations using THERMOCALC on the Grt–Bt gneiss yielded ca. 720–730 °C and 4–6 kbar, suggesting amphibolite- to granulite-facies conditions. The Late Devonian metamorphism of the Xingxingxia Complex is possibly related to orogenic low-pressure/high-temperature metamorphism in the middle or upper crust during the closure of the eastern segment of South Tianshan Ocean. Our new data, together with the occurrences of Ordovician–Silurian eclogites and HP mafic granulites along the northeastern margin of the Tarim Craton, indicate that progressive continental collisions occurred in the southern CAOB during the Paleozoic. | zh_CN |
语种 | en | zh_CN |
出版者 | Institute of Geology Chinese Academy of Geological Sciences | zh_CN |
主题关键词 | Central Asian Orogenic Belt Central Tianshan Block Late Devonian metamorphism Mesoproterozoic crust Xingxingxia Metamorphic Complex | zh_CN |
成果名称 | Zircon U–Pb and Hf isotopic studies of the Xingxingxia Complex from Eastern Tianshan (NW China): Significance to the reconstruction and tectonics of the southern Central Asian Orogenic Belt | zh_CN |
类型 | Book | zh_CN |
所属集合: | 科技成果 |
文件中的条目:
条目 | 描述 | 大小 | 格式 | |
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Zircon U–Pb and Hf isotopic studies of the Xingxingxia Complex from Eastern Tianshan (NW China).pdf | 3.39 MB | Adobe PDF |
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