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Provenance and tectonic implications of early Paleozoic sedimentary rocks in the Central Altyn Tagh terrane, southeast of the Tarim craton
International Journal of Earth Sciences ( IF 1.8 ) Pub Date : 2021-07-09 , DOI: 10.1007/s00531-021-02030-y
Qian Liu 1, 2 , Toshiaki Tsunogae 2, 3 , Guochun Zhao 4, 5 , Peng Wang 4 , Yigui Han 5 , Zengchan Dong 5, 6 , Ningchao Zhou 5, 6 , Jinlong Yao 5 , Yu Wu 7
Affiliation  

Considerable controversy concerns the consumption and closure processes of the North and South Altyn Oceans resulting in the formation of the North Altyn Tagh subduction-accretion belt and the South Altyn Tagh subduction-collision belt in the Altyn Tagh orogen in southeastern Tarim. This study focused on U–Pb ages and Hf isotopes of detrital zircons from early Paleozoic sedimentary rocks in the Central Altyn Tagh terrane. Our dating results revealed that the studied sedimentary rocks were deposited at ca. 467–429 Ma. The predominant early Paleozoic detrital zircons demonstrate negative εHf(t) values, highlighting their derivation from the coeval intermediate-felsic magmatic rocks sourced from ancient supracrustal materials with enriched isotopes. These inferred, enriched intermediate-felsic magmatic rocks were probably generated in different consumption and closure processes of the North and South Altyn Oceans, based on geochronology and geochemistry of the early-middle Paleozoic intermediate-felsic magmatic rocks in the Altyn Tagh orogen. A number of ca. 520–490 Ma detrital zircons were primarily derived from the coeval, enriched intermediate-felsic magmatic rocks in the local Central Altyn Tagh terrane and the adjacent North Altyn Tagh subduction-accretion belt associated with the advancing subduction of the North Altyn Ocean. The ca. 490–470 Ma detrital zircons are most prominent and suggest a derivation from the coeval, enriched magmatic rocks subject to the rollback of the North Altyn Ocean. These inferred magmatic rocks might have once existed in the region but have been intensely exhumed to be source material for the studied sedimentary rocks. A few ca. 450 Ma detrital zircons indicate a provenance from the North Altyn Tagh subduction-accretion belt during collision after the final closure of the North Altyn Ocean. In contrast, some ca. 470–460 Ma detrital zircons were probably derived from the coeval intermediate- to felsic-magmatic rocks in the Central Altyn Tagh terrane during the exhumation stage of the deep continental collision after the final closure of the South Altyn Ocean. Combination of provenance study and magmatic record provides potential to establish complicated orogenic evolution.



中文翻译:

塔里木克拉通东南部阿尔金地体早古生代沉积岩物源及构造意义

北阿尔金洋和南阿尔金洋的消耗和闭合过程导致塔里木东南部阿尔金造山带形成北阿尔金俯冲-增生带和南阿尔金俯冲-碰撞带,引起了相当大的争议。本研究重点研究了阿尔金地体中部早古生代沉积岩中碎屑锆石的 U-Pb 年龄和 Hf 同位素。我们的测年结果显示,所研究的沉积岩沉积于约。467–429 马。占优势的早古生代碎屑锆石显示负ε Hf ( t) 值,突出显示它们源自同时代的中长英质岩浆岩,这些岩浆岩源自具有丰富同位素的古代上地壳材料。根据阿尔金造山带早中古生代中长英质岩浆岩的年代学和地球化学,推测这些富集的中长英质岩浆岩可能是在阿尔金洋北部和南部不同的消耗和闭合过程中产生的。一些ca。520-490 Ma 碎屑锆石主要来自当地阿尔金中部地体和邻近的北阿尔金俯冲-增生带与北阿尔金洋的推进俯冲相关的同时期富集的中长英质岩浆岩。约。490-470 Ma 碎屑锆石是最突出的,表明它是从同时代的、受北阿尔金洋回滚的富集岩浆岩。这些推断的岩浆岩可能曾经存在于该地区,但已被强烈挖掘,成为研究沉积岩的源材料。几个ca。450 Ma 碎屑锆石表明北阿尔金洋最终闭合后碰撞期间来自北阿尔金俯冲-增生带的出处。相比之下,一些ca。470-460 Ma 碎屑锆石可能来源于南阿尔金洋最终闭合后深部大陆碰撞的折返阶段中阿尔金地体中同时期的中长英质岩浆岩。物源研究和岩浆记录的结合为建立复杂的造山演化提供了潜力。这些推断的岩浆岩可能曾经存在于该地区,但已被强烈挖掘,成为研究沉积岩的源材料。几个ca。450 Ma 碎屑锆石表明北阿尔金洋最终闭合后碰撞期间来自北阿尔金俯冲-增生带的出处。相比之下,一些ca。470-460 Ma 碎屑锆石可能来源于南阿尔金洋最终闭合后深部大陆碰撞的折返阶段中阿尔金地体中同时期的中长英质岩浆岩。物源研究和岩浆记录的结合为建立复杂的造山演化提供了潜力。这些推断的岩浆岩可能曾经存在于该地区,但已被强烈挖掘,成为研究沉积岩的源材料。几个ca。450 Ma 碎屑锆石表明北阿尔金洋最终闭合后碰撞期间来自北阿尔金俯冲-增生带的出处。相比之下,一些ca。470-460 Ma 碎屑锆石可能来源于南阿尔金洋最终闭合后深部大陆碰撞的折返阶段中阿尔金地体中同时期的中长英质岩浆岩。物源研究和岩浆记录的结合为建立复杂的造山演化提供了潜力。

更新日期:2021-07-09
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