Provenance of early Paleozoic sedimentary rocks in the Altyn Tagh orogen: Insights into the paleoposition of the Tarim craton in northern Gondwana associated with final closure of the Proto-Tethys Ocean
Provenance of early Paleozoic sedimentary rocks in the Altyn Tagh orogen: Insights into the paleoposition of the Tarim craton in northern Gondwana associated with final closure of the Proto-Tethys Ocean
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阿尔金造山带早古生代沉积岩的物源：了解冈瓦纳大陆北部塔里木克拉通与原特提斯洋最终闭合相关的古位置
DOI：
10.1130/b35576.1
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发表时间：
2021
影响因子：
4.9
通讯作者：
Tsunogae T.
中科院分区：
文献类型：
--
作者：
Liu Q.;Zhao G.C.;Li J.H.;Yao J.L.;Han Y.G.;Wang P.;Tsunogae T.
冈瓦纳大陆北缘的演化，尤其是印度和澳大利亚北部的演化，仍然是个谜。由于南北阿尔金海（塔里木东南部和冈瓦纳北部之间的原特提斯洋的两个分支）最终闭合，塔里木克拉通何时何地与冈瓦纳北部合并，存在很多争议。本研究通过对阿尔金造山带早古生代沉积岩进行系统的现场锆石 U-Pb 定年和 Hf 同位素分析来解决这些问题。新的测年结果揭示了沉积年龄约。 494 至 426 Ma。来源追踪表明大约。 494–477 Ma 样品主要来自北阿尔金洋以南的当地阿尔金塔格地区，而约 494–477 Ma 样品主要来自北阿尔金洋以南的阿尔金地区。 465–449 Ma 样品的特点是约显着增加。 2.7–2.4 Ga、2.0–1.7 Ga 和 840–780 Ma 碎屑锆石，表明从塔里木克拉通到北阿尔金洋以北的碎屑供应增加。这一变化表明大约从单一来源地区到多个来源地区的主要起源转变。 477 Ma和465 Ma，标志着北阿尔金洋最终闭合的时间。来自 ca 的锆石 U-Pb 和 Hf 同位素数据。 444–426 Ma 样本与来自约 444–426 Ma 的样本相似。 465–449 Ma 样本，表明局部沉积物循环与碰撞后状态有关。考虑到南阿尔金洋和原特提斯洋的其他分支，我们推断整个原特提斯洋可能在大约500–420 Ma，导致大多数东亚地块与冈瓦纳北部合并。碎屑锆石U-Pb和Hf同位素比较表明，塔里木与许多东亚地体（如北祁连、北秦岭、华南、印度支那、南羌塘等）有北印度亲缘关系，而不是与阿拉伯-伊朗或沿冈瓦纳大陆北缘毗邻西澳大利亚的其他地体（如拉萨和斯布马苏）有亲缘关系。
The evolution of the northern margin of Gondwana, especially to the north of India and Australia, remains enigmatic. Much controversy concerns when and where the Tarim craton was amalgamated with northern Gondwana due to final closure of the North and South Altyn Oceans (two branches of the Proto–Tethys Ocean between southeastern Tarim and northern Gondwana). This study addressed these issues through systematic field-based zircon U-Pb dating and Hf-isotope analyses of early Paleozoic sedimentary rocks in the Altyn Tagh orogen. New dating results reveal depositional ages from ca. 494 to 426 Ma. Provenance tracing indicates the ca. 494–477 Ma samples were dominantly sourced from local Altyn Tagh areas to the south of the North Altyn Ocean, whereas the ca. 465–449 Ma samples are characterized by a significant increase in ca. 2.7–2.4 Ga, 2.0–1.7 Ga, and 840–780 Ma detrital zircons, indicating an augmented supply of detritus from the Tarim craton to the north of the North Altyn Ocean. This change indicates a major provenance shift from a single to multiple source regions between ca. 477 and 465 Ma, marking the timing of the final closure of the North Altyn Ocean. Zircon U-Pb and Hf-isotopic data from the ca. 444–426 Ma samples resemble those from the ca. 465–449 Ma samples, suggesting local sediment recycling related to a postcollisional regime. Considering the South Altyn Ocean and other branches of the Proto–Tethys Ocean, we infer that the entire Proto–Tethys Ocean might have been progressively closed at ca. 500–420 Ma, leading to the amalgamation of most East Asian blocks with northern Gondwana. Detrital zircon U-Pb and Hf-isotope comparisons indicate that Tarim shared a North Indian affinity with many East Asian terranes (such as North Qilian, North Qinling, South China, Indochina, South Qiangtang, etc.), rather than with Arabia-Iran or other terranes (eg, Lhasa and Sibumasu) that were adjacent to western Australia along the northern margin of Gondwana.