Lhasa terrane: A key piece of the supercontinent reconstruction puzzle from Rodinia to Gondwana

Here we report in detail on new U–Pb zircon dating, geochemical and Sr–Nd–Hf-O isotopic data of the late Neoproterozoic ophiolite fragments and island arc magmatic rocks from Lhasa terrane, central Tibet, China, and reveal that they generally experienced a distinctive metamorphic event (~660–650 Ma). These results, combined with previous provenance analysis, Lhasa terrane is firstly proposed to locate in the late Neoproterozoic juvenile arc system (Madagascar-Seychelles-NW India) laying either along the periphery of Rodinia or outboards of the supercontinent, recording the history of subduction and closure of the Mozambique ocean and later lateral-escape tectonics.

本研究详细报道了采自中国藏中拉萨地体（Lhasa terrane）的新元古代晚期蛇绿岩岩片与岛弧岩浆岩的铀-铅锆石定年（U–Pb zircon dating）、地球化学以及锶-钕-铪-氧同位素数据，并揭示它们普遍经历了一期独特的变质事件（约660~650 Ma）。结合前人物源分析结果，本研究首次提出拉萨地体应位于新元古代晚期的幼年岛弧体系（马达加斯加-塞舌尔-印度西北部）中，该体系要么处于罗迪尼亚超大陆（Rodinia）周边，要么位于该超大陆的外侧，记录了莫桑比克洋的俯冲与闭合过程，以及后期的侧向逃逸构造演化历史。