Abstract The tectono-magmatic evolution of the Bangong-Nujiang Tethyan Ocean (BNO) plays a crucial role in understanding the Tibetan Plateau accretion before the Cenozoic India-Asia collision. The microcontinents and oceanic plateau recognized recently within the BNO provide important clues for constructing the subduction process between BNO and the Qiangtang terrane. In this contribution, we provide a comprehensive overview of the multidisciplinary information from magmatism, metamorphism, stratigraphy, geochronology, geochemistry, Hf isotopic data, ophiolite suites, and paleomagnetism to gain insights into the spatially and temporally related geodynamic processes of the BNO. A compilation of geochronological data indicates that the emplacement of the diverse igneous suites occurred mainly during three stages: stage 1 (190–150 Ma), stage 2 (130–110 Ma), and stage 3 (110–70 Ma). The igneous suites, including granitoids, mafic intrusions and volcanic rocks, formed two arcuate E–W trending belts that parallel the Bangong-Nujiang suture zone and are correlated to the double sided subduction of the BNO. We infer that the BNO initially opened at ~270Ma between the Lhasa terrane and Qiangtang terrane, although the relationship between the BNO and Longmu Tso-Shuanghu paleo-Tethyan ocean is still unclear. Age data related to metamorphism, arc magmatism, supra-subduction zoneophiolites, and sedimentary strata indicate that the northward subduction of the BNO started at ~190 Ma, followed by the subduction of microcontinents beneath the Qiangtang terrane at 195 Ma. In contrast, the subsequent southward subduction of the BNO started at ~170 Ma, resulting in the opening of the Shiquanhe-Namuco ocean. As indicated by the high Mg volcanic suite, intra-ocean subduction within the BNO also occurred during 170-145Ma, possibly related to the resistance from subduction of ocean plateau and slab retreat. Based on evidence from petrology, isotope geochronology, and isotopic geochemistry, we also infer that the magmatic lull during 145-130Ma is related to the slab subduction of ocean plateau beneath the southern Qiangtang subterrane. The closure of the BNO was most likely diachronous, which started as early as Late Jurassic and continued to the late Early Cretaceous (120-110Ma).

中文翻译：

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新生代印亚碰撞前青藏高原增生的奥德赛——班公—怒江缝合带中生代构造演化探讨

摘要 班公-怒江特提斯洋(BNO)的构造-岩浆演化对理解新生代印亚碰撞前青藏高原的增生具有重要意义。近期在 BNO 内发现的微大陆和大洋高原为构建 BNO 与羌塘地体之间的俯冲过程提供了重要线索。在这篇文章中，我们全面概述了来自岩浆作用、变质作用、地层学、地质年代学、地球化学、Hf 同位素数据、蛇绿岩组和古地磁学的多学科信息，以深入了解 BNO 的空间和时间相关的地球动力学过程。年代学数据的汇编表明，不同火成岩套的就位主要发生在三个阶段：阶段 1（190-150 Ma）、第 2 阶段（130-110 Ma）和第 3 阶段（110-70 Ma）。包括花岗岩、镁铁质侵入体和火山岩在内的火成岩套组形成了两条与班公-怒江缝合带平行的东西向弧形带，与BNO的双侧俯冲有关。我们推断BNO最初在拉萨地体和羌塘地体之间的~270Ma开放，尽管BNO与龙木措-双湖古特提斯洋之间的关系尚不清楚。与变质作用、弧形岩浆作用、超俯冲带蛇绿岩和沉积地层相关的年龄数据表明，BNO 向北俯冲开始于~190 Ma，随后在 195 Ma 发生在羌塘地体下方的微大陆俯冲。相比之下，随后的 BNO 向南俯冲开始于~170 Ma，导致狮泉河-纳木科洋的开放。高镁火山岩套件表明，170-145Ma期间也发生了BNO内的洋内俯冲，可能与大洋高原俯冲和板块退缩的阻力有关。根据岩石学、同位素年代学和同位素地球化学的证据，我们还推断145-130Ma期间的岩浆停滞与羌塘南部地下大洋高原板块俯冲有关。BNO的闭合最有可能是历时的，早在侏罗纪晚期就开始，一直持续到早白垩世晚期（120-110Ma）。根据岩石学、同位素年代学和同位素地球化学的证据，我们还推断145-130Ma期间的岩浆停滞与羌塘南部地下大洋高原板块俯冲有关。BNO的闭合最有可能是历时的，早在侏罗纪晚期就开始，一直持续到早白垩世晚期（120-110Ma）。根据岩石学、同位素年代学和同位素地球化学的证据，我们还推断145-130Ma期间的岩浆停滞与羌塘南部地下大洋高原板块俯冲有关。BNO的闭合最有可能是历时的，早在侏罗纪晚期就开始，一直持续到早白垩世晚期（120-110Ma）。