An intraoceanic Trans-Tethyan subduction zone has been identified in both the Kohistan-Ladakh arc and the West Burma Terrane. This has significant implications for the India-Eurasia collision. Concurrently, the dismembered ophiolites within the Yarlung-Tsangpo Suture Zone likely originated from the intraoceanic Trans-Tethyan subduction zone or the Andean-type southern Eurasian continental margin. A paleomagnetic study was conducted on the Lower Cretaceous (∼120–130 Ma) mafic dykes in the Xiugugabu ophiolite to resolve the uncertainty of its origin. The characteristic remanent magnetization (ChRM) obtained through stepwise thermal demagnetization successfully passed consistency/fold and reversal tests. After tilt correction, the overall mean direction of the ChRM was D = 296.9°, = −25.5°, k = 47.6, α = 4.5°, and = 22, indicating a paleolatitude of 13.4°N/S and a paleopole at 15.0° N, 326.6°E with A = 3.8°. Compared with previous paleomagnetic data from the Trans-Tethyan subduction zone, our findings strongly support the involvement of the Xiugugabu ophiolite in the intraoceanic Trans-Tethyan subduction zone. This finding reinforces the hypothesis that there were two distinct subduction zones in the Neotethyan Ocean during the Early Cretaceous. One subduction zone was situated on the southern margin of the Gangdese Arc. The second was the intraoceanic subduction zone, located approximately 3500 km from the southern margin of Eurasia, in the southern hemisphere. Our results also support a multistage India–Eurasia collision process involving continental plates, intraoceanic arcs, and terranes within the Neo-Tethyan Ocean.

中文翻译：

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修古嘎布蛇绿岩中基性岩脉的古纬度：对洋内跨特提斯俯冲带和多期印度-欧亚大陆碰撞的影响


在科希斯坦-拉达克弧和西缅甸地体中均发现了洋内跨特提斯俯冲带。这对印度-欧亚大陆碰撞具有重大影响。同时，雅鲁藏布江缝合带内的肢解蛇绿岩可能起源于洋内跨特提斯俯冲带或安第斯型欧亚大陆南部边缘。对秀古嘎布蛇绿岩中的下白垩统（~120-130 Ma）基性岩脉进行了古地磁研究，以解决其起源的不确定性。通过逐步热退磁获得的特征剩磁（ChRM）成功通过了一致性/折叠和反转测试。倾斜校正后，ChRM 的总体平均方向为 D = 296.9°、= -25.5°、k = 47.6、α = 4.5°、= 22，表明古纬度为 13.4°N/S，古极点为 15.0°北纬 326.6°E，A = 3.8°。与之前跨特提斯俯冲带的古地磁数据相比，我们的研究结果有力地支持了秀古嘎布蛇绿岩参与了洋内跨特提斯俯冲带。这一发现强化了这样的假设：早白垩世新特提斯洋存在两个不同的俯冲带。冈底斯岛弧南缘有一个俯冲带。第二个是洋内俯冲带，位于南半球，距离欧亚大陆南缘约3500公里。我们的结果还支持印度-欧亚大陆的多阶段碰撞过程，涉及大陆板块、洋内弧和新特提斯洋内的地体。