Abstract The collision between the Qiangtang and Lhasa blocks is a critical factor in understanding the geodynamics of the central Tibetan Plateau. However, the process of the Qiangtang-Lhasa collision remains contentious. A direct way to study the history of the Qiangtang-Lhasa collision would be to determine the evolution of the paleolatitude positions of the Qiangtang and Lhasa blocks during the Jurassic-Cretaceous. In this study, we present a combined paleomagnetic and geochronological study of the Early Cretaceous volcanic rocks dated at ~120–115 Ma in the western Qiangtang block. Stepwise thermal demagnetization succeeded in isolating the high-temperature characteristic directions of the samples. The tilt-corrected mean direction of the 16 sampling sites was Ds = 60.9°, Is = 45.9° with ɑ95 = 4.4°, which indicates that the Qiangtang block was situated at 27.6 ± 5.0°N during the Early Cretaceous (~120–115 Ma) (reference point: 32.9°N, 83.5°E). Our new data combined with previous reliable Cretaceous paleomagnetic results for the Lhasa block indicate that the collision between the western parts of the Qiangtang and Lhasa blocks may occur later than 115 Ma. The extent of the western segment of the Bangong-Nujiang Tethys Ocean was ~825 ± 600 km (7.5° ± 5.5° in latitude) at 120–115 Ma.

中文翻译：

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青藏高原羌塘地块早白垩世火山岩的古地磁和U-Pb年代学：对羌塘-拉萨碰撞的启示

摘要 羌塘地块与拉萨地块的碰撞是了解青藏高原中部地球动力学的关键因素。然而，羌塘-拉萨碰撞的过程仍有争议。研究羌塘—拉萨碰撞历史的一个直接途径是确定侏罗纪—白垩纪羌塘和拉萨地块古纬度位置的演化。在这项研究中，我们对羌塘地块西部约 120-115 Ma 的早白垩世火山岩进行了古地磁和地质年代学联合研究。逐步热退磁成功地隔离了样品的高温特性方向。16 个采样点的倾斜校正平均方向为 Ds = 60.9°，Is = 45.9°，ɑ95 = 4.4°，这表明早白垩世（~120-115 Ma）羌塘地块位于27.6±5.0°N（参考点：32.9°N，83.5°E）。我们的新数据结合先前可靠的拉萨地块白垩纪古地磁结果表明，羌塘地块西部与拉萨地块的碰撞可能发生在 115 Ma 之后。班公-怒江特提斯洋西段的范围在 120-115 Ma 时约为 825 ± 600 公里（纬度 7.5° ± 5.5°）。