Abstract The Early Cretaceous collision between the Lhasa and Qiangtang terranes is one of the critical tectonic events that shaped the southern margin of the Eurasian continent, and that impacted the formation of the Cenozoic Tibetan Plateau. However, how far north this collision affected the structural and sedimentary geology of the Early Cretaceous remains uncertain. To address this issue, we present results from an integrated study of Lower Cretaceous strata in the Northeastern Qaidam Basin (NEQB), northern Tibetan Plateau, based on field observations, detrital zircon U–Pb analyses, and seismic profile interpretations. The Lower Cretaceous mainly consists of deltaic, fluvial, and alluvial sandstone and conglomerate with a pattern of orogeny-related molasse deposits and a provenance in the nearby South Qilian Shan to the north. A number of south-directed reverse faults developed and formed piggy-back basins in the Early Cretaceous. These reverse faults remained active and affected erosion during the Late Cretaceous, leaving an unconformity above the Cretaceous strata. These observations indicate a foreland-like NEQB due to the uplift and southward thrusting of the South Qilian Shan in the Early Cretaceous. We further interpreted the NEQB and the South Qilian Shan to be the northern edge of the compressional regime associated with the Lhasa-Qiangtang collision in the Early Cretaceous, which contrasts with the contemporaneous extensional setting in the North Qilian Shan and further north. We also observed that some Early Cretaceous faults were rejuvenated as major thrusts in the South Qilian Shan thrust belt in the Cenozoic. For the first time, this study maps the northern boundary of the Late Mesozoic Qiangtang Plateau and highlights a protracted influence on Tibetan Plateau tectonism since the Early Cretaceous.

中文翻译：

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青藏高原柴达木盆地东北部早白垩世前陆样及其构造意义：来自沉积调查、碎屑锆石 U-Pb 分析和地震剖面的见解

摘要 拉萨与羌塘地体早白垩世碰撞是欧亚大陆南缘形成的关键构造事件之一，对青藏高原的形成产生了影响。然而，这次碰撞对早白垩世的构造和沉积地质的影响究竟有多大仍不确定。为了解决这个问题，我们根据野外观测、碎屑锆石 U-Pb 分析和地震剖面解释，对青藏高原北部柴达木盆地东北部 (NEQB) 下白垩统地层进行了综合研究。下白垩统主要由三角洲、河流和冲积砂岩和砾岩组成，具有与造山作用相关的磨拉石沉积模式，物源位于北部附近的南祁连山。早白垩世多条南向逆断层发育并形成背负盆地。这些反向断层在晚白垩世期间仍然活跃并影响侵蚀，在白垩纪地层上方留下不整合面。这些观测表明，由于早白垩世南祁连山的抬升和南冲，形成了前陆状NEQB。我们进一步将NEQB和南祁连山解释为与早白垩世拉萨-羌塘碰撞相关的挤压机制的北缘，这与北祁连山和更北部的同期伸展环境形成对比。我们还观察到一些早白垩世断裂在新生代南祁连山逆冲带中作为主要逆冲断层恢复活力。首次，