The Eocene/Oligocene transition (EOT) was marked by a major environmental reorganization accompanied by an abrupt shift of the Earth system from “greenhouse” to “icehouse” conditions, which is well documented in marine sedimentary records. Although there are an increasing number of terrestrial records documenting this major climatic reorganization, high-resolution sedimentologic and petrographic evidence from terrestrial contexts is sparse, and the processes driving the EOT which affected the formation of continental detrital sediments are unclear. Here we present evidence from lithofacies, lithology, sediment color, and sediment grain size from a section in the northern part of the NE Tibetan Plateau (TP), which spans the EOT. The results indicate that major changes in the grain size (coarsening), chromaticity a* (redness increasing), thick gypsum layers (disappearance), structural maturity (decreasing roundness and sorting), sediment compositional maturity (increasing content of lithic, feldspar and mafic minerals) of silt and sandstone occurred at ~33.8 Ma, which were considered as a response to the EOT. The synchronous changes in sedimentological and petrological characteristics and weathering proxies in the Qaidam Basin (QB) and neighboring basins suggest that the climate-forced weakening of weathering and erosion may be the direct cause of those proxy change. Global cooling is speculated to have been the first-order driving factor in regulating climatic evolution and weathering responses in the QB and even the Asian interior at the EOT. A conceptual model is presented which summarizes the mechanisms responsible for the observed changes in sedimentary characteristics across the EOT.

始新世/渐新世过渡（EOT）的标志是一次重大的环境重组，伴随着地球系统从“温室”到“冰屋”条件的突然转变，这在海洋沉积记录中已得到充分证明。尽管越来越多的陆地记录证明了这种重大的气候重组，但来自陆地背景的高分辨率沉积学和岩石学证据稀少，而且影响EOT的影响陆相碎屑沉积物形成的过程尚不清楚。在这里，我们从东北青藏高原（TP）北部一段横跨EOT的岩相，岩性，沉积物颜色和沉积物粒度提供了证据。结果表明，晶粒尺寸（粗化），色度a *发生了重大变化（发红），厚石膏层（消失），结构成熟度（圆度和分选减少），粉砂和砂岩的沉积物组成成熟度（片状，长石和镁铁质矿物含量增加）在〜33.8 Ma发生，被认为是对EOT的回应。柴达木盆地（QB）及其邻近盆地的沉积，岩石学特征和风化代理的同步变化表明，气候强迫的风化和侵蚀减弱可能是这些代理变化的直接原因。据推测，全球冷却是调节QB甚至EOT亚洲内部气候变化和风化响应的首要驱动因素。