近日，中国地质大学（武汉）曹凯团队研究了西藏东南部晚新生代河流构造挤压改造形成现代水系。该研究于2025年9月22日发表在《美国科学院院刊》杂志上。

西藏东南部水系的形成和组织反映了构造、气候和景观演变之间的反馈。然而，研究组对这些相互作用的理解尚不清楚。他们认为，河流切割历史及其推移质来源为重建古代河流系统的演变提供了补充证据。金沙江中游（长江上游）峡谷的锆石和磷灰石（U-Th）/He数据揭示了18-17 Ma和8-7 Ma的两次加速河流切割事件。前一次切割事件的发生与金沙江中上游和澜沧江沿岸的其他切割事件同时发生，暗示了它们的水文联系和南流河流系统的形成。

此外，红河流域渐新世晚期-中新世河流冲积沉积物的碎屑年代学和热年代学数据对其年龄和物源提供了限制，表明在中新世早期出现了贯穿的古红河。这条古老的红河与金沙江上游断开，但与雅砻江（长江上游支流）相连，形成了另一个向南流动的河流系统。景观演化模型支持这样一种观点，即这些南流河流在中新世中期被向西传播的长江相继捕获，产生了西藏东南部的现代水系。金沙江中上游和下游的整合表现为沿峡谷从13-9Ma到6-5Ma的河流切口向上游传播的加速。研究组在西藏东南部的研究结果表明，挤压构造驱动了造山带规模的地形变化、河流重组和同时代生物多样性的增加。 

附：英文原文

Title: Late Cenozoic river reorganization related to tectonic extrusion formed the modern drainage system in southeastern Tibet

Author: Cao, Kai, Wang, Guocan, Harrison, T. Mark, Yuan, Xiaoping, Leloup, Philippe Hervé, Kusky, Timothy M., Cao, Licheng, Shen, Xiaoming, Cheng, Yizhuang, Yao, Junzhe, He, Xiang, Zhu, Zongmin, Xie, Shucheng

Issue&Volume: 2025-9-22

Abstract: The formation and organization of southeastern Tibetan river systems reflect feedbacks between tectonics, climate, and landscape evolution. However, our understanding of these interactions remains unclear. We approach this issue from the view that the river incision histories and their bedload provenance provide complementary evidence for reconstructing the evolution of the ancient river system. Zircon and apatite (U-Th)/He data from the middle Jinsha (upper Yangtze) River gorge reveal two episodes of accelerated river incision at 18-17 Ma and 8-7 Ma. The onset of the former incision event, coeval with other incision events along the upper-middle Jinsha and Lancang Rivers, implies their hydrological connection and formation of a south-flowing river system. Additionally, detrital geochronology and thermochronology data of late Oligocene–Miocene fluvial-alluvial sediments along the Red River valley provide constraints on their ages and provenance, suggesting emergence of a throughgoing paleo-Red River in the early-middle Miocene. This ancient Red River was disconnected from the upper Jinsha River but connected with Yalong River (upper Yangtze tributary), forming another south-flowing river system. Landscape evolution modelling supports the view that these south-flowing rivers were successively captured by the westward-propagating Yangtze River in the middle-late Miocene, giving birth to the modern drainages of southeastern Tibet. The resultant integration of the upper-middle and lower Jinsha River is manifested by the progressively upstream-propagating acceleration in river incision from 13-9 Ma to 6-5 Ma along the gorges. Our findings from southeastern Tibet suggest that orogen-scale topographic change, river reorganization, and a coeval increase in biodiversity were driven by extrusion tectonics.

DOI: 10.1073/pnas.2424554122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2424554122