渭河盆地河流阶地演化及其构造—气候意义  

Fluvial terrace evolution and its tectonic—climatic significance in the Weihe Basin

作　　者：王迎国 常宏[1] 周卫健[1,2] WANG Yingguo;CHANG Hong;ZHOU Weijian(State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an,710061;Shaanxi Key Laboratory of Accelerator Mass Spectrometry(AMS)Technology and Application,National Center for AMS in Xi’an,Xi’an,710061;University of Chinese Academy of Science,Beijing,100049)

机构地区：[1]中国科学院地球环境研究所,黄土与第四纪地质国家重点实验室,西安710061 [2]陕西省加速器质谱技术及应用重点实验室,西安加速器质谱中心,西安710061 [3]中国科学院大学,北京100049

出　　处：《地质论评》2021年第4期1033-1049,共17页Geological Review

基　　金：中国科学院战略性先导科技专项(B类)(编号:XDB40000000);国家自然科学基金重点项目(编号:41930321)的成果。

摘　　要：渭河盆地渭河及其各支流演化历史与区域构造、气候变化密切相关,因此盆地内各河流阶地的成因和演化是研究渭河盆地环境演变的重要科学问题。河流阶地之上黄土的磁性地层学被普遍用来获得盆地内河流阶地形成的年龄。尽管粉尘物质在第四纪以来覆盖了盆地大范围区域,河流阶地形成与粉尘物质最终保存在阶地之间可能还存在一定的时间差异。所以,尽管借鉴黄土—古土壤序列的区域对比,能够推断河流阶段的年代范围,仍需更多绝对年龄方法对其进行约束。本文通过渭河盆地内渭河不同支流河流阶地形成年代、拔河高度等的综合分析,结合大范围区域隆升过程及第四纪气候演化序列对比,发现并不是所有气候变化的重要节点就有相应的河流阶地形成,河流阶地年龄空间分布也有一定的区域性特征,提出渭河盆地河流演化与构造运动造成潜能及气候变化诱发这些潜能的释放密切相关。所以,渭河盆地河流阶地主要是在大范围的构造隆升和气候变化共同作用下的构造—气候旋回阶地。渭河盆地水系演化史的重建对全面认识黄河中游水系早期的形成演化具有重要意义,尤其是解决渭河、黄河贯通三门峡的争议,但还需要更多可靠的不同河流地质证据和多种分析数据的印证和约束。The evolution history of the Weihe River and its tributaries is closely related to regional tectonic deformation and climate changes.Therefore,the genesis and temporal evolution of river terraces in the basin is an important scientific issue for studying the environmental evolution of the Weihe Basin.The loess magnetostratigraphy is generally used to obtain the relatively ages to terraces in the Weihe Basin.Although dust materials have covered a large area of the basin since the Quaternary,there may still be a certain time difference between the formation of river terraces and the final preservation of dust materials on the terraces.Although the regional comparison of loess—paleosol sequence can be used to infer the age range of fluvial stage,more absolute age methods are still needed to constrain it.Based on the comprehensive analysis of the formation ages and heights above river of the different tributary river terraces in the Weihe Basin,combined with the large-scale regional uplift and the Quaternary climate evolution sequence for comparison,it is found that not every important node of climate change corresponds to fluvial terraces,and the age spatial distribution of river terraces also has certain regional characteristics.Therefore,it is proposed that the evolution of rivers in the Weihe Basin is closely related to the potentials caused by tectonic movement and the release of these potentials induced by climate change.Above all,the river terraces in the Weihe Basin are mainly tectonic—climate cycle terraces under the combined action of largescale tectonic uplift and climate change.Reconstruction of the evolution history of the fluvial system in the Weihe Basin is of great significance for a comprehensive understanding of the early formation and evolution of the fluvial system in the middle reaches of the Yellow River,especially for solving the dispute over the time when the Weihe River and the Yellow River run through the Sanmen Gorge.However,more reliable geological evidences and various analytical data

关 键 词：渭河盆地 河流阶地 年代分布 构造阶段 气候演变 

分 类 号：P53[天文地球—古生物学与地层学]