晚更新世以来长江流域河流阶地年龄数据库及其对成因分析的指示意义  

River Terrace Age Database in Yangtze River Basin,China Since Late Pleistocene and Its Implications for Genetic Analysis

作　　者：李龙康 许冰[1,2] 崔慧琪 LI Long-kang;XU Bing;CUI Hui-qi(Key Laboratory of Lithospheric Evolution and Environmental Coevolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地质与地球物理研究所岩石圈演化与环境演变重点实验室,北京100029 [2]中国科学院大学,北京100049

出　　处：《地球科学与环境学报》2025年第1期34-46,共13页Journal of Earth Sciences and Environment

基　　金：第三次新疆综合科学考察项目(2022xjkk0300)。

摘　　要：研究长江流域河流阶地的形成规律,对深入理解河流阶地的主要驱动因素,预测长江流域演化趋势以及保障沿岸人民生存发展具有重要意义。系统收集并整理了长江流域河流阶地的660条年代学数据,建立了河流阶地年龄数据库及其年龄概率密度函数,并探讨了长江流域河流阶地的形成机制。结果表明:近200 ka以来,长江流域中游和上游地区河流阶地概率密度曲线在约11 ka、约23 ka、约40 ka、约44.8 ka、约56.25 ka等多个时期出现了明显的峰值,这些峰值与全球气候变暖、黄土高原古降水量和洞穴氧同位素值的剧烈波动时期高度吻合,长江流域上游地区的河流阶地在山地地区的发育频率较高;长江流域中游和上游地区河流阶地年龄概率密度曲线的峰值主要出现在全球气候突变期,且河流阶地在构造抬升强烈的时期及地区发育更广泛;长江流域河流阶地是在构造运动和气候变化共同作用下形成的,其中气候的剧烈变化作为触发因子通过破坏河道稳定性,促使河流下切并形成阶地,而区域构造抬升运动则为河流提供了下切的空间,使得河流阶地对气候变化的响应更加敏感,从而推动了河流阶地的形成,尤其在气候相对变暖的时期,河流阶地的形成频率明显更高。The Yangtze River as the largest river in Asia,plays a crucial role in understanding the primary driving factors behind river terrace formation,predicting the evolutionary trends of Yangtze River Basin,and ensuring the survival and development of the surrounding populations.660 chronological data of river terraces in Yangtze River Basin were systematically collected and organized,a river terrace age database was established,and an age probability density function was constructed,and the formation mechanisms of river terraces in the region were explored.The results show that over the past 200 ka,the probability density curve of river terrace ages in the upper and middle Yangtze River Basin exhibits clear peaks at~11 ka,~23 ka,~40 ka,~44.8 ka,and~56.25 ka,which correlate strongly with periods of global warming,significant shifts in paleoprecipitation of Loess Plateau,and changes in cave oxygen isotope values,the frequency of river terrace development is higher in the mountainous areas of the upper Yangtze River Basin;the age peaks of the river terrace probability density curve in the middle and upper Yangtze River Basin primarily coincide with global climate abrupt events,the formation of river terraces is more widespread in regions and periods of intense tectonic uplift;river terraces in Yangtze River Basin are formed under the combined influence of tectonic activity and climate change;climate's abrupt changes act as short-term trigger mechanisms,destabilizing river channels and driving incision that leads to terrace formation,while regional tectonic uplift provides the necessary space for river incision,thereby enhancing the sensitivity of river terraces to climate fluctuations;this,in turn,facilitates the formation of river terraces,with a notably higher frequency of terrace formation during relatively warmer climatic periods.

关 键 词：年龄数据库 概率密度函数 河流阶地 气候因子 气候突变 构造抬升 河流失稳 长江流域 

分 类 号：P532[天文地球—古生物学与地层学] P931.1[天文地球—地质学]