末次冰期河流下切行为对气候变化的响应模式

发布时间：2018-05-28 00:40

本文选题：末次冰期 + 河流阶地　；参考：《现代地质》2017年02期

【摘要】：末次冰期是距离人类最近的一次冰期,气候异常寒冷且存在高频高幅波动,河流系统如何响应冰期气候的变化值得关注与研究。基于河流系统对气候变化的敏感响应,传统的经典地貌理论认为河流下切在河流阶地形成过程中起着至关重要的作用,河流的下切行为发生在间冰期或者冰期向间冰期的过渡阶段,堆积行为发生于冰期,然而近年来最新的河流地貌研究成果表明,末次冰期河流下切较为普遍。首先对河流阶地形成的传统模式进行总结分析,认为单纯的构造驱动模式存在不合理性,气候也发挥着重要的调节作用;单一的气候变化无法驱动多级且高差较大阶地的形成,地壳抬升往往是必要因素;气候变化是引发河流堆积-下切行为转换形成河流阶地的关键因素。其次通过前人的研究案例总结出末次冰期河流下切行为响应气候变化的三种模式:(1)气候的高度不稳定性引发大规模的洪水事件驱动河流快速下切;(2)快速隆升区气候高频波动叠加构造抬升驱动河流下切;(3)沿海平原地区海平面大幅度下降驱动河流下切。这三种模式对于理解末次冰期河流系统对短尺度高频气候变化的响应以及对河流阶地成因的判断具有十分重要的指导意义。
[Abstract]:The last glacial age is the closest ice age to human being. The climate is extremely cold and there are high frequency and high amplitude fluctuations. How the river system responds to the climate change of the glacial period deserves attention and research. Based on the sensitive response of river system to climate change, the traditional classical geomorphological theory holds that river undercutting plays an important role in the formation of river terraces. The undercutting behavior of rivers occurs in the interglacial or the transition from interglacial to interglacial, and the accumulation occurs in glacial period. However, the latest research results of river landforms in recent years show that the last glacial river undercutting is more common. Firstly, the traditional model of river terrace formation is summarized and analyzed. It is concluded that the simple tectonic driving model is irrational, and climate also plays an important role in regulating the formation of multi-level and high-difference terraces, a single climate change can not drive the formation of multi-level and high-difference terraces. Crustal uplift is often a necessary factor, and climate change is a key factor in the formation of river terraces. Secondly, through previous research cases, three models of river down-cutting behavior in the last glacial period responding to climate change were summarized. (1) the high instability of climate caused large-scale flood events to drive the rapid down-cutting of rivers. 2) the rapid uplift of gas in the region. The high frequency fluctuating superimposed tectonic uplift drives the river to cut down. (3) the sea level in the coastal plain area drops sharply and drives the river to cut down. These three models are of great significance in understanding the response of the last glacial fluvial system to short-scale high-frequency climate change and in judging the origin of river terraces.
【作者单位】：中国地质大学(北京)地球科学与资源学院;北京矿产地质研究院;中国地质科学院地质力学研究所;
【基金】：内蒙古国土资源厅2014年地质遗迹保护专题“内蒙古巴彦淖尔狼山晚更新世(Qp3)以来构造运动及其环境效应研究”(BSZFCG2015-HW-00403) 中国地质调查局地质调查工作项目“金沙江流域河谷区第四纪地质环境调查”(12120114001501)
【分类号】：P532

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