吴运鹏^1,2,,
杨蓉^1,2,,
1. 浙江省地学大数据与地球深部资源重点实验室, 浙江大学地球科学学院, 浙江 杭州 310027
2. 教育部含油气盆地构造研究中心, 浙江 杭州 310027

基金项目: 国家自然科学基金项目（批准号：41972214）资助


详细信息

作者简介: 吴运鹏, 男, 23岁, 硕士研究生, 构造地质学专业, E-mail: yunpeng_wu@zju.edu.cn

通讯作者: 杨蓉, E-mail: royang1985@zju.edu.cn

中图分类号: P931.2

收稿日期:2020-12-18
修回日期:2021-05-25
刊出日期:2021-11-30

Lithologic control on landscape evolution in the drainage basin of Changshan River

WU Yunpeng^1,2,,
YANG Rong^1,2,,
1. Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou 310027, Zhejiang
2. Research Center for Structures in Oil and Gas Bearing Basins, Ministry of Education, Hangzhou 310027, Zhejiang


More Information

Corresponding author: YANG Rong,E-mail:royang1985@zju.edu.cn

MSC: P931.2

--> Received Date: 18 December 2020
Revised Date: 25 May 2021
Publish Date: 30 November 2021


摘要
摘要:地貌形态是构造活动、气候变化和地表过程相互作用的结果。在构造活跃地区，控制地貌演化的因素已有大量讨论，而在构造沉寂地区，相关研究却相对缺乏。常山港是钱塘江南源，其流域盆地位于扬子地块东南缘。新生代以来区内构造运动并不活跃，岩性、地貌较为复杂，河流网络显示出非稳态特征。文章以常山港流域为研究对象，探讨构造沉寂地区控制地貌演化的因素，并使用积分方法对常山港流域进行地貌分析，提取出河道参数X以及河道标准化陡峭指数（k_sn），进而从X图中提取出河道裂点与河道k_sn的空间分布，将其与区域内的断裂分布进行比较。结果显示，河道裂点和河道k_sn与断裂无显著关系，现今常山港流域范围内构造活动性弱，但众多河流裂点的出现说明地貌演化尚未达到稳定状态。河道k_sn空间分布与岩性单元分布的对比结果显示，河道k_sn与岩性差异显著相关，表明岩性是现今控制常山港流域地貌演化的主要因素。
关键词: 构造沉寂/
岩性/
地貌演化/
标准化陡峭指数/
积分方法

Abstract:Tectonic activities, climate change and surface processes all contribute to landscape evolution. The dominant factors of landscape evolution in tectonic active settings were widely discussed, while those in tectonic quiescent regions remain relatively poorly studied. In this study, we chose the drainage basin of Changshan River at the southern margin of the Yangtze Block, Southeast China, where regional post-tectonic geological structures and lithologies are complex with dissected landscapes by river networks, as an instance to study the mechanism of fluvial landscapc evolution in post-tectonic area.
Fistly, we contrasted the X-plot of 81 rivers in various m/n values to find the best-fit value, extracted the channel parameter X and normalized steepness index(k_sn) of the Changshan River networks by using an integral approach and analysed the spatial distribution of knickpoints discerned from X-plots. The appearance of numerous widespread knickpoints indicates disequilibrated landscape in the drainage basin of Changshan River. The distribution pattern of channel k_sn and knickpoints, however, shows no significant spatial correlation with the development of faults in this drainage basin, which demonstrates weak tectonic activity within the drainage basin of Changshan River.
Then we compared k_sn with the classification of local lithology which is divided into 14 lithologic units, and we found that the distribution of channel k_sn is related to that of lithologic units. Channel averaged k_sn of all lithologic units, which shows significant variation between channels of different lithologic units, indicates the diversity of rock erodibility: harder rock such as igneous rock with high k_sn, softer rock such as siltstone and mudstone with low k_sn, and sandstone, conglomerate and limestone with intermediate k_sn.
These analyses show disequilibrated landscapes controlled by the lithologic variety in the tectonic quiescent region. We conclude that lithology is the dominant factor in the landscape evolution in the drainage basin of Changshan River.
Key words:tectonic quiescent/
lithology/
landscape evolution/
normalized steepness index/
integral approach



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