globalchange  > 气候变化事实与影响
CSCD记录号: CSCD:5944987
论文题名:
河流瞬时地貌:特征、过程及其构造-气候相互作用内涵
其他题名: TRANSIENT FLUVIAL LANDSCAPE: FEATURES, PROCESSES AND ITS IMPLICATION FOR TECTONIC-CLIMATE INTERACTION
作者: 李雪梅; 张会平
刊名: 第四纪研究
ISSN: 1001-7410
出版年: 2017
卷: 37, 期:2, 页码:327-333
语种: 中文
中文关键词: 瞬时地貌 ; 河流纵剖面 ; 裂点 ; 地貌过程 ; 构造-气候
英文关键词: transient landscape ; process ; tectonics-climate interaction ; review
WOS学科分类: GEOSCIENCES MULTIDISCIPLINARY
WOS研究方向: Geology
中文摘要: 河流系统在造山带长期演化过程中会趋于均衡状态,在纵剖面形态上表现为光滑的下凹样式。均衡地貌常常由于构造活动、气候变化等条件的改变而被打破,在达到下一个均衡状态之前,会一直处于不均衡的瞬时演化阶段,此时河流系统的地貌特征则称为瞬时地貌。通过河流瞬时地貌研究,可以理解造山带内部河流系统的演化阶段、构造活动以及气候变化的强弱、幅度等信息。本文在简要概述河流瞬时地貌概念的基础上,引出瞬时地貌在河流纵剖面的典型标志,即河流裂点;进而详细介绍河流裂点的形成过程及其机制;以河流纵剖面分析为基础,提出了河流裂点识别和提取方法;再以北美内华达山系,南美安第斯山脉以及青藏高原东南缘、东北缘等地区为例,总结了瞬时地貌研究中河流纵剖面分析的主要手段,并探讨了上述研究所揭示出的构造-气候相互作用内涵及其意义。
英文摘要: Within the orogenic belts of long-term evolution history, river system will eventually reach an equilibrium state. Under this steady state condition,the rate of vertical incision by a river channel is exactly balanced by rock uplift, and the gradient of the river channel is inversely proportional to the upstream drainage area. Therefore, the longitudinal profiles of steady state river channels are smooth and concave-upward. If the steady state condition is perturbed by tectonic activity,climate change and other conditions change,and it would have been in the evolution of transient non-equilibrium phase until reaching the next equilibrium state. We can understand the stages of evolution of drainage system in orogenic belts,tectonic activity,as well as the strength and scope of climate change by studying river transient landscape. After a brief overview of concepts of river transient landscape, we will introduce the knickpoint as the typical expression of the transient landscape in river longitudinal profile. Knickpoints, or comparatively diffuse knickzones, are convex-upward segments within the river profile, in which channel gradient changes very rapidly across knickzones. Initiation of the knickpoint is usually controlled by the lithologic difference, transient knickzones may be generated by differential uplift (thrust and normal faulting), and/or base level change due to eustatic change of sea level or drainage network capture. We propose the up-to-data methods of identification and extraction of kinckpoint on the basis of river longitudinal profile analysis. Longitudinal river profiles contain information about the mechanisms of fluvial incision. Recently, the stream-power incision model has been widely used to analyze river erosion rate and landscape evolution. We know channel concavity and steepness may be quantified by linear regression of channel slope and drainage area data, plotted in log-log space. Channel concavity is equivalent to the slope of the regression line and steepness is equivalent to the y-intercept. A channel reach with an abnormally high gradient will plot above the regression line. Therefore, by referring to the higher gradient in the log-log space,together with analyzing the general longitudinal profile,we can precisely locate the knickpoints along the channel profile. Following the summary of river longitudinal profile analysis in transient landscape study,we aim to explore the significance of tectonic-climate interactions the available examples, such as the Sierra Nevada Mountain range in North America, the Andes range in South America, the southeastern and northeastern margin of the Tibet Plateau. Clark et al. (2005) revealed geomorphologic evolution of the Sierra Nevada Mountains by using channel parameters to reconstruct paleo-elevation profile of the channel, estimate the total river incision and paleo-topography relief. Schlunegger et al. (2011) explored the relationship between geometry of river basin, mode of uplift and regional precipitation by analyzing channel steepness index, concave index and gradient of regional precipitation.
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/152371
Appears in Collections:气候变化事实与影响

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作者单位: 中国地震局地质研究所, 地震动力学国家重点实验室, 北京 100029, 中国

Recommended Citation:
李雪梅,张会平. 河流瞬时地貌:特征、过程及其构造-气候相互作用内涵[J]. 第四纪研究,2017-01-01,37(2):327-333
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