DOI: 10.1038/ngeo2171
论文题名: Topographic relief driven by variations in surface rock density
作者: Braun J. ; Simon-Labric T. ; Murray K.E. ; Reiners P.W.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 7 起始页码: 534
结束页码: 540
语种: 英语
Scopus关键词: crustal thickness
; data set
; erosion
; erosion rate
; gneiss
; mantle convection
; relief
; thermochronology
; topographic mapping
; Borneo
; Pamirs
英文摘要: Earth's surface topography is generated by tectonically induced variations in crustal thickness combined with erosion and, to a lesser degree, by vertical stresses caused by convection in the underlying mantle. Rock hardness and resistance to erosion are also commonly thought to influence topography because hard rocks, such as granites and basalts, usually form topographic highs in the landscape. Here we use analytical and numerical models to simulate the erosion-induced isostatic rebound of rocks. We find that the isostatic rebound that accompanies erosion causes denser rocks to occupy higher elevations in the landscape, thereby creating topographic relief that is proportional to surface rock density differences rather than rock hardness. We quantify this effect, taking into account the flexural strength of the continental lithosphere. We show that in a steady-state erosional setting, density-dependent isostatic rebound can cause the densest rocks to be exhumed at double the rate of surrounding, less-dense rocks and has a stronger effect than typical rock hardness variations. The results imply that denser rock formations should erode faster and therefore be characterized by younger thermochronological ages. Thermochronological data sets from the Kinabalu granite in Borneo and the Shakhdara-Alichur gneiss domes in Pamir confirm this counter-intuitive result. Our findings imply that lateral variations in surface rock density have significant control on the shaping of the large-scale features of Earth's surface. © 2014 Macmillan Publishers Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106487
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: ISTerre, Université Grenoble-Alpes, F-38000 Grenoble, France; Institute of Earth Surface Dynamics, University of Lausanne, CH-1015 Lausanne, Switzerland; Department of Geosciences, University of Arizona, Tucson, AZ, 85721, United States
Recommended Citation:
Braun J.,Simon-Labric T.,Murray K.E.,et al. Topographic relief driven by variations in surface rock density[J]. Nature Geoscience,2014-01-01,7(7)