Topography associated with crustal flow in continental collisions, with application to Tibet

被引:23
作者
Bendick, R. [1 ]
McKenzie, D. [2 ]
Etienne, J. [3 ]
机构
[1] Univ Montana, Dept Geol, Missoula, MT 59812 USA
[2] Univ Cambridge, Bullard Labs, Cambridge CB3 0EZ, England
[3] Univ Grenoble 1, Spectrometrie Phys Lab, CNRS, F-38402 St Martin Dheres, France
关键词
Numerical solutions; Continental tectonics: compressional; Dynamics of lithosphere and mantle; Asia;
D O I
10.1111/j.1365-246X.2008.03890.x
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Collision between an undeformable indenter and a viscous region generates isostatically compensated topography by solid-state flow. We model this process numerically, using a finite element scheme. The slope, amplitude and symmetry of the topographic signal depend on the indenter size and the Argand number of the viscous region, a dimensionless ratio of gravitational body forces to viscous forces. When applied to convergent continental settings, these scaling rules provide estimates of the position of an indenter at depth and the mechanical properties of the viscous region, especially effective viscosity. In Tibet, forward modelling suggests that some elevated, low relief topography within the northern plateau may be attributed to lower crustal flow, stimulated by a crustal indenter, possibly Indian lithosphere. The best-fit model constrains the northernmost limit of this indenter to 33.7 degrees N and the maximum effective viscosity of Eurasian middle and lower crust to 1 x 10(20) +/- 0.3 x 10(20) Pa s.
引用
收藏
页码:375 / 385
页数:11
相关论文
共 54 条
[1]   Crustal channel flows: 1. Numerical models with applications to the tectonics of the Himalayan-Tibetan orogen [J].
Beaumont, C ;
Jamieson, RA ;
Nguyen, MH ;
Medvedev, S .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 2004, 109 (B6) :B064061-29
[2]   Reconciling lithospheric deformation and lower crustal flow beneath central Tibet [J].
Bendick, R. ;
Flesch, L. .
GEOLOGY, 2007, 35 (10) :895-898
[3]   LIMITS ON LITHOSPHERIC STRESS IMPOSED BY LABORATORY EXPERIMENTS [J].
BRACE, WF ;
KOHLSTEDT, DL .
JOURNAL OF GEOPHYSICAL RESEARCH, 1980, 85 (NB11) :6248-6252
[4]   Spatial variations of flexure parameters over the Tibet-Quinghai plateau [J].
Braitenberg, C ;
Wang, Y ;
Fang, J ;
Hsu, HT .
EARTH AND PLANETARY SCIENCE LETTERS, 2003, 205 (3-4) :211-224
[5]   Bright spots, structure, and magmatism in southern Tibet from INDEPTH seismic reflection profiling [J].
Brown, LD ;
Zhao, WJ ;
Nelson, DK ;
Hauck, M ;
Alsdorf, D ;
Ross, A ;
Cogan, M ;
Clark, M ;
Liu, XW ;
Che, JK .
SCIENCE, 1996, 274 (5293) :1688-1690
[6]   THE EFFECTIVE ELASTIC THICKNESS (T-E) OF CONTINENTAL LITHOSPHERE - WHAT DOES IT REALLY MEAN [J].
BUROV, EB ;
DIAMENT, M .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1995, 100 (B3) :3905-3927
[7]   Correlation between seismic anisotropy and Bouguer gravity anomalies in Tibet and its implications for lithospheric structures [J].
Chen, WP ;
Ozalaybey, S .
GEOPHYSICAL JOURNAL INTERNATIONAL, 1998, 135 (01) :93-101
[8]  
Clark MK, 2000, GEOLOGY, V28, P703, DOI 10.1130/0091-7613(2000)28<703:TOBTEM>2.0.CO
[9]  
2
[10]   Models of crustal flow in the India-Asia collision zone [J].
Copley, Alex ;
McKenzie, Dan .
GEOPHYSICAL JOURNAL INTERNATIONAL, 2007, 169 (02) :683-698