Dynamic rheology and strength of the lithosphere

Weinberg, Roberto F., Regenauer-Lieb, Klaus and Rosenbaum, Gideon (2009). Dynamic rheology and strength of the lithosphere. In: Geodynamics of the Australian Plate: Abstract Volume. Geodynamics of the Australian Plate Research Meeting: Geology, Geophysics, Hazards & Resources, Caulfield, VIC, Australia, (21-21). 8 - 9 June 2009.

Author Weinberg, Roberto F.
Regenauer-Lieb, Klaus
Rosenbaum, Gideon
Title of paper Dynamic rheology and strength of the lithosphere
Conference name Geodynamics of the Australian Plate Research Meeting: Geology, Geophysics, Hazards & Resources
Conference location Caulfield, VIC, Australia
Conference dates 8 - 9 June 2009
Proceedings title Geodynamics of the Australian Plate: Abstract Volume
Publication Year 2009
Sub-type Published abstract
Start page 21
End page 21
Total pages 1
Language eng
Abstract/Summary The strength of the lithosphere is the integrated force required to cause deformation at a given rate. It has previously been assumed that continents subject to deformation are weaker when they are hotter. We argue that it is not the steady-state heat flow of continents that control their strength, but time-dependent feedback effects, triggered by shear heating and thermal expansion. These effects localize strain into weak shear zones which control the time-dependent strength of continents. Here we present numerical results showing that a cold and strong continent is substantially weakened by development of intensely localized shear zones. In contrast, weakening effects are less efficient in an initially warmer continent where shear zones are more diffuse. This leads to self-organization of the dissipative structures, i.e. the width, length, distribution and heat generation of shear zones. As a result, regardless of initial temperature profiles and crustal thicknesses, all modelled continents yield similar time-dependent strengths that follow similar temporal evolution defining a lithospheric strength attractor. An important implication is that even cold and deeply-rooted Archaean cratons may be vulnerable to deformation as evidenced by a number of cratons that were rifted apart during the break-up of Gondwana.
Subjects 0403 Geology
970104 Expanding Knowledge in the Earth Sciences
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Conference Paper
Collection: School of Earth Sciences Publications
 
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Created: Wed, 05 May 2010, 17:58:32 EST by Tracy Paroz on behalf of School of Earth Sciences