Interaction between mantle and crustal detachments: a non-linear system controlling lithospheric extension

Rosenbaum, Gideon, Regenauer-Lieb, Klaus and Weinberg, Roberto F. (2009). Interaction between mantle and crustal detachments: a non-linear system controlling lithospheric extension. In: The 17th Deformation Mechanisms, Rheology and Tectonics 2009 Martin Casey Memorial Meeting: Abstract Volume. DRT 2009: Deformation, Rheology & Tectonics 2009, Liverpool, U.K., (136-136). 7-9 September 2009.

Author Rosenbaum, Gideon
Regenauer-Lieb, Klaus
Weinberg, Roberto F.
Title of paper Interaction between mantle and crustal detachments: a non-linear system controlling lithospheric extension
Conference name DRT 2009: Deformation, Rheology & Tectonics 2009
Conference location Liverpool, U.K.
Conference dates 7-9 September 2009
Convener The University of Liverpool; The University of Manchester
Proceedings title The 17th Deformation Mechanisms, Rheology and Tectonics 2009 Martin Casey Memorial Meeting: Abstract Volume
Place of Publication Liverpool, U.K.
Publisher The University of Liverpool
Publication Year 2009
Sub-type Published abstract
Start page 136
End page 136
Total pages 1
Collection year 2010
Formatted Abstract/Summary
We use numerical modelling to investigate the development of crustal and mantle detachment faults during lithospheric extension. Our models simulate a wide range of rift systems with varying values of crustal thickness and heat flow, showing how strain localization in the mantle interacts with localization in the upper crust and controls the evolution of extensional systems. Model results reveal a richness of structures and deformation styles, which grow in response to a self-organized mechanism that minimizes the internal stored energy of the system by localizing deformation at different levels of the lithosphere. Crustal detachment faults are well developed during extension of overthickened (60 km) continental crust, even when the initial heat flow is relatively low (50 mW/m2). In contrast, localized mantle deformation is most pronounced when the extended lithosphere has a normal crustal thickness (30-40 km) and an intermediate (60-70 mW/m2) heat flow. Results show a nonlinear response to subtle changes in crustal thickness or heat flow, characterized by abrupt and sometime unexpected switches in extension modes (e.g. from diffuse rifting to effective lithospheric-scale rupturing) or from mantle- to crust-dominated strain localization. We interpret this non-linearity to result from the interference of doming wavelengths. Disharmony of crust and mantle doming wavelengths results in efficient communication between shear zones at different lithospheric levels, leading to rupturing of the whole lithosphere. In contrast, harmonious crust and mantle doming inhibits interaction of shear zones across the lithosphere and results in a prolonged rifting history prior to continental breakup.
Subjects 970104 Expanding Knowledge in the Earth Sciences
040313 Tectonics
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Presented during Poster Programme "GROUP A: Crustal Kinematics & Mechanics" as Poster A8.

Document type: Conference Paper
Collection: School of Earth Sciences Publications
 
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Created: Wed, 05 May 2010, 18:30:06 EST by Tracy Paroz on behalf of School of Earth Sciences