Stress-strength relationship in the lithosphere during continental collision

Research Article| September 01, 2009 Stress-strength relationship in the lithosphere during continental collision Stefan M. Schmalholz; Stefan M. Schmalholz * 1Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092 Zürich, Switzerland *E-mail: schmalholz@erdw.ethz.ch. Search for other works by this author on: GSW Google Scholar Boris J.P. Kaus; Boris J.P. Kaus 1Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092 Zürich, Switzerland2Department of Earth Sciences, University of Southern California, Los Angeles, California 90089, USA Search for other works by this author on: GSW Google Scholar Jean-Pierre Burg Jean-Pierre Burg 1Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information Stefan M. Schmalholz * 1Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092 Zürich, Switzerland Boris J.P. Kaus 1Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092 Zürich, Switzerland2Department of Earth Sciences, University of Southern California, Los Angeles, California 90089, USA Jean-Pierre Burg 1Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092 Zürich, Switzerland *E-mail: schmalholz@erdw.ethz.ch. Publisher: Geological Society of America Received: 30 Nov 2008 Revision Received: 19 Mar 2009 Accepted: 09 Apr 2009 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2009 Geological Society of America Geology (2009) 37 (9): 775–778. https://doi.org/10.1130/G25678A.1 Article history Received: 30 Nov 2008 Revision Received: 19 Mar 2009 Accepted: 09 Apr 2009 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Stefan M. Schmalholz, Boris J.P. Kaus, Jean-Pierre Burg; Stress-strength relationship in the lithosphere during continental collision. Geology 2009;; 37 (9): 775–778. doi: https://doi.org/10.1130/G25678A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Lithospheric strength profiles generated for a shortening continental lithosphere generally predict excessively high differential stresses in the sub-Moho continental mantle; this seems inconsistent with the relative scarcity of earthquakes at this depth. This inconsistency was put forward as evidence for weak mantle rheology. However, this argument implicitly assumes that strength envelopes are valid in actively deforming regions. We test this assumption on two end-member model lithospheres having identical upper crustal rheologies, but with (1) a weak lower crust and strong mantle, and (2) a strong lower crust and weak mantle. For this purpose, we compare one-dimensional (1-D) with 2-D visco-elastoplastic numerical models of continental shortening. The 2-D models show that strongly heterogeneous deformation typically follows initially homogeneous deformation. Lithospheric-scale buckle folds and shear zones result in strain rate variations of as much as three orders of magnitude. Differential stresses in the upper crust are close to yield, as predicted by 1-D models. Stresses in deeper lithospheric regions, however, are significantly smaller than in 1-D models, especially in actively deforming regions. Systematic numerical simulations as a function of temperature and deformation rate reveal that 1-D models are reliable in hot and/or slowly deforming lithospheres only. The relative scarcity of earthquakes at mantle levels should thus be interpreted as an intrinsic consequence of strong lithospheric deformation rather than as evidence for a weak upper mantle. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.