Symmetric alternative to asymmetric rifting models

Abstract

Research Article| November 01, 2004 Symmetric alternative to asymmetric rifting models Thorsten J. Nagel; Thorsten J. Nagel 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10640, USA Search for other works by this author on: GSW Google Scholar W. Roger Buck W. Roger Buck 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10640, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Thorsten J. Nagel 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10640, USA W. Roger Buck 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10640, USA Publisher: Geological Society of America Received: 30 Apr 2004 Revision Received: 23 Jul 2004 Accepted: 06 Aug 2004 First Online: 03 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2004) 32 (11): 937–940. https://doi.org/10.1130/G20785.1 Article history Received: 30 Apr 2004 Revision Received: 23 Jul 2004 Accepted: 06 Aug 2004 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Thorsten J. Nagel, W. Roger Buck; Symmetric alternative to asymmetric rifting models. Geology 2004;; 32 (11): 937–940. doi: https://doi.org/10.1130/G20785.1 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 We describe the first numerical simulation of continental rifting that reproduces the three major structures observed at magma-poor margins such as the Galicia Margin west of the Iberian Peninsula or the Apulia Margin in the Alps: (1) Distal continental margins consist of fault-bounded blocks separated by oceanward-dipping normal faults. (2) At the tip of the continent, lower crust is scarcely preserved or absent, and upper crust directly overlies exhumed mantle. (3) The base of the rotated crustal blocks is a prominent seismic reflector and represents a high strain zone with a top-to-the-ocean sense of shear. In our model, these structures do not reflect asymmetric rift geometry at a lithospheric scale. Instead, they derive from upper-crustal collapse over a mid-crustal shear zone into the rift center and are present on both sides of the rift axis. The model has a horizontal weak zone in the middle crust on top of strong lower crust and a localized vertical zone of thermal weakness in the rift center. We hypothesize that the development of a thermal perturbation and associated strain localization in the deeper lithosphere may cause the transition from widely distributed faulting and crustal thinning to constricted faulting directed toward a well-defined rift center. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.