Influence of the state of stress on the brittle-ductile transition in granitic rock: Evidence from fault steps in the Sierra Nevada, California

Abstract

Research Article| July 01, 1992 Influence of the state of stress on the brittle-ductile transition in granitic rock: Evidence from fault steps in the Sierra Nevada, California Roland Bürgmann; Roland Bürgmann 1Department of Geology, Stanford University, Stanford, California 94305-2115 Search for other works by this author on: GSW Google Scholar David D. Pollard David D. Pollard 1Department of Geology, Stanford University, Stanford, California 94305-2115 Search for other works by this author on: GSW Google Scholar Author and Article Information Roland Bürgmann 1Department of Geology, Stanford University, Stanford, California 94305-2115 David D. Pollard 1Department of Geology, Stanford University, Stanford, California 94305-2115 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (7): 645–648. https://doi.org/10.1130/0091-7613(1992)020<0645:IOTSOS>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Roland Bürgmann, David D. Pollard; Influence of the state of stress on the brittle-ductile transition in granitic rock: Evidence from fault steps in the Sierra Nevada, California. Geology 1992;; 20 (7): 645–648. doi: https://doi.org/10.1130/0091-7613(1992)020<0645:IOTSOS>2.3.CO;2 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 Left-lateral strike-slip faults in the Lake Edison granodiorite (central Sierra Nevada, California) are composed of en echelon segments. Relative displacements across the faults apparently are transferred between segments by ductile shearing at right steps, and by extensional fracturing at left steps. The granodiorite within right steps displays mylonitic foliation, and thin sections show textures in quartz associated with dislocation glide, recovery processes, and dynamic recrystallization, whereas textures in feldspar are related to fracturing. Only centimetres outside the right steps, the rock fabric is approximately isotropic and deformation is accommodated by mineralized opening- mode fractures. The stress field calculated for the right-step geometry, when a boundary element model is used, shows an increase in mean compressive stress of up to 25 MPa within the step relative to that outside. This difference in stress apparently produced the contrasting behaviors of the granitic rock. Experimentally derived power-law flow laws do not predict these behaviors. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.