Ductile deformation zones in Blue Ridge basement rocks and estimation of finite strains

Research Article| October 01, 1979 Ductile deformation zones in Blue Ridge basement rocks and estimation of finite strains GAUTAM MITRA GAUTAM MITRA 1Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland 21218 Search for other works by this author on: GSW Google Scholar Author and Article Information GAUTAM MITRA 1Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland 21218 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1979) 90 (10): 935–951. https://doi.org/10.1130/0016-7606(1979)90<935:DDZIBR>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation GAUTAM MITRA; Ductile deformation zones in Blue Ridge basement rocks and estimation of finite strains. GSA Bulletin 1979;; 90 (10): 935–951. doi: https://doi.org/10.1130/0016-7606(1979)90<935:DDZIBR>2.0.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 SocietyGSA Bulletin Search Advanced Search Abstract The deformation of basement massifs in orogenic belts presents several fundamental problems—what is their mechanical response to deformation, how does the strain vary through them, and how does one explain the "missing" basement suggested by palinspastic reconstructions? The Blue Ridge anticlinorium in northern Virginia has at its core Precambrian granitic basement deformed during the late Paleozoic orogeny; there is a major cleavage fan across this anticlinorium. The deformation in the basement is inhomogeneous, being concentrated along narrow zones of ductile deformation where rocks are mylonitized. These zones may range in size from microscopic dimensions to tens of metres wide, and they tend to develop preferentially in certain basement rock types. Narrow deformation zones in coarse granitic rocks often occur in conjugate sets whose bisector is the regional cleavage. Integration of strain across these zones added to the penetrative strain, calculated from the rotation of these zones, and the shortening due to displacement on thrust faults, give the total shortening of the basement. Such shortening must be taken into account in attempting any kind of geologic reconstructions. 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.