Shear structures within deformed granites: Mechanical and thermal indicators

Research Article| December 01, 1989 Shear structures within deformed granites: Mechanical and thermal indicators Denis Gapais Denis Gapais 1Laboratoire de Tectonique, Campus de Beaulieu, Université de Rennes, 35042 Rennes Cedex, France Search for other works by this author on: GSW Google Scholar Geology (1989) 17 (12): 1144–1147. https://doi.org/10.1130/0091-7613(1989)017<1144:SSWDGM>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Denis Gapais; Shear structures within deformed granites: Mechanical and thermal indicators. Geology 1989;; 17 (12): 1144–1147. doi: https://doi.org/10.1130/0091-7613(1989)017<1144:SSWDGM>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 Granitic rocks are here described as mixtures of weak and more resistant fractions whose proportions vary with strain and temperature and control some macroscopic characteristics of shear structures produced during deformation. Three main structural fields are distinguished on a strain/temperature diagram: (1) discrete shear zones anastomosed around low-strain domains, (2) microscale associations of pervasive foliation and ductile shear bands (e.g., C-S structures), and (3) "steady state" homogeneous foliations. We outline the following: a sharp drop in bulk strength is expected to occur around 500 °C within wet granites; the widespread occurrence of pervasive ductile shear bands is diagnostic of retrograde deformation histories, especially as encountered within syntectonic plutons; and most prograde deformation histories, as expected during reworking of pretectonic basement, should produce heterogeneous strain patterns associated with discrete shear zones. 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.