Nanograins form carbonate fault mirrors

Abstract

Research Article| June 01, 2013 Nanograins form carbonate fault mirrors Shalev Siman-Tov; Shalev Siman-Tov 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Search for other works by this author on: GSW Google Scholar Einat Aharonov; Einat Aharonov 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Search for other works by this author on: GSW Google Scholar Amir Sagy; Amir Sagy 2Geological Survey of Israel, 30 Malkhe Israel, Jerusalem 95501, Israel Search for other works by this author on: GSW Google Scholar Simon Emmanuel Simon Emmanuel 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Search for other works by this author on: GSW Google Scholar Author and Article Information Shalev Siman-Tov 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Einat Aharonov 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Amir Sagy 2Geological Survey of Israel, 30 Malkhe Israel, Jerusalem 95501, Israel Simon Emmanuel 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Publisher: Geological Society of America Received: 01 Oct 2012 Revision Received: 25 Jan 2013 Accepted: 26 Jan 2013 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2013 Geological Society of America Geology (2013) 41 (6): 703–706. https://doi.org/10.1130/G34087.1 Article history Received: 01 Oct 2012 Revision Received: 25 Jan 2013 Accepted: 26 Jan 2013 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Shalev Siman-Tov, Einat Aharonov, Amir Sagy, Simon Emmanuel; Nanograins form carbonate fault mirrors. Geology 2013;; 41 (6): 703–706. doi: https://doi.org/10.1130/G34087.1 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 Many faults are characterized by naturally polished, reflective, glossy surfaces, termed fault mirrors (FMs), that form during slip. Recent experiments also find that FMs form during rapid sliding between rock surfaces, and that FM formation coincides with pronounced friction reduction. The structure of FMs and the mechanism of their formation are thus important for understanding the mechanics of frictional sliding, particularly during earthquakes. Here we characterize the small-scale structure of natural carbonate FMs from three different faults along a tectonically active region of the Dead Sea transform. Atomic force microscopy measurements indicate that the FMs have extremely smooth surface topography, accounting for their mirror-like appearance. Electron microscope characterization revealed a thin (<1 µm) layer of tightly packed nanoscale grains coating a rougher layer comprising micron-size calcite crystals. The crystals contain closely spaced, plastically formed twins that define new subgrain boundaries. The narrow subgrains are observed to break into submicron pieces near the sheared surface. This observation suggests a new brittle-ductile mechanism for nanograin formation. The role of ductility during frictional sliding, both in forming the nanograin layer, and in the deformation process of the powder, may be critical for understanding shear on geological faults. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.