Pseudotachylite vein hosted by a clast in the Vredefort Granophyre: characterization, origin and relevance

Abstract

Research Article| March 01, 2018 Pseudotachylite vein hosted by a clast in the Vredefort Granophyre: characterization, origin and relevance E. Kovaleva; E. Kovaleva Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail] Search for other works by this author on: GSW Google Scholar M.S. Huber; M.S. Huber Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail] Search for other works by this author on: GSW Google Scholar F. Roelofse; F. Roelofse Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail] Search for other works by this author on: GSW Google Scholar M. Tredoux; M. Tredoux Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail] Search for other works by this author on: GSW Google Scholar H. Praekelt H. Praekelt Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail] Search for other works by this author on: GSW Google Scholar Author and Article Information E. Kovaleva Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa M.S. Huber Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa F. Roelofse Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa M. Tredoux Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa H. Praekelt Department of Geology, University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail] Publisher: Geological Society of South Africa First Online: 03 May 2018 Online Issn: 1996-8590 Print Issn: 1012-0750 © 2018 March Geological Society of South AfricaGeological Society of South Africa South African Journal of Geology (2018) 121 (1): 51–68. https://doi.org/10.25131/sajg.121.0002 Article history First Online: 03 May 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation E. Kovaleva, M.S. Huber, F. Roelofse, M. Tredoux, H. Praekelt; Pseudotachylite vein hosted by a clast in the Vredefort Granophyre: characterization, origin and relevance. South African Journal of Geology 2018;; 121 (1): 51–68. doi: https://doi.org/10.25131/sajg.121.0002 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 SocietySouth African Journal of Geology Search Advanced Search Abstract A small, meta-granitic clast with a crosscutting microcrystalline vein was found enclosed within the Vredefort Granophyre. Semi-quantitative chemical analyses of the granophyre, granitic clast, and the vein were obtained in situ, demonstrating affinity to granitic composition for the vein. Microstructural and geochemical evidence is consistent with the vein representing pseudotachylite derived from granite.Within the granitic clast, evidence of high-grade metamorphism with preferential melting of biotite was observed. Brittle, ductile and shock deformation microstructures were found in quartz grains in the granite ground mass, including mosaicism, undulatory extinction, non-planar and curviplanar fractures and planar deformation features (PDFs) with crystallographic orientations {1121} and {2241}. Similar deformation features were observed in quartz clasts within the vein. Pods of in situ pseudotachylitic material have been documented in foliated granite around the vein.The vein suggests that a generation of pseudotachylite was evolved and already solidified when the granophyre dyke intruded. Therefore, a minimum age of pseudotachylite emplacement is suggested by the presence of the pseudotachylite vein within the granophyre. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.