Microdiamond daughter crystals precipitated from supercritical COH + silicate fluids included in garnet, Erzgebirge, Germany

Abstract

Research Article| May 01, 2001 Microdiamond daughter crystals precipitated from supercritical COH + silicate fluids included in garnet, Erzgebirge, Germany Bernhard Stöckhert; Bernhard Stöckhert 1Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität, D-44801 Bochum, Germany Search for other works by this author on: GSW Google Scholar Johannes Duyster; Johannes Duyster 1Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität, D-44801 Bochum, Germany Search for other works by this author on: GSW Google Scholar Claudia Trepmann; Claudia Trepmann 1Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität, D-44801 Bochum, Germany Search for other works by this author on: GSW Google Scholar Hans-Joachim Massonne Hans-Joachim Massonne 2Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Azenbergstrasse 18, D-70174 Stuttgart, Germany Search for other works by this author on: GSW Google Scholar Geology (2001) 29 (5): 391–394. https://doi.org/10.1130/0091-7613(2001)029<0391:MDCPFS>2.0.CO;2 Article history received: 29 Aug 2000 rev-recd: 05 Jan 2001 accepted: 21 Jan 2001 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 Bernhard Stöckhert, Johannes Duyster, Claudia Trepmann, Hans-Joachim Massonne; Microdiamond daughter crystals precipitated from supercritical COH + silicate fluids included in garnet, Erzgebirge, Germany. Geology 2001;; 29 (5): 391–394. doi: https://doi.org/10.1130/0091-7613(2001)029<0391:MDCPFS>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 SocietyGeology Search Advanced Search Abstract Microdiamonds associated with phlogopite, quartz, paragonite, phengite, apatite, and rutile are found as regular constituents of minute polyphase inclusions in garnet of ultrahigh-pressure (P) metamorphic gneiss lenses within migmatites of the gneiss-eclogite unit, Erzgebirge, Germany. These aggregates are interpreted to represent original inclusions of a supercritical dense COH fluid rich in K, Na, and SiO2. From this fluid, diamond was precipitated as a daughter crystal due to cooling at ultrahigh-P conditions. Brittle failure of the garnet host due to overpressure during release of confining pressure is demonstrated by healed radial cracks. During further cooling, the silicate phase assemblage of the inclusions crystallized at reduced internal pressures outside the stability field of diamond, as indicated by the presence of quartz, paragonite, and plagioclase. It is proposed that the mica-dominated mineral assemblage of the inclusions formed by reaction between the fluid and the garnet host, the previously formed diamond daughter crystals being preserved metastably. These diamond-bearing inclusions provide an unequivocal record of dense supercritical COH fluids rich in alkalies and silica within subducted continental crust during ultrahigh-P metamorphism. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.