High-pressure granulites at the dawn of the Proterozoic

Abstract

Research Article| May 01, 2012 High-pressure granulites at the dawn of the Proterozoic Jade R. Anderson; Jade R. Anderson 1Centre for Tectonics, Resources and Exploration (TRaX), University of Adelaide, Adelaide SA 5005, Australia Search for other works by this author on: GSW Google Scholar Justin L. Payne; Justin L. Payne 1Centre for Tectonics, Resources and Exploration (TRaX), University of Adelaide, Adelaide SA 5005, Australia Search for other works by this author on: GSW Google Scholar David E. Kelsey; David E. Kelsey 1Centre for Tectonics, Resources and Exploration (TRaX), University of Adelaide, Adelaide SA 5005, Australia Search for other works by this author on: GSW Google Scholar Martin Hand; Martin Hand 1Centre for Tectonics, Resources and Exploration (TRaX), University of Adelaide, Adelaide SA 5005, Australia Search for other works by this author on: GSW Google Scholar Alan S. Collins; Alan S. Collins 1Centre for Tectonics, Resources and Exploration (TRaX), University of Adelaide, Adelaide SA 5005, Australia Search for other works by this author on: GSW Google Scholar M. Santosh M. Santosh 2Division of Multidisciplinary Science, Faculty of Science, Kochi University, Akebono-cho 2-5-1, Kochi 780-8520, Japan Search for other works by this author on: GSW Google Scholar Geology (2012) 40 (5): 431–434. https://doi.org/10.1130/G32854.1 Article history received: 23 Sep 2011 rev-recd: 11 Dec 2011 accepted: 14 Dec 2011 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 Jade R. Anderson, Justin L. Payne, David E. Kelsey, Martin Hand, Alan S. Collins, M. Santosh; High-pressure granulites at the dawn of the Proterozoic. Geology 2012;; 40 (5): 431–434. doi: https://doi.org/10.1130/G32854.1 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 High-pressure metamorphism is uncommon in the ancient geological record. Kanja Malai, in the Salem crustal block (southern India), contains high-pressure kyanite-garnet−bearing felsic granulites that equilibrated at 14–16 kbar and ∼820–860 °C. Laser ablation−inductively coupled plasma−mass spectrometry U-Pb zircon and in situ monazite geochronology indicate that these assemblages grew ca. 2490 Ma. These pressure-temperature-time constraints provide a rare record indicating that thickened crust and low apparent thermal gradient conditions existed during the Archean-Proterozoic transition, a period of Earth history for which the rock record commonly preserves evidence for comparatively high apparent thermal gradients. The thermal regimes required to generate these metamorphic conditions are typical of collisional orogenesis, and suggest that the continental lithosphere was capable of supporting crustal thickening to ≥45–50 km. Such crustal thickening provides supporting evidence that tectonic regimes similar to modern Earth–style tectonics were in operation at the Archean-Proterozoic transition. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.