Duality of thermal regimes is the distinctive characteristic of plate tectonics since the Neoarchean

Abstract

Research Article| November 01, 2006 Duality of thermal regimes is the distinctive characteristic of plate tectonics since the Neoarchean Michael Brown Michael Brown 1Laboratory for Crustal Petrology, Department of Geology, University of Maryland, College Park, Maryland 20742, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Michael Brown 1Laboratory for Crustal Petrology, Department of Geology, University of Maryland, College Park, Maryland 20742, USA Publisher: Geological Society of America Received: 28 Mar 2006 Revision Received: 07 Jun 2006 Accepted: 10 Jun 2006 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 The Geological Society of America, Inc. Geology (2006) 34 (11): 961–964. https://doi.org/10.1130/G22853A.1 Article history Received: 28 Mar 2006 Revision Received: 07 Jun 2006 Accepted: 10 Jun 2006 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Michael Brown; Duality of thermal regimes is the distinctive characteristic of plate tectonics since the Neoarchean. Geology 2006;; 34 (11): 961–964. doi: https://doi.org/10.1130/G22853A.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 Ultrahigh-temperature (UHT) granulite metamorphism is documented predominantly in the Neoarchean to Cambrian rock record, but UHT granulite metamorphism also may be inferred at depth in Cenozoic orogenic systems. The first occurrence of UHT granulite metamorphism in the record signifies a change in geodynamics that generated transient sites of very high heat flow. Many UHT granulite metamorphic belts may have developed in settings analogous to modern continental backarcs; on a warmer Earth, destruction of oceans floored by thinner lithosphere may have generated hotter backarcs than those associated with the modern Pacific ring of fire. Medium-temperature eclogite–high- pressure (EHP) granulite metamorphism is documented in the Neoarchean rock record and at intervals throughout the Proterozoic and Paleozoic record. EHP granulite metamorphic belts are complementary to UHT granulite metamorphic belts in that they are generally inferred to record subduction-to-collision orogenesis. Blueschists become evident in the Neoproterozoic rock record, but lawsonite blueschist–eclogite metamorphism (high pressure [HP]) and ultrahigh-pressure metamorphism (UHP) characterized by coesite or diamond are predominantly Phanerozoic phenomena. HP-UHP metamorphism registers the low thermal gradients and deep subduction of continental crust during the early stage of subduction-to-collision orogenesis. A duality of metamorphic belts—reflecting a duality of thermal regimes—appears in the record only since the Neoarchean Era. A duality of thermal regimes is the hallmark of modern plate tectonics, and the duality of metamorphic belts is the characteristic imprint of plate tectonics in the rock record. The occurrence of both UHT and EHP granulite metamorphism since the Neoarchean marks the onset of a “Proterozoic plate tectonics” regime, which evolved during a Neoproterozoic transition to the modern plate tectonics regime, characterized by colder subduction as chronicled by HP-UHP metamorphism. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.