Hadean greenstones from the Nuvvuagittuq fold belt and the origin of the Earth’s early continental crust

Abstract

Research Article| April 01, 2012 Hadean greenstones from the Nuvvuagittuq fold belt and the origin of the Earth's early continental crust John Adam; John Adam 1GEMOC, Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia Search for other works by this author on: GSW Google Scholar Tracy Rushmer; Tracy Rushmer 1GEMOC, Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia Search for other works by this author on: GSW Google Scholar Jonathan O'Neil; Jonathan O'Neil 2Department of Terrestrial Magmatism, Carnegie Institution of Washington, 5241 Broad Branch Road N.W., Washington, D.C. 20015, USA Search for other works by this author on: GSW Google Scholar Don Francis Don Francis 3Earth and Planetary Sciences Department, McGill University, 3450 University Street, Montreal, Quebec H3A 2A7, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information John Adam 1GEMOC, Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia Tracy Rushmer 1GEMOC, Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia Jonathan O'Neil 2Department of Terrestrial Magmatism, Carnegie Institution of Washington, 5241 Broad Branch Road N.W., Washington, D.C. 20015, USA Don Francis 3Earth and Planetary Sciences Department, McGill University, 3450 University Street, Montreal, Quebec H3A 2A7, Canada Publisher: Geological Society of America Received: 06 Jul 2011 Revision Received: 13 Nov 2011 Accepted: 24 Nov 2011 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2012 Geological Society of America Geology (2012) 40 (4): 363–366. https://doi.org/10.1130/G32623.1 Article history Received: 06 Jul 2011 Revision Received: 13 Nov 2011 Accepted: 24 Nov 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 John Adam, Tracy Rushmer, Jonathan O'Neil, Don Francis; Hadean greenstones from the Nuvvuagittuq fold belt and the origin of the Earth's early continental crust. Geology 2012;; 40 (4): 363–366. doi: https://doi.org/10.1130/G32623.1 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 To investigate formation of the Earth's earliest continental crust, partial-melting experiments were conducted (at 900–1100 °C and 0.5–3.0 GPa) on two greenstones from the 4.3 Ga Nuvvuagittuq complex of Quebec, Canada. For comparison, experiments were also conducted on a compositionally similar but modern arc volcanic (a Tongan boninite). At 1.5–3.0 GPa and 950–1100 °C, the experimentally produced melts are compositionally similar to the tonalite-trondhjemite-granodiorite (TTG) granitoids that compose most of Earth's early continental crust, including a 3.66 Ga tonalite that encloses the Nuvvuagittuq Complex. Because the degree of melting needed to produce the TTG-like melts is comparatively high (>30%), the relative concentrations of most incompatible elements in the melts are similar to those in their greenstone parent rocks. These greenstones have compositional affinities with modern subduction zone magmas and do not resemble mid-oceanic ridge basalts. That arc-like mafic rocks could have been selectively involved in TTG formation (in spite of their volumetrically subordinate status in most greenstone terrains) must reflect tectonic circumstances that were specific to their generation. These must have enabled accumulations sufficiently deep to melt at the 1.5–3.0 GPa needed to generate TTG magmas from eclogitic sources. They are also likely to have been related to some form of crustal recycling whereby mafic crust and water were returned to the mantle and arc-like mafic magmas generated as a consequence. To what degree these circumstances replicated modern plate tectonics is difficult to say, but it seems likely that, as in the modern Earth, the Hadean crust was organized into different tectonic environments and that one of these gave rise to the first continental crust. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.