Genesis of Archean Peridotitic Magmas and Constraints on Archean Geothermal Gradients and Tectonics

Research Article| January 01, 1975 Genesis of Archean Peridotitic Magmas and Constraints on Archean Geothermal Gradients and Tectonics D. H. Green D. H. Green 1Research School of Earth Sciences, Australian National University, Canberra, A.C.T., Australia Search for other works by this author on: GSW Google Scholar Author and Article Information D. H. Green 1Research School of Earth Sciences, Australian National University, Canberra, A.C.T., Australia Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1975) 3 (1): 15–18. https://doi.org/10.1130/0091-7613(1975)3<15:GOAPMA>2.0.CO;2 Article history 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 D. H. Green; Genesis of Archean Peridotitic Magmas and Constraints on Archean Geothermal Gradients and Tectonics. Geology 1975;; 3 (1): 15–18. doi: https://doi.org/10.1130/0091-7613(1975)3<15:GOAPMA>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 The experimentally determined extrusion temperature (1650° ± 20°C) for Archean peridotitic komatiite magma implies diapirism of upper mantle peridotite from a depth of at least 200 km. Models of magma genesis are developed in which selective removal of garnet during ascent produces CaO/Al2O3 > 1 and heavy rare-earth element depletion in the resultant peridotitic or mafic extrusions. Magma genesis can be interpreted with a model of the Archean geotherm, lithosphere, and plate tectonics processes resembling the modern Earth, but this does not account for the distinctive preservation and character of Archean greenstone belts. A preferred model of a steeper Archean geotherm, thin lithosphere (≃50 km), and asthenosphere with approximately 5 percent melting does not allow eclogitization and subduction of basaltic oceanic crust, but it postulates scraping off of such crust against and between primitive sialic nucleii. This model may account for the distinctive characteristics of the Archean greenstone and “granite” terranes. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.