Sinking intrusion model for the emplacement of garnet-bearing peridotites into continent collision orogens

Abstract

Research Article| July 01, 1998 Sinking intrusion model for the emplacement of garnet-bearing peridotites into continent collision orogens Hannes K. Brueckner Hannes K. Brueckner 1Queens College and the Graduate Center, City University of New York, Queens College, Flushing, New York 11367 and Lamont-Doherty Earth Observatory, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar Author and Article Information Hannes K. Brueckner 1Queens College and the Graduate Center, City University of New York, Queens College, Flushing, New York 11367 and Lamont-Doherty Earth Observatory, Palisades, New York 10964 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1998) 26 (7): 631–634. https://doi.org/10.1130/0091-7613(1998)026<0631:SIMFTE>2.3.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 Hannes K. Brueckner; Sinking intrusion model for the emplacement of garnet-bearing peridotites into continent collision orogens. Geology 1998;; 26 (7): 631–634. doi: https://doi.org/10.1130/0091-7613(1998)026<0631:SIMFTE>2.3.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 Garnet- (and probably spinel-) bearing ultramafic rocks that form tectonic lenses within high-metamorphic-grade gneisses in mountain core zones may intrude by moving downward or laterally into deeply subducted continental crust from the overlying mantle wedge. This model is most credible for garnet peridotites associated with ultrahigh-pressure metamorphic terranes in mountains formed by continent-continent collision. The extremely high pressures implied by ultrahigh-pressure metamorphism indicate that continental crust was subducted to mantle depths >100–120 km, where the mantle is in the garnet peridotite facies. Exchange between mantle and crust seems likely, particularly the transfer of mantle from the hanging wall into the crustal footwall. The mantle wedge overlying the subducted crustal terrane creates a denser over lighter configuration that is gravitationally unstable. If the interface becomes hot or wet enough so that peridotite can deform by ductile flow, it would sink as mantle blobs into the underlying crustal rocks. If not, the exchange presumably occurs through a brittle mechanism. The intruded bodies will be transported to the surface passively as the host crustal terrane is exhumed buoyantly toward the surface. This mechanism is proposed in particular to explain the intrusion of garnetiferous peridotites in the ultrahigh-pressure Western Gneiss region of the Norwegian Caledonides during the Caledonian orogeny. 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.