First evidence for ultrahigh-pressure metamorphism in the North- East Greenland Caledonides

Research Article| June 01, 2002 First evidence for ultrahigh-pressure metamorphism in the North- East Greenland Caledonides Jane A. Gilotti; Jane A. Gilotti 1Department of Geoscience, University of Iowa, Iowa City, Iowa 52242, USA Search for other works by this author on: GSW Google Scholar Erling J. Krogh Ravna Erling J. Krogh Ravna 2Department of Geology, University of Tromsø, N-9037 Tromsø, Norway Search for other works by this author on: GSW Google Scholar Author and Article Information Jane A. Gilotti 1Department of Geoscience, University of Iowa, Iowa City, Iowa 52242, USA Erling J. Krogh Ravna 2Department of Geology, University of Tromsø, N-9037 Tromsø, Norway Publisher: Geological Society of America Received: 22 Nov 2001 Revision Received: 21 Feb 2002 Accepted: 04 Mar 2002 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (6): 551–554. https://doi.org/10.1130/0091-7613(2002)030<0551:FEFUPM>2.0.CO;2 Article history Received: 22 Nov 2001 Revision Received: 21 Feb 2002 Accepted: 04 Mar 2002 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Jane A. Gilotti, Erling J. Krogh Ravna; First evidence for ultrahigh-pressure metamorphism in the North- East Greenland Caledonides. Geology 2002;; 30 (6): 551–554. doi: https://doi.org/10.1130/0091-7613(2002)030<0551:FEFUPM>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 first evidence for ultrahigh-pressure (P) metamorphism in the Greenland Caledonides is reported from kyanite eclogites and associated host gneisses on an island in Jøkelbugt. Polycrystalline quartz inclusions in garnet and omphacite exhibit palisade quartz rims that are a diagnostic feature of quartz pseudomorphs after coesite, thus providing textural evidence for ultrahigh-P conditions. Geothermobarometry on the mineral assemblage garnet + omphacite + kyanite + quartz and/or coesite ± phengite confirms the microstructural interpretation of ultrahigh-P metamorphism. Peak pressure and temperature conditions (∼972 °C at 3.6 GPa) are well within the coesite stability field. The host gneisses are more retrograded than the kyanite eclogites and only record high-P conditions of 2.5 GPa at 826 °C; however, garnet contains polycrystalline quartz inclusions with radial fractures, suggesting that the gneisses also were subject to ultrahigh-P conditions. The presence of high- and ultrahigh-P metamorphism along the Laurentian and Baltica margins, the high temperatures recorded by the ultrahigh-P terranes in Greenland and Norway, and the absence of mantle peridotites in Greenland suggest that crustal thickening may have played an important role in the formation of an extensive orogenic root in the Greenland and Scandinavian Caledonides. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.