Timing and conditions for peak metamorphism in Isua (Western Greenland)
We present a Lu-Hf-garnet-amphibole-whole rock age of 2.59 ± 0.11 Ga for a carbonaceous garnet-hornblende-mica schist from the Isua supracrustal belt (western Greenland). Petrological data indicate prograde garnet growth towards regional peak-metamorphism at amphibolite-facies conditions. Mylonitic foliation in the sample formed at least partly during and after garnet growth. The sample does not show any hints of earlier metamorphism. These results cast doubt on the accepted concept that peak metamorphism and associated deformation in the Isua supracrustal belt are attributed to Eoarchean tectonics. This is remarkable as deformation style and metamorphism have been viewed as reflecting intense horizontal accretion or even subduction and are the one of pillars, on which models of early plate tectonics rest.
Details
Author
Benjamin Chaim Fievé Eskesen1, Kathrin Fassmer2, Carsten Münker3, Thomas Ulrich1, Kristoffer Szilas4, Thorsten Nagel1Institutionen
1Aarhus University, Denmark; 2University of Innsbruck, Austria; 3Cologne University, Germany; 4University of Copenhagen, DenmarkVeranstaltung
GeoMinKöln 2022Datum
2022DOI
10.48380/8gr3-zd78Geolocation
Western Greenland
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