Detrital garnet petrology challenges Paleoproterozoic ultrahigh-pressure metamorphism in western Greenland ...

• Main Authors: Schönig, Jan, Benner, Carsten, Meinhold, Guido, von Eynatten, Hilmar, Lünsdorf, N. Keno
• Format: Text
• Language: English
• Published: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV) 2023
• Subjects: Greenland; Nordre Strømfjord; Nordre strømfjord
• Online Access: https://dx.doi.org/10.48380/4crq-er37; https://www.dggv.de/e-publikationen/detrital-garnet-petrology-challenges-paleoproterozoic-ultrahigh-pressure-metamorphism-in-western-greenland

Modern-style plate tectonics is characterized by the global operation of deep and cold subduction involving ultrahigh-pressure and blueschist-facies metamorphism. This is a common process since the Neoproterozoic, but a couple of studies indicate similar processes have been active in the Paleoproterozoic, at least on the local scale. Particularly conspicuous are extreme ultrahigh-pressure conditions of ~7 GPa at thermal gradients <150°C/GPa proposed for metamorphic rocks of the Nordre Strømfjord shear zone in the western part of the Paleoproterozoic Nagssugtoqidian Orogen of Greenland (Glassley et al., 2014). By acquiring a large dataset of heavy minerals (n = 52,130) and garnet major-element composition integrated with mineral inclusion analysis (n = 2,669) from modern sands representing fresh and naturally mixed erosional material from the metamorphic rocks, we here intensely screened the area for potential occurrences of ultrahigh-pressure rocks and put constraints on the metamorphic evolution. Apart ...