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Mesoarchean melt and fluid inclusions in garnet from the Kangerlussuaq basement, Southeast Greenland Cover

Mesoarchean melt and fluid inclusions in garnet from the Kangerlussuaq basement, Southeast Greenland

Open Access
|Feb 2022

Abstract

The present work reports the first anatectic melt inclusions found so far in the Mesoarchean basement in East Greenland. Using optical microscope observations and MicroRaman spectroscopy, we show that garnets in metasedimentary migmatite contain primary polycrystalline aggregates which can be confidently interpreted as former droplets of anatectic melt, i.e. nanogranitoids. In some cases, they coexist with coeval fluid inclusions under conditions of primary fluid-melt immiscibility. The re-evaluation of the metamorphic pressure and temperature conditions with up-to-date phase equilibria modelling, combined with the identification of nanogranitoids and fluid inclusions, suggests metamorphic peak equilibration and partial melting in presence of a COH-fluid at T ~1000°C and P > 7 kbar. To date, this is the oldest verified occurrence of nanogranitoids and fluid-melt immiscibility during garnet growth in a partially molten environment.

DOI: https://doi.org/10.2478/mipo-2022-0001 | Journal eISSN: 1899-8526 | Journal ISSN: 1899-8291
Language: English
Page range: 1 - 9
Submitted on: Nov 18, 2021
Accepted on: Jan 12, 2022
Published on: Feb 14, 2022
Published by: Mineralogical Society of Poland
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year

© 2022 Gautier Nicoli, Kerstin Gresky, Silvio Ferrero, published by Mineralogical Society of Poland
This work is licensed under the Creative Commons Attribution 4.0 License.