Charnockite microstructures: from magmatic to metamorphic

Touret, Jacques L.R., and Huizenga, Jan Marten (2012) Charnockite microstructures: from magmatic to metamorphic. Geoscience Frontiers, 3 (6). pp. 745-753.

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Abstract

Charnockites sensu lato (charnockite-enderbite series) are lower crustal felsic rocks typically characterised by the presence of anhydrous minerals including orthopyroxene and garnet. They either represent dry (H2O-poor) felsic magmas that are emplaced in the lower crust or granitic intrusions that have been dehydrated during a subsequent granulite facies metamorphic event. In the first case, post-magmatic high-temperature recrystallisation may result in widespread metamorphic granulite microstructures, superimposed or replacing the magmatic microstructures. Despite recrystallisation, magmatic remnants may still be found, notably in the form of melt-related microstructures such as melt inclusions. For both magmatic charnockites and dehydrated granites, subsequent fluid-mineral interaction at intergrain boundaries during retrogradation are documented by microstructures including K-feldspar microveins and myrmekites. They indicate that a large quantity of low-H2O activity salt-rich brines, were present (together with CO2 under immiscible conditions) in the lower crust.

Item ID: 30653
Item Type: Article (Research - C1)
ISSN: 1674-9871
Keywords: charnockite; petrology; microstructure; melt inclusions
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This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Date Deposited: 07 Jan 2014 04:14
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040304 Igneous and Metamorphic Petrology @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%
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