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 |
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Item Type: | Article (Research - C1) |
ISSN: | 1674-9871 |
Keywords: | charnockite; petrology; microstructure; melt inclusions |
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Additional Information: | 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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