Sokol, K and Finch, AA and Cloutier, J and Humphreys, MCS, Fenitisation associated with alkaline-silicate complexes. Implications for HFSE mobility in late-stage fluids, Gardar Rift, SW Greenland, Proceedings of the 15th SGA Biennial Meeting: Life with Ore Deposits on Earth, volume 4, 27-30 August 2019, Glasgow, Scotland, pp. 1840-1841. ISBN 9780852619643 (2019) [Conference Extract]
Official URL: https://www.sga2019glasgow.com/abstract
Alkali metasomatism associated with carbonatitic-alkaline magmatism (or fenitisation) is of interest for our understanding of chemical behaviour of economically important high-field-strength (HFSE) and rare-earth (REE) elements during late-stage magmatic-hydrothermal activity.
In this project, we explore the expression of alteration and the physic0-chemical factors controlling fenitisation across the Proterozoic Gardar Province of Southern Greenland. We present our findings of bulk-rock (XRF/ICP-AES) and microbeam (BSE-SEM-EDAX/ EPMA) analyses.
Our main case study, the lllerfissalik centre, comprises a series of nested syenitic intrusions. Fenites are exposed at its western margin, where a feldspar-poor Eriksfjord Formation quartz arenite protolith experienced intense metasomatism and deformation.
Detailed petrography demonstrates interstitial K-feldspar (commonly perthitic), mafic minerals including pyroxene or Na-amphibole, and titanite (often LREE-bearing) in the proximal high-grade fenite zone. The absence of feldspar in unaltered arenite (<5% mode further than 1.5 km distance from the contact zone) suggests that K-feldspar was introduced by early-stage fenitisation, along with the relatively Na-poor pyroxene. The presence of HFSE-rich phases i.e. Sr-chevkinite also attests to variable mobility of numerous alkali, alkali-earth metals and HFSE in fenitising fluids. Bulk-rock geochemical trends away from the contact are also presented. Further work including isotope systematics will constrain the geochemistry of fenitising fluids.
|Item Type:||Conference Extract|
|Research Division:||Earth Sciences|
|Research Field:||Exploration geochemistry|
|Objective Division:||Mineral Resources (Excl. Energy Resources)|
|Objective Group:||Other mineral resources (excl. energy resources)|
|Objective Field:||Other mineral resources (excl. energy resources) not elsewhere classified|
|UTAS Author:||Cloutier, J (Mr Jonathan Cloutier)|
|Deposited By:||CODES ARC|
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