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Emerald from the Habachtal: new observations
Citation
Thomas, R and Davidson, P and Rericha, A, Emerald from the Habachtal: new observations, Mineralogy and Petrology, 114 pp. 161-173. ISSN 0930-0708 (2020) [Refereed Article]
Copyright Statement
Copyright 2020 Springer-Verlag GmbH Austria, part of Springer Nature
DOI: doi:10.1007/s00710-020-00700-4
Abstract
The emerald mineralization in the Habachtal (Austria) is geologically and tectonically complex, and previous investigators have identified fluid inclusion evidence for a hydrothermal/metamorphic origin for the emeralds. In this paper we report the discovery of emeralds with a distinctly different inclusion population including melt inclusions, which demonstrates that at least some and probably most of the emerald mineralization in the Habachtal occurred from an extremely fluid-rich pegmatite-like aluminosilicate melt under supercritical conditions, at high temperatures and moderate pressures (~700 °C, 5 kbar). This conclusion is based on the presence of very highly-ordered graphite, and extremely water-rich melt inclusions in emerald. The Lorentz distribution of MgCO3 against the water concentration is a very robust proof for the supercritical state. We suggest that the purely metamorphic model, based on the extrapolation of fluid inclusion data to the regional metamorphic conditions (550 °C and 5 kbar) by some previous investigators are inconsistent with our finding of high-temperature indications (well-ordered graphite, high-temperature fluid inclusions and melt inclusions). This apparent conflict suggests a more complex situation and requires a re-investigation of the emerald genesis in the Habachtal deposit.
Item Details
Item Type: | Refereed Article |
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Keywords: | melt inclusion, fluid inclusion, well-ordered graphite, supercritical state, emerald |
Research Division: | Earth Sciences |
Research Group: | Geology |
Research Field: | Mineralogy and crystallography |
Objective Division: | Mineral Resources (Excl. Energy Resources) |
Objective Group: | Mineral exploration |
Objective Field: | Mineral exploration not elsewhere classified |
UTAS Author: | Davidson, P (Dr Paul Davidson) |
ID Code: | 139137 |
Year Published: | 2020 |
Web of Science® Times Cited: | 1 |
Deposited By: | CODES ARC |
Deposited On: | 2020-05-27 |
Last Modified: | 2020-08-17 |
Downloads: | 0 |
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