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The fluorine link between a supergiant ore deposit and a silicic large igneous province
journal contribution
posted on 2023-05-17, 08:58 authored by Jocelyn McPhieJocelyn McPhie, Vadim Kamenetsky, Sharon AllenSharon Allen, Ehrig, K, Agangi, A, Bath, AOlympic Dam is a supergiant Fe oxide Cu-U-Au-Ag ore deposit (~9 × 109 t) that is also enriched in rare earth elements (REEs) and fluorine (F). The immediate host to the ore is hydrothermal breccia within granite and volcanic rocks of a Mesoproterozoic silicic large igneous province. Analyses of melt inclusions in quartz phenocrysts in rhyolite show that the silicic magmas of this province were unusually rich in F (up to 1.3 wt%). Fluorite and other F-rich minerals that crystallized from these magmas provided a gigantic reservoir of F. As a result, the Olympic Dam ore-forming fluid was F-rich and had exceptional capacity to transport diverse elements. Further, we infer that hydrofluoric acid, the most corrosive acid known, contributed to hydrothermal breccia formation by dissolution that in turn increased permeability and accelerated the rate of fluid-rock interaction. It is no accident that the world’s largest hydrothermal ore deposit occurs in an F-rich silicic large igneous province.
History
Publication title
Geology (Boulder)Volume
39Issue
11Pagination
1003-1006ISSN
0091-7613Department/School
School of Natural SciencesPublisher
Geological Soc AmericaPlace of publication
Inc, Po Box 9140, Boulder, USA, Co, 80301-9140Rights statement
© 2011 Geological Society of America. Geological Society of America, P.O. Box 9140, Boulder, CO 80301-9140 USA (http://www.geosociety.org)Repository Status
- Restricted