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Defining trace-element alteration halos to skarn deposits hosted in heterogeneous carbonate rocks: Case study from the Cu-Zn Antamina skarn deposit, Peru
journal contribution
posted on 2023-05-19, 23:00 authored by Escalante, A, Dipple, GM, Shaun BarkerShaun Barker, Tosdal, RThe presence of geochemical anomalies, defining haloes around hydrothermal ore deposits, can be used to vector towards mineralization, or identify ore bodies buried at depth. Several important types of ore deposits, including skarn deposits, are often hosted within carbonate-rich sedimentary rocks. Identifying anomalous trace-element concentrations in carbonate rocks is complicated by variable lithology (i.e. siliciclastic component) and volume loss during hydrothermal alteration. In this study of the world-class Antamina skarn deposit in Peru, we use the ratio of metals:immobile elements (e.g. La, Al2O3) to differentiate genuine and false geochemical anomalies in limestones and marbles surrounding the skarn deposit. Unaltered limestones are used to define threshold values for metal:immobile element ratios (through use of the median value ± 2 median absolute deviations). Genuine anomalies are identified when metal concentrations exceed those predicted using median + 2 median absolute deviations. In addition, comparison of “four acid” and lithium-borate fusion analytical techniques reveals that the lower cost four-acid techniques give reliable results. Our approach can be used to identify geochemical anomalies and halos related to hydrothermal alteration of carbonate-rich rocks, which have direct application to skarn deposits.
History
Publication title
Journal of Geochemical ExplorationVolume
105Pagination
117-136ISSN
0375-6742Department/School
School of Natural SciencesPublisher
Elsevier Science BvPlace of publication
Po Box 211, Amsterdam, Netherlands, 1000 AeRights statement
Copyright 2010 Elsevier B.V.Repository Status
- Restricted