Trace-metal content of the Cerro Quema Au-Cu deposit (Azuero Peninsula, Panama): implications for exploration

Corral Calleja, Isaac, Corbella, Mercè, Gómez-gras, David, and Griera, Albert (2018) Trace-metal content of the Cerro Quema Au-Cu deposit (Azuero Peninsula, Panama): implications for exploration. Boletin de la Sociedad Geologica Mexicana, 70 (2). pp. 549-565.

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Abstract

Cerro Quema (Azuero Peninsula, Panama) is a high-sulfidation epithermal Au-Cu deposit hosted by a dacite dome complex of the Río Quema Formation (late Campanian to Maastrichtian). High-sulfidation mineralization at Cerro Quema occurs within a lithocap of vuggy quartz and advanced argillic alteration, and comprises a first stage of disseminations and microveinlets of pyrite, chalcopyrite, enargite, tennantite, and minor sphalerite. This stage is crosscut by younger veins that contain quartz, barite, pyrite, chalcopyrite, sphalerite, and galena. Later weathering and oxidation processes have produced two distinct mineralized zones at Cerro Quema: (1) Sulfide ore zone-a deeper zone of hypogene alteration and sulfide mineralization with some secondary enrichment but unaffected by oxidation, and (2) Oxide ore zone-a thick iron oxide-rich zone that overprints the hypogene alteration/ mineralization in the upper ~150 m of the deposit. To characterize the concentrations and distribution of metals in the two ore zones, and to develop geochemical tools for exploration, we analyzed 34 samples of both oxide (n = 23) and sulfide ore (n = 11) for Au, Ag, Cd, Cu, Mn, Mo, Ni, Pb, Zn, S, As, Ba, Hg, Sb, and W by INAA and ICP-MS. The results show that the oxide ore has the highest concentration of Au (2.4 g/t), Ag (2.0 g/t), Pb (432 ppm), and Sb (317 ppm), whereas the sulfide ore has the highest concentration of Cu (> 1%), Zn (403 ppm), As (2.74%), and Cd (15.2 ppm). The enrichment factor calculation (oxide/ sulfide ore) indicate that Au, Ag, Pb, and Sb are concentrated in the oxide zone whereas Cu, Zn, Ba, Ni, As, and S are concentrated in the sulfide zone. Exploration for Au should target the oxide ore zone, in areas where the Ba concentration is also high. Exploration for Cu should target the sulfide ore zone, below the oxidation boundary, where primary and secondary Cu sulfides coexist.

Item ID: 58652
Item Type: Article (Research - C1)
ISSN: 1405-3322
Keywords: Cerro Quema, Cerro Quema, Epitermal, Epithermal, Exploración, Exploration, Gold-Copper, Oro-Cobre, Panama, Panamá
Copyright Information: © 2018, Instituto de Geologãa, Universidad Nacional Autanoma de Maxico.
Funders: Spanish Ministry of Science and Education (SMSE), Departament d’Universitats, Recerca i Societat de la Informació (Generalitat de Catalunya), SEG Foundation, SEG Canada Foundation
Projects and Grants: SMSE (CGL2007-62690/BTE)
Date Deposited: 16 Jun 2019 05:17
FoR Codes: 04 EARTH SCIENCES > 0402 Geochemistry > 040201 Exploration Geochemistry @ 100%
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