U-Pb, Re-Os, and 40Ar/39Ar geochronological constraints on the Cerros Taguas deposit, northern El Indio belt (29°S): implications for the timing of high-sulfidation and porphyry-style mineralization
Laura Maydagán, María Agustina Cócola, David Selby, Andrea Montoya, Federico Mateos, Martín Gonzalo Vallejos, Sergio Palma, Guillermo Delle Vedove, Raúl Alvarez Cifuentes
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引用次数: 0
Abstract
Cerros Taguas is one of the high-sulfidation epithermal Au-Ag deposits (131.35 Mt @ 0.29 g/t Au, 8.8 g/t Ag, 0.11% Cu) of the Taguas project, located in the northern sector of the El Indio belt (~ 29°S), Central Andes, Argentina. Zircon LA-ICP-MS U-Pb dating of a rhyolitic tuff that hosts Au-Ag mineralization constrain the timing of volcanism to the middle Miocene (12.14 ± 0.14 to 11.85 ± 0.26 Ma). Above 3800 m.a.s.l., the rocks display advanced argillic alteration, characterized by alunite + pyrophyllite + dickite ± diaspore ± topaz. Hypogene alunite associated with epithermal Au-Ag mineralization yielded a 40Ar/39Ar plateau date of 9.5 ± 0.4 Ma. Below 3800 m.a.s.l., the presence of sericitic alteration (muscovite + illite + quartz) and a molybdenum halo associated with molybdenite-bearing B-type and pyrite ± quartz D-type veins suggests a transition from epithermal to porphyry-style mineralization. Molybdenite in quartz-dominated B-type veins and molybdenite ± quartz veins cross-cutting the rhyolitic tuff yielded ID-NTIMS Re-Os dates of 10.60 ± 0.06 and 10.48 ± 0.05 Ma. A nominally older molybdenite ID-NTIMS Re-Os date (11.10 ± 0.11 Ma) was obtained for the hydrothermal cement of a breccia. The timing of molybdenum mineralization at Cerros Taguas was broadly coeval with the emplacement of inter-mineralization porphyritic stocks and slightly older than molybdenite mineralization in the nearby Valeriano and El Encierro porphyry deposits. The occurrence of a porphyry-style mineralization at Cerros Taguas reflects the prospectivity for porphyry deposits beneath Miocene-age volcanic rocks and advanced argillic alteration zones in the northern sector of the El Indio belt.
期刊介绍:
The journal Mineralium Deposita introduces new observations, principles, and interpretations from the field of economic geology, including nonmetallic mineral deposits, experimental and applied geochemistry, with emphasis on mineral deposits. It offers short and comprehensive articles, review papers, brief original papers, scientific discussions and news, as well as reports on meetings of importance to mineral research. The emphasis is on high-quality content and form for all articles and on international coverage of subject matter.