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Title

Multiple Porphyry Events at Cerro de Pasco, Central Peru

Authors
Cuellar, David
Published in Mineral Resources in a Sustainable World, 13th SGA Biennial Meeting 2015. Proceedings, Volume 1. 2015, p. 351-354
Abstract Cerro de Pasco, part of the Miocene metallogenic belt of central Peru, is one of the largest known epithermal base metal deposits. The deposit formed along the eastern margin of a diatreme-dome complex emplaced in the Mid-Miocene. It is interpreted to represent the upper part of a porphyry Cu system but until now no evidence of porphyry mineralization has been found. We report the first evidence of multiple porphyry events at Cerro de Pasco. First, hornfels and magmatic clasts with typical A- and B-type quartz-molybdenite porphyry veins were found incorporated in a magmatic breccia, part of the diatreme-dome complex. In addition, direct evidence of porphyry-style mineralization at surface has been found in a silica-rich andesitic plug-like body crosscutting the diatreme-dome complex. The body is affected by a network of quartz-magnetite-chalcopyritepyrite veins. Petrography, SEM-CL imaging, mineral thermometry and fluid inclusion studies indicate that quartz-molybdenite porphyry veins are formed in hightemperature and pressure environment, up to 600°C and 1.4 kbar. Late quartz-magnetite-chalcopyrite-pyrite veining affecting the andesitic plug shares characteristics with shallow porphyry-style mineralization. These new observations suggest that Cerro de Pasco is a long-lived mineralized system, product of multiple overprinting mineralizing events.
Keywords Deep porphyryShallow porphyryCerro de PascoClasts
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Structures
Research group Mineral Resources and Geofluids
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(ISO format)
ROTTIER, Bertrand et al. Multiple Porphyry Events at Cerro de Pasco, Central Peru. In: Mineral Resources in a Sustainable World, 13th SGA Biennial Meeting 2015. Proceedings, Volume 1. [s.l.] : [s.n.], 2015. p. 351-354. https://archive-ouverte.unige.ch/unige:76246

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Deposited on : 2015-10-19

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