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Agua Rica |
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Catamarca, Argentina |
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Cu Au
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Agua Rica porphyry copper - molybdenum - gold deposit is located in the Farallon Negro region of Catamarca Province, ~34 km from the Alumbrera mine in northwest Argentina.
(#Location: 27° 22' 13"S, 66° 16' 53"W)
The Agua Rica deposit consists of two porphyry copper centres (Quebrada Seca-Trampeadero and Melcho) associated with several porphyritic stocks and hydrothermal breccias of late Miocene-early Pliocene age that intrude a basement of probable Precambrian to early Palaeozoic meta-sedimentary rocks and Palaeozoic granitoids.
The deposit is a large Cu-Mo-Au porphyry deposit with a polymetallic epithermal overprint. Three major stages of alteration and mineralisation are recognised: i). early porphyry Cu-Mo-Au; ii). later epithermal Cu-Au-Ag-As-Pb-Zn; and iii). supergene Cu enrichment. Supergene leaching and enrichment has replaced pyrite, chalcopyrite and bornite with near surface high grade chalcocite, covellite and digenite which grades down to a zone of covellite and digenite without chalcocite and then into primary chalcopyrite-pyrite mineralisation. Almost all copper ore in the planned pit is covellite or chalcocite.
The main stage Cu-Au mineralisation is of epithermal, high sulphidation type and is associated with pyrite rich assemblages of covellite, chalcopyrite, bornite and enargite emplaced in advanced argillic alteration. The alteration is dominated by sericite, pyrophyllite, zunyite, dickite, kaolinite, alunite, vuggy silica and silicification. Supergene Cu-Au mineralisation is present as an immature chalcocite blanket that consists of an upper part rich in chalcocite, underlain by a covellite-bearing zone.
Hypogene Cu-Au mineralisation at Agua Rica formed over a period of 1.4 my, between 6.29 and 4.88 Ma. Syn-mineralisation uplift and erosion, induced by regional tectonism, caused the superposition of main stage Cu-Au mineralisation over higher temperature, deep seated K-silicate alteration-mineralisation assemblages.
Supergene chalcocite formation, dated at 3.9 Ma, was favoured by the pyrite rich, main stage Cu-Au mineralisation and advanced argillic alteration associated with hydrothermal telescoping, and the pluvial regime of the elevated topography of the area.
Twenty nine years elapsed between when the existence of porphyry copper mineralisation was first recognised in the area and when the real dimensions of the system were realised. Geological mapping, coupled with rock chip geochemistry and relict sulphide studies, resulted in the siting of the discovery holes.
In 1996, the deposit was quoted as containing (Rojas, et al., 1998):
750 Mt @ 0.62% Cu, 0.037% Mo, 0.23 g/t Au, with a further 90 Mt @ 0.4 g/t Au in the leached cap.
Pre-mining ore reserves and mineral resources at 31 December 2015, (Yamana Gold website) were:
Proven + probable reserves - 908.9 Mt @ @ 0.49% Cu, 0.22 g/t Au, 3.5 g/t Ag, and 0.031% Mo.
Measured + indicated resources - 201 Mt @ 0.39% Cu, 0.14 g/t Au, 2.8 g/t Ag, and 0.039% Mo.
Inferred resources - 642 Mt @ 0.34% Cu, 0.12 g/t Au, 2.33 g/t Ag, and 0.034% Mo.
This deposit was the subject of one of the papers delivered at an international conference in Perth in late 1998, and printed in the associated volume: Porter T M (Ed.) "Porphyry and Hydrothermal Copper and Gold Deposits: A Global Perspective", now available through PGC Publishing, Adelaide, Australia
The full Abstract of the paper detailing the geology and mineralisation can be displayed by selecting the option offered below.
For more detail consult this paper or other reference(s) listed below
The most recent source geological information used to prepare this decription was dated: 1998.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
Agua Rica
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Franchini, M., Impiccini, A., Lentz, D., Rios, F.J., OLeary, S., Pons, J. and Schalamuk, A.I., 2011 - Porphyry to epithermal transition in the Agua Rica polymetallic deposit, Catamarca, Argentina: An integrated petrologic analysis of ore and alteration parageneses: in Ore Geology Reviews v.41, pp. 49-74.
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Franchini, M., McFarlane, C., Maydagan, L., Reiche, M., Lentz, D.R., Meinert, L. and Bouhier, L., 2015 - Trace metals in pyrite and marcasite from the Agua Rica porphyry-high sulfidation epithermal deposit, Catamarca, Argentina: Textural features and metal zoning at the porphyry to epithermal transition: in Ore Geology Reviews v.66, pp. 366-387.
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Landtwing M R, Dillenbeck E D, Leake M H, Heinrich C A 2002 - Evolution of the breccia-hosted Porphyry Cu-Mo-Au deposit at Agua Rica, Argentina: progressive unroofing of a magmatic hydrothermal system: in Econ. Geol. v97 pp 1273-1292
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Perello J, Rojas N, Devaux C, Fava L, Etchart E and Harman P, 1998 - Discovery of the Agua Rica Porphyry Cu-Mo-Au Deposit, Catamarca Province, Northwestern Argentina Part 2: Geology: in Porter T M (Ed.), 1998 Porphyry and Hydrothermal Copper and Gold Deposits - A Global Perspective PGC Publishing, Adelaide pp. 117-132
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Rojas N, Perello J, Harman P, Cabello J, Devaux C, Fava L and Etchart E, 1998 - Discovery of the Agua Rica Porphyry Cu-Mo-Au Deposit, Catamarca Province, Northwestern Argentina Part 1: Exploration and Discovery: in Porter T M (Ed.), 1998 Porphyry and Hydrothermal Copper and Gold Deposits - A Global Perspective PGC Publishing, Adelaide pp. 111-117
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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