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San Rafael |
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Peru |
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Sn Cu
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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 San Rafael Sn-Cu deposit is located on the upper slopes of the Cordillera de Carabaya, northern Puno Department, southeastern Peru, <100 km northwest of the Bolivian border. It lies close to the apparent northwestern limit of the Bolivian/Andean Sn-Ag belt, which flanks the eastern margin of the Altiplano (#Location: 14° 13' 58"S, 70° 19' 18"W).
All economic cassiterite occurs within a series of broadly northwest striking laterally and vertically extensive brittle shear zones generated by regional tectonism which cut the San Rafael stock, a small, <1 sq. km, 24.6 to 24.7 ± 0.2 Ma epizonal granitic stock. This body is a member of the more extensive Oligocene to lower Miocene (22 to 26 Ma) Picotani intrusive suite, the hypabyssal component of the volcano-sedimentary Picotani Group, representing the commencement of Cenozoic magmatism in the region.
The stock was emplaced into clastic rocks of the Ordovician Sandia Formation which had been weakly metamorphosed and underwent polyphase deformation in the Early Carboniferous, (early Hercynian) orogeny. Southeast of the mine the Ordovician sequence is overlain by the openly folded lower Carboniferous Ambo Group above a 15 to 20° SSE dipping thrust fault.
The host intrusion is dominated by coarse, porphyritic monzogranitic and finer-grained, less porphyritic monzogranitic to granodioritic facies, both of which are characterised by phenocrysts of alkali feldspar, quartz, biotite and pinitized cordierite.
The mineralised structures in the San Rafael mine have a well developed vertical zonation, represented by a chalcopyrite-rich zone which passes down into one dominated by cassiterite. Sphalerite, galena and Ag sulphides and sulfosalts, accompanied by ankerite, siderite, and calcite, are modestly enriched at the lateral extremities of the vein system.
Mineralisation was introduced in three stages, namley: 1). an early stage that introduced swarms of tourmaline-quartz veins and hydrothermal breccias, with minor arsenopyrite, löllingite and pyrrhotite (but no Sn or Cu) with narrow selvedges of pervasive tourmalinisation to intense quartz >muscovite alteration, 2). a superimposed phase that introduced 97% of the cassiterite in the lodes, with botryoidal "wood tin" in the upper 150 m of the tin zone, and coarsely crystalline cassiterite below that, all with intergrown quartz and chlorite, 3). an overprinted sulphide rich phase with abundant chlorite, characterised by chalcopyrite, pyrrhotite, pyrite and minor stannite in the upper parts of the veins, while iron sulphides dominating the lower portions of the system.
The San Rafael Lode, the most important of the veins, extends over a vertical interval of >1 km and over a horizontal distance of 2.4 km.
The reserve at San Rafael in 2001 was 14.460 Mt at 5.14% Sn
Production in 2001 amounted to 38 182 tonnes of fine tin.
This summary is taken from Kontak & Clark, 2002.
For detail consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 2002.
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.
San Rafael
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Harlaux, M., Kontak, D.J., Clark, A.H., Kouzmanov, K., Holm-Denoma, C.S., Gialli, S., Laurent, O., Spikings, R., Chauvet, A., Dini, A., Kalinaj, M. and Fontbote, L., 2023 - Depositing >1.5 Mt of Tin Within <1 m.y. of Initial Granitic Intrusion in the San Rafael Tin (-Copper) Deposit, Southeastern Peru: in Econ. Geol. v.118, pp. 1371-1396. doi: 10.5382/econgeo.5021.
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Harlaux, M., Kouzmanov, K., Gialli, S., Laurent, O., Rielli, A., Dini, A., Chauvet, A., Menzies, A., Kalinaj, M. and Fontbote, L., 2020 - Tourmaline as a Tracer of Late-Magmatic to Hydrothermal Fluid Evolution: The World-Class San Rafael Tin (-Copper) Deposit, Peru: in Econ. Geol. v.115, pp. 1665-1697.
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Kontak D J, Clark A H 2002 - Genesis of the giant, bonanza San Rafael lode Tin deposit, Peru: origin and significance of pervasive alteration: in Econ. Geol. v97 pp 1741-1777
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Mlynarczyk M S J, Sherlock R L, Williams-Jones A E 2003 - San Rafael, Peru: geology and structure of the worlds richest tin lode: in Mineralium Deposita v38 pp 555-567
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Wagner, T., Mlynarczyk, M.S.J., Williams-Jones, A.E. and Boyce, A.J., 2009 - Stable Isotope Constraints on Ore Formation at the San Rafael Tin-Copper Deposit, Southeast Peru : in Econ. Geol. v.104, pp. 223-248.
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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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