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Mineralium Deposita

, Volume 38, Issue 2, pp 208–216 | Cite as

Ore mineralogy, fluid inclusion, and stable isotopic characteristics of stratiform copper deposits in the coastal Cordillera of northern Chile

  • Shoji Kojima
  • José Astudillo
  • Juan Rojo
  • Dania Tristá
  • Ken-ichiro Hayashi
Article

Abstract.

Late-Jurassic stratiform copper deposits in the coastal range of northern Chile (Susana-Lince and Buena Vista of the Carolina de Michilla district, and Mantos de La Luna) are hosted in an andesite-dominant volcanic pile of the Jurassic La Negra Formation which is extensively intruded by gabbroic to granodioritic plutons and dikes. Primary copper mineralization is characterized by chalcocite (~Cu1.90S) + digenite + bornite ± chalcopyrite + hematite. Supergene alteration of these minerals has produced chalcocite (djurleite), covellite, atacamite, chrysocolla and copper oxides (copper wad). Fluid-inclusion data indicate a variable temperature of formation (200 to 380 °C) and a wide range of fluid salinities (7 to 34 wt% NaCl). Carbon and oxygen isotopic compositions of calcite from the Susana-Lince deposit (δ13C=–2.6 to –3.6‰, δ18O=13.7 to 18.7‰) combined with the thermometric data suggest that the fluid responsible for the calcite mineralization derives from mixing of high-temperature meteoric water with cooler basinal brines. These data imply that the stratiform copper deposits of the coastal Cordillera are epigenetic and formed from non-magmatic, moderately oxidized hydrothermal solutions.

Chile Coastal Cordillera Stratiform copper Fluid inclusions Stable isotopes 

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Shoji Kojima
    • 1
  • José Astudillo
    • 1
  • Juan Rojo
    • 1
  • Dania Tristá
    • 1
  • Ken-ichiro Hayashi
    • 2
  1. 1.Departamento de Ciencias Geológicas, Universidad Católica del Norte, Av. Angamos 0610, Casilla 1280, Antofagasta, Chile
  2. 2.Institute of Mineralogy, Petrology and Economic Geology, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan

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