Abstract

PUTZ, Hubert; PAAR, Werner H  and  TOPA, Dan. A contributionto the knowledge of the mineralization at mina Capillitas, Catamarca. Rev. Asoc. Geol. Argent. [online]. 2009, vol.64, n.3, pp.514-524. ISSN 0004-4822.

The Capillitasdeposit is part of the Farallón Negro Volcanic Complex, Catamarca Province, northwestern Argentina. The epithermal mineralization is related to the Capillitas diatreme,a volcanic pipe composed of intrusive and volcanoclastic rocks of rhyolitic todacitic composition of Miocene age which is located in the granitic basementblock of the Sierra de Capillitas. The deposit consists of numerous mineralizedveins which crosscut the diatreme volcanics and the adjacent Capillitasgranite. The different geological environments, the alteration features and theore mineralogy enable to distinguish between highand intermediate-sulfidationenvironments, which are overprinted by supergene processes. The first group isaccompanied by advanced argillic alteration and silicification and in thesecond rhodochrosite and quartz are the predominant gangue minerals. Thepolymetallic character of the Capillitas epithermal deposit is clearlyemphasized by its complex Cu-Pb-Zn-Fe-Mn- As-Sb paragenesis, with minor W, Bi,Sn, Te, Ag and Au and traces of Ge, Cd, In, V, Ni and Tl, present in more than150 different minerals. Additionally, Capillitas represents the type localityfor the two new mineral species putzite and catamarcaite. The hydrothermal veinsystem at Capillitas was formed under strongly changing p-T-X conditions. Cu,As, Te, Sn, Bi and Au represent the key metals of the high-sulfidation stagewhereas the metal association Zn-Pb-Ag is typical for the intermediate-sulfidation stage. Based on fluid inclusion studies, the Capillitas deposit canbe characterized by temperatures of ore formation mostly below 300 °C and lowsalinities (< 6 wt. % NaCl equivalent).

Keywords : Capillitas diatreme; Epithermal veins; High-sulfidation; Intermediate-sulfidation; Bornite.

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