Abstract
The tin-rich polymetallic epithermal deposit of Poopó, of plausible Late Miocene age, is part of the Bolivian Tin Belt. As an epithermal low sulfidation mineralisation, it represents a typological end-member within the “family” of Bolivian tin deposits. The emplacement of the mineralisation was controlled by the regional fault zone that constitutes the geological border between the Bolivian Altiplano and the Eastern Andes Cordillera. In addition to Sn and Ag, its economic interest resides in its potential in critical elements as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Poopó deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring to ascertain plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. The poor development of hydrothermal alteration assemblage, the abundance of sulphosalts and the replacement of löllingite and pyrrhotite by arsenopyrite and pyrite, respectively, indicate that this deposit is ascribed to the low-sulphidation subtype of epithermal deposits, with excursions into higher states of sulphidation. Additionally, the occurrence of pyrophyllite and topaz has been interpreted as the result of discrete pulses of high-sulphidation magmatic fluids. The δ34SVCDT range in sulphides (−5.9 to −2.8‰) is compatible either with: i. hybrid sulphur sources (i.e., magmatic and sedimentary or metasedimentary); or ii. a sole magmatic source involving magmas that derived from partial melting of sedimentary rocks or underwent crustal assimilation. In their overall contents in critical elements (In, Ga and Ge), the key minerals in the Poopó deposit, based on their abundance in the deposit and compositions, are rhodostannite, franckeite, cassiterite, stannite and, less importantly, teallite, sphalerite and jamesonite.
Highlights
The Bolivian Andes include important resources in Sn and Ag, minor resources in base metals as Cu, Zn and Pb, and in rare metals as In, Ge or Ga, and constitute the famous Bolivian Tin (Sn–W–Ag–Sb–Bi) Belt [1,2,3,4,5] (Figure 1)
The dominantly cataclastic character of textures in the Poopó deposit is due to the contemporaneity between the activity of the Poopó–Uyuni fault and the mineralisation processes in the associated veins (Figure 4A–C)
Based on the mineralogy determined in this study, we can endorse the interpretation that the Poopó deposits correspond to the Sn-rich low-sulphidation epithermal type, as formulated in Reference [8]
Summary
The Bolivian Andes include important resources in Sn and Ag, minor resources in base metals as Cu, Zn and Pb, and in rare metals as In, Ge or Ga, and constitute the famous Bolivian Tin (Sn–W–Ag–Sb–Bi) Belt [1,2,3,4,5] (Figure 1). In the particular case of Bolivia, the organisation of most mining activities is twofold: it is either carried out by cooperative organisations grouped into the National Federation of Mining Cooperatives of Bolivia (FENCOMIN) and that operate by means of traditional and non-industrial methods, or by the government itself by means of the Bolivian Mining Corporation (COMIBOL), private corporations operate in the country. This complexity in the management of mining activities in Bolivia results in strong differences in exploitation and exploration strategies and their efficiency between different mines, let alone the metallurgical processes involved.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
