Title
Trace element composition and U-Pb ages of cassiterite from the Bolivian tin belt
Date Issued
01 November 2021
Access level
open access
Resource Type
journal article
Publisher(s)
Springer Science and Business Media Deutschland GmbH
Abstract
The Bolivian tin belt is a metallogenic province in the Eastern Cordillera of the Andes known for its Sn, W, Ag, and base metal deposits. Cassiterite, which is a major constituent in many magmatic-hydrothermal ore deposits from the Bolivian tin belt, can incorporate dozens of elements within its crystal lattice, making it a useful geological tracer mineral and also a potential host of critical elements. New U-Pb dating of cassiterite yields Late Triassic (Kellhuani deposit) and Late Oligocene to earliest Miocene (Viloco, Huanuni, and Llallagua deposits) ages. These ages confirm that Sn mineralization in the Bolivian tin belt occurred at least in two separate events during two major magmatic episodes apparently triggered by mantle upwelling, decompression melting, and basalt production promoting high heat flow into the overlying crust. The composition of studied hydrothermal cassiterite yields some geochemical trends that are attributed to its distance to the causative intrusion and/or level of emplacement. For example, cassiterite is generally enriched in Nb and Ta and yields higher Ti/Zr and Ti/Sc ratios in samples from xenothermal ore deposits located adjacent to intrusive complexes relative to shallow xenothermal and epithermal ore deposits. Therefore, these geochemical trends in cassiterite are useful tracers pointing to magmatic-hydrothermal centers. REE distribution in cassiterite was likely influenced by boiling processes, which resulted in tetrad-type irregularities. Cassiterite from the Bolivian tin belt is unattractive as a source for Nb (interquartile range [IQR] 4.84–0.037 ppm), Ta (IQR 0.0924–0.0126 ppm), and Ge (IQR 3.92–0.776 ppm). Some deposits, however, contain cassiterite relatively enriched in In (IQR 96.9–9.78 ppm, up to 1414 ppm) and Ga (IQR 92.1–3.03, up to 7437 ppm), that could constitute an attractive supplementary source for these elements in addition to sulfide minerals in the same deposits.
Start page
1491
End page
1520
Volume
56
Issue
8
Language
English
OCDE Knowledge area
Mineralogía Geoquímica, Geofísica
Scopus EID
2-s2.0-85099238722
Source
Mineralium Deposita
ISSN of the container
00264598
Sponsor(s)
This study was economically supported by the Peruvian CONCYTEC-FONDECYT-World Bank project 107-2018-FONDECYT-BM-IADT-AV and the Catalan project 2017-SGR-00707. We gratefully acknowledge Pura Alfonso (Polytechnic University of Catalonia) for providing cassiterite samples from the Llallagua deposit. The Bolivian State Mining Company (Corporación Minera de Bolivia (COMIBOL)) granted its permission to the authors to access the Huanuni mine and to perform the necessary sampling; J.C. Ayaviri, J. Araca, R. Condori, N. Guevara, and all individuals at COMIBOL are cordially thanked for their kind and efficient help during field work. The help and hospitality extended by the miners from mining cooperatives during sampling and field work are most gratefully acknowledged. We appreciate the technical support by Xavier Llovet (CCiT-UB) during the acquisition of EPMA data and by Peter Tollan (ETH) during the acquisition of LA-ICP-MS data. We are grateful to Daniel Kontak, Matthieu Harlaux, and Editor-in-Chief Bernd Lehmann for their constructive comments which significantly improved the manuscript.
Sources of information: Directorio de Producción Científica Scopus