GSA 2020 Connects Online

Paper No. 216-12
Presentation Time: 4:05 PM


CARABALLO, Enzo, Géologie et génie géologique, Université Laval, 1065, avenue de la Médecine, Québec, QC G1V 0A6, Canada, BEAUDOIN, Georges, Département de géologie et de génie géologique, Université Laval, 1065 ave de la Médecine, Québec, QC G1V 0A6, Canada, DARE, Sarah, Département des Sciences Appliquées, Université du Québec à Chicoutimi, 555 Boule. de l'Université Est, Chicoutimi, QC G7H 2B1, Canada, PETERSEN, Sven, GEOMAR, Helmholtz Centre for Ocean Research, Wischhofstrasse 1-3, Kiel, 24148, Germany and RELVAS, Jorge M.R.S., IDL, University of Lisbon, Edifício C6, Piso 4, Lisbon, 1749-016, Portugal

The aim of this study is to investigate the variation of a full suite (36) of trace elements in chalcopyrite from Volcanogenic Massive Sulfides (VMS) as a function of lithological units and age of magmatic-hydrothermal system, from a wide range of volcanogenic sulfides deposits and evaluate its potential as indicator mineral. Samples (N=58) from representative deposits, belonging to ancient VMS (2700-300 Ma) according to typical deposit lithological units and to active submarine hydrothermal systems were studied. Trace elements were analyzed by LA-ICP-MS. Data were investigated with univariate, bivariate and multivariate statistical methods.

Lead-Tl-Ge diagram show that ancient VMS are lower in Ge and higher in Pb than active systems. Partial least squares-discriminant analysis (PLS-DA) shows that chalcopyrite from siliciclastic-felsic deposits (ancient and active) is associated to high Sb (4.58 ± 3.58 ppm), Bi (3.89 ± 5.31 ppm), Sn (597 ± 448 ppm) and Ga (2.96 ± 3.67 ppm), whereas that from mafic and bimodal-mafic are high in Ag (113 ± 115 ppm) and Cd (4.02 ± 2.83 ppm). Chalcopyrite from active ultramafic hosted submarine hydrothermal systems is associated with high Te (25.5 ± 19.3 ppm) and Co (275 ± 140 ppm).

The trace element variation in chalcopyrite is probably related to composition of host rocks. Dunite and harzburgite could be the source of Co and Te in active ultramafic-hosted deposits. In siliciclastic-felsic deposits (i.e. Iberian Pyrite Belt) and less strongly in active felsic-hosted systems, rhyolitic sequences (and rhyodacite) in association with sedimentary facies (siliciclastic and pelitic) could be a source of Bi, Sb, Ga and Sn principally. In mafic-dominated deposits Cd, Ag and Zn could be provided by basaltic sequences (i.e. Horne, Lasail).