T216 Advances in Mineral Chemistry for Petrogenesis and Exploration of Mineral Deposits

Thursday, 29 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

TRACE ELEMENT COMPOSITION OF CHALCOPYRITE FROM VOLCANOGENIC MASSIVE SULFIDES DEPOSITS: APPLICATION TO MINERAL EXPLORATION

Paper number: T216-12
Program: Technical Sessions
Time: 4:05 PM – 4:15 PM

Authors

Abstract

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).

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-359284

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