Tsumoite (BiTe) and associated Ni-PGE mineralization from Gondpipri mafic-ultramafic complex, Bastar Craton, Central India: mineralogy and genetic significance

Abstract

This paper reports the occurrence of Tsumoite (a bismuth telluride) in the Heti Cu-Ni-PGM prospect, Gondpipri mafic-ultramafic complex, Central India. The Gondpipri complex consists of several tectonically dismembered gabbronorite-gabbro-anorthositic gabbro -olivine gabbro -websterite disposed in~10 km long tonalite-trondhjemitegranodiorite (TTG) and charnockite-enderbite suite of rocks. The mineralization occurs in the sulphide zone hosted by gabbro variants. The host rocks have been deformed and metamorphosed to granulite grade and subjected to various degrees of hydrothermal alteration. The mineralization comprises chalcopyrite, pentlandite, pyrrhotite, cubanite, millerite, and pyrite. In addition to these, occur (1) tsumoite (2) PGM in the form of moncheite, merenskyite, Pd-mellonite, and Pt-Pd-Te-Bi-Fe-S alloy. The present study indicates that the mineralization occurs in two stages related to: (i) magmatic and (ii) hydrothermal remobilization and transport of Cu-rich sulphides, tsumoite and PGM, and their re-deposition in hydrosilicate alteration zones. It is possible that the mineralization at Heti formed at different stages of bismuth activity under variable fS 2 , T, and fTe 2 conditions due to change in total concentration of Te and S and /or cooling. Since the role of S is limited, Te and cooling are important factor influencing mineralogy and composition of tsumoite and associated mineralization. Mineralization occurs in two different modes of occurrences. The early mineralisation occur as blebs, specks and dissemination of sulphides, viz. pyrrhotite, chalcopyrite, pentlandite and minor pyrite ± PGM, whereas later mineralisation occur as stringers, minor veins of sulphides viz. pyrite, millerite, cubanite, sijenite, tsumoite and ± PGM. Mineral assemblages and textural relationships at Heti has indicated precipitation of tsumoite and associated PGM along fractures and secondary silicates, which confirms their hydrothermal origin.

Mafic-ultramafic rocks and alkaline-carbonatitic magmatism and associated hydrothermal mineralization: A special issue (Part-I) dedicated to Piero Comin-Chiaramonti

“…On the other hand, late-stage fluids derived from alkaline felsic complexes can parallel those in ultramafic complexes as suggested in the paper by Singh et al [4], who studied bastnäsite-(Ce) from the Kanigiri alkaline felsic complex of Andhra Pradesh, South India. Hydrous fluids from less alkaline mafic-ultramafic complexes seem different and are more specific for tellurium and PGE concentration as suggested by the papers of Dora et al [5], who studied the mineralisation of Gondpipri, Central India, and the paper by Devaraju et al [6], which describes the Channagiri complex, India. Even small volcanic or subvolcanic outcrops may have undergone the intense action of magmatic fluids as observed in the small melilitolitic sub-volcanics in Central Italy described by Stoppa and Schiazza [7], or the regional swarm of ultramafic dykes described by Comin-Chiaramoti et al [8] from Planalto da Serra, Brazil, which show several generations of latestage minerals.…”

Rare minerals of noble metals in the collection of the Mining Museum: new data

“…Both minerals were first described in the ores of the Monchegorsk deposit in 1963 [29]. Subsequently, they were found in many platinum-metal deposits and occurrences in Russia, Brazil [30,31], Canada [18,32], Japan [33], and India [34].…”