Major and trace element and multiple sulfur isotope composition of sulfides from the Paleoproterozoic Surda copper deposit, Singhbhum shear Zone, India: Implications for the mineralization processes

摘要: Abstract The present study combines major and trace element composition, sulfur (S) isotope data of pyrite chalcopyrite from the Surda copper sulfide deposit in Singhbhum Shear Zone, most important uranium producing belt (Singhbhum Cu-U Belt) India. Three textural compositional types both were distinguished; unzoned to partially zoned Pyrite IA with high Co (up 54900 ppm) low Ni content is earliest, followed by oscillatory IB As 25600 ppm) 46800 ppm), occurring I + chalcopyrite I + pyrrhotite + magnetite + apatite vein; Cobaltite-type substitution (Fe1−xCox)(S1−xAsx)2 suggested for IB. Gold occurs I as minor “invisible” gold electrum inclusions. It also along Cu, Mn, Ni, Hg, Ag, Pb, Sb, Zn, Ce, Y, U, Th micro-fractures that transgress primary zoning pattern defined As, Co, early inclusion-rich generation (Chalcopyrite I) contains concentration Zn Se, amounts Te, Bi, appeared between II. Low 37700 ppm) II, inclusion-free Chalcopyrite II enriched V, Pb are cogenetic, II + pyrrhotite + pentlandite + chalcopyrite II ± violarite vein. containing III + Chalcopyrite III occur mainly disseminated grains. relative timing formation II + Chalcopyrite remains uncertain. Pyrite + chalcopyrite textures indicate all pyrite + chalcopyrite formed at some time prior end deformation metamorphism. Both situ mineral separates associated yield a narrow range positive δ34S values (between +3.8  +6.9‰) suggesting being derived similar source. Consistent other circumstantial evidence was seawater sulfate or modified (brine/evaporite). Δ33S revealed mass dependent fractionation (MDF) signature. proposed incorporation MDF mineralization event Paleoproterozoic Belt took place after great oxidation event. Se concentrations (260–400 ppm) ∑Se/∑S ratios (4.4–5.7 × 10−4) suggest temperature Cu–rich ores (250°–350 °C), precipitation metalliferous fluid ratio (10−4 10−3) consistent igneous input these elements.