Geochemical characteristics of trace elements,fluid inclusions and carbon-oxygen isotopes of calcites in the Jinding Zn-Pb deposit,Lanping,China

The metallogenic mechanism of the Jinding Zn-Pb deposit is always of catholic concern,but it cannot reach a consensus.One of important causes is ascribed to limiting understanding in ore-forming fluid properties and its sources.Therefore,systematic geochemical studies of trace elements,fluid inclusions and carbon-oxygen isotopes on vein calcites and nodule calcites,formed in early and late mineralization respectively,have been carried out to investigate the ore-forming fluid nature and its potential sources.It is discovered that both vein and nodule calcites are characterized by sharing sharp right-dipped chondrite-normalized REE patterns with LREE enriched and LREE-HREE distinctively differentiated,as well as similar Mg,Fe and Mn contents.However,distinct discrepancies exist between two kinds of calcite in trace elements,fluid inclusions and carbon-oxygen isotopes.Relative to nodule calcites,vein calcites have higher ∑REE and are rich in Co-Ni-(W)-Mo-Bi.Fluid inclusions in vein calcites show relative high temperature-high salinity(Th250℃,S8.0% NaCleqv),while that in nodule calcites display relative low temperature-low salinity(Th200℃,S 8.0% NaCleqv).Besides,carbon isotopes spread dispersively(δ13CPDB=-22.95‰~-2.56‰),indicative of carbonic multi-sources for vein calcites,but concentrate(δ13CPDB=-7.02‰~-6.18‰) for nodule calcites.Two groups of oxygen isotopes(δ18OSMOW=20.16‰~23.49‰) resemble sedimentary rocks.To be comprehensively analyzed,vein calcites and nodule calcites,both due to hydrothermalism,represent two different hydrothermal systems:early ore-forming fluid resulting from multi-sources with deep components added in and late ore-forming fluid dominated by meteoric water.