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 Sigma REE and are rich in Co-Ni-(W)-Mo-Bi. Fluid inclusions in vein calcites show relative high temperature-high salinity (T-h > 250 degrees C, S >8. 0% NaCleqv), while that in nodule calcites display relative low temperature-low salinity (T-h <200 degrees C, S <8. 0% NaCleqv). Besides, carbon isotopes spread dispersively (delta C-13(PDB) = -22. 95 parts per thousand similar to -2. 56 parts per thousand), indicative of carbonic multi-sources for vein calcites, but concentrate (delta C-13(PDB) = -7. 02 parts per thousand similar to -6. 18 parts per thousand) for nodule calcites. Two groups of oxygen isotopes (delta O-18(SMOW) = 20. 16 parts per thousand similar to 23. 49 parts per thousand) 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.