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

Abstract 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-narmalized 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 XREE and are rich in Co-Ni-(W)-Mo-BL Fluid inclusions in vein calcites show relative high temperature-high salinity ( T h >250°C, S > 8.0% NaCleqv) , while that in nodule calcites display relative low temperature-low salinity (T h<200 °C, S <8.0% NaCleqv). Besides, carbon isotopes spread dispersively (S 13Cp 1)B= -22.95%e-2.56%c), indicative of carbonic multi-sources for vein calcites, but concentrate (δ 13C PDB = -7.02%o∼-6.18%e) far nodule calcites. Two groups of oxygen isotopes (δ O SMOW =20.16%c ∼23.49%o) 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 multisources with deep components added in and late ore-forming fluid dominated by meteoric water.