赣南淘锡坝锡锂矿床成矿作用研究:来自矿物地球化学和流体包裹体的证据OA

The Taoxiba deposit is located at the junction of the Wuyishan metallogenic belts and Nanling metallogenic belts in South China,and is a large-scale tin deposit iscovered within the Xikengjing ore field.Recent studies have revealed that biotite in the greisen of its contact zone contains relatively high Li concentrations,indicating potential exploitation value for lithium.To systematically clarify the ore-forming fluid characteristics,fluid evolu-tion processes,and Sn-Li metallogenic conditions of the deposit,this study conducts a comprehensive investiga-tion on alteration minerals and ore-forming fluids using electron probe microanalysis(EPMA),LA-ICP-MS trace element analysis,microthermometry of fluid inclusions,and X-ray diffraction(XRD).The results show that mica in the greisen of the study area is characterized by Si enrichment and depletion in Mg and Ti,belonging to protoli-thionite and acting as the dominant Li-bearing mineral,with an average Li2O content of 1.51％.Chlorite is identi-fied as chamosite,exhibiting geochemical features of Fe enrichment and depletion in Mg and Al.Fluorite inter-grown with cassiterite is enriched in Sn,As and Fe,and depleted in Bi,Sb and Ba.Fluid inclusion microthermom-etry yields homogenization temperatures of 151～326℃ and salinities(w(NaCleq))of 1.74％to 13.07％,indicating that the ore-forming fluid belongs to medium-high temperature and low salinity type.Fluid cooling is the domi-nant mechanism triggering tin mineral precipitation.XRD results demonstrate that silicification,greisenization,topazization and fluoritization are closely associated with Sn-Li mineralization.In the Taoxiba deposit,tin and lithium underwent coupled enrichment and mineralization during the high-temperature and relatively oxidizing stage.With the decrease of temperature and oxygen fugacity,tin continued to precipitate and form ore deposits,whereas lithium mineralization was poorly developed,leading to the decoupling of Sn and Li.