| Zhaxikang antimony polymetallic ore field is located in which about 50km west of Longzi county,Shannan area of Tibet.Including deposits of Zhaxikang,Keyue,Zedang and Suoyue.Zhaxikang deposit scale is large to super large,and the Keyue,Zedang,Suoyue deposit are smaller.Basded on the previous research we studied the inclusions,trace elements and hydrogen-oxygen isotope geochemical of different minerals from each deposit of this ore field in this article.The type of fluid inclusion can be classified into three categories:H2O inclusions,CO2 inclusions and CO2-H2O inclusions.The three types of inclusions are closely coexisting,showing that they are formed by fluid immiscibility.Gas and liquid H2O inclusions homogenization temperature range in the Ore field is 132303?,the average value is 232.21?,salinity range is 0.350.35?wt%NaCl?,with a mean of6.25?wt%NaCl?.The Zhaxikang deposit's homogenization temperature range is 185289?,average value is 238.57?,salinity range is 1.5712.51?wt%NaCl?,average value is 6.07?wt%NaCl?;The Keyue deposit's homogenization temperature range is 173303?,the average value is 232.51?,salinity are in the range of 6.317.08 wt%?NaCl?,average value is 11.63?wt%NaCl?;The Suoyue deposit's homogenization temperature are in the range of 132253?,the average value is213.64?,salinity range is 0.351.57?wt%NaCl?,average value is 1?wt%NaCl?,and the mineralization temperature and salinity of the Suoyue deposit are significantly lower than those in the Zhaxikang and Keyue deposits.The homogenization temperature of each metallogenic stage of Zhaxikang deposit have little difference,but the salinity of?stage is much higher than the others,and the mean value reachs10.52?wt%NaCl?,the homogenization temperature and salinity of inclusions in rhodochrosite are slightly higher than those in sphalerite.The homogenization temperature of stage?to?of Keyue deposit are 261?,238?and 238?respectively,and the average value of salinity are 14.1 wt%?NaCl?,12.7?wt%NaCl?,8.6?wt%NaCl?respectively,it is obviously that the temperature and salinity are gradually reduce from morning till night.The metallogenic temperature of each deposit in the Ore field have little difference,the majority of inclusions are moderate temperature,but some inclusions have reached the high temperature level.And early in the iron manganese carbonatite inclusion the salinity were higher than that of other minerals,which indicates that the ore-forming fluid within the mine field has the characteristics that the salinity in the early stages is higher than the late stages.The?DV-SMOW??of each deposits in this ore field are in the range of-16593.4,the averages is 139.56,and the?18OH2Oare in the range of 13.713.7,averages is 1.33.The?DV-SMOW??of the Zhaxikang deposit is in the range of-165103.6,the averages is-148.5,and the?18OH2Oare in the range of-13.712.4,the averages is-3.41.The?DV-SMOW??of the Keyue deposit are in the range of 124.193.4,averages is 108.73,and the?18OH2Oare in the range of3.323.32,the average is 6.06.The?DV-SMOW??and?18OH2Oof Keyue deposit are much more higher and concentrated than those of Zhaxikang deposit.The?DV-SMOW???average-106.53?of?stage is significantly higher than??stages?averages-160,160,155.8?in Zhaxikang deposit.And the?18OH2O2O of??stages are 11.6,0.03,7.39respectively,decreased gradually from morning till night,shows the trend of close to the geothermal water of Tibet.While the?DV-SMOW??and?18OH2Oof each stage in the Keyue deposit are concentrated,from?stage to?stage the averages of?DV-SMOW??are-101,-115,-109respectively,and the?18OH2Oare 6.82,5.62,5.76.The hydrogen and oxygen isotope characteristics of this ore field indicate ore-forming fluid should mainly be the primary magmatic water which come from Leucogranite and/or pegmatite,then mix the atmospheric precipitation.The REE curve of quartz,sphalerite and galena are both the right type which enrich the light REE,the anomaly of?Eu are mainly slightly negative,the anomaly of?Ce is not obvious,and the characteristics of very low gross volume of the rare earth are very similar to the pegmatite of Cuonadong.And the total content of HFSE is low,the ratio of Hf/Sm,Nb/La and Th/La are basically less than 1,indicating the ore-forming fluid is mainly riched in Cl.Trace element characteristics and the lnGa-lnIn diagram of sphalerite,lnBi-lnSb diagram of galena all indicates the ore-forming fluid has the remarkable properties of magmatic hydrothermal origin,and ore formation also provided some ore-forming materials.The composition of immiscible fluid inclusion,the result of microthermometry and the macroscopic geological phenomenon indicated that immiscible of the ore-forming fluid in the ore field is the main reason for the metal elements precipitate. |
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