| The tin-polymetallic deposit of the Xiangkaling skarn in Hunan is rich in fluorites with different colors.In order to study the characteristics and genesis the fluorites with different colors in the Xianghualing skarn,fluid inclusion temperature measurement,electron microprobe,scanning electron microscopy and LA-ICP-MS were applied to analysis the green,purple,yellow and colorless fluorites.The results show that the main component of Xianghualing skarn fluorite in Hunan is CaF2,Ca contents range from 47.80%to 56.95%,the inclusion uniform temperatures range from 95.2°C to 240.0°C,the fluorites contain high contents of rare earth elements,the differences of?REE within different fluorites of different colors are obvious(the?REE does not contain Y,×10-6).The?REE of green fluorite ranges from 547.580×10-6to 3135.421×10-6,with an average value of 1107.770×10-6,The?REE of purple fluorite ranges from 8.884×10-637.043×10-6,with an average value of 22.964×10-6,the?REE of yellow fluorite ranges from 15.137 to 26.091×10-6,with an average value of 21.376×10-6,the?REE of colorless fluorite ranges from 8.559 to9.016,with an average value of 8.788.Through the preliminary analysis and research based on the inclusion temperature measurement,trace elements and rare earth element composition and characteristics of fluid inclusions of different colors of fluorite,the following conclusions were obtained:1.The fluorites contain high REE contents in the Hunan Xianghualing skarn,and it shows a strong negative Eu anomaly in the samples,indicating that fluorites are crystallized in a reducing,low oxygen fugitive and rare earth-rich ore-forming environment.With the crystallization of fluorite,rare earth elements are continuously enriched in fluorite,exhibiting rare earth element enrichment and Eu negative anomaly characteristics.2.Combined with the temperature measurement results of fluorite fluid inclusions and the Tb/Ca-Tb/La atomic ratio analysis of fluorite in Xianghualing skarn,the results show that the origin of the fluorites is closely related to the hydrothermal genesis,and fluorites crystallized in a medium-low temperature environment of 95.2°C to 240°C.The green fluorite crystallized prior to the yellow,purple and colorless fluorite.3.The distribution pattern of REE in fluorite in Xianghualing skarn is similar to the Laiziling granite.There are strong negative Eu anomalies in both regions.The Xianghualing skarn is closely related to the of Laiziling granite in both time and space scale.It is,therefore,speculated that the rare earth elements of fluorite in the Xianghualing skarn and the source of F are closely related to the Laiziling granite.4.The coloration mechanism of fluorite in the Xiangkaling skarn of Hunan is mainly the color centering,and the rare earth element plays an important role in the coloration of fluorite.The color of fluorite is positively correlated to the rare earth element contents.The deeper the color of the fluorite,the higher the content of REEs within the fluorite;the lighter the color of the fluorite,the lower the content of the REEs within fluorite.In addition,the coloration of green fluorite is Th and U related;coloration of purple fluorite is closely related to Y element;the coloration of yellow fluorite color is related to Mg,Mn,Y. |
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