Abstract:
A new type of copper deposits is discovered in the La n ping and Simao Basins.It is named after vein tetrahedrite-type copper deposits. δ
13C values for carbonate vein and CO
2 inclusions from the studied deposits range from-4‰ to -7 ‰,indicating mantle-derived carbon.Pb isotopic compositions for sulfides fr om the studied ores are comparable to those for feldspar Pb from the Himalayan alkaline rocks and
87Sr/
86Sr ratios for calcite and ankerite are similar to or higher th an those for the Himalayan alkaline rocks,indicating mantle-derived Sr and Pb.Most of δ
34S values for the sulfide from the studied ores range from 0 to-4‰,showing mantle-derived sulfur mixed with crustal sulfur.δD and δ
18O values for water in fluid inclusions reveal that water in ore fluid are derived mainly from meteoric water,secondly,from magmatic water and metamorphic water.Combined with geologic-geochemical features,this paper puts forward that the wein tetrahedrite-type copper deposits belong to mixed mantle-crust hydrothermal genetic type of co pper deposits.