Lead isotopes in the sulfide ores from the Shesuo and Lawu copper deposits, northern Xizang

The emphasis in the present paper is placed upon the lead isotopic compositions and their origins in the sulfide ores from the Shesuo and Lawu copper deposits, northern Xizang. The analytical results include ²⁰⁶Pb/²⁰⁴Pb ratios from 18.517 to 18.776, ²⁰⁷Pb/²⁰⁴Pb ratios from 15.671 to 15.756, ²⁰⁸Pb/²⁰⁴Pb ratios from 38.955 to 39.33 for the Shesuo copper deposit, while ²⁰⁶Pb/²⁰⁴Pb ratios from 18.651 to 18.757, ²⁰⁷Pb/²⁰⁴Pb ratios from 15.707 to 15.823, ²⁰⁸Pb/²⁰⁴Pb ratios from 39.183 to 39.561 for the Lawu copper deposit. The above-mentioned lead isotopic values for the sulfide ores indicate the upper crustal origin of the ore-forming matter in the Shesuo and Lawu copper deposits. More precisely, the ore-forming matter in the Shesuo copper deposit may come mainly from the remelted crust during the Yanshanian, while those in the Lawu copper deposit may be locally originated from the mantle matter during the Late Carboniferous. In the Shesuo-Duoba metallogenic belt in Gangdise, the skarn-type deposits could be found in the contact zones between the Lower Cretaceous carbonate-clastic rocks and moderately acidic rocks, whereas in the Nyainqentanglha area, SEDEX type deposits may be hosted in the Upper Carboniferous Laigu Formation.