Rb-Sr isotopic age of sphalerite from the Paoma lead-zinc deposit in Sichuan Province and its implications

Abstract：Located in Nanning County of Sichuan Province, the Paoma lead-zinc deposit is a stratabound deposit in a cataclastic zone of Lower Cambrian Maidiping dolomite. Being a reworked sedimentary stratoid (irregular) lead-zinc deposit, it includes two ore horizons. Pb and Zn in the ore deposit are economic elements possessing an average grade of 6%～9%, with the grade of rich ore in excess of 30%. The sphalerite Rb-Sr isochron age of 200±1Ma by TIMS method suggests an age of Late Indosinian-Early Yanshanian. This ore deposit has the same age as the Huize lead-zinc deposit in Yunnan Province, and therefore it is inferred that they had the same ore-forming setting.