Re-Os Isotopic Age of the Hongqiling Cu-Ni Sulfide Deposit in Jilin Province, NE China and its Geological Significance

摘要

The Hongqiling Cu-Ni sulfide deposit in central Jilin Province is located in the eastern part of the Central Asian Orogenic Belt. Rhenium and osmium isotopes in sulfide minerals from the deposit are used to determine the timing of mineralization and the source of osmium, and ore metals. Sulfide ore samples have osmium and rhenium concentrations of 0.28-1.07 ppb and 2.39-13.17 ppb, respectively. Ten analyses yield an isochron age of 223 ± 9 Ma, indicating that the Cu-Ni sulfide deposit in the area formed in the Triassic. The initial ~(187)Os/~(188)Os ratio is around 0.295 + 0.019 (MSWD = 1.14) and the δ~(34)S values of sulfide ores vary from -1.50 to +3.00 %o. These data indicate that the mineralizing materials were derived mainly from a mantle with some quantities of crustal components introduced into the rock-forming and ore-forming systems during mineralization and magmatic emplacement.