Re-Os dating of the Suoerkuduke Cu (Mo) deposit, Fuyun County, Xinjiang, and its geodynamic implications

Abstract

The Suoerkuduke (索尔库都克) Cu (Mo) deposit, in the same metallogenic belt with Xilekuduke (希勒库都克) Cu-Mo deposit, is located in the Armantai (阿尔曼太) island arc belt on the northern margin of East Junggar, Northwest China. Rhenium and osmium isotopic analysis of seven molybdenite samples from the deposit was used to determine the age of mineralization. A seven-point isochron age of 317.7±7.6 Ma, which is consistent, within analytical error, with the average model age of 323.3±1.9 Ma indicates that this deposit was formed at transitional period between the Early and Late Carboniferous. This age is obviously later than that of the Lower Devonian Tuoranggekuduke (托让格库都克) Formation acting as the wall rock but contemporaneous with the early stage of plutonism (330–268 Ma) in East Junggar. Based on the characteristics of mineralization age and tectonic setting of many typical deposits on the northern margin of East Junggar, we proposed that the mineralization age of Suoerkuduke deposit is a key period of East Junggar for the tectonic regime transforming from compression to extension and also the time when granitoids and deposits widely spread in this area. Mineralization and formation of skarn in this deposit are closely related to felsic-intermediate magmatism. The distinct characteristic from typical skarn-type deposits is that the metallogenic parent intrusion is a huge batholith in the depth. The Cu (Mo) mineralization, moyite, and granite porphyry are all derived products of the batholith.