1 3 Int J Earth Sci (Geol Rundsch) DOI 10.1007/s00531-015-1178-y ORIGINAL PAPER Re–Os geochronology on sulfides from the Tudun Cu–Ni sulfide deposit, Eastern Tianshan, and its geological significance Minfang Wang 1,2 · Wei Wang 1 · Jens Gutzmer 2,3 · Kun Liu 1 · Chao Li 4 · Przemyslaw P. Michalak 2 · Qinlin Xia 1 · Xiaonan Guo 1 Received: 22 October 2014 / Accepted: 29 March 2015 © Springer-Verlag Berlin Heidelberg 2015 Introduction The Eastern Tianshan metallogenic belt in northwestern China forms a significant part of the Central Asian Oro- genic Belt (CAOB) and is increasingly recognized as a tec- tonomagmatic province with Ni–Cu sulfide potential (Zhou et al. 2004; Mao et al. 2008; Tang et al. 2012; Gao and Zhou 2013; Gao et al. 2013; Deng et al. 2014; Han et al. 2014a; Yang et al. 2014; and references therein). The basic features and metallogenic characteristics of the Baishiquan, Tianyu, Huangshan, Huangshandong, Hulu and Tula’ergen deposits in Eastern Tianshan have been the subject of a number of publications (Wang et al. 1987; Wang et al. 2006a, b; Tang et al. 2012, 2014; Gao and Zhou 2013; Gao et al. 2013; Deng et al. 2014; Mao et al. 2014), suggesting that the deposits have an Early Permian age (290–270 Ma). However, the nature of the mantle sources and the key factors important for the formation of magmatic deposits in orogenic belts remain controversial, that is, the magmatism resulted from lateral flow of the Tarim plume material along the margins of the Tarim Craton (Zhang et al. 2008a, b; Qin et al. 2011) or from the collision between the Kanggur–Yamansu arc and the Middle Tianshan Terrane (Fig. 1) at the southern margin of the CAOB in Early Permian time (Mao et al. 2003; Zhou et al. 2004; Xia et al. 2008; Han et al. 2010; San et al. 2010; Xiao et al. 2010a; Song et al. 2011, 2013; Wang et al. 2012, 2014)? The Tudun Cu–Ni deposit is located at the westernmost edge of the Huangshan–Jing’erquan Belt and has estimated reserves of 3,000 tons of Cu with ore grades of 0.20 wt% Cu, as well as 15,000 tons of Ni with an average grade of about 0.30 wt% (Mao et al. 2008; Han et al. 2010; Wang et al. 2015). Since the discovery of the deposit in 1980s, some studies have addressed the geology and geochemis- try of the deposit (Yong 2002; Liu 2012; Wang et al. 2012, Abstract The Tudun deposit is a medium-sized Cu–Ni sulfide deposit, located at the westernmost edge of the Huangshan–Jing’erquan Belt in the northern part of East- ern Tianshan, NW China. Sulfide separates including pentlandite, pyrrhotite and chalcopyrite from the Tudun deposit, contain Re, common Os and 187 Os ranging from 40.46 to 201.2, 0.8048 to 6.246 and 0.1709 to 0.9977 ppb, respectively. They have very low 187 Os/ 188 Os ratios of 1.224–2.352. The sulfides yield a Re–Os isochron age of 270.0 ± 7.5 Ma (MSWD = 1.3), consistent within uncer- tainty with the SHRIMP zircon U–Pb age for the Tudun mafic intrusion (gabbro) of 280.0 ± 3.0 Ma. The calculated initial 187 Os/ 188 Os ratio is 0.533 ± 0.022, and γOs values range from 283 to 307, with a mean of 297, indicating sig- nificant crustal contamination of the parent melt prior to sulfide saturation. The Tudun deposit shares the same age and Re–Os isotopic compositions with other orthomag- matic Cu–Ni sulfide deposits in Huangshan–Jing’erquan Belt, suggesting that they have formed in Early Permian. Keywords Tudun Cu–Ni deposit · Re–Os geochronology · Early Permian · Eastern Tianshan * Minfang Wang wang_minfang@163.com 1 Faculty of Earth Resources, China University of Geosciences, Wuhan 430074, China 2 Institute of Mineralogy, TU Bergakademie Freiberg, 09599 Freiberg, Germany 3 Helmholtz Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, 09599 Freiberg, Germany 4 National Research Center of Geoanalysis, Chinese Academy of Geological Sciences, Beijing 100037, China