Sulfur-isotope characteristics and discussion on the source of ore-forming material of the Xilekuduke Cu-Mo deposit, Xinjiang Province

The Xilekuduke Cu-Mo deposit is a molybdenum-rich porphyry deposit, which located in the northern margin of the East Junggar and formed at the Early Carboneferous. The delta S-34 values for the sulfide from the Xilekuduke deposit vary from 0. 4 parts per thousand to 7. 6 parts per thousand, with an average of 4. 1 parts per thousand. The delta S-34 values of pyrite, molybdenite and chalcopyrite show ranges of 0. 4 parts per thousand similar to 7. 6 parts per thousand, 3. 2 parts per thousand 4. 7 parts per thousand and 1. 6 parts per thousand similar to 2. 5 parts per thousand, with the averages of 4. 2 parts per thousand, 4. 2 parts per thousand and 2. 1 parts per thousand, respectively, indicating that the sulfur in the sulfides was sourced from a magma. REE geochemical characteristics of sulfides from the Xilekuduke deposit are similar to those of the ore-bearing porphyry, suggesting that the ore-forming materials were came from ore-bearing porphyry. Fluid inclusions and H-O isotope systematic also indicate that ore-forming fluids were derived mainly from magma. While, the high positive epsilon(Nd)(t) values and low Sr-87/Sr-86 initial ratios of the ore-bearing porphyry show that the ore-bearing magma sourced mainly from the mantle. We thus conclude that the ore-forming materials of the Xilekuduke Cu-Mo deposit were mainly sourced from the mantle, and the ore-bearing magma maybe undergone a process of mixing and uniformization between crust and mantle in deep crust.