Petrology, geochemistry and petrogenesis of the ore-bearing trachydacite porphyry from the Suoerkuduke Cu-Mo deposit, Xinjiang, NW China
ZHAO Lu-tong;WANG Jing-bin;WANG Yu-wang;DING Ru-fu;LONG Ling-li;ZOU Tao;SHI Yu;GAO Yi-han;Faculty of Land Resources Engineering, Kunming University of Science and Technology;Beijing Institute of Geology for Mineral Resources;Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, CAS;
The Suoerkuduke Cu-Mo deposit is located in the northeastern margin of East Junggar. It was traditionally regarded as a stratabound skarn deposit associated with pyroxene andesite porphyrite. Based on investigation of open-pit and the exploration borehole in the mining area, this paper considers that the host rock of this deposit may be the trachydacite porphyry, evidenced by that the trachydacite porphyry developed veinlet copper and molybdenum mineralization, and the hydrothermal activity became much stronger from the shallow to deep. The K2 O+Na2 O content in fresh trachydacite porphyry reaches 9.38% 10.3%, the K2 O/Na2 O value is 2.63 3.17, and its A/CNK value is 0.91 1.04, indicating that the trachydacite porphyry belongs to the metaluminous and high-K calc-alkaline rock series being affinity of "I" type granite. The geochemistry of enriching in large-ion lithophile elements(LILE, such as Rb, Ba and K) and strong incompatible elements(such as U, and Th), relatively depleting in high field strength elements(HFSE, such as Sr, Nb, Ta and Ti) suggest that the trachydacite porphyry may display a characteristics of the arc magma. The isotope characterized by(87Sr/86Sr)i ratio of 0.70100 0.70384,(143Nd/144Nd)i ratio of 0.512387 0.512436, εNd(t) value of +4.8 +5.8, and young Nd two-stage model age of 663 741 Ma, indicate that the trachydacite porphyry may be derived from the partial melting of mantle wedge.