Abstract:The Hongshigangbei mafic intrusion was discovered by No.704 Geological Party,Xinjiang Geological Exploration Bureau for Nonferrous Metals in 2014. It is located in East Tianshan, and controlled by the KangguerHuangshan ductile shear zone. The mafic intrusion is composed predominantly of diorite, hornblende gabbro and olivine gabbro, with a minor amount of sufide droplets in gabbro occasionally. Sulfide mineral assemblages are composed of pyrrhotite, pentlandite and chalcopyrite. In order to accurately evaluate the prospecting potential of the intrusion, we investigated the zircon UPb chronology, mineral chemistry, geochemical and SrNd isotopic characters of the intrusion. Combining with the geophysical characteristics, we compared the Hongshigangbei intrusion with the typical NiCu sulfide deposit in East Tianshan area. The zircon UPb isotope age of 276.1±5.4 Ma reveals that the mafic intrusion was formed in Early Permian. Olivine crystals in the Hongshigangbei rocks have a narrow range (Fo=69.9~72.6) and the Ni content of 101×10-6~1326×10-6. The clinopyrexene and orthopyroxene belong to endiopsidediopside and enstatite respectively. The values of MgO (5.95%~13.06%) and FeOT show positive correlation, but there is negative relation between MgO and SiO2, CaO and Al2O3. All the samples are slightly enriched in LREE and positive Eu anomaly. Trace elements show a LILErich and HFSEdepleted(Nb,Ta) pattern. The (87Sr/86Sr)i and εNd(t) rations range from 0.70342~0.70349 and +7.51~+8.25(t=276Ma) respectively, indicating that the source of intrusion was depleted mantle. The SrNd isotope trend reveals that the parental magma of the Hongshigangbei intrusion experienced about 5% crustal contamination during upwelling. Compared with the typical NiCu sulfide deposits in East Tianshan, the Fo contents and major elements contents of the Hongshigangbei intrusion are in a low and narrow range. But they are similar in isotope age, trace elements, SrNd isotopic characteristics, degree of crustal contamination and material. This indicates that the characteristics of magma sources, tectonic setting, composition of parental magma and evolution process may have obvious similarity between Hongshigangbei intrusion and Huangshandong, Huangshan deposit. On the basis of the study above, we speculate that the deep of intrusion may exist ultramfic rocks.Geophysical data also indicate that the Hongshigangbei intrusion has lower polarization rate than the typical NiCu sulfide deposit in East Tianshan. But they have similarity in surface magnetic anomaly, residual gravity anomaly and resistivity. These characters show that the deep of the Hongshigangbei intrusion may exist orebearing ultramafic intrusion. In conclusion, we believe that the deep of Hongshigangbei intrusion has large NiCu prospecting potential.