Geochemistry and Prospecting Potential of Datonggou South Mountain Basic-ultrabasic Rocks in Northwest Qaidam Basin

The Datongnanshan basic-ultrabasic rocks are located at the northwest margin of Qaidam block, which were intruded into the Neoproterozoic formation. These rocks are distributed in the northeast direction, which are mainly occurred as vein and lens. The rocks are composed of olivine pyroxenite, pyroxene amphibolite, pyroxene peridotite and olivine websterite, The Cu-Ni mineralization is primarily occurred in olivine pyroxenite and pyroxene amphibolite. These rocks are characterized by low silicon, middle magnesium, high titanium and high calcium, which are enriched in light rare earth elements and large ion lithopile elements (Th, U, Rb), and relatively depleted in high field strength elements (Nb, Ta, Ti). Petrological and geochemical studies indicate that the crystallization differentiation and crustal contamination were occurred during the process of magma evolution, showing a good potential for forming copper and nickel deposits. The MgO content and m/f ratios of these rocks indicate that they have a good property of bearing copper and nickel. After studying the formation environment, petrogeochemistry, geophysical and geochemical characteristics of these rocks comprehensively, the results show that the Datonggounanshan basic-ultrabasic rocks have good prospecting prospect and forming conditions of Cu-Ni sulfide deposits.