Geochemical Characteristics, Zircon U-Pb Dating and Cu-Ni Mineralization Analysis of the Hongliuhe North Diabase-Porphyrite in Hami, Xinjiang

The diabase-porphyrite in the North of Hongliuhe, Hami City, Xinjiang, is distributed in the central-southern part of the Cu-Ni ore district located to the north of Hongliuhe. It occurs as small dikelets with a nearly east-west trending long axis, and exhibits typical porphyritic texture and diabase texture. Zircon U-Pb dating results indicate that the diabase-porphyrite formed at 337±12 Ma (Late Carboniferous). Geochemically, it is characterized by high MgO, low SiO2, TiO2, and alkali metals, with significant depletion of high field strength elements such as Nb, Ta, and Ti, and enrichment of light rare earth elements. These features collectively suggest that the rock was derived from a depleted mantle modified by subduction fluids, and experienced high-degree partial melting in an extensional setting under a subduction system. During the magmatic ascent, it may have undergone contamination with crustal materials, which promoted sulfide saturation and Cu-Ni mineralization.