Mineral characteristics and metallogenesis of the Wajilitag layered mafic–ultramafic intrusion and associated Fe–Ti–V oxide deposit in the Tarim large igneous province, northwest China

摘要: Abstract The Wajilitag layered mafic–ultramafic intrusion, as an important lithological unit of the Permian Tarim large igneous province, has genetic link with a scale V-bearing ilmenite–titanomagnetite series mineralization. It consists mainly olivine pyroxenite, pyroxenite and gabbro structures. Olivine from rocks low Fo values [molar 100 × Mg/(Mg + Fe)] 67–76 mol%, probably indicating that magmas have experienced fractional crystallization early removal olivine. Magmas in equilibrium high FeO/MgO ratios ranging 1.1–1.6. Ilmenite exsolution lamellae are present clinopyroxene. therefore considered to be enriched iron titanium, which may account for amounts Fe–Ti oxides hosted therein. High Sm/Yb indicate Fe–Ti-rich produced by degree partial melting mantle source. Layered structures variable mineral compositions clinopyroxene intrusion suggest become more under extensively evolved magma. A few oxide crystals enclosed slightly higher Cr2O3 contents than other minor crystallized stage magmatic process, whereas most interstitial silicate minerals denote they were accumulated late process. We propose formed fractionation processes two-stages. presence ilmenite magnetite suggests massive ore deposits therein slowly cooling process deep magma chamber.