新疆巴楚小海子岩体铁钛成矿特征及资源利用前景OA北大核心CSTPCD

The Xiaohaizi is a low-grade but large-tonnage magmatic Fe-Ti deposit that newly discovered in the Tarim Large Igneous Province.The sequence of magma evolution,the genetic relationship with other deposits in the same area,as well as the resource utilization prospect of the Xiaohaizi deposit remain unclear.This study carried out geological and geochemical studies of two types of ore bearing rock facies of olivine gabbro and olivine py-roxenite.Although the facies of olivine gabbro and olivine pyroxenite are not spatially in contact,petrographic ob-servations indicate that the differences in their mineral assemblages are related to mineral accumulation.These two facies show similar chondrite-normalized REE patterns and primitive mantle-normalized patterns,suggesting a comagmatic feature.The low Fo values(67.9～72.5)of olivine indicate significant differentiation of mantle-de-rived magma in the deep magma chamber.The Xiaohaizi and Wajilitage intrusion show similar petrographic and geochemical characteristics,indicating that they are comagmatic.However,the latter has a larger range of mineral composition,which implies that the Wajilitage intrusion experienced a higher degree of fractional crystallization during magma evolution,and this may be the reason why the Wajilitage intrusion having higher w(TiO2)contents than the Xiaohaizi intrusion.Although the w(TiO2)contents(3%～4%)of the Xiaohaizi intrusion is relatively low,the features of nondevelopment of solid solution separation structure and coarse grain size are in favor of iron and titanium separation in the beneficiation process.Thus,it is recommended to establish a regional exploration tech-nical specification for the low-grade but large-tonnage Fe-Ti resources in South Xinjiang.