Study on the occurrence and enrichment regularity of cobalt and nickel in albitite (breccia) rock in Fengtai ore concentration area, Shaanxi Province

The Fengtai area is an important polymetallic ore concentration area in China. In order to explore the occurrence law of albite (breccia) cobalt-nickel deposits in this area, this study takes the albite (breccia) rock belt in Shuangwang and Qingyagou areas of the basin as the research object, and reveals its metallogenic characteristics and element distribution law through field geological survey, geochemical profile measurement and petrographic analysis. Geochemical analysis shows that the average contents of Co and Ni in-pyrite-vein-cemented breccia are 710 ppm and 900 ppm, respectively. The average contents of Co and Ni in pyritization altered rocks are 790 ppm and 1300 ppm, respectively, showing higher enrichment characteristics. In addition, multi-stage hydrothermal activities resulted in the inherited enrichment of Ni in pyrite, while the distribution of Co was significantly controlled by hydrothermal physical and chemical conditions, exhibiting marked differentiation in enrichment and depletion. Based on the above analysis, it is considered that the cobalt-nickel mineralization of albite (breccia) type in Fengtai area is closely related to pyritization in space and genesis, and the superposition of multi-stage hydrothermal fluids is the key factor leading to the continuous enrichment of nickel and the selective migration and precipitation of cobalt.