Micro-textural and chemical fingerprints of hydrothermal cobalt enrichment in the Jingchong Co-Cu polymetallic deposit, South China

•Pyrite, arsenopyrite and cobaltite-alloclasite dominate the Co occurrence.•A Co- and As-rich magmatic-hydrothermal fluid pulse contributed to the Co enrichment.•Decreasing temperature together with increasing oxygen and sulfur activity controlling Co precipitation from solutions.