Physicochemical Condition of the Dafang Skarn Au-Ag-Zn-Pb Polymetallic Deposit in the Nanling Metallogenic Belt (south China), a Perspective from Sphalerite Mineralogy and Geochemistry

•Four generations of sphalerite behave distinct ore textures and mineral assemblages.•Enrichment mechanisms of minor/trace elements in sphalerite were investigated.•The physicochemical conditions related to mineralization featured moderate to high temperature (319–410 °C), intermediate sulfur fugacity and reduced to oxidized state.•The Dafang Au-Ag-Zn-Pb polymetallic deposits resemble a skarn system.