Distribution and occurrence of Ge and related trace elements in sphalerite from the Lehong carbonate-hosted Zn-Pb deposit, northeastern Yunnan, China: Insights from SEM and LA-ICP-MS studies

•Ge and Cu should be coupled substituted as 3Zn2+ ↔ Ge4+ + 2Cu+.•Cu enrichment in early sphalerite leads to the coupling of Fe and Ge.•Vertical zoning of Mn, Ge, Cu and Cd in sphalerite may be a mineral exploration tool.