Evolution of Ore Fluids and Hydrocarbons in the Benue Trough Lead-Zinc Deposits, Nigeria

摘要

Epigenetic lead-zinc-barite-fluorite deposits in Nigeria are located within the Middle Cretaceous shales, carbonates and sandstones of the Benue rift structure. A regional study of fluid inclusions microthermometry, stable isotopes, rare earth and Rock Eval pyrolysis of the intraformational veins and host sediments were carried out to ascertain the nature of fluids for the mineralization and relation with hydrocarbons at this stratigrahic interval. Results indicate that hot 170 to 230°C metal rich brines migrated through the sediments for the first time through faults, causing the thermal degradation of petroleum source rock facies and precipitated base metal sulfides, sulfates, fluorites and hydrocarbons within the Albian-Cenomanian interval.