Massive sulphides and carbonate mineral deposits as well as hydrocarbons associated with sublacustrine hydrothermal activity were discovered at two sites, Pemba and Cape Banza, along the western side of the north Tanganyika trough (Zaire). This hydrothermal activity was investigated by scuba diving at a maximum depth of 20 m. Results presented here are from mineralogical and geochemical analyses of sulphide and carbonate deposits, hydrothermal fluids, and associated hydrocarbons. At Cape Kalamba, south of Cape Banza, a sublacustrine oil seepage has also been observed, sampled, and analyzed. This oil has a carbon-14 age of 25 000 a B.P. and is a biodegraded residue with biomarkers similar to typical crude oils. There are no hydrothermal poly-nuclear aromatic hydrocarbons detectable.Present analytical results are interpreted in terms of fluid temperature at depth, nature of organic matter forming the hydrocarbons, and origin of heat.
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- Hydrocarbons, Sulphides, and Carbonate Deposits Related to Sublacustrine Hydrothermal Seeps in the North Tanganyika Trough, East African Rift
J. -J. Tiercelin
B. R. T. Simoneit
- Springer Berlin Heidelberg