Biostratigraphic and Palaeoenvironmental Study of the Tob?ne Phosphatic Series (Western Senegal)

The geological section of the phosphate quarry of Tobne associated with the boreholes of prospecting, carried out by miners, confirms the Tobnes lithostratigraphic and biostratigraphic settings. A lithostratigraphic analysis [1], [2] highlights three sedimentary formations, in agreement with previous results [3] From a biostratigraphic point of view, the planktonic microfauna highlighted E8 to E13 biozones in the phosphatic group, dating it to the early Lutetian to Bartonian age and helping to develop a more complete biozonation throughout the deposit. The pelagism index indicates an evolution of sedimentary environment between a slightly opened internal platform, favourable to detrital and siliceous deposits, and an intermediate platform more conducive to calcium phosphate deposits.