Mineralogical Characterisation of the Sedimentary Phosphate Deposit of Tobene （Western Senegal）

The Tobrne panel is the third of the Ta＇fba phosphate deposit. This mineralogical study contributes to the improved knowledge of the various facies that comprise the phosphate series of Tobrne. Based on X-ray diffraction results, the Tobrne panel yielded minerals that are primarily divided into four groups： minerals of the original phosphate phase： apatite, fluorapatite; carbonate minerals： calcite and dolomite; clay minerals： palygorskite, smectite, kaolinite and illite; minerals of altered facies： alteration minerals （analcime, millisite, crandallite and wavellite） and ferruginous minerals （goethite and gibbsite）. This succession of mineralogical associations reflects a polyphase alteration leading to a vertical and lateral facies sequence. This alteration intensifies the phosphate series upward and laterally from West to East.