Mineralogical Analysis Of The Djebel Dyr Phosphorites (Algerian-Tunisian Confines)
The sedimentary phosphorites of marine origin mark the Paleo-Eocene period in the region of Tebessa, as
elsewhere in northern Africa. The study sector of Djebel dyr is considered a part of the eastern Saharan Atlas. The
lithological description of the studied Cups has allowed showing a bundle of phosphate take by carbonate formations with
sprinkle of flint. Sorting and litho-morphological observation have identified coprolites, fish teeth, granules, but mainly
phosphatic pellets and uncommon non-phosphatic minerals. Analysis by X-ray diffractometry whole rock has confirmed the
presence of apatite minerals (hydroxylapatite, Fluroapatite, francolite and dahlite), carbonates (calcite, magnesium calcite,
ankerite and dolomite), Quartz, Opal-CT, Zeolites, Feldspar, Clays, Sulphides and Gypsum. Furthermore recounts the RX
recordings on the purified grains were identified different mineral phases. Coprolithes and the pellets showed the
hydroxylapatite and fluoroapatite sometimes associated with the dahllite, however granules of different forms revealed
hydroxylapatite associated fluoroapatite or francolite .Thus, XRD analysis performed on teeth from the phosphate beam
Jebel Dyr has overwhelmingly demonstrated the systematic presence of fluorapatite Ca 5 (PO 4) 3F.
Keywords- sedimentary phosphates - Paleo-Eocene - Tebessa - Diffractometry RX - apatite minerals.