Auteur
Al-Kholidi, Mogeeb Qassim
Directeur de thèse
Boutaleb, A. (Professeur)
Filière
Sciences de la Terre
Diplôme
Magister
Titre
Etude des minéralisation à Pb-Zn de Jabal El Kawl-(région de Jabali)-Yemen
Mots clés
Gites minéraux : Yémen ; Plamb : Minerais ; Zinc : Minerais ; Dolomite ; Géologie économiques : Yémen ; Prospection : Yémen
Résumé
The mineralization is exposed on a small plateau (150m wide by 200m long) at an altitude of 2100m in a mountainous area to the southwest of the Mesozoic Wadi Al-Jawf basin, this site of large oil discovered in the early 1980s (Al-Sharjabi., 2001). In 1980, discovered the small Wadi As Salsal Pb-Ag-bearing gossan during direct outcrop prospecting of the brownish-altered zone occurring along the northern fault edge of Jabal Haylan. Detailed prospecting in 1982 led to the discovery of two other gossans at Wadi Al-Hiniwah and Wadi Al-Jawah, the latter extending over 1.3km along the fault. Geophysical survey (SP, Maxmin, EM-VLF,IP and Mag) detected only shallow conductive anomaly in Wadi Al-Hiniwah and a small SP anomaly related to the Wadi As Salsal gossan. Drilling of the easily accessible Wadi Al-Jawah gossan was carried out in 1984. At 75m depth, 4m of limonitic ore grading 2.45% Zn, 0.21% Pb and 4ppm Ag was intersected. Late Tertiary tectonic movements along the Jabal Haylan northern fault edge caused intense alteration of the partly dolomitized limestones of (unit 7). Along fractures and initial bedding, these were transformed to dark "de-dolomite" consisting of brown Fe-Mn oxide-rich sparite and calcite druses. The de-dolomitized zone is about 10km long and several hundred meters wide and shows anomalous Mn (3%MnO), Zn (0.43%), Pb (0.11%) and Sb (140ppm) values. The gossans correspond to the filling of dissolution cavities, within the de-dolomitized limestones, by bedded limestones, brecciated goethite, amorphous silica and clays. The oxidation of former framboidal pyrite or marcasite (significant Mo grades) is complete and no lead-zinc minerals have been found except small veinlets of barite and galena in Wadi As Salsal. Grades are always low. The small Wadi Al-Hiniwah gossans (maximum dimensions of 60m by 40m) grade 0.1%Zn, 0.03%Pb and 3 ppm Ag on average. The 50 x 15m gossan of Wadi As Salsal grades 0.27% Zn, 0.97% Pb (max 1.38%) and 31ppm Ag (max 64ppm). The extensive Wadi Al-Jawah gossan grades 0.51%Zn (max. 1.79% in its upper part).0.46% Pb (max. 0.94% in its upper part), 2.5ppm Ag (max. 24.5ppm) and up to 0.22% Ba.
Date de soutenance
19-12-2012
Cote
553.4-533
Pagination
89 p.
Illusatration
ill.
Format
30 cm.
Notes
support papier accompagné d'un CD-Rom.-Bibliogr.p.84-87
Statut
Traitée