Massive ore body occurrence in the Dure section. a) Sulfide assemblage seen in hand specimens collected from massive ore body. Large, coarse aggregates of sphalerite (brown) are surrounded primarily by pyrite (brass-yellow). Galena (silver-gray) is also present. Photomacrograph, hand sample, (DO 26). b) Veins in massive pyrite (Py) are filled by sphalerite (Sp) and galena (G). Photomicrograph, reflected light, scale bar is 1mm. (DO 10). c) Alternation of sub-millimeter to centimeter bands of pyrite (Py) and thin sphalerite (Sp) with disseminated galena (G) shows a banded structure hosted by gray dolostone. Thin vein filled by pyrobitumen (Pyb) and saddle dolomite (SD) are also present. Photomacrograph, hand sample (DO 11). 

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Context 1

... ore body in the Dure section occurs as a stratabound demarcates the unconformity between the upper Triassic dolostones of the Kurra Chine Formation and overlying Tertiary rock units. The Dure ore deposits occur as: massive, banded and vein-type style of mineralization. The ore body consists of massive pyrite with small veins and patches of sphalerite and galena (Figs. 4a, b), which are highly deformed, brecciated, and recrystallized. The banded structure is characterized by an alternation of sub-millimeter (laminations) to centimeter bands (Fig. 4c). The main-stage of mineralization involved the progressive replacement of pre-existing iron sulfides and the dolostone breccias, initially by replacement of the breccia matrix and ultimately by replacement of clasts. The sulfides are intermixed with dolomite ( Fig. 4c), whereas calcite is more frequent in the oxidized zone. Petrographic observations of polished sections and XRD indicate that ore minerals in the Dure section ( Fig. 5) consist of pyrite, sphalerite, galena, goethite, smithsonite, cerussite and anglesite. Pb-Zn deposit in the Lefan is strata-bound sulfides hosted in the Upper Cretaceous dolomitic limestone of the Bekhme Formation and occurs mainly as open-space fillings or lodes within fractures (Figs. 6a, b). They can be described as tabular fracture fillings and replacement-type ores. These vein-type bodies vary in width from few centimeters up to 2 meters. They are discontinuous along strike and extend into the country rock for several tens of meters. Coarse crystalline sphalerite and galena occur as open space and fracture-fill mineralization within the main ore-stage assemblages where they occur with euhedral dolomite and calcite (Figs. 6c, d). Barite was reported by Awadh (2006) to occur in association with ore and sometimes as an independent mineral in veins, but in the present study it has been observed only in small veins ( Fig. 6b). Ore minerals in the Lefan section consist, in decreasing order of abundance, of sphalerite, galena, and minor pyrite, goethite, smithsonite, and cerussite ( Fig. ...

Context 2

... ore body in the Dure section occurs as a stratabound demarcates the unconformity between the upper Triassic dolostones of the Kurra Chine Formation and overlying Tertiary rock units. The Dure ore deposits occur as: massive, banded and vein-type style of mineralization. The ore body consists of massive pyrite with small veins and patches of sphalerite and galena (Figs. 4a, b), which are highly deformed, brecciated, and recrystallized. The banded structure is characterized by an alternation of sub-millimeter (laminations) to centimeter bands (Fig. 4c). The main-stage of mineralization involved the progressive replacement of pre-existing iron sulfides and the dolostone breccias, initially by replacement of the breccia matrix and ultimately by replacement of clasts. The sulfides are intermixed with dolomite ( Fig. 4c), whereas calcite is more frequent in the oxidized zone. Petrographic observations of polished sections and XRD indicate that ore minerals in the Dure section ( Fig. 5) consist of pyrite, sphalerite, galena, goethite, smithsonite, cerussite and anglesite. Pb-Zn deposit in the Lefan is strata-bound sulfides hosted in the Upper Cretaceous dolomitic limestone of the Bekhme Formation and occurs mainly as open-space fillings or lodes within fractures (Figs. 6a, b). They can be described as tabular fracture fillings and replacement-type ores. These vein-type bodies vary in width from few centimeters up to 2 meters. They are discontinuous along strike and extend into the country rock for several tens of meters. Coarse crystalline sphalerite and galena occur as open space and fracture-fill mineralization within the main ore-stage assemblages where they occur with euhedral dolomite and calcite (Figs. 6c, d). Barite was reported by Awadh (2006) to occur in association with ore and sometimes as an independent mineral in veins, but in the present study it has been observed only in small veins ( Fig. 6b). Ore minerals in the Lefan section consist, in decreasing order of abundance, of sphalerite, galena, and minor pyrite, goethite, smithsonite, and cerussite ( Fig. ...