ABSTRACT The chemical analysis by EMPEDS of 140 samples in cores from six Red Sea troughs and basins has led to the discovery in the Nereus Deep of high vanadium concentrations (up to 1.3% V 2 O 3 ) in several bulk samples, and to the isolation of a major magnetite phase. This vanado‐magnetite, remarkable for its high content of vanadium (mean = 1.45% V 2 O 3 ) and its lack of titanium, is frequently zoned, the V‐content decreasing toward the outer zones. Oxides with up to 42% V 2 O 3 , have also been found. Since the origin of the magnetite is clearly authigenic, its high vanadium and low titanium concentrations are traced back to the differential hydrothermal leaching of Fe—Ti‐oxides which occur profusely in basic eruptive rock clasts, actually present in some of the overlying seams.
Abstract Verbeekite, ideally PdSe 2 , monoclinic with space-group choices C 2/ m , C 2 or C m ; a = 6.659(7), b = 4.124(5), c = 4.438(6) Å, ß = 92.76(3)°, V = 121.7(4) Å 3 ; a : b : c = 1.6147:1:1.0761, Z = 2, is a new, very rare, primary mineral, intimately associated with secondary oosterboschite {(Pd,Cu) 7 Se 5 }, from the Musonoi Cu-Co-Mn-U mine, near Kolwezi, Shaba Province, Democratic Republic of Congo. Additional associated minerals are Cu- and Pd-bearing trogtalite {(Co,Cu,Pd)Se 2 }, Se-bearing digenite and Se-bearing covellite. The strongest five lines of the X-ray powder-diffraction pattern { d in Å ( I ) ( hkl )} are: 4.423(30)(001), 3.496 (30)(110), 2.718(100)(111), 1.955(50)(310 and 1.896(50)( 12). The mineral has also been identified, as a single anhedral 25 µm-sized grain, from Hope's Nose, Torquay, Devon, England where it is associated with native gold, chrisstanleyite Ag 2 Pd 3 Se 4 , oosterboschite(?), unnamed Pd 2 HgSe 3 and cerussite. At Musonoi, altered verbeekite grains do not exceed 200 µm in size and are anhedral, black, with a black streak and a metallic lustre. The mineral is opaque, brittle, has an uneven fracture, and lacks discernible cleavage. The VHN 5 ranges 490–610, mean 550 kp/mm 2 (2 indentations), roughly approximating a Mohs' hardness of 5Ý. D calc. = 7.211 g/cm 3 for the ideal formula. Electron-microprobe analyses (mean of 4 spot analyses) yielded Pd 39.6, Cu 0.5, Se 58.8, total 98.9 wt.%. The empirical formula is (Pd 0.99 Cu 0.02 ) σ1.01 Se 1.99 , based on Pd+Cu+Se = 3. In plane-polarized reflected light, the mineral is a nondescript grey and is neither pleochroic nor perceptibly bireflectant. Anisotropy is moderate with rotation tints in varying shades of brown. Reflectance spectra and colour values are tabulated. The name honours Dr Théodore Verbeek (1927–1991) who was the first geoscientist to study the Musonoi palladium mineralization in the Democratic Republic of Congo (1955–1967) and who co-discovered this new mineral phase.
A summary is given of the most important works on coal as a possible source of Be. The fifteen references cited show the existence of coals with important Be concentrations. The possibility of the eventual utilization of coal ash as a Be ore is indicated. (J.S.R.)
Spectrochemical analyses have shown the constant presence of Be in the coals of Bonne-Esperance at Lambusart. The values vary between 20 and 500 ppm in the ashes, for a mean of 200 ppm. Regularities of the distribution of Be (effect of the concentration in the ash and proximity of walls) can be tentatively determined from the small number of available data. (tr-auth)
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