Isotope signatures in phosphate deposits: Formation and diagenetic history

Geochemistry and microprobe investigations of Abu Tartur REE-bearing phosphorite, Western Desert, Egypt

“…(2) Diffusion of dissolved U(VI) from sea water into bottom sediments followed by its reduction to insoluble U(IV) in the anoxic zone of the sediment layer (Anderson, 1987;Kolodny and Luz, 1992). (3) Adsorption or organic complexation of dissolved U(VI) by settling particulate organic matter or uranyl adsorption on Fe-oxyhydroxides (Hsi and Langmuir, 1985. The diagnostically low U phosphorites in Western Desert can be interpreted to the fact that they lie high above of the water table, under very arid regime.…”

Geochemistry of Late Cretaceous phosphorites in Egypt: Implication for their genesis and diagenesis

“…McArthur (1985), Jarvis et al (1994) and Kolodny and Luz (1992) proposed several controlling factors for the variation in francolite composition. Namely, mechanism of formation, formation environment, diagenetic alterations, metamorphism, and weathering.…”

Geology and mineral resources of the Southwestern and South-Central Wyoming Sagebrush Focal Area, Wyoming, and the Bear River Watershed Sagebrush Focal Area, Wyoming and Utah: Chapter E in <em>Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming</em>

“…Within the francolite crystal lattice, VO 4 is among the ions that may substitute for PO 4 (Cathcart, 1991;Kolodny and Luz, 1992;Jarvis and others, 1994). Vanadium in carbonaceous shales and phosphorite beds of the Phosphoria Formation occurs in trace amounts that exceed the average for marine shales (Fischer, 1962;Maughan, 1994).…”

“…Uranium is among the ions that can substitute for calcium in the francolite crystal lattice (Cathcart, 1991;Kolodny and Luz, 1992;Jarvis and others, 1994). Marine phosphorite deposits contain 6 to 120 ppm uranium, and organic phosphorites have as much as 600 ppm (Ragheb and Khasawneh, 2010).…”