الفهرس | Only 14 pages are availabe for public view |
Abstract The present study focuses mainly on the mineralogy and radioactivity of the Oligocene sedimentary rocks, north Fayoum area, Egypt. The study area is bound by latitudes 29{u00B0} 35{u00B4} - 29{u00B0} 43{u00B4} N and longitudes 30{u00B0} 32{u00B4} - 30{u00B0} 42{u00B4} E, and covers about 140 km2. Several samples, representing the main country rocks (sandstone, calcrete, dolocrete, and mudstone) in addition to a large number of fossil bone fragments were collected from the Oligocene Qatrani Formation, Fayoum, Egypt. Petrographically, the fossil bones are composed essentially of weakly birefringent apatite. Ferrugination of both bones and country rock is frequent. The sandstone country rock is composed essentially of angular to sub-rounded quartz grains, K-feldspar and plagioclase. Muscovite, zircon, cassiterite and biotite grains are common as accessory minerals. Dolocrete country rock is composed of microcrystalline dolomite affected by secondary filling by micrite and later by gypsum or microcrystalline silica. Calcrete consists of cementing calcite embedding clastics of angular to sub-angular poorly sorted quartz grains. The main mineral composition of the fossil bones is carbonate fluorapatite (francolite), while dolocrete consists of microcrystalline dolomite and it is cemented by gypsum and/or silica. Kaolinite and montmorillonite represent the main clay minerals in mudstone |