الفهرس 
ABSTRACTOnly 14 pages are availabe for public view
 |  | from | 191 |  |  |
| | | from | 191 | | |
Abstract
Due to mining activity of phosphate occurrences at Abu Tartur area, huge amounts of rock wastes are rejected causing a negative environmental impact. The present work deals with the use of some mining waste materials, belonging to the Duwi Formation (dolomite and glauconite) to minimize the environmental pollution, and to solve some environmental problems (water purification), medical uses (antibacterial activity) and domestic problems (biofuel production).
The first academic part of the study includes previous notes on the geological and environmental studies, that have been conducted in the Western Desert in general and at Abu Tartur in particular. These include: lithostratigraphy, sedimentology, structural geology, mineralogical and geochemical, soil treatment, water purification, upgrading of Abu Tartur phosphorites, radioactivity, biodiesel production, medical fields and geotechnical studies.
Special attention was paid to the origin of glauconite, as it was a controversial problem in the previous studies concerning its origin. Aerially, glauconite rocks in Egypt are confined to the Western Desert at both Abu Tartur Plateau and Bahariya Oasis, with different geologic ages. Close inspection of the sedimentary succession at Abu Tartur mine site, revealed that there is a remarkable vertical gradual and transitional change from black shales to the evolved glauconite. It is suggested that both syntectonics and sea level oscillation, controlled principally such vertical turnover.
The transition starts with deposition of green beds of illite-rich claystone at the top of Quseir Formation (Hindaw Member) during Early to Middle Campanian. The suggested mechanism for glauconite formation urges uptaking of K from precursor detrital materials. Propagation of K was obtained from the seawater transgression, over Abu Tartur area. The underlying K-rich claystone (illite) layers were considered as a transitional phase between the low K2O and Fe2O3 illite precursor and high K2O and Fe2O3 glauconite end member of glauconitization process. By applying X-ray analysis, it revealed that the green claystone is exclusively represented by illite and quartz.
Afterwards, the following transgression covered the underlying Quseir Formation sequence, with shallow water. Through this condition, upwelling currents created a high productivity, which is succeeded by direct deposition of authigenic phosphatic muds, mixed with skeletal bioclasts and quartz, during sea level rise. High energies played the role of exhumation, fragmentation, and in-situ reworking of the phosphorite muds followed by a rapid deposition in amalgamated composite beds during Middle-Late Campanian, giving rise to a high-grade phosphorite.
Shortly afterwards, the high influx of fresh water on the elevated coastal lands led to disintegration, fragmentation and erosion of those terrains. The transportation of fine-siliciclastics was achieved by the fluvial processes from the intensively weathered platform in the south of Egypt. The deposited shales are black to grayish black, finely laminated, fissile and organic-rich and entombed tremendous amounts of smectite (bentonite) and traces of kaolinite as well as sparsely scattered silt and fine sand grains, indeed, a missing of bioturbation signals deposition in a restricted basin.
With time elapse, fine glauconite grains scattered randomly in the matrix. Presence of tiny glauconite grains points to a high quantity of K and detrital and may be tied to the high sea level, that generated extensive epeiric seas with wide continental shelves. Glauconite, quartz and smectite are the main constituents as evidenced by x-ray investigation.
Following up, scattered bioturbation tubes that filled with glauconite, punctuated the black shale with fill contrasting with the host rock, sharp walls of tubes and missing of lining indicate a moderately cohesive substrate.
During Early Maastrichtian, the rising of sea level led to increasing the glauconite rapidly near the middle part of the black shales. As a result, glauconite thin layers of greenish color interlaminated with the black shales and mixed other material infilling burrow tubes, or occur as thin discontinuous or bifurcating beds. The presence of erosive bases and scour and fill structures indicating high-energy depositing processes. X-ray investigation demonstrates the co-existence of glauconite and siderite.
Later on and during Early to Middle Maastrichtian, siderite started to form and co-exist with glauconite, along with coal pockets. Siderite occurs as compact homogeneous ellipsoidal nodules covered with glauconite outer layer and envelop some scattered glauconite pellets and islands. Siderite concretions in the Duwi Formation signifies that there was a high availability of dissolved iron, rapidly buried organic matter, and little-or-no seawater input during concretion formation. Coal and seams pockets were deposited in lakes or lagoons adjacent to the coastline, where the terrestrial plants colonized the basin peripheries.
The final stage of glauconitization process took place during Middle to Late Maastrichtian, when the prevailed lowstand conditions led to exposing the authigenic glauconite mud to high-energy conditions (i.e. storms ?). The interplay between these high-energy events and sea floor