الفهرس 
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Abstract
Glauconite deposits are distributed in the Western Desert mainly in the Bahariya Oasis and in the Abu Tartur Plateau. In the Bahariya Oasis, the glauconite deposits are parts of the Middle to Late Eocene Hamra Formation. At Abu Tartur Plateau, on the other hand the glauconite deposits (greensand) overlay the phosphate deposits of the Duwi Formation. In the different localities, glauconite exhibits considerable petrologic variations that could be attributed to formational and/or diagenetic conditions. Various paleogeographic implications are obvious from the distribution of facies in the studied formations. The Naqb Formation has been deposited in tidal flat and lagoonal conditions with a scattered shell banks and the Qazzun Formation under slightly deeper water. The shoreline during the deposition of the Naqb and Qazzun formations remained approximately at the same position. During deposition of the Hamra Formation, the shoreline has been retreated farther to the north at Gar El Hamra area. The glauconite deposits of El-Gedida Mine consist mainly of green to dark grains with size range of 0.1-0.5 mm. These grains show different morphological varieties such as ovoidal, lobate and composite grains. The green to dark green color of lobate grains and other morphological types that contain cracks suggests that they are a highly mature glauconite variety. The X-ray analyses of the studied bulk samples consist mainly of glauconite in association with quartz, calcite, feldspar, alunite, hematite and halloysite. Whereas, the clay fraction was definitely glauconite, with main peaks occurring in air-dried samples at approximately 10Å, 4.5Å 3.3Å, 3Å and 2.53Å. Since the (001) peak occurs mostly close to 10Å rather than 14Å, this suggests that the glauconite is evolved to highly evolved glauconitic mica. Geochemically, the glauconite in El-Gedida Mine has a high maturity due to its K2O content of 7.2 wt%, making it evolved glauconitic mica. Based on the potassium content, color, mineralogical structure, and XRD (001) peak position, the glauconites of El-Gedida Mine can be classified as mature evolved type that indicate an actively authigenic origin for the grains. Geochemically, the glauconite of the Duwi Formation has K2O content ranging from 4.56 to 6.19 wt%, making it slightly evolved to evolved glauconitic mica. The positive correlation between K2O and Fe2O3 indicates the diagenetic deformation of illite-smectite mixed layer and the evolving character of Fe2O3 which was incorporated with the K2O in the smectite layer structure of glauconite. The existence of the pyrite, gypsum and anhydrite minerals is an indicator of glauconite surface alteration. All these features show that the Abu Tartur glauconites were altered by weathering and transformed into iron-rich illte/smectite mixed layers. The chemical composition of the studied samples, from both El-Gedida and Abu Tartur localities have a high potassium content ranges from 5 to 7 wt%. In general these glauconitic deposits will be assessed to be a fertilizer (source of potassium). Potassium (K) fertilization is one of the vital income-earning inputs that enables farmers to produce crops and boost yields. Potassium is one of the essential major macronutrients needed for plant growth. Over 90% of mined potassium is used as fertilizer, and greensand is one of the main mined deposits. So that, the main use of glauconite is as a soil fertilizer or conditioner due to its ability to slowly release the high contained amounts of potassium and other nutrients. Two experiments were conducted; the first one was used to determine which type of soil has the ability to adsorb more K from the glauconite deposits. Three different soils; the sandy clay loam soil, the sandy loam soil and the calcareous silty clay loam soil have been examined. It was found that the sandy clay loam soil is the best one in fixing K from glauconite. The second experiment was used to evaluate the influence of glauconite on the maize growth and yield. The results clearly indicate that potassium fertilization (glauconite) enhanced the growth parameters significantly such as ear leaf area, plant height and shoot weight. Finally, the studied glauconite deposits are recommended to be used for potassium fertilization as it improves growth and physiological characteristics and shoot dry weight ratio of maize. These all parameters finally results in high yield with minimum water usage.