Standard Global Journal of Geology and Explorational Research (SGJGER)

Number 2, 2014

009-026
Gabal El Faliq Granitoid rocks of the Southeastern Desert, Egypt: Geochemical constraints, mineralization and Spectrometric Prospecting

Authors: Gehad M. Saleh, Doaa A. Mostafa, Mostafa E. Darwish and Ibrahim A. Salem

Abstract

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The granitoid rocks in G. El Faliq area, southeastern Desert of Egypt, consist of granodiorites, tonalities, monzogranites and alkali feldspar granites. The G. El-Faliq area is composed of ophiolitic mélange, gneisses, older granitoids, younger granitoids and post granitic dykes and veins. Altered granites are encountered at shears and fault zones at G. El Faliq, they rich by uranium and base metals mineralization. Geochemically, the older granitoids are peraluminous to metaluminous granites and fall in volcanic arc granites, while the younger granitoids are calc-alkaline and metaluminous to peralkaline granites and display most of the chemical characteristics of within plat granites setting. The altered granites show argilic facies with a relative depletion in K2O and Na2O + CaO oxides. The comparison between the average of the major oxides of the fresh samples of younger granitoids related to altered ones in the studied area shows that, the younger granitoids rich in SiO2, Na2O and K2O but depleted in TiO2, Al2O3, Fe2O3, FeO, MnO, CaO, MgO and P2O5 related to altered ones. Also, regard to trace elements they are rich in Sr and depleted in Ni, Zn, Zr, Y, Ba, Nb, U and Th. The mineralization of G. El Faliq can be classified on the basis of mode of occurrence and lithological associations into: a) secondary uranium minerals (uranophane), b) niobium-tantalum minerals, c) sulphide minerals and d) accessory minerals. The spectrometric survey revealed the presence of enriched zones with a maximum eU content of 650 ppm and the maximum eTh is 350 ppm. The evidence of hydrothermal mineralization in the alteration of rock-forming minerals such as feldspars and the formation of secondary minerals such as uranophane and pyrite. The pre-existing primary uranium minerals are the source of the present secondary uranium minerals by the action of oxidizing fluids, mobilization of uranium and then redeposition in other forms. Redistribution by circulating meteoric waters might have taken place. Keywords: G. El-Faliq, altered granites, uranium mineralization, spectrometric prospecting

027- 031
Studies on environmental impact assessment of waste water pit in Izombe flow station, South-Eastern Nigeria

Authors: P. O Youdeowei and H. O Nwankwoala

Abstract

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Three (3) wells were sunk with a hand – operated light cable percussion rig to maximum depth of 15.00 to 21.00m. The static water levels recorded after drilling for each well were 8.00m for borehole 1 (BH 1), 4.40m for BH 2, and 5.00m for BH 3. The soil stratigraphy reveals a uniform correlation in the three (3) boreholes of medium to very coarse grained sand and gravelly sand. The lower layers are coarser, so that there appears to be a downward coarseness of the grains. There is also a downward decrease in the shade of brownish colour. In BH 1, there is an upper stratum of dark brown, medium grained, friable sand to a depth of about 9.00m. This is underlain by light brown, very coarse grained, gravelly sand. BH 2 and BH3 display similar profiles of overlying dark brown, medium grained, friable sands of about 3.0m in thickness. This is followed by light brown, coarse grained sands to depths of about 15.00m. Light brown, very coarse grained, gravelly sands extend from this depth to the maximum drilled depth of 21.00m. Results also reveal that the soil is non-plastic and fall within the soil classification group of SP under the Unified Soil Classification System. Permeability tests of the samples are moderately high values as expected for the sandy soils and range from 7.83 x 10-1cm/s to 8.92 x 10-1cm/s. The hydraulic gradient between BH 1 and BH 3 is about 6% or 1m in 16m (1:16) while that between BH 1 and BH 2 is about 7% or 1m in 14m (1:14). Since the hydraulic gradient between BH 1 and BH 2 is slightly higher, more rapid effluent discharge is expected towards BH 1. This may explain the higher concentration of crude oil contamination of the groundwater, particularly within the region of the waste pit. Keywords: Soil, groundwater, Environmental Impact Assessment, Contamination, Wastewater