Al NEELAIN JOURNAL OF GEOSCIENCES - VOL : 02 - ISSUE - 01

Permanent URI for this collectionhttps://repository.neelain.edu.sd/handle/123456789/13547

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Geo-environmental Risks Assessment along Abu Hamad-Karima Proposed Road, River Nile and Northern States, Sudan
(Faculty of Petroleum and Minerals, Al Neelain University, 2018) Esamaldeen Ali, Mahamoud M. Shoaib
Recently, the Sudanese government proposed to construct a 230 km new highway that will link River Nile and Northern States which represented by Abu Hamad and Karima city respectively. In fact, better engineering design of road requires better knowledge to characterize, monitor and assess geological and environmental hazards along the road and then mitigate their risks during constructions. Therefore, this study aimed to determine the surface and subsurface geological and structural conditions and try to identify the risks and effects of the geohazards in order to assess the suitability of the site to construct the road. In this study four geo-environmental factors have been adopted, which include sand activity, structural lineaments; drainage pattern and the Lake of Merowe Dam inundation through paleo-channels. An integrated remote sensing, (GIS), geological, structural and environmental investigations were conducted in this study. The analysis and interpretations of all available data show that the proposed road passes through medium to low risk zones. Hence, in order to significantly reduce construction costs, subsequent maintenance costs and to mitigate future geohazards, this study recommended that the proposed road way should be re-aligned in order to avoid endangered locations or put the above factors under consideration when constructing the road.
Digital Image Processing of Landsat 8 and Spectral Analysis of ASTER data for Mapping Alteration Minerals, Southern Hamisana, NE Sudan
(Faculty of Petroleum and Minerals, Al Neelain University, 2018) Elsheikh Edrees A.H. Omer, Khalid A. Elsayed Zeinelabdein
The study area lies in the southern part of the Hamisana Shear Zone (HSZ), within the Nubian Shield as a transitional area between Gebeit and Gabgaba terrains. The objective this work is to use remote sensing and GIS techniques for geological mapping and prospecting for gold mineralization in the study area. A set of four Landsat 8 scenes has been mosaicked and subset to obtain a full coverage of the study area, in addition to subset of ASTER (AST_L1T) as semi-hyperspectral data for spectral analysis. The geological mapping was carried out based on interpretation of enhanced satellite image and field work. The study area is dominated by metavolcanic assemblage ranging from basic to acid in composition. The Meta volcano-sedimentary include dacite, andesite, greywacke, meta-conglomerate, rhyolite and basalt, and mafic-ultramafic rock with less common other volcanic varieties. These layered meta-volcano-sedimentary sequences are intruded by the syn-to late-orogenic and post-organic igneous intrusions. Different digital image processing techniques (True and false color combinations and image ratio) have been applied in this work in order to increase the discrimination between various lithological units and to delineate alteration zones which represent possible target zones for gold mineralization. The Principal Component Analysis (PCA) yielded saturated images that are more interpretable than the original data, especially for discriminating between metavolcanic and metasediments. The sultan ratio image was used in this work for lithological discrimination to help in geological mapping. Mapping hydrothermal alterations products associated with gold mineralization has been conducted through the spectral analysis of semi-hyperspectral ASTER data, where the Spectral Angle Mapper (SAM) technique has been used to identify the alteration minerals related gold mineralization, such as kaolinite, muscovite, dolomite, hematite, and Buddingtonite. The result of the spectral analysis of ASTER data indicated the probable target zone of alteration related to mineralization existing in the study area. Moreover, many exploration targets have been identified within the study area on the basis of the results of the spectral analysis. The targets are represented mostly by gold-bearing quartz veins.
Lithofacies analysis and depositional model of the Late Quaternary sediments of southeast Atbara River, East– Central Sudan
(2018-12-30) Madibbo A. M. Ahmed; Ali A. M. Eisawi; Robert Bussert; Ronny Schomacker
The Quaternary sediments of the lower reaches of Atbara River in southeast Atbara town, East- Central Sudan have been investigated. The aim is to study the palaeo-environmental and palaeo-climatic changes that took place in the area during Late Quaternary time, using evidence from sediments and fossils association. Three vertical sedimentary profiles were measured and five sedimentary depressions have been studied. Five lithofacies have been recognized: massive sandstone (Sm), planar cross-bedded sandstone (Sp), horizontal bedded sandstone (Sh), massive siltstone lithofacies (Fsl) and paleosol (P). The identified lithofacies exhibit extensive bioturbation representative of typical sand ridge, shoreline, near shoreline and lake shrinkage deposits of Atbara Palaeolake during Late Pleistocene to Early Holocene; being totally dry by the end of middle Holocene. Grain size analysis, binocular microscopic analysis and bulk XRD mineralogical analysis have been carried out. Grain size analysis results showed a fluvio-lacustrine setting for the Atbara sediments. Binocular microscopic study and bulk XRD mineralogical analysis signify considerable amounts of kaolinites and k-feldspars which reflect warm and humid climate. A shift to semi-arid and arid climate by mid Holocene is supported by the widespread deposition of calcretes and carbonate concretions in the upper part of most of the studied depressions. The presence of opal clasts within the studied sandy sediments suggests that the source area could be the Ethiopian highland. Two hundred specimens of Late Quaternary molluscs and mammals remains have been collected and studied. The molluscs are dominated by Corbicula spp. and Anadonta grandis, which are excellent colonizers of Late Quaternary freshwater lakes. Faunal remains such as bones, jaws and teeth of subfamily Bovinae, task of hippopotamus and turtles suggest the occurrence of grassland savannah, which contained a major lake..