Al NEELAIN JOURNAL OF GEOSCIENCES - VOL : 01 - ISSUE - 01
Permanent URI for this collectionhttps://repository.neelain.edu.sd/handle/123456789/11373
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Item Application of ASTER data in the identification of alteration zones - related to mineralization around Wadi El Milk, North Kordofan, Sudan(جامعة النيلين, 2017) Randa G. M. Ali; Sami O. H. El Khidir; Mohammed Y. AbdelgalilAbstract: Hydrothermal alteration zones- related to mineralization can be identified and discriminated based on distinctive spectral properties that appears in ASTER satellite data. The image processing techniques are mostly used for medium to regional scale geological mapping. In this study, we aimed to conduct a more exploration studies by utilizing the ASTER data to enhance and delineate the hydrothermal alteration zones - related to mineralization in North Kordofan, Sudan. In this work, resampled and co-registered ASTER (VNIR- SWIR) data have been used. The obtained co- registered nine bands (VNIR-SWIR) were subjected to different methods of spectral indices and spectral analysis techniques such as Spectral Analysis Mapper. The spectral mineral indices (hematite, Alunite, Kaolinite and Muscovite Mineral Indices) results were found conformable with results of Spectral Angle Mapper Classifier (SAM) for the same minerals. However, SAM rule images and vector format yielded an overall good discrimination of the four minerals indicating the alteration zones- related to mineralization.Item Quantification of Groundwater Recharge in the Midstream Area-Gash River Basin Using the Water Table Fluctuation Method(جامعة النيلين, 2017) Hago, A. H. AliAbstract Quantification of groundwater recharge differs in their methods of estimation and therefore gives variable recharge estimates whenever a groundwater system is evaluated. Quantifying the fraction or the percentage of infiltrated water which reaches the water table is a key factor in any sustainable planning scheme for groundwater resource management. The water table fluctuation method was used to evaluate the seasonal and annual variations in water level rise and to estimate the groundwater recharge. The method used in this study includes monitoring of groundwater level measurements to estimate groundwater recharge using Water Table Fluctuation “WTF” to determine sustainable withdrawal. The average annual discharge of the River Gash is estimated to be 1,031×106 m3 at El Gera gage station (upstream) and 711× 106 m3 at Kassala bridge gage station (downstream). The annual loss mounts up to 29% of the total discharge. The water loss is attributed to infiltration and evapotranspiration. The present study showed that the monitoring of groundwater level measurements indicates that the water table rises during the rainy season by 9 m in the upstream and 6 m in the midstream areas. The average rise in groundwater table (ΔHn) in the period from 1999 to 2013 found to be 8.36 meters. The average annual groundwater recharge during the period 1999 to 2013 is 107 × 106 m3 whereas average difference in Gash river discharge at Kassala Bridge during the same period is 320 × 106 m3.Item The use of logarithmic fitting in interpreting gravity data, Tokar Delta, Sudan(جامعة النيلين, 2017) Gamal A. A. Et Toam; Abdalla G. FarwaAbstract Gravity data are incorporated with surface geology, seismic and borehole data to study the subsurface geology of Tokar Delta, Sudan. Gravity data obtained by Agip Mineraria, Chevron and Technoexport were compiled by Robertson Research International to produce the Bouguer anomaly map of the area. Five profiles are constructed across this map in an approximately ENE direction perpendicular to the Red Sea main structural trend. Two of the conventional analytical methods are attempted to separate the residual anomaly: least-square and polynomial fitting with different orders, but neither of them was found to be convenient, as they give positive residual anomalies in areas of known considerable thickness of sediments. Logarithmic fitting gives the best result over the other two methods. In three of the five profiles the residual anomaly obtained by the logarithmic fitting coincides typically with the geological constraints of the profile. The residual anomaly for the other two profiles is obtained by calculating the gravity effect of a presumed body controlled by the geological constraints of the profile. Five models are constructed for these profiles from which a depth to Basement map is constructed. Geological sections are drawn along three of these profiles. Borehole data of Digna-1, Durwara-2, and Marafit-1 are incorporated in the construction of these sections. Tokar Delta is a part of a NW-SE trending fault-controlled sedimentary basin. The basin is of an average width of 180 km and maximum thickness of 7. 5 km. The sediments are generally deposited in horst and graben structures.Item Subsurface Cavities Development Detection Using Resistivity and some Geotechnical Properties, Red Sea, Sudan(جامعة النيلين, 2017) Omar A.O. Al-Imam; Siddig M. ElzienAbstract Resistivity method with some geotechnical properties (TOP, Densities and Bearing Capacities) were used to evaluate the development of cavities to sinkholes in the area between Port-Sudan and Suakin, Red Sea coast. The interpretation of resistivity values show that, the subsurface uncompact, unconsolidated layers are characterized by low resistivity values. The Standard Penetration Test (SPT) and wet densities in sites (Green area, Dama Dama and Suakin) were give a fit overlap results after data processing by Rockware -4 program. In contrast, the resistivity values define the approximately the same localities of weakness and under developing cavities.Item Flash Floods Risk Assessment of Sharg Alneel area, Khartoum State, Sudan Using Remote Sensing, GIS and Geophysical Techniques(جامعة النيلين, 2017) Esamaldeen Ali; Khalid A. Elsayed Zeinelabdein; Khatab A. RahamtallahAbstract This study was carried out to investigate the geological sources that may cause the flash floods of Shareg Alneel area in the eastern part of Khartoum City, Sudan which lead to damage of property and the infrastructures of the residential areas. In this study, remote sensing technique using Landsat-8 images together with Shuttle Radar Topography Mission (SRTM) elevation data and geophysical techniques (resistivity and gravity) have been adopted. Wadi Soba, Green valley and Wadi El Sileit are the main seasonal water courses in the study area that drain into the Blue Nile with a regional parallel pattern. The results show that relatively steep slope from east to west may represent one of the factors contributing to the flood hazard during the rainy season. Also, it can be noted from band ratio technique that high concentration of clay sediment is located close to the River Nile and along these three valleys. This result was confirmed by resistivity technique which shows an existence of considerable amount of clayey sediments that obstruct water infiltration. The residual gravity reveals that the three valleys are characterized by relatively lower gravity anomaly indicating thicker sediments than the surrounding plains. From the obtained results, Flood hazard map has been created which divided the area into low, moderate and high risk areas. Accordingly, it was conducted that that the residential areas were superimposed over high risk zones. This study recommends re-planning of residential areas and construct dykes in the upper stream of the main valleys to decrease the flood hazard effects.