Masters theses:Petroleum

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Geophysical Study on Groundwater Structure at two localities in Central Butana (Sudan)
(Neelain University, 2001) Khalid Mustafa Kheiralla.
ABSTRACT The study area lies between latitudes 14° 30‘ and 16° 00‘ N, and longitudes 33° 30‘ and 35° 30‘ E. A negative Bouguer gravity anomaly was identiﬁed in the area and referred to as Jebel Mundara. Also the drainage system shows the anomaly area as a delta of four Wadis (valleys). A number of isolated outcrops of l?re-Cambrian Basement Complex rocks scatter over the central plains of Sudan. In the Butana region, several hills occur prominent landmarks within the predominai;ttly ﬂat clay plains. The solid geology of the Butana plain is rather concealed under a feneer of variable thickness of superﬁcial clays covering over 70% of its total area. The present study was suggested in an effort to delineated and deﬁne the mentioned anomaly in more detail and to give a reasonable geological and hydrogelogical exploration for its existence. Also to check the delta of another four Wadies lying on the opposite side and shearing the same water divide with the mentioned ones. Integrated geophysical methods (Regional Gravity, EM Survey, and Electrical-Sounding) were applied to achieve the above aims. A total of 100 gravity points were conducted in the study area and they are compile to 275 gravity points acquired, by Sun Oil Company (approximately 2475 krnz were covered in the study area). Gravity data analyses were perfonned by "GEOSOFT" packages. The results show that the gravity lows is largely attributed to the occurrence of low-density rocks (granite intruded) into the high-density rocks (green schist) of the Butana region. On the other hand the gravity high zones unambiguously coincide with the areas of known shallow Basement Complex. A total of 57 VES were carried outs in the study area and distributed a long 7 proﬁles, cover almost the two interested areas. The results indicate‘ that the sedimentary cover'is relatively thin, and the Basement Complex is‘very shallow in the study area. The total length of the EM Survey is about 35 km. The EM measurements reﬂects considerable fracturing (faults and shear zones). Threc sets of fractures are identiﬁed with NE, NW and N-S trending. ' Finally, one of the objective of this work is to delineate lineaments in more details using geological informations and the geophysical data (gravity, resistivity, and electromaghetic) in the study area. They are also merged and combined with image data for a given geographic area using "GIS" software, to produce an integrated map of the area. Water supply'for settlement in the study area requires a different approach. The Basement rocks outcrop on the surface and the area is sloping to the north, therefore, seepage of water through the fracture system is negligible, in this case storing of rainwater through surface dams is more appropriate. ll
Geology and Potential Economic Georesources of El Jebelein Area — White Nile Willayia - Sudan
(Al Neelain University, 2001-03) Mohammed Yahya Abdelgalil
This study was carried-out in El J ebelein area-southeastern part of White Nile Willayia-Central Sudan. Setting and regional geological map, prospecting and exploration of building rocks and industrial minerals are the main objectives of the study. Fieldwork followed with laboratory investigation including petrographic, geochemical and geostatistical analyses were the methods adopted in this research. The geology of the stu_dy area is composed of polymetamorphosed and multi-deformed Basement Complex rocks, which is consisting of older gneisses and rnigrnatites of the hi glr-grade arnplribolite facies. They were overlain by rnetasediments of low-grade greerrsclrist facies. Grantoidal rocks intruded both of these units. Reminants of Upper Cretaceous sandstone overlain by Umm Rrrwaba Formation are preserved in basement troughs. The whole area, is covered by Quaternary Superﬁcial deposits. Chemical analysis of the carbonate rocks _in four out of ﬁve localities proved them to be suitable for potential Portland Cement Industry with raw mix of the two components: clay and limestone, with a Lime Saturatin Factor (L.S.F) =96. Using arithimatic mean method for reserve estimations of marble deposits. Four sites (I, ll, III and IV) in Naﬁrr are ﬁguring approximate potential Calcium Carbonate of 36, 20, 45 andl8 million tons, respectively. The discovery of gossans has encouraged carrying a geochemical prospecting in the suspected localities. Revealed trace elements anomalous content of element suggests gossan secondary minerlization, which may be reﬂected to primary massive sulphides of polymetallic nature (Ag, Pb, Zn, Cu, Co, etc.). The geological and tectonic natures of 'tlre study area suggest that the area belong to older crustal rocks with srrpracrustal metasedimentary rocks. Shear zones are responsible for showing of sulphide mineralization. ‘Morphological clraracteristics, the physical-meclranical tests and nice appearance of granite and marble in the study area encourages quarrying of decorative and dimension block stones.
HYDROCHEMISTRYOF GROUNDWATER IN KHARTOUM STATE CENTRAL SUDAN
(ALNEELAIN UNIVERSITY, 2002-02) Hussien Salim Awad
Abstract The groundwater chemistry of Khartoum State between longitudes 32° 00'-33° 0O’E and latitudes 15° O0’-16° 00'N was evaluated and assessed using different hydrogeological methods. Groxmdwater in the region occurs in two hydraulically interconnected aquifers. The siliciclastic sediments of the Cretaceous Omdurman Formation form the lower one, and the mostly unconsolidated sediments of the Cretaceous-Tertiary- Quaternary Umm Ruwaba Formation comprise the upper one. The evaluated hydrodynamic properties revealed unconﬁned conditions in most parts of the aquifers system and partial conﬁnement in some parts, where clayey zones occur. The analysis of ﬂow system indicated a regional flow direction towards the northwest, with a local ﬂow regime towards the east. Preliminary assessment of grormdwater chemistry was investigated by using different statistical technique such as X-Y plots, correlation, cluster, principle components, and factor analyses. The results of analyzing data by these techniques showed negative correlation between the exchangeable ions, Na-Ca and Na-Mg, which means ion exchange process is active. The strong correlations among Na’ and Cl‘ ions, TDS and EC indicate that salinization is related to the increase of concentration of these ions. Dissolution process of evaporitic mineral is suggested by the strong positive correlations between Ca”, Mg” and SO42" Groundwaters were classiﬁed by -grouping them‘ into faeies~ For ~the—purpose of -classiﬁcation, the pattern diagram of Lee, trilinear plots of Hill-Piper, Durov and by Chadha diagram. Three main types of hydrochemical facies were recognized, Ca-Mg-HCO,, Ca-SO,-HCO, and Na-Ca-S04-Cl. The spatial distribution of these facies and hydrochemical sections, indicate that the anionic facies changes in the ﬂow direction from HCO,’ to SO42’ and ﬁnely to Cll. The cationic facies is mostly affected by ion-exchange process of calcium and magnesium by sodium. Mixing is an important and active process that has affected the water facies in the region. The saturation state of groundwater showed that, it is saturated with respect to carbonate minerals and undersaturated with respect to CO2 and sulphate. Assessment of groundwater quality at different locations indicated its suitability for all purposes except at few speciﬁed localities.
Resistivity and Self-Potential InvestigationsOfSubsurface Water Seepage PhenomenonAt Omdurman
(ALNEELAIN UNIVERSITY, 2002-08) Mohsin Ali Elhag Fahal
ABSTRACT The Omdurman subsurface water seepage problem constitutes a serious phenomenon at present because of the high- density population and lavish use of water. The Omdurman region is covered by rather ﬂat Cretaceous Nubian sandstones with gentle centripetal dips that hinder the outﬂow of the groundwater into the River Nile. The sandstone bands are intercalated with mudstone layers or lenses, and injected by Tertiary basalts along the bedding planes. Both rock types are impervious and retard the inliltration of the surface water, hence over-ﬂooding. Plastic clay soil (Banat east, Al- Abassia and AL-Ahlya square) when present may also hamper vertical water seepage, cause swelling potential and consequent damage. Geophysical investigations applying resistivity and selt potential (SP) methods are conducted to reveal the occurrence and distribution of the impervious layers underneath, and to detect the location and characteristic features of the subsurface streamlines. The results obtained indicate the presence of signiﬁcant almost horizontal bands and lenticular bodies of mudstone intercalated with the sandstones of the Nubian formation. Some of these bands are situated close to the land surface e.g. at Bait- Almal, Al-Mulazmean, A1-Busta, Banat east and Al-Arda l districts. These layers have been successfully delineated by the electrical resistivity method. Geo-electrical sections and maps were constructed to show their locations, thicknesses, attitudes and inclinations. The mudstone layers being impervious prevent water inﬁltration from natural and artiﬁcial sources and can therefore, create temporary perched aquifers located at the interface between the superﬁcial deposits and the top very layer or lens of the mudstones. From these aquifers water is expected to rise up and seep into the surface land and cause damage. Negative SP anomalies show the occurrence and variable intensities of the subsurface streamlines. The distribution of the SP contour lines indicate the haphazard orientation of water ﬂow, hence, the phenomenon appears to be of local nature. 2
THE MAGNETIC FIELD GENERATED BY TWO ELECTRONS BOUND IN SOME ANGULAR MOMENTUM EIGENSTATES
(Al Neelain University, 2003-03) AMANI SALAH MOHAMMED
Application of a direct general method for calculating the magnetic ﬁeld gen- erated by two electrons bound in angular momentum eigenstates is presented, illustrated and applied to the ground states of the tripositive ions Pr“ and V3+. The ground state wave functions are written as a four components spinor and the operators for‘ the orbital current and spin densities as a 4 >< 4 matrices. Analytical expressions for the expectation values of these opera- tors are presented by making use of hydrogenic wave function. The resulttent expressions of the current densities are substituted in the components of the magnetic ﬁeld which gives unexpected results.
The Geology and Structural Evolution of the Area Around the River Nile Between /lthara and Ahidiya, Nile State, Sudan; Remote Sensing, Structural and Geochemical Approaches.
(Neelain University, 2005) Esam Aldeen Ali Mohammed Ahmed
ABSTRACT The study area covers 8100 Kmz in north central Sudan bounded by Latitudes 17° 50‘- 18° 30‘ N and Longitudes 33° 40‘ and 34° 30‘ E. Different digital image processing techniques applied to enhance the geological and structural details of the study area, using Landsat Thematic Mapper (TM) and Enhance Thematic Mapper (ETM 7). The (ETM+) images show that the southeast trending structural lineaments of the Nakasib Suture Zone (N SZ) continue to the southeastern part of the Bayuda Desert north of Atbara. Geologically, the area is underlain by highly sheared maﬁc-ultramaﬁc rocks, volcanosedimentary sequences and supracrustal metasediments. All of the units are invaded by calc-alkaline and post to anorogenic intrusions. The maﬁc-ultramaﬁc masses have all the features characteristic of ophiolite suits including layered cumulate, sheeted dolerite dykes, pillow lavas section and associated deep marine sediments, but are dismembered and recrystallized. The pillow lava sections have typical mid-oceanic ridge basalt geochemical signature as indicated by discriminate diagrams. The ophiolitic massifs identiﬁed in this work have been grouped into three complexes, namely Sotrebab, Qurun and El-Fadlab complexes forming discontinues NE-SW trending belt that merges with the ophiolitic fragments along the Nakasib Suture Zone. Therefore, these complexes may represent the southwestern continuation of the Nakasib Suture Zone. The volcanosedimentary sequence is comprised of turbidities besides massive volcanic ﬂows which have been recrystallized in the condition of the greenschist facies of regional metamorphism. They have predominantly tholeiitic to mild calc- alkaline geochemical afﬁnity, thus suggesting subduction related geotectonic setting. XIII
Geochemical Studies and Tectonic Control of Gold Mineralization in the Bayuda Desert, Northern Sudan with Especial Emphasis on Hagaggia Area
(Al Neelain University, 2005-01) ELSAYIED RABEH SALIH
The study area is located in the northern sector of the Sudan; at the western side of the River Nile. Geotraverses and laboratory examinations indicate that the area comprises different Lithological Lmits; high-grade gneisscs, Volcanosedimentary sequences intercalated with minor intrusions (quartz veins, dykes and amphibolite bands). The tectonic boundary that separates the high- grade rocks ﬁ'om the low-grade rocks is a thurst boundary as conﬁnned by petrographic descriptions of the rocks. The study area is subjected to multiphase of deformation, the evidence for this deformation, which has been seen in the area, includes folding, faulting and shearing, in addition to microscopic evidence. Low-grade rocks (sercite-mica schist, muscovite schist), and calcsilicate host the sulphides and associated gold elements, in addition to diorite and felsite dykes). The sulphides minerals and gold deposit are controlled by major deformation zone. The gold occurrences in the area seem to be situated in brittle- ductile structure that formed as the result of extensional shear deformation. The geochemical samples for gold prospecting and its associated elements include stream sediments, residual soil and rock chip samples. The soil samples were collected from the B-horizon, prepared and ﬁnally analyzed for Au, Ag, Zn, Pb and Cu.The results obtained revealed that, the effective use of stream sediments and soil samples for detecting gold mineralization. The discrimination diagrams indicate that, the rocks of the study area are of volcanic arc tholeiitic and calc-alkaline setting, which were probably formed at ﬁrst stage of subduction and island arc.
Geochemical Studies and Tectonic Control of Gold Mineralization in the Bayuda Desert, Northern Sudan with Especial Emphasis on Hagaggia Area
(Al Neelain University, 2005-01) ELSAYIED RABEH SALIH
The study area is located in the northem sector of the Sudan; at the western side of the River Nile. Geotraverses and laboratory examinations indicate that the area comprises different Lithological units; high-grade gneisses, Volcanosedimentary sequences intercalated with minor intrusions (quartz veins, dykes and amphibolite bands). The tectonic boundary that separates the high- grade rocks from the low-grade rocks is a thurst boundary as conﬁrmed by petrographic descriptions of the rocks. The study area is subjected to multiphase of deformation, the evidence for this deformation, which has been seen in the area, includes folding, faulting and shearing, in addition to microscopic evidence. Low-grade rocks (sercite-mica schist, muscovite schist), and calcsilicate host the sulphides and associated gold elements, in addition to diorite and felsite dykes). The sulphides minerals and gold deposit are controlled by major deformation zone. The gold occurrences in the area seem to be situated in brittle- ductile structure that formed as the result of extensional shear deformation. The geochemical samples for gold prospecting and its associated elements include stream sediments, residual soil and rock chip samples. The soil samples were collected from the B-horizon, prepared and fmally analyzed for Au, Ag, Zn, Pb and Cu.The results obtained revealed that, the effective use of stream sediments and soil samples for detecting gold mineralization. The discrimination diagrams indicate that, the rocks of the study area are of volcanic arc tholeiitic and calc-alkaline setting, which were probably formed at ﬁrst stage of subduction and island arc.
Sedimentological and Geochemical Characteristics’ of the Sediments West of Al Bauga Area, River Nile State, Sudan
(Al Neelain University, 2005-02) Hamed Basher Osman Hamed
The study area lies about l O0 km n orth ofAtbara town in the River Nile State, in the central north of the Sudan, and located between latitudes 18° 00/ and l8" 18/ N and longitudes 33° 38/ and 33° 57/ E with an extending area about 300 kmz. The aim of the study is to determine the sedimentological, geochemical and hydrological characters to clarify the depositional palaeoenvironment. Four surface vertical proﬁles were examined in the field and several techniques were applied including grain size analysis, thin sections, x ~ ray diffraction, infrared spectroscopy, x — ray ﬂuorescence, atomic absorption spectroscopy, spectrophotometer and water analysis. The lithofacies analysis of the Al Bauga sediments reveals seven facies types on the basis of their lithology, grain size and sedimentary stmctures. The depositional environments are including three different sedimentary facies sequences, ﬂuvio-lacustrine, aeolian and ﬂuvial sediments. Texturally most of the sandstones of Al Bauga sediments are medium grained, poorly to very poorly sorted, and ﬁne skewed very leptokurtic with unimodal and bimodal size distribution. The grain size parameters coupled with the observed sedimentary structures indicated that the sandstones of Al Bauga sediments have been deposited in both ﬂuvial and aeolian environments. The sandstones of Al Bauga sediments are characterized by a high concentration of SiO2 and are dominantly quartz arenite including a percent of suture polycrystalline quaitz and epidote which reﬂects an increased mineralogical maturity and indicated metamorphic source rocks. Clays are dominantly detrital kaolinite which suggested tropical humid paleoclimate. The lower part of Al Bauga sediments contains black phytoclast (black wood) high concentration of Sr and relatively high content of organic matter which suggested that these sediments were deposited under oxidizing condition in ﬂuvial e lacustrine environment nearby the source area. The sediments sequence of the Al Bauga sediments is divided into ﬁve geochemical units using bulk geochemistry, especially those of iron, manganese, calcium and potassium. The unit boundaries are correlated with the signiﬁcant lithologic boundaries. From the chemical data for groundwaters it is evident that the chemistry of groundwater from the region of Al Bauga sediments is controlled by the chemical and mineralogical composition of both the basalts and the basement rocks and the waters are medium to high saline. The groundwaters in the Al Bauga sediments area show the dominance of Ca+Mg,Na+K cations hydrochemical facies and HCO3,Cl+CO3 anion hydrochemical facies.
Geophysical Exploration for Groundwater in Crystalline Rocks, El Obeid Area, North Kordofan, Sudan
(Alneelain University, 2005-04) Abd El Rahman Ahmed Abbashar
The study area lies between latitudes 13° 22’ and 13° 05’ North and longitudes 30° 20’ and 30° 12’ East. The geology of the study area comprises the superﬁcial deposits of Qoz sand, sands of different grain size, sandy clay, clay and silt overlie the Basement complex rocks. The Basement complex rocks consist of gneiss, quartzite, schist, granite and pegmatite. This type of geological formation is recognized as a poor aquifer for occurrence and accumulation of groundwater. Only in certain circumstances water may exist; that is in the presence of geological structures like fractures, joints, cracks faults.... Etc. The water quantity depends on resistivity of rainfall and inﬁltration in the study area. - In the current study geophysical techniques (electromagnetic and resistivity) were conducted to investigate the groundwater occurrence in the area. Ten electromagnetic proﬁles of total length 11.5 km, were conducted in the study area. The measurement reﬂects considerable fracturing, faults and cracks trending in North-South direction parallel to the streams or Wadis channel. ' Seven horizontal electrical resistivity proﬁles of total length 4.3 Km were carried out in the study area to locate anomaly sites and to verify the measurement done by electromagnetic proﬁles. These resistivity measurements insure the viability of locating sites by using the electromagnetic methods by giving better results in delineation of Basement rock structures. \ Finally ﬁfteen vertical electrical soundings were applied in the study area in the center of the anomaly that shown by conduction of electromagnetic and electric resistivity proﬁles. These VES results conﬁrm the result depicted by electromagnetic and electric resistivity proﬁles and, show depth to fresh Basement rock more than 54 meter in Kurbage locality, 77 — 135 m in El Sunut locality and 69 — 75 m in Jebel Kordofan locality which is a best locality compared to other two localities ( Kurbage and Elsunut ) in term of water quantity, quality and depth to water.
Elemental Constituents of Crude Oil, Formation Water, and Source Rocks in Muglad Basin - Sudan
(Al Neelain University, 2005-08) Rahmat Alla Hassan Saeed Babiker
This study had been done on the elemental constituents of the oilﬁeld water, crude oil, and the source rocks in Muglad basin using the atomic absorption spectroscopy (AAS) technique in order to ﬁnd out the source of trace elements found in crude oil and to evaluate the quality of Sudanese crude oil on the basis of the concentration of trace elements, which have adverse effects on the speciﬁcations of the crude oil. Twenty four representative samples of different types were collected from different sites and tested for detemnnation of concentration of the elements: Ca, Mg, Na. Cu, Co, Ni, Zn, Pb, Cd, and Fe. The evaluation of the data obtained, for the concentration of these elements, had been done by applying non-parametric test to ﬁnd out the p-values in order to prove whether these results are statistically signiﬁcant or not. All the p-values obtained were found to be less than 0.05, which indicate that all tests, carried out through this work, are statistically signiﬁcant. By comparison of elemental constituents of Sudanese crude oil, regionally with Libya crude oil and intemationally with Venezuela, Califomia, and Canada crude oils, it was found that the Sudanese crude oil contains the lowest concentration of some harmful trace elements like nickel (Ni) and lead (Pb) which can verify its quality. Also it was found that the concentrations of the elements under study show very high values in case of source rocks, which indicate that the source rocks can be considered as the main possible source of trace elements, found in crude oil. The element cadmium (Cd) was not detected in all samples of the source rocks, which had been analyzed for determination of trace elements, because of its low concentration in the earth crust (0.2- 0.5ppm).
The Geology and Structural Evolution of the Area Around the River Nile Between Atbara and Abidiua, Nile State, Sudan} Remote Sensing, Structural and Geochemical Approaches.
(Al Neelain University, 2005-09) Esam Aldeen Ali Mohammed Ahmed
The study area covers 8100 Kmz in north central Sudan bounded by Latitudes 17° 50‘- 18° 30‘ N and Longitudes 33° 40‘ and 34° 30‘ E. Different digital image processing techniques applied to enhance the geological and structural details of the study area, using Landsat, Thematic Mapper (TM) and Enhance Thematic Mapper (ETM 7). The (ETM+) images show that the southeast trending structural lineaments of the Nakasib Suture Zone (NSZ) continue to the southeastem part of the Bayuda Desert north of Atbara. Geologically, the area is underlain by highly sheared maﬁc-ultramaﬁc rocks, volcanosedimentary sequences and supracrustal metasediments. All of the units are invaded by calc-alkaline and post to anorogenic intrusions. The maﬁc-ultramaﬁc masses have all the features characteristic of ophiolite suits including layered cumulate, sheeted dolerite dykes, pillow lavas section and associated deep marine sediments, but are dismembered and recrystallized. The pillow’ lava sections have typical mid-oceanic ridge basalt geochemical signature as indicated by discriminate diagrams. The ophiolitic massifs identiﬁed in this work have been grouped into three complexes, namely Sotrebab, Qurun and El-Fadlab complexes forming discontinues NE-SW trending belt that merges with the ophiolitic fragments along the Nakasib Suture Zone. Therefore, these complexes may represent the southwestem continuation of the Nakasib Suture Zone. The volcanosedimentary sequence is comprised of turbidities besides massive volcanic ﬂows which have been recrystallized_in the condition of the greenschist facies of regional metamorphism. They have predominantly tholeiitic to mild calc- alkaline geochemical affinity, thus suggesting subduction related geotectonic setting.
Assessment and Evaluation of Groundwater Resources in Abu Habil Watershed North Kordofan State— Western Sudan
(Neelain University, 2006) MOHAMED ALI HASSAN DAHAB
Structural Control, Metamorphic Evolution and Genesis of the Gold Mineralization of Abu Khalag area, Central Bayuda Desert, River Nile State, Sudan.
(Al-Neelain University, 2006-08) Mohammed Al Nagashi
The study area constitutes part of east central Bayuda Desert; it lies about 400 Km North of Khartoum. It is composed of gneisses, schists, quartzites, calcsilicate rocks, marbles and amphibolites, which are metamorphosed under greenschist facies of regional metamorphism. These rocks were subjected to folding, shearing and fracturing accompanying metamorphism. The results of Abu Khalag rocks geochemical data show tholeiitic trends of high- grade amphibolites which indicate oceanic environment. The low-grade metavolcanosedimentary rocks show a calc-alkaline afﬁnity, which suggests an island arc paleotectonic environment. The syn-tectonic intrusions have calc-alkaline afﬁnity indicating a subduction related emplacement setting. The low-grade metasediments show a shelf environment of deposition. i Syn to late-granitoid intrusions were emplaced in weak planes of the above- mentioned units and have local thermal and metasomatic aureoles. Field observations have indicated that most of Au mineralized quartz veins in the study area are structurally and lithologically controlled. The auriferous quartz veins can be sub-divided into two phases, occupying fault planes, schistosity, bedding and traces of axial fold planes in permeable and reactive amphibolites and calcsilicate host rocks. The structural, mineralogical and geochemical characteristics together with the style of wall rock alteration of the investigated auriferous quartz veins suggest that they belong to the mesothermal type of gold mineralization. The study involves collecting samples of quartz veins and stream sediments. The background and threshold values are proposed for quartz veins as 0.2 ppm and 0.57 ppm respectively, and for stream sediments as 0.041 ppm, 0.3 ppm respectively. This study indicates that the trace elements Cu, Pb and Zn have greatest potential as indicator of gold mineralization and pathfinders.
Assessment and, Evaluation of Groundwater Resources in Abu Habil Watershed North Kordofan State— Western Sudan
(Al Neelain University, 2006-11) MOHAMED ALI HASSAN DAHAB
Khor Abu Habil is the main source for water in North Khordofan state and plays a considerable role in agricultural and economic growth in the state . It is appiixmatily 1000 kilometers in length and covers an area of bout 6000kilometers square. It is located in west
HYDROGEOPHYSICAL INVESTIGATION In E1 BAGAIR AREA Gezira State
(Neelain University, 2007) Mohamed Mustafa Abd El magid
Abstract The study area is coverd by recent deposits, overlying Gezira Formation. The water bearing strata comprises two separated aquifers; the upper is the Gezira Formation and the lower aquifer is the Nubian sandstone Formation and they are separated by a thick layer of clay or mudstone. The Nubian aquifer is mainly composed of medium to coarse sand and gravels, the aquifer recharges directly from the Blue Nile. The Gezira aquifer consists of unconsolidated clays, silts, sands and gravels which represent alluvial fan deposits carried out from Ethiopia by the Blue Nile system. The aquifer geometry was ascertained by geo-electric investigation coupled with data from existing boreholes. From pumping test the hydrogeological parameters were calculated using different methods. The transmisivity values are in the range of 100 m2/d -3 000 m2/d, and the average hydraulic conductivity between 3.53x10'l and 1.03xl0'l m/day, and the storativity varies between 1x10“ _ hlOTl .The chemical quality of the ground water is generally good and in general the groundwater of the area is suitable for all purposes, the TDS ranged from 168-800 mg_/1. The saturation state of groundwater showed that it is saturated with carbonate minerals.About 51 Vertical Electrical Soundings (VES) were conducted along 12 proﬁles to delineate aquifer extents, its lithological characteristics as well as the lenses of basalt in the area. Results of the VESs have shown variations in depth, thickness and resistivity of the saturated zones indicating inhomogenity of the aquifer. The resistivity of aquifer ranges between 40 - 200 Qm, while its thickness varies from 40 m to 320 m. Though it's rather ambiguous to map basalts, lenses intruded in the Nubian sandstone Fonnation, basalt has been detected in a number of boreholes in El Bagair area. It is massive rock and black in colour, and non-water bearing.
Palynological and palaeoenvironmental interpretation of the Late Cretaceous to Tertiary strata of the Melut Basin (southeast Sudan)
(ALNEELAIN UNIVERSITY, 2007) Ali Ahmed Mohamed Eisawi
m ABSTRACT A Late Cretaceous to Tertiary non-marine sequence of the Melut Riﬁ Basin in the southeastem Sudan was palynologically investigated. The recovered palynomorphs are overwhelmingly of terrestrial origin; few specimens of brackish water dinoﬂagellates and scolecodonts were encountered within the Lower Miocene and Oligocene/Miocene assemblages. The recovered palynomorphs are generally well preserved and fairly diversiﬁed. Based on the stratigraphic distribution of ninety-ﬁve selected spores and pollen species, compiled from three wells in the northem Melut Basin, eight palynozones covering the Campanian through the Neogene have been proposed. The identiﬁed zones are designated as Assemblage Zone I through VIII in stratigraphically ascending order as follows: Assemblage Zone I (Campanian), Assemblage Zone II (Campanian/Maastrichtian), Assemblage Zone III (Maastrichtian), Assemblage Zone IV (Mid-Late Paleocene), Assemblage Zone V (Early-Mid Eocene), Assemblage Zone VI (Oligocene/Miocene), Assemblage Zone VII (Early Miocene) and Assemblage Zone VIII (Late Miocene/ Pliocene). Out of more than 150 palynomorphs identiﬁed in the present investigation, only 25% of the species are Late Cretaceous elements, the remaining are Cenozoic material. In the Cenozoic assemblage, angiosperm pollen are most diverse, but pteridophytic spores and freshwater algae are most abundant. The angiosperm pollen are represented, among others, by Striatopollis, Bambacacidites, Retitricolpites, Retitrescolpites, Psilarriporites, Peregrinipollis, Pachydermites and Graminidires. The fem spores are represented by genera such as Deltoidospora, Cyathidires, Polypodiaceoisporites, Pteridacidiles, and Verrucatosporites, which represent the most abundant component of the Paleogene/Neogene palynomorph assemblages. Late Cretaceous angiosperm pollen are represented by Fuveotricolpites cf. giganleus, Cristaecolpites echinaceus, Monocolpopolleniles spheroidires, Auriculiidiles reticulatus, Syncolporites schrankii, as well as several pollen attributed to the Palmae and Proteaceae. Aquatic fern spores such as Gabonisporis vigourouxii and Ariadnaesporites spinosus and the hepatic spore Zlivisporis blanensis are present in the Campanian-Maastrichtian assemblages but disappear from the record in the Cenozoic assemblages.iv The coexistence of abundant structured organic palynodebris with the spores of aquatic ferns of the families Salviniaceae and Marsiliaceae observed within the Late Cretaceous sediments suggests swampy conditions within a predominantly ﬂuvial setting. Frequent occurrence of pollen grains assigned to the Palmae group indicates the prevalence of warm, humid conditions during the Late Cretaceous, although seasonal aridity might be suggested due to the presence of Ephedripites spp. recorded from the Campanian and Campanian/Maastrichtian of well AY-3. Late Paleogene and Neogene assemblages are characterized by abundant amorphous organic matter, freshwater algae, appreciable amounts of fem spores and Gramineae pollen. Deposition in aquatic habitats such as ﬂuvial plain and coastal swamps under warm-humid conditions is inferred. The occurrence of Gramineae pollen points towards the development of grassy areas under generally dry climate with marked rainy seasons. A presumably short marine invasion might have taken place during the Oligocene-Miocene, inferred from the rare occurrence of brackish water dinoflagellates and scolecodonts within the assemblage.
Facies Associations and Depositionai Environments of Miocene and Pieistocene Sedimentary Successions in Eit Area, Red Sea Coastai Piain, Sudan
(Neelain University, 2007) MUDATHER ABDO MOHAMMED OSMAN SANBARY
Abstract Eit area lies at about 61 km to the north of Port Sudan town in Red Sea State. It located within Mohamed Qol topographic sheet (No 37 - M), which cover the northern edge of the Red Sea region. Sedimentologically, the Eit succession formed of Miocene and Pleistocene deposits, it consists of continental, transitional and marine sediments. The continental deposits include sandstone sequence and older gravels facies. The marine deposits consist of large - scale carbonate sequence and emergent coralline limestone unit. The transitional deposits include mixed carbonate and clastic sequence, evaporite deposits, bedded calcareous marlstone and dolomitized marlstone sequence. Detailed sedimentological studies had been conducted in the Eit succession. The study reveals seven sedimentary units based on variation in lithology, grain - size and fossil remains. Field measurements of the lithological units, microfacies analysis and modal analysis and as well as geochemical investigation were made to describe and classify the facies associations and depositional environments of the Eit succession. The microfacies analysis of the carbonate sequence revealed that it formed of sorted oosparite, shelly biomicrite, pelecypoda biomicrite, pelecypoda biosparimicrite, foraminiferal biosparite, lithmicrite, lithbiomicrite, dismicrite and biolithite microfacies. The modal analysis of the mixed carbonate - clastic detected that the sequence formed of hematitic quartz arenite petrofacies, siliceous quartz arenite petrofacies, calcitic quartz arenite petrofacies and lithic arenite petrofacies. Microscopic inspection of the sandstone sequence reveals that it formed of quartzwacke petrofacies, greywacke petrofacies and lithic arenite petrofacies. The mixed carbonate - clastic sediments includes quartz arenite petrofacies, which cemented by calcareous, iron oxide and silica overgrowth materials. The gypsum deposit divided according to crystal form to massive alabaster gypsum facies, laminated alabaster gypsum facies, selenite gypsum facies and ﬁbrous satin spar gypsum facies. The geochemical analysis presented the affection of seawater into all the clastic deposits in the area studied. The mudstone horizons in the Eit\ succession appear to be dolomitized marlstone facies and calcareous marlstone facies. Analysis of depositional environments reveals that the continental environment includes ﬂuvial and alluvial fan systems in where the sandstone sequence and the older gravel facies were accumulated. The transitional environment includes marine shoreline, lagoonal and tidal ﬂat systems. The quartz arenite petrofacies, the gypsum facies, the dolomitized marlstone facies and the calcareous marlstone facies were deposited in these environments. The marine environment represented by shallow - marine carbonate deposits and the biolithite microfacies. Three phases of regression and transgression of marine water were recognized in the Eit succession. Before the transgression of the marine water, an alluvial extraformational conglomerate facies, the greywacke facies and the lithic arenite petrofacies were deposited. The large - scale carbonate facies were deposited during the Miocene transgression. Pleistocene transgression characterized by development of the emergent coralline limestone unit.
Geology and Estimate of Reserves of Marble as Raw Material for Cement industry Southeast Bayuda Desert River Nile State, SUDAN
(Al-Neelain University, 2008) Mohamed El Khalifa El Sayed
Abstract: The area of study is located in southeastern Bayuda desert o / o / o / bounded by latitudes 17 41, 17 56 N, and longitudes 33 41, o / 33 52 E. The Bayuda desert is covered with the Basement Complex rocks which are intruded by Syn -to Late and Post – orogenic intrusions, followed by the deposition of Cretaceous to Tertiary sediments and the extrusion of Cenozoic volcanics. The Basement Complex rocks are divided into four units; High – grade gneisses and migmatites, Ophiolitic mafic – ultramafic rocks, Low – grade metavolcano sedimentary sequences, and the Supracrustal metasediments. The area is affected by folding, refolding, faulting and shearing. In the area of study two major bands of marble were mapped in details. The length of the eastern band is 29 km. while that of the western one is 19 km. This marble is suitable for cement industry according to the high percentage of Ca O and the very low Mg O. The reserves of the marble are estimated applying different methods of calculation. The total reserve has been noted to be approximately three hundred million tons for the seven studied blocks. As confirmed by the results of this study the approved reserves of marble deposits are not sufficient for the planned production of any of the seven enterprises, considering that the optimum depth of quarrying is only 30 meters, and the minimum lifetime of a cement plant is 50 years. ملخص البحث تقع منطقة الدراسة بجنوب شرق صحراء بيوضة بولةية نهر النيل . تحد المنطقة خطوط o / o / o / o / . شرقا 33 52 , 33 41 الطول خطوط و شمال17 56 , 17 41 العرض تغطى صحراء بيوضة الصخور الساسية و التى تعرضت لعدة تشوهات مثل الطى و الفوالق و القص , كما توجد كذلك بعض الصخور النارةية والصخر الرملى النوبى و ترسبات جبل النخرة بالضافة الى الترسبات الحدةيثة. الصخور الساسية تنقسم الى اربعة اقسام هى؛ صخور القنيس و الميقماتيت, صخور الوفيولةيت, الصخور البركانية و الرسوبية المتحولة, و الصخور الرسوبية فوق القشرةية المتحولة. توجد بمنطقة الدراسة طبقات من الرخام بالوان متعددة وةيصل طول الطبقات الشرقية الى 29 كلم بينما ةيصل طول الطبقات الغربية الى 19 كلم. الرخام ةيصلح لصناعة السمنت نسبة لرتفاع نسبة اكسيد الكالسيوم وقلة نسبة اكسيد الماغنيزةيوم. تمت دراسة و تقدةيرات خام الرخام بالمنطقة بواسطة طرق مختلفة اهمها طرةيقة الوسط الحسابى. أجمالى الخام بالمنطقة ةيصل الى مثلمثمائة مليون طن . أثبتت الدراسة أن كمية الخام ل ى من المواقع السبعة التى منحت تراخيص استثمار لصناعة السمنت ل يكفى للنتاجية المقترحة للعمر التفتراضي للمصانع الذي يتراوح بين 50 إلى 100 عام واضعين تفى العتبار أن عمق المحاجر يصل إلى 30 مترتفقط .إن توتفر الخام تفي تلك البعاد تحت سطح الرض
GEOLOGY AND GEOCHEMISTRY OF EL TUWAL OPHIOLITIC COMPLEX AND ENVIRONS — EAST CENTRAL SUDAN
(Al Neelain University, 2008) Musab Awad Ahmed Hassan Eljah
Some 22400 sq. km have been regionally mapped around El Tuwal ophiolitic complex, east-central Sudan, together with a detailed geological map of the complex. The area is composed of gneisses, schists, quartzites and marbles, together with the ophiolitic rocks of El Tuwal complex, and basic metavolcanics of island-arc character. The layered sequences are intruded by syn-orogenic, I-type granitoids and unfoliated, “younger granite”, A-type complexes. The latter occur as hilly massifs rising above the subdued, ﬂat clayey plains. Numerous dykes and quartz veins cut the older sequences among which is a prominent andesite dyke, some 20 km. long, cutting the syn-orogenic granites. .Late Cretaceous Nubian sediments overlie unconformably the basement sequences along the northeastern margin of the Butana area, and southeast of El Tuwa] ophiolitic complex. Tertiary to Quaternary clayey cover usually obscures the subdued layered sequences. The ophiolitic rocks are clearly emplaced onto the other basement rocks by a SE-dipping thrust fault. They are composed of serpentinites and minor pyroxenites, which occupy the base of the complex, followed by gabbros and pillowed basic volcanics. Juxtaposed with structural contacts are the basic island-arc metavolcanics. The syn-orogenic granites cover a wide compositional spectrum exempliﬁed by biotite and hornblende granites, granodiorites and tonalities to gabbros in decreasing abundance. The younger granite complexes are made up of granites, syenites, gabbros and volcanics in decreasing order of abundance. New geochemical data revealed that the ophiolitic rocks, associated arc metavolcanics and the syn-orogenic granitoids have geochemical signatures of subduction zone magmatism found in supra-subduction zone ophiolites and other are rocks. The presence of podiform chromites in the studied serpentinites is considered to be typical of supra-subduction ophiolites with Cr# similar to those of subvolcanic ophiolites and boninite-derived chromites particularly those thought to be associated with fore-are rifting. The “younger granite” complexes represent alkaline, within-plate continental igneous activity. The amphibolite facies gneisses, schists and marbles possibly represent earlier continental shelf sediments of the Saharan Metacraton. The ophiolitic rocks and the metavolcanics possibly represent ensimatie, thrusted material after the collision of the Nubian-Arabian Shield with the older sialic continental Saharan Metacraton during the late Proterozoic, Pan-African tectono-thermal event. The geological setting of the Butana area favours gold mineralization, and the granitoid rocks and the marbles can sustain successful building materials industry.