Browsing by Author "Godfray, Godson"

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    Assessment of ground water potentiality in semi-arid area of central Tanzania. implication from geology and geomorphology of the dodoman supergroup
    (Taylor & Francis, 2022) Godfray, Godson; Tembo, Malugu M.
    Semiarid areas face challenges in the availability of water for domestic, agricultural and industrial use. The freshwater availability in semi-arid is limited due to low periods of rainfall and high evaporation rate. Groundwater resource is the only promisingsource of freshwater in semi-arid regions. The increased demand for freshwaterin the semiarid region has increased the demand for groundwater exploration. Theavailability of groundwater in the subsurface is influenced by the subsurfacegeology, geomorphological properties and climatical condition of the region. This review aimed to analyse and combine pieces of available information on groundwater potential assessments in the central part of Tanzania. Central TANZANIA is within the craton basement rocks, where most aquifers are crystalline and fractured crystalline rocks. The groundwater origin, movement and existence rely upon numerous geomorphological and geological factors. Because of the terrain's geology and the compartmentalization of aquifers, determining the groundwater potential is difficult in basement terrain. Studying the geomor-phology and geology of groundwater recharge zones is the key to exploring groundwater availability. The integration of geomorphological, geological and geophysical information yields a promising groundwater potential zone for placement of a well. The selection of the geophysical methods depends on the nature and geology of the area. Electrical Resistivity Tomography (ERT) can beutilized in combination with other geophysical methods in fractured andweathered crystalline rocks in the semiarid environment, as in the Dodomaregion, because it is the best geophysical tool for groundwater exploration in thefractured aquifer
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    Geochemical evaluation of the in situ regolith at Madengi Hill, Dodoma, Tanzania: implications for bedrock mapping and delineating gold mineralization targets
    (The Geological Society of London, 2022) Godfray, Godson
    Successful gold exploration projects depend on a piece of clear information on the association between gold, trace elements and mineralization controlling factors. The use of soil geochemistry has been an important tool in pinpointing exploration targets during the early stage of exploration. This study aimed to establish the gold distribution, the elemental association between gold and its pathfinder elements such as Cu, Zn, Ag, Ni, Co, Mn, Fe, Cd, V, Cr, Ti, Sc, In and Se, and identify lithologies contributing to the overlying residual soils. From cluster analysis, a high similarity level of 53.93% has been shown with Ag, Cd and Se at a distance level of 0.92. Au and Se have a similarity level of 65.87% and a distance level of 0.68; hence, is proposed to be the most promising pathfinder element. Principal component analysis (PCA), factor analysis (FA) and the Pearson’s correlation matrix of transformed data of V, Cu, Ni, Fe, Mn, Cr and Co, and a stronger correlation between Pb and U, Th, Na, K, Sn, Y, Ta and Be shows that source gold mineralization might be associated with both hornblende gneisses interlayered with quartzite, tonalite and tonalitic orthogneiss. From the contour map and gridded map of Au and its pathfinder elements, it has been noted that their anomalies and generated targets are localized in the northern part of the area. The targets trend ESE–WNW, nearly parallel to the shear zones as a controlling factor of Au mineralization emplacement.
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    Physicochemical parameters and stable isotope composition of water in Northern Mara Sub-Goldfield, Tanzania: Implications for groundwater-surface water interaction
    (EGU General Assembly, 2022) Myovela, Justine L.; Godfray, Godson; Salimu, Mohamedi
    This study focuses on water quality assessment and hydrological aspects around northern Mara Sub-Goldfield (Tanzania). A total of 26 water samples were collected from different sampling sites for physicochemical characterization and H-O isotopes analysis. Parameters such as pH, electrical conductivity (EC), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and total hardness were analyzed for each water sample. The 18O/16O and 2H/1H ratios were measured in water samples and expressed as δ18O and δ2H relative to Vienna Standard Mean Ocean Water (V-SMOW). The study revealed that the majority of drinking water sources meet the recommended World Health Organization (WHO) and Tanzania Bureau of Standards (TBS) levels. Drinking water from Kegonga community borehole (pH=6.62, EC=1690 µs/cm, TDS=1080 mg/l), shallow well east of Ingwe Dam (pH=7.32, EC=1720 µs/cm, TDS= 1000mg/l), shallow well south of tailings dams (pH=7.6, EC=2670 µs/cm, TDS=1780 mg/l) and traditional well (pH=5.76) are not suitable for drinking purposes. Isotopic values of studied water samples have shown a wide variation from -28.5 to 21.4 ‰ for δ2H, -5.37 to 2.37 for δ18O ‰, and -3.7 to 16.08 ‰ for D-excess values. The slope of Local Meteoric Water Line (δ2H = 5. 9 δ18O + 5.51; R2=0.94) is slightly lower than the slope of Global Meteoric Water Line (δ2H = 8.2 δ18O + 11.27; R2=1), which indicates that the majority of studied water samples have been isotopically modified. The study demonstrated that the majority of groundwater has been recharged by more evaporated sources likely wastewater from tailings dams. This finding is supported by the consistency of isotopic signature and physicochemical parameters of several groundwater sources with those of surface water discharged from the mines.
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    Sedimentology and compositional characteristics of siliciclastic and associated sediments in Ruvu basin: implication on paleo-depositional environment, provenance, and tectonic setting
    (Informa UK Limited, 2021) Godfray, Godson; Kabohola, Joyna; Msabi, Michael
    The paleo-depositional environment of theRuvu basin ranges from alluvial,floodplain, low- and high-energy fluvial channels, and deltaic sub-environments of Ngerengere beds, Tanga beds, and Jurassic Msata formations. Amboni limestones that overlap the Karoo sequences, Bagamoyo Formation and Sakura Formation were probably deposited in a shallow marineenvironment. Trace elements show that the sediments were deposited in oxic environments with a V/Cr ratio of 0.85 and Ni/Co ratio of 2.9 to anoxic environments with a V/Cr ratio >4.3.Low Cr, Ni, Co, and V, high Y/Ni and Zr/Crratios of up to 0.83 and 3.6, respectively, and low Ti/Zr ratios ranging from 0.004 to 0.01 indicate a contribution from afelsic source, and few ratios >1show some contribution from a mafic source. This is supported by the diverse enrichment inlight rare earth elements (LREEs), small negative Eu anomaliesand modest heavy REEs reflecting a dominantly granitic source. Theprovenance is probably from the Usagaran mobile belt and Proterozoic Mozambiquemobile belt. The cross-plot between Th and Ta from midJurassic to Cretaceoussediments indicates that the basin was essentially developed as a passivecontinental margin; however, discriminant factor plots of the Karoo indicatethe existence of a rift setting.
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    Unconventional hydrocarbon resources in Tanzania: insight from geology and previous exploration of conventional resources
    (Springer, 2021) Godfray, Godson; Msabi, Michael
    Unconventional oil and gas exploration has been developing rapidly in recent decades, while Tanzania has been paid very little consideration. This review aimed to infer these unconventional hydrocarbon resources in some basins, mostly the intracratonic Karoo basins and one coastal basin (Ruvu basin), from a piece of the very limited information available from the previous exploration of conventional resources. The presence of thick dark carbonaceous shales of Makarawe formation at Ruvu basin with TOC% 2.4–4.0% and a thickness between 107 and 698 m capped with non-porous oncolitic limestone and the gas shows encountered at an interval of 107 m of Makarawe shales at Makarawe-1 well makes Ruvu basin as important play for unconventional shale gas. The intracratonic Karoo basins have a thick deposit of Karoo sediments interbedded with coal deposits. Coal bedded methane has been encountered in a deep coal exploration borehole at Songwe-Kiwira coalfield. Geochemical analysis of outcrop samples from Namwele, Mbamba Bay, Njuga, and Mhukuru coalfields shows that the interbeds of coal-carbonaceous shales/mudstone have the rich organic matter of type III or both II and III and trace of oil on samples from Ketewaka and Ngaka coalfield make these sub-basins to be considered as potential plays for shale oil/gas. The presence of probable shale gas resources ranging from 50 to 200 trillion cubic feet at the Selous basin increases Karoo basins’ potentiality in exploring unconventional gas resources. In addition to the discovered conventional gas resource in offshore Tanzania, any unconventional resources will impact the country’s economic growth.