Showing papers in "Global Journal of Geological Sciences in 2019"

Physicochemical and bacteriological parameters of surface water quality in part of Oban Massif, Nigeria

Abstract: The present study presents preliminary investigation on the physico-chemical and bacteriological parameters of surface water samples collected, during the wet and dry seasons, from streams in Orem and environs, a typical Basement terrain in southeastern Nigeria. The intension was to evaluate the suitability of the water for domestic and agricultural uses. Results generally indicate normal water temperature, especially for the tropic; pH reflecting slightly acidic conditions; low EC and water hardness which respectively qualifies the water as excellent and soft; turbidity values that points to the water as a possible sources of water-borne diseases; DO values that are reasonable, to support good fish production, throughout the year; low levels of nutrients and heavy metals that pose no detrimental effect for the aquatic ecosystem; and low Salinity and Total Dissolved Solids (TDS) that reflects water of low mineralization. The major dissolved cations points to a possible geogenic source for the major ions, while the anion levels supports agricultural and anthropogenic pollutions. Values recorded during the dry season were frequently higher than those recorded during the wet season, possibly reflecting dilution and evaporation effects during the wet and dry seasons, respectively. With minor exceptions, the levels of almost all the tested parameters were within the respective permissible limits of the Nigerian standards for drinking water quality (NSDWQ). Among the exceptions in this regards, is the unacceptable and alarmingly high volume of bacteriological inputs recorded for the waters. Clearly, this renders the water unfit for consumption and various other usage, in its present form.

Geoelectrical exploration for groundwater in crystalline basement rocks of Gbongudu community, Ibadan, Southwestern Nigeria

Abstract: Gbongudu community, Ibadan underlain by crystalline rocks of Basement Complex of Southwestern Nigeria has need for alternative water supply due to inadequacies of surface water supply and common occurrences of low yield or dry boreholes coupled with rapid development within the community. Geophysical investigation involving electrical resistivity was carried out with the aim of evaluating the groundwater potential of the community. Thirty-three (33) Vertical Electrical Soundings were acquired across the community adopting Schlumberger electrode configuration with current electrode separation (AB) varying from 2 to 200 m. The acquired field data were interpreted using partial curve matching with suitable auxiliary chart and “RESIST” resistivity sounding interpretation software was also used for iteration. The results revealed two to five geo-electric layers, namely, topsoil, clayey soil, lateritic clay, weathered layer, fractured unit and fresh basement. The weathered and the fractured units form the aquiferous zones in the area investigated. Thematic maps of geoelectric and Dar-Zarrouk parameters produced from the interpreted VES data are aquifer unit (weathered layer) thickness map, aquifer unit (weathered layer) resistivity map, overburden thickness map, basement resistivity map, basement topography map, reflection coefficient map, total longitudinal conductance map, total transverse resistance map and electrical anisotropy (coefficient of anisotropy) map. The thematic maps were combined to form a single component which gives the groundwater potential map of the study area. The groundwater potential map was used to classify the study area into poor, low and good aquifer potential zones. The study reveals that the weathered and fractured zone that occur in the southeastern part of the study area constitute the water bearing zone which can be regarded as good groundwater potential. This study has provided evidence on the hydrogeologic framework and subsurface nature of main aquifer units in the area. KEY WORDS : Groundwater exploration, RESIST, Dar-Zarrouk parameters, Electrical anisotropy, Borehole drilling.

Calcium and magnesium distribution in groundwater and food substances in parts of Central plateau state, Northcentral Nigeria.

Abstract: Adequate intakes of calcium and magnesium in water have been found to reduce the risk of some diseases (cardiovascular, diabetes, rectal cancer, neurological disturbances and pre-eclemsia in women) especially where adequate amount of these ions are not supplemented in foods. The dependence on waters abstracted directly from hand dug wells and other sources without any form of treatment and or regulation are of great concern to the health of humans and animals. Groundwater abstracted from hand dug wells and hand pumps without any form of treatment, are the main sources of water supply for rural inhabitants of central Plateau State, Nigeria. The aim of this study was to map out the distribution of calcium and magnesium using GIS in parts of central Plateau State. Multivariate analysis to explain the variation of these ions in aquifers of the area was also employed. Four rock types constitute the aquifers from which water is abstracted for drinking (migmatite, biotite granite, granite gneiss and basalts) exhibiting variations in their contents of calcium and magnesium. Averagely, content of calcium and magnesium are higher in the migmatite compared to the other rock types. Generally the total content of calcium in both foods and water do not meet the recommended daily intake of 1000 mg for an adult. Although, magnesium is quite low in 90% of water points, the daily recommended daily intake of 200 – 400 mg for adult is supplemented in (Zea Mays, and sorghum) staple foods consumed daily by every household in the area. There is the need for calcium supplements in the area to meet the recommended daily intake.

Subsurface electrical resistivity imaging and electromagnetic conductivity profiling at a proposed construction site at Adekunle Ajasin University campus, Akungba-Akoko, South-Western Nigeria

Abstract: Electrical resistivity imaging and co-planar loop electromagnetic conductivity measurements have been employed to delineate the bedrock topography and subsurface distribution of structural features at a construction site on the campus of Adekunle Ajasin University. The goal was to map the subsurface geological disposition and to identify features which could adversely impact on the ongoing construction works. Data were collected along three geophysical traverses using the ABEM1000 Terrameter unit and the EM34 Co-planar loop electromagnetic system. Traverse 1 trend roughly east-west for a total length of 155m while traverses 2 and 3 are trend north-south for 80m each. The collection of electrical resistivity data utilized the dipole-dipole array with an electrode separation of 5 m and maximum dipole spread of 35m. Observed field data were processed and inverted using a finite-element modelling inversion algorithm. Conductivity were collected at 10m coil separation and plotted against station positions. A station separation of 5m was maintained on all traverses for both data sets. Three geo-electric layers were delineated; a thin highly discontinuous low resistivity layer representing the humus-rich top soil, a continuous consistently high resistivity layer with a highly rugose upper layer and several near vertical scarps representing the fresh bedrock and intermediate resistivity layer representing the weathered bedrock separating the upper low resistivity and basal high resistivity signatures. Overburden thickness rarely exceeds 4 m with the exception of the deep weathering section in the southwest and at fracture points with the bedrock. Perennial groundwater flow at the site is restricted to the southeastern sections of the site. KEYWORDS : Akungba-Akoko, electrical resistivity imaging, ground conductivity, bedrock structure, foundation studies.

Preliminary review of the geology of the hornblende biotite gneisses of Obudu Plateau Southeastern Nigeria

Abstract: The Obudu Plateau, southeastern Nigeria is dominantly underlain by gneissose rocks with migmatitic characteristics, one of which is the hornblende-biotite gneiss. The gneisses are banded with quartz and plagioclase as the major minerals in the leucosome while hornblende and biotite occur in the palaeosome. Geochemically, the rocks are enriched in silica and alumina with an average of 71.6wt% and 14wt% respectively. Geochemical plots indicate that they are calc-alkaline to tholeiitic in character and derived from protholiths of igneous origin with minor sedimentary input. KEYWORDS : Obudu Plateau, migmatitic gneiss, calc-alkaline

The basement and tectonism of the river Jama’are floodplain: deduction from DC resistivity data

Abstract: The analysis of DC resistivity data of part of the River Jama’are Floodplain, Northeastern Nigeria was carried out with a view to mapping the basement and the subsurface structures. One hundred and six Schlumberger Vertical Electrical Sounding (VES) stations located at the corners of a 225 x 225m square grid network were occupied. The interelectrode spacing (AB/2) was varied from 1-225m. Results identified four subsurface geologic layers; topsoil, alluvial sand, Chad Formation/weathered column and basement bedrock as undulating and basal unit at different depths. Four major parallel basement depressions suspected to be regional faults striking approximately NW-SE were delineated. This trend correlated with the general trend of the regional structures in the Chad Basin. The isopach maps of the topsoil and alluvial sand mirrored a more recent NE-SW trend that correlated with the Tibesti-Cameroon trough. However, this recent induced tectonics was adjudged significant to hydrogeology in the area. KEYWORDS : Resistivity, floodplain, basement, sounding, tectonics, hydrogeology

Origin and sandstone classification of the upper Cretaceous Lokoja sandstone in Southern Bida basin, as determined from geochemical data

Abstract: This study was carried out with a view of using an innovative approach (strictly geochemical) in determining the origin of Sandstone Formation within the Southern Bida Basin. The Lokoja Formation (Sandstone) unconformably overlies the basement complex. It consist of sandstones, which crop out around Lokoja area between Felele and Koton-Karfi. Field observations show that lithology includes conglomerates at the base, with coarse-grained to fine-grained sandstones, siltstones and claystones overlying it. Analysis of the collected ten (10) outcrop samples from the study area aided in the deduction of geochemistry, classification and period of deposition of the sandstone facies of the Lokoja Formation. The geochemical analysis revealed the major oxides and the heavy minerals that are present in the samples. From the geochemical analysis of the samples at different locations revealing the major oxides, the percentage of SiO 2 in the selected sample compared to the other oxides is very high.Al 2 O 3 , Fe 2 O 3 , CaO, MgO, MnO, P 2 O 5 , K 2 O, Na 2 O and SO 3 were all found to decrease as SiO 2 increases. A major reason for this is clastic mixing. The low values observed from the result of ratio of SiO 2 / Al 2 O 3 indicate that the collected samples have a high degree of clayness, which can suggest mineralogical immaturity. Al 2 O 3 / (CaO+MgO+Na 2 O+K 2 O) ratio has been reported useful in the determination of stability of mobile oxides. This was applied in this work, where positive values obtained (2.73 to 8.27)indicate the presence of stable mobile oxides in the Lokoja Formation sandstone facies.The Zircon Tourmaline Rutile (ZTR) Index for the selected samples range from 30% to 44% with an average of 38%. All the selected samples have Zircon –Tourmaline –Rutile maturity index less than 75% suggesting that nearly all the sediments are mineralogically immature to sub mature. The heavy minerals recovered from the selected samples of the Lokoja sandstone show that the origin of the collected samples from the basin is mainly sedimentary. KEYWORDS : Provenance, Bida Basin, Geochemical, Maturity, Stability, Clayness.

Structural pattern deduced from aeromagnetic dataover parts of Nasarawa and environs Northcentral Nigeria.

Abstract: Interpretation of high-resolution aeromagnetic data over Nasarawa area was carried out to observe near surface source magnetic features that are associated with geological structures in the study area, Prominent lineaments in this study may be related to fractures that were not revealed by previous studies. Some of these lineaments coincide with concealed faults and fractures at Akiri warm spring and vicinity. Because this area has known warm springs, faults or fault intersections at depth can lead to upward movement of warm water that enhances permeability. Thus, mapping concealed fractures provides a focus for follow-up geothermal studies. Fault interpretation was accomplished by synthesizing interpretative maps derived from first vertical derivative and analytical signal along with preliminary depth estimates. Faults were interpreted along linear aeromagnetic anomalies and breaks in anomaly patterns. Many linear features correspond to topographic features, such as drainages. A few of these are inferred to be fault-related. The interpreted faults show criss-crossing pattern of fault zones, some of which appear to step over where they cross, and show zones of west-northwest, north-, and northwest-striking faults that cross west-northwest around Akiri warm spring. North easterly striking faults extend east from this juncture. The associated aeromagnetic anomalies are likely caused by magnetic contrasts associated with rifting of crust beneath the Benue Trough. KEY WORDS: Derivative, Structural Pattern, Rift Zones, Akiri.