Geo-investigation on groundwater control in some parts of Ogun state using data from Shuttle Radar Topography Mission and vertical electrical soundings

Groundwater is a vital natural resource that plays a significant function in sustainability of living things on earth. Its exploration requires special skill for optimum exploitation. Shuttle Radar Topography Mission (SRTM)and Vertical Electrical Sounding (VES) were used to detectthe stratigraphy and subsurface structures controlling the groundwater system around Iju – Ota, Ogun State, Southwestern Nigeria. Nineteen (19) VES points were carried out where there were dense concentrations of lineaments and interconnected to establish the connection of the observed lineaments with groundwater occurrence in the study area using Schlumberger array, with electrode spacing of AB/2 varying from 180 to 320 m. The analysis of SRTM data revealedthe dominating structural NE-SW and NW-SE trends, which control aquifer structure. The geoelectrical parameters from the VES results were used to map the stratigraphic sequences in the study area. Six (6) units that comprisethe topsoil, lateritic clay, clayey sand, mudstone, sand (main aquifer), and shale or clay were identified in the study area. The aquiferous unit around Iju – Ota axis ranged from 30 to 80 m. Theextracted from the hill shaded SRTM data and the result of VES revealed that the thickness of the aquifer is as a result of interconnectivity of the lineaments observed in the SRTM data suggesting that the groundwater occurrence in the study area is chiefly controlled by these fractures

Contrasting styles of lead-zinc-barium mineralization in the Lower Benue Trough, Southeastern Nigeria

In the Lower Benue Trough of Southeastern Nigeria, lead-zinc-barium mineralization occurs as widely distributed epigenetic fracture-controlled vein deposits which are restricted to Albian – Turonian sediments. Detailed field studies carried out in Ishiagu, Enyigba-Ameki-Ameri, Wanikande-Wanakom, and Gabu-Oshina which together constitute the four main areas of mineralization in the Lower Benue Trough, show that mineralization appears restricted to NW-SE and N-S fractures while the more common NE-SW fractures are barren. Apart from the Enyigba area, igneous bodies are found in the vicinity of the ore deposits while in the Wanikande area, barite veins and veinlets were observed to be closely interwoven with intrusive bodies. The host lithologies are highly varied, ranging from shales to siltstones, sandstones and occasionally igneous bodies. The ore assemblage also varies remarkably, with lead:zinc:barium ratios ranging from approximately 3:1:0 at Ishiagu, to 2:1:0 at Enyigba, 1:0:2 at Wanikande and nearly 100% barite at Gabu-Oshina. Thus, there is a remarkable increase in barite content from the southwest (Ishiagu) to the northeast (Gabu). The characteristics of the ore deposits roughly fit the base metal type mineralization known as clastic dominated lead-zinc-barium deposits. This study forms part of a mineral potential database which is invaluable for any detailed exploration venture in the area

Spatial Distribution of Gamma Dose Rates in the Marine Environment of Unumherin Community in Niger Delta, South-South, Nigeria

This work investigates the radioactivity distribution of coastal polluted areas of Unumherin Community in Niger Delta, Nigeria. The measurement of the outdoor dose rate of the polluted coastlines was carried out using calibrated hand-held gamma detector, (RS-125 Gamma-Spec). The spatial distribution of gamma dose rate indicates the hotspot at location 4 with a value of 100 nGy/h. Maximum and minimum values of the absorbed dose-rate was observed in location 4 with the value of 100 nGyℎ−1 and location 15 with the value of 2 nGyℎ−1, respectively. This is an indicative that the risk of ionizing radiation exposures is much higher for location 4 than other locations. This higher value of 100 nGyℎ−1 is far more than the recommended limit of 59.00 and 84.00 nGyℎ−1 provided by UNSCEAR, 2000. The community requires much more radiological monitoring for the safety of human and ecosystem

Radioactivity distributions and biohazard assessment of coastal marine environments of niger-delta, Nigeria

ABSTRACTThe Unumherin community in Nigeria’s Niger Delta is home to coastal marine polluted zones, and this research examines the radioactivity distributions and biohazard in the coastal environment. The activity concentrations of 40K, 238U, 232Th, as well as the outdoor dose rate of contaminated coastlines were measured using a calibrated RS-125 Gamma-Spec and a NaI(Tl) gamma-detector. The laboratory examination of sediments, water, and fish from the same coastal region – Clarias gariepinus Pseudotropheus elongated Oreochromis niloticus and Stromateus fiatola – was combined with the in-situ observations of gamma dose rates. With a value of [Formula: see text], the hotspot at site 4 is shown by the geographic distribution of gamma dose rates. The findings showed that the activities of the primordial radionuclides varied, with average values for the sediments and water exceeding suggested limits. Similarly, the corresponding mean hazard indices mostly exceeds the allowable limits. The species specificity of the fish species accounts for the variation in the mean concentrations of 40K, 238U and 232Th. C. gariepinus, having accumulated higher concentrations of 40K and 238U, may be the first to elicit health hazards in the future if pollution continues unmonitored. Hence, continuous monitoring of the aquatic environment alongside is highly recommended