Sedimentology and maturity of Ajali formation, Benin flank Anambra basin, Nigeria

Ilevbare, M.; Imasuen, O.I.

doi:10.4314/ijs.v22i1.13

Cited by 3 publications

(3 citation statements)

References 8 publications

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“…From the heavy mineral result, ZTR index of 67.96% which according to the maturity classification scheme of Manger and Maurer, 1992, is sub-mature. The mineralogical maturity index (MMI), of 17.4 which is mature (Ilevbare and Imasuen, 2020), and the mesokurtic and leptokurtic nature of sediments which again reflects compositionally and mineralogically mature sands. These sub-mature to mature sandstone indicates a groundwater with excellent aquifer properties, (Blatt, 1992) elucidated by figure 5.…”

Section: Resultsmentioning

confidence: 99%

Grain Size and Heavy Minerals Analysis of Maastrichtian Sandstone, Anambra Basin, Nigeria: Implication for Aquifer Properties

Ilevbare¹,

Imasuen²

2020

jasem

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The Maastrichtian sediments of Anambra Basin, south western Nigeria was studied for grain characteristics and maturity of the sediments, so that by combining sedimentological characteristics, maturity and its paleoenvironment of deposition of the Ajali sandstone, in order to ascertain the aquifer properties of the groundwater within the study area and by extension the availability of drinking water for both the urban and rural settlers. Grain size analysis (51 samples) and heavy mineral analysis (15 samples each) were analyzed. The textural parameters show that the Sandstone are medium sand, poorly to moderately sorted, coarse to strongly coarse skewed with mesokurtic to leptokurtic grains. The heavy minerals present in lithologic sand and sandstone units of Ajali Formation are mainly zircon, rutile, tourmaline, apatite, staurolite, and opaque minerals (Goethite, hematite, ilmenite), these heavy minerals found in the sandstone are associated with igneous and metamorphic source which indicates that these maastritchian sediments are from basement complex rock The ZTR index of 67.96% and the values of the kurtosis indicates a sub-mature sandstone to mature sandstone, which gives an excellent aquifer properties. Also, the paleoenvironment of deposition of the Maastrichtian sediments is Fluvial. The sand and sandstone bodies deposited in a fluvial system have sheet-like geometries and due to the differences in the extent of aquifer compartmentalization, Sandstone deposited in fluvial environment normally has better hydraulic conductivity which again reveals a good aquifer property. The sedimentological characteristics for the Sandstone exposed at Fugar and environs, is a coarsening upward sequence (increasing grain sizes) with a progressive increase in sorting. since hydraulic conductivity increases with increasing grain sizes and sorting, hence, excellent aquifer characteristics for the groundwater within the study area. The foregoing revealed that the aquifer geometry and properties of the study areas is favourable for the availability of drinking water for both the Urban and rural dwellers within these communities. Keywords: Aquifer geometry, groundwater, hydraulic conductivity, Anambra Basin

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Section: Resultsmentioning

confidence: 99%

Grain Size and Heavy Minerals Analysis of Maastrichtian Sandstone, Anambra Basin, Nigeria: Implication for Aquifer Properties

Ilevbare¹,

Imasuen²

2020

jasem

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“…Generally, REEs content increase with decreasing particle size and with increasing proportion of clay content (Rao et al, (2011);Kimoto et al, (2006). Ilevbare and Imasuen, (2020) ; Ilevbare and Omodolor, (2020) from their study revealed that the textural parameters show that the Ajali Sandstone are medium sand, poorly to moderately sorted, coarse to strongly coarse skewed with mesokurtic to leptokurtic grains shows a coarsening upward sequence, with dispersed intercalations of clay, been predominately sand/sandstone. The little or no clay within the Ajali Sandstone together with the increasing particle size of the grains, explains why the REEs of the Formation are very low, which is consistent with the already established trend by Rao et al, (2011) ;Kimoto et al, (2006).…”

Section: Fig 2 Ree Concentrations Of Ajali Sandstone At Fugarmentioning

confidence: 96%

“…Mihajlovic et al, (2018), reported that REEs contents increases with increasing Fe oxide content (and vis-versa) and decreases with surface soils in this order: lower slope > middle slope >upper slope. Ilevbare and Imasuen, (2020), in a related study on the Ajali Sandstone, showed that the mean value of Fe2O3 from their table of weathering indices to be 0.46, which is extremely low, hence, low REEs adsorption rate and subsequently the very low Concentrations of the REEs within the Ajali Formation.…”

Section: Fig 2 Ree Concentrations Of Ajali Sandstone At Fugarmentioning

confidence: 97%

Rare Earth Elements of Ajali Sandstone, SW, Anambra Basin in Nigeria: Implication for Soil Genesis

Ilevbare¹

2021

jasem

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The Ajali Sandstone, South-western, Anambra Basin, was studied for Rare Earth Elements (REEs), using a Phillips 45 channel Inductively Coupled Plasma (ICP) Emission Spectrometer. The standard deviation of the REEs (Dy, Er, Eu, Y, Yb, La and Nd) averages 3.5 mg/L, 0.34 mg/L, 0.32 mg/L, 3.93 mg/L, 1.96 mg/L, 4.02 mg/L and 2.24 mg/L respectively for each of the sampled locations. The REEs concentrations showed both positive and negative concentration anomalies. The enrichment or depletion of the REEs is generally attributed to their tendency to be incorporated into plagioclase preferentially over other minerals. The Ajali Formation is predominantly sand/sandstone, with clay occurring only as intercalations/thin beds of clay drapes with the increasing particle size of the sand grains, makes the rate of adsorption and distribution of REEs in the soil low, and explains the low values of REEs concentration. Soil organic matter (SOC) plays an important role in the adsorption and migration of REEs in the Ecosystems. The SOC is linearly associated with REEs Concentration as it increases with increasing content of SOC. The Ajali Sandstone studied falls in the vicinity of abandoned cropland to cropland in a lower/gentle slope region, correspondingly low in soil organic matter content and as such slow rate of distribution and migration of REEs concentrations in the Ajali Sandstone. The sesquioxides such as Fe oxides increases as REEs contents increases. The 0.46 mean value of Fe2O3 in the Sandstone of the area studied implies a low REEs adsorption rate and subsequently the very low REEs concentrations of the soils. The istribution of REEs within the Ajali Formation soils were grossly affected by the factors that influenced the adsorption and migration rate of the minerals during magmatic fractionation process, hence the low REEs concentration of the Sediments. Keywords`: Sansdstone, Anambra Basin, Rare Earth Elements, Magmatic fractionation

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Geology, Sedimentological and Hydraulic Conductivity of Ajali Potential Reservoir Sandstone Exposed Around Gra in Idah, Northern Anambra Basin

Yusuf,

Obaje,

Adedosu

et al. 2023

FJS

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The Ajali sandstone is a possible reservoir rock in the Lower Benue Trough (LBT)/Anambra Basin (AB), and understanding its geological, sedimentological distribution is essential for accurate prediction of fluid flow dynamic. Geological, granulometric analysis and laboratory hydraulic conductivity test are integrated for this investigation. Results from geological studies reveals three sandstone lithofacies; namely; AJALI L2A a sandstone intermixed with siltstone, lamination, bioturbated, and crossed bedded, AJALI L2B sandstone mixed with silty clay, crossed bedded and bioturbated and AJALI L2C an excessive weathered sandstone with visible ripple and ridges with all sedimentary features supporting the earlier proposed fluvio-deltaic depositional environments. The granulometric analysis reveals medium to coarse grain, poorly sorted sandstone lithofacies. Hydraulic conductivity test for AJALI L2A crossed bedded and lamination sandstone contributes smaller pore spaces between grains, which reduce overall interconnectivity of the pore network primarily decreasing the fluid hydraulic flow conductivity and thus lowers the permeability value to 75mD. While in the AJALI L2B intermixed with siltstone and clay sandstone, lowers porosity; but cross-bedding may have contributed positively to increase in permeability value to 1850 mD in this lithofacies. The weathered AJALI L2C sandstone with visible ripples and ridges significantly affect the physical properties and pore spaces obliteration by iron oxide, by contributing to reduction in the permeability value to 60 mD. In overall it is concluded that the Ajali sandstones generally will exhibits an average moderate permeability of 662 mD.

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Sedimentology and maturity of Ajali formation, Benin flank Anambra basin, Nigeria

Cited by 3 publications

References 8 publications

Grain Size and Heavy Minerals Analysis of Maastrichtian Sandstone, Anambra Basin, Nigeria: Implication for Aquifer Properties

Grain Size and Heavy Minerals Analysis of Maastrichtian Sandstone, Anambra Basin, Nigeria: Implication for Aquifer Properties

Rare Earth Elements of Ajali Sandstone, SW, Anambra Basin in Nigeria: Implication for Soil Genesis

Geology, Sedimentological and Hydraulic Conductivity of Ajali Potential Reservoir Sandstone Exposed Around Gra in Idah, Northern Anambra Basin

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