The Benue Trough is an elongate rifted depression in which the sediments reach well over m thickness in places and have been strongly folded, probably by later adjustments along faults in the underlying basement. The Bida Basin is a shallow unfaulted arm of the Benue Trough. The Niger Delta at the southern end of the Benue Trough has been building out into the Atlantic since the end of the Cretaceous. Of the other coastal basins, the Senegal Basin is by far the largest, but the basins along the southern coast of West Africa are larger than their surface extents suggest, as substantial parts of their successions are offshore. Unable to display preview. Download preview PDF.
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The origin and peculiarities of the nigerian benue trough : Another look from recent gravity data obtained from the middle benue. The origin of the Benue trough has been a controversial subject. Previous workers in the area have evolved several theories ranging from a rift, with or without plate tectonic concepts King, ; Wright, , ; Burke et al.
One of the aims of the gravity survey, carried out in the middle Benue and discussed in this paper, was to attempt to resolve some of the problems associated with the origin of the trough as proposed by previous workers and in so doing to explain the geological peculiarities associated with the trough.
Interpretations of the gravity data along two north—south profiles in the survey area indicated the existence of a rift, of normal width about 40 km buried under the Cretaceous cover and located between the central axis ridge of the trough and the northern boundary of the trough.
The gravity minimum which occurs south of the central axis of the trough , was also ascribed to another rift. Thus the Benue trough is considered to consist of two parallel rifts separated by the axial ridge which partly explains the abnormal width of the trough. The interpreted models also indicate a low-angle thrust fault, with a small displacement, which may be related to the folding of the sediments in the trough and also to the asymmetry of the trough.
Furthermore, the gravity data suggest that oceanic crust might not have reached the ground surface in the Benue trough , as in the Red Sea, before rifting ceased.
Petroleum prospects of Benue trough , Nigeria. Exploration activities in the Benue trough have been minimal over the years, mainly because of large petroleum deposits found in the adjoining Niger delta and early gas finds in the Anambra basin, south of the Benue trough.
The recent increase in exploration activities in the trough has necessitated a reevaluation of the petroleum potentials of the basin. In this study, the time-temperature index TTI method was used to evaluate petroleum prospects of the basin. An increase in geothermal gradient resulted in a decrease in depth to the oil window, with the sediments maturing earlier at higher geothermal gradients.
The Awgu Shale and the Nkporo Shale are capable of generating gas at geothermal gradients of 2. The Benue trough is essentially a gas-condensate basin with little oil. Exploration targets in the basin include both the sub-Santonian and superSantonian sediments, with the Eze-Aku Group, Awgu Shale, and Nkporo Shale being more prospective than the stratigraphically lower Asu River Group.
In general, the middle Benue trough is considered to be the most prospective area within the trough because depths to the mature zones are moderate 6,, ft; km. These depths are variable, decreasing northeastward and increasing southwestward toward the Niger delta. Thermal and chemical variations of the Nigerian Benue trough lead-zinc-barite-fluorite deposits.
The Benue trough is an intra-continental rift initiated in the Cretaceous during the opening of the South Atlantic Ocean. Lead-zinc-barite-fluorite mineralization occurs along the km axis of the trough in three discrete sub-basins which coincide with the lower, middle and upper mineral districts of the Benue Valley.
Lithologically these sub-basins are dominated by black carbonaceous shale in the Lower Benue , platform carbonates in the Middle Benue and sandstones in the Upper Benue. Micro-thermometric analysis of fluid inclusions in sphalerite, fluorite, barite and quartz have shown that each mineral district has its own unique thermal and chemical imprint.
This study shows that inter-district thermal and chemical variations exist between the ore-stage sulfide and post-sulfide gangue minerals of the entire Benue Valley. Similarly, intra-district thermal and chemical variations have also been observed among all the paragenetic minerals of each district. The thermal variations may be as a result of variations in the geothermal gradient accompanying continental rifting from one district to the other. The variations in the chemistry between the Lower Benue and the Upper Benue paragenic minerals may be as a result of the distinct lithological differences across the Benue Trough.
Sarki Yandoka, Babangida M. The Benue Trough of Nigeria is a major rift basin formed from the tension generated by the separation of African and South American plates in the Early Cretaceous. It is geographically sub-divided into Southern, Central and Northern Benue portions. The Bima Formation is the oldest lithogenetic unit occupying the base of the Cretaceous successions in the Northern Benue Trough.
Facies and their stratigraphical distribution analyses were conducted on the Lower Bima Member exposed mainly at the core of the NE-SW axially trending Lamurde Anticline in the Yola Sub-basin, with an objective to interpret the paleodepositional environments, and to reconstruct the depositional model and the stratigraphical architecture.
Ten 10 lithofacies were identified on the basis of lithology, grain size, sedimentary structures and paleocurrent analysis. The facies constitute three 3 major facies associations; the gravelly dominated, the sandy dominated and the fine grain dominated. These facies and facies associations were interpreted and three facies successions were recognized; the alluvial-proximal braided river, the braided river and the lacustrine-marginal lacustrine.
The stratigraphic architecture indicates a rifted? The facies stacking patterns depict sedimentation mainly controlled by allogenic factors of climate and tectonism. The Benue trough of west Africa is commonly believed to be a rift feature that originated in the Cretaceous at about the time that Africa and South America began to separate.
Bouguer gravity and available geological data in the trough indicate that its formation was probably the result of regional horizontal stresses in the lithosphere, causing crustal extension and surface subsidence. By contrast, the data for the adjoining Cameroon volcanic line suggests that the associated tensional stresses relate to mantle upwarp causing thinning of the lithosphere and regional crustal uplift similar to that associated with the Kenya rift.
Thus the association of passive and active rifts seen in the Afro-Arabia rift system is also a feature of the Cretaceous rift system in west Africa. Facies analysis of the Cretaceous Bima Formation in the Gongola Sub -basin of the Northern Benue Trough northeastern Nigeria indicated that the Lower Bima Member is composed of alluvial fan and braided river facies associations.
The alluvial fan depositional environment dominantly consists of debris flow facies that commonly occur as matrix supported conglomerate.
This facies is locally associated with grain supported conglomerate and mudstone facies, representing sieve channel and mud flow deposits respectively, and these deposits may account for the proximal alluvial fan region of the Lower Bima Member.
The distal fan facies were represented by gravel-bed braided river system of probably Scot - type model. This grade into sandy braided river systems with well developed floodplains facies, forming probably at the lowermost portion of the alluvial fan depositional gradient, where it inter-fingers with basinal facies. In the Middle Bima Member, the facies architecture is dominantly suggestive of deep perennial sand-bed braided river system with thickly developed amalgamated trough crossbedded sandstone facies fining to mudstone.
Couplets of shallow channels are also locally common, attesting to the varying topography of the basin. The Upper Bima Member is characterized by shallow perennial sand-bed braided river system composed of successive succession of planar and trough crossbedded sandstone facies associations, and shallower channels of the flashy ephemeral sheetflood sand - bed river systems defined by interbedded succession of small scale trough crossbedded sandstone facies and parallel laminated sandstone facies.
The overall stacking pattern of the facies succession of the Bima Formation in the Gongola Sub - basin is generally thinning and fining upwards cycles, indicating scarp retreat and deposition in a relatively passive margin setting.
Dominance of kaolinite in the clay mineral fraction of the Bima Formation points to predominance of humid sub - tropical. Sedimentary and petrofacies analyses of the Amasiri Sandstone, southern Benue Trough , Nigeria: Implications for depositional environment and tectonic provenance.
This study was undertaken to determine the depositional environment, provenance and tectonic setting for the Turonian Amasiri Sandstone, southern Benue Trough , Nigeria, using lithofacies analysis and re-appraisal of petrography of the sandstones. Lithofacies analysis reveals 9 lithofacies suggestive of storm mass flow and tidal shelf processes.
Petrofacies analysis identifies the sandstones as feldspathic and arkosic arenites. Ternary plot of framework mineralogy indicates derivation from an uplifted continental block related to the nearby Oban Massif and Cameroon Basement Complex.
Hydrocarbon potential, palynology and palynofacies of four sedimentary basins in the Benue Trough , northern Cameroon. Organic geochemical, palynological and palynofacies analyses were carried out on 79 selected samples from four sedimentary basins Mayo-Rey, Mayo-Oulo-Lere, Hamakoussou and Benue in northern Cameroon.
Rock-Eval pyrolysis and Total Organic Carbon results indicate that most of the samples of the studied basins are thermally immature to mature. The organic matter consists of terrestrial components peat, lignite, bituminous coal, and anthracite associated with organic matter of marine origin. The source rock quality ranges from poor to very good.
The source material is composed of both algae and higher plants. Samples from these basins yielded palynological residue composed of translucent and opaque phytoclasts, Amorphous Organic Matter AOM , fungal remains, algal cysts pollen and pteridophyte spores. Age assigned confidently for all these basins the palynological data except for one sample of Hamakoussou that can be dated as Early to Mid-Cretaceous in age.
Callialasporites dampieri, Classopollis spp. The other pollen and spores recovered may indicate a Tertiary or younger age especially Monoporopollenites annulatus , or. The shallow marine shales of the Cretaceous formations namely Yolde, Dukul, Jessu, Sekuliye and Numanha ranging in age from Cenomanian to Coniacian within the Yola Sub-basin in the Northern Benue Trough , northeastern Nigeria were analysed to provide an overview on their hydrocarbon generation potential.
This study is based on pyrolysis analysis, total organic carbon content TOC , extractable organic matter EOM , biomarker distributions and measured vitrinite reflectance. The present-day TOC contents range between 0. Based on the present-day kerogen typing, the shale sediments are expected to generate mainly gas. Biomarker compositions indicates deposition in a marine environment under suboxic conditions with prevalent contribution of aquatic organic matter and a significant amount of terrigenous organic matter input.
This study shows that the organic matter has been affected by volcanic intrusion and consequently, have reached post-mature stage of oil generation. These higher thermal maturities levels are consistent with the vitrinite reflectance ranging from 0.
Based on this study, a high prospect for major gas and minor oil generation potential is anticipated from the shallow marine Cretaceous formations from Yola Sub-basin. Field occurrence and geochemical characteristics of the baryte mineralization in Lessel and Ihugh areas, Lower Benue Trough , Nigeria. The Lessel and Ihugh areas are underlain by Precambrian rocks comprising of banded gneiss, medium-grained muscovite granite, coarse-grained biotite muscovite granite, and Turonian arenaceous Lessel Sandstone in the Lower Benue Trough , southeastern Nigeria.
Major oxides and trace element analysis of baryte and the host rocks was undertaken using Inductively Coupled Plasma Mass Spectrometry ICP-MS , in order to establish the geochemical characteristics and to constrain the origin of the baryte mineralization. Negative Ce anomaly 0. The structurally controlled nature of the mineralization, depleted major and trace elements concentration in the barytes in addition to REE anomalies indicate that mixing of a strongly differentiated residual Ba-bearing fluid and sulphur-rich seawater occurred under low temperature and oxidizing-reducing conditions.
Aliyu, Abdulkarim H. Sedimentogical and palynological investigations of the Kanawa Member of Pindiga Formation in the Gongola Sub-basin, Northern Benue Trough , NE Nigeria were carried out in order to determine the paleoenvironment and age of the sediments. Three main lithofacies were identified from the measured sedimentary log section, namely; the wave rippled sandstones, the limestones with ammonites, bivalves and gastropods and the clay-shale.
The facies were interpreted to have been deposited in a marine environment. Based on palynological studies, Kanawa Member consists of two palynozones, namely; Cretacaeiporites scabratus and Triorites africaensis. The Triorites africaensis zone is characterized by species of T.
The Early Cretaceous lacustrine sediments from Bima Formation in the Yola Sub-basin, Northern Benue Trough , northeastern Nigeria were studied based on organic geochemistry and petrology. The total organic carbon TOC contents ranges from 0. Based on kerogen pyrolysis and microscopy coupled with biomarker parameters, the organic matters contain Type I lacustrine algae , Type III terrestrially derived land-plants and Type IV kerogens deposited in a mixed lacustrine-terrestrial environment under suboxic to relatively anoxic conditions.
This suggest potential occurrence of Early Cretaceous lacustrine sediments perhaps Lower Cretaceous petroleum system in Yola Sub-basin of the Northern Benue Trough as present in the neighbouring basins of Chad, Niger and Sudan Republics that have both oil and gas generation potential within the same rift trend WCARS. This is supported by the presence of dark brown palynomorphs, amorphous organic matter and phytoclasts as well as inertinite macerals.
Consequently, the organic matters in the lacustrine shales of Bima Formation in the Yola Sub-basin appeared as a source of oil most likely even waxy and gas prone at a relatively deeper part of the basin. However, the high thermal maturity enhanced the organic matters and most of the hydrocarbons that formed in the course of thermal maturation were likely expelled to the reservoir rock units. Environmental risk assessment of lead-zinc mining: a case study of Adudu metallogenic province, middle Benue Trough , Nigeria.
Assessment of the impacts of lead-zinc mining in Adudu-Imon metallogenic province was carried out. Reconnaissance and detailed field studies were done. Lithologies, stream sediments, farmland soils, mine tailings, artificial pond water, stream water, well water, and borehole water were collected and subjected to atomic absorption spectrometry AAS and X-ray fluorescence XRF analyses.
Geochemical maps were generated using ArcGIS Significant contamination with cadmium Cd , iron Fe , and lead Pb was recorded in the collected water samples.
The Benue Trough and coastal basins
The trough has its southern limit at the northern boundary of the Niger Delta , where it dips down and is overlaid with Tertiary and more recent sediments. The trough is arbitrarily divided into lower, middle and upper regions, and the upper region is further divided into the Gongola and Yola arms. The Anambra Basin in the west of the lower region is more recent than the rest of the trough, being formed during a later period of compression, but is considered part of the formation. The Benue Trough was formed by rifting of the central West African basement, beginning at the start of the Cretaceous period. During the Late Early to Middle Cretaceous, the basin subsided rapidly and was covered by the sea. Sea floor sediment accumulated, especially in the southern Abakaliki Rift, under oxygen-deficient bottom conditions. A common explanation of the trough's formation is that it is an aulacogen , an abandoned arm of a three-armed radial rift system.
The Benue Trough