Calabar Flank Research Articles

Comparative Studies of Ekenkpon Shale Subsurface Distribution in the Calabar Flank

The Ekenkpon Shale is one of the Cretaceous sequences of the Calabar Flank with the structural and subsurface facies studied in terms of their distribution and lateral. Materials used in this research are processed seismic and well log data from Wells A, B and C drilled within the study area. The procedure adopted was to compare the structural and stratigraphic analysis of previous and current research carried out in the study area. Well log data were viewed matched with processed seismic data. Composite stratigraphic section generated showed correlatable the Ekenkpon Shale facies, their lateral extents and subsurface distribution. Wells A and B drilled 0.8km apart in south-central Calabar Flank and well C drilled 4.7km from well B encountered Ekenkpon Shale. Comparison of the subsurface facie distribution of Ekenkpon Shale, in Wells A, B and C showed identified facies correlated across the studied wells whereas correlations modified after Nyong, Reijers and Petters, showed that only Well B penetrated the Ekenkpon Shale which pinched out before getting to Well C NE and SW of the Calabar Flank. Analysis of works by Nyong, Reijers and Petters when compared with the current study modified the subsurface distribution of the Ekenkpon Shale. The stratigraphy established in this study showed a continuous sequence of Ekenkpon Shale from the SW to the NE of the Calabar Flank compared with the surface Ekenkpon Shale as observed at different outcrop locations by the works of Nyong, Reijers and Petters is not extensive.

MID CRETACEOUS SUBSURFACE CARBONATE DEPOSIT AND RESERVOIR DEVELOPMENT OF THE MFAMOSING LIMESTONE CALABAR FLANK

This research analyzed the reservoir quality of the Mfamosing Limestone with a view to classifying it as a potential reservoir rock within the Calabar Flank. Materials used in this research are processed seismic data acquired around the Calabar flank and well logs of three wells (A, B, C) drilled at different periods within the study area, core as well as mud log data. The procedure used involved prospect identification and mapping, structural and stratigraphic analysis, reservoir quality and classification of the carbonate rock in the study area. The results were analyzed and classified the Mfamosing Limestone using hydrocarbon storage capacity and deliverability potential. Wells A and B was drilled 0.8km apart and well C drilled 4.7km from well B which encountered the Mfamosing Limestone with logs indicating hydrocarbon in Well A which had a shallower sandstone lenses. The sandstone lens in Well A was tested for hydrocarbon and flowed briefly and stopped. Wells B and C were planned and drilled using Well A as reference amongst other parameters to evaluate the hydrocarbon potential of the Mfamosing Limestone. Wells B and C were found completely dry. Two conventional coring runs at depths 10,490ft-10,552.5ft and 10,552.5ft-10,614ft in Well B indicated that the cored intervals are light grey, moderate to very hard, and fossil rich limestone with no direct fluorescence. The core analysis results suggest that limestone is dry and highly indurated with no evidence of physical porosity. This suggest that the Mfamosing Limestone penetrated by all three wells though massive has no hydrocarbon storage capacity and deliverability potential typical of a reservoir rock. This research therefore suggests that the Mid Cretaceous subsurface Mfamosing Limestone is more of a mineral carbonate deposit than a hydrocarbon reservoir.

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This research is focused on the structural setting and subsurface distribution of cretaceous facies in the Calabar Flank, Lower Benue Trough. The aim of this research is to compare the works of Nyong (1995), Reigers and Petters, (1997) in light of new available subsurface data. Materials used are data sets from three wells drilled at different periods within the same acreage (Wells A, B and C). Seismic data, well logs and mud log data have been used to analyze and study the subsurface geology of the study area. Well data from the three wells were viewed and matched with processed seismic data. A composite stratigraphic section produced show correlatable facies, their lateral extents and the subsurface facies distribution in the study area. Well A drilled, south central Calabar Flank encountered shale and sandstone, very thick shale unit with limestone overlying sandstone at the base. Well B also drilled south central Calabar Flank about 0.8km from Well A encountered the same sequence. Whereas Well C drilled about 4.7km from Well B encountered sandstone, shale, marlstone and limestone. This research shows that only well C encountered marlstone. Observations from the well sections, show the penetrated limestone unit appears disconnected, with very high resistive anomaly suggesting that the limestone reservoir penetrated by the three wells are not laterally continuous. These findings tend to modify the earlier published articles on the structural setting and subsurface distribution of Cretaceous sediments SW to NE of the Calabar Flank South Eastern Nigeria in terms of facies distribution, facies lateral extent and structural variability or changes.

Leachate delineation and aquifer vulnerability assessment using geo-electric imaging in a major dumpsite around Calabar Flank, Southern Nigeria.

A near-surface resistivity investigation was undertaken to investigate soil contamination and aquifer vulnerability due to leachate percolation in a major dumpsite in Calabar. The study was undertaken using 2-D electrical resistivity tomography (ERT) and vertical electrical sounding. Ten traverse lines were created within and outside the dumpsite and geo-electric measurement was conducted using dipole-dipole and Schlumberger electrode configurations. Interpretation of the measured data was carried out using DIPROWIN and WinResist program. 2-D resistivity structures were produced, showing four resistivity layers. Conductive layers with a resistivity of less than 14Ωm were delineated as leachate infiltrated and soil-contaminated zones. The study has shown that leachate has spread across all the survey lines except the two control stations outside the dumpsite. The investigation has further revealed that leachate has percolated the subsurface up to 25m in the area. Subsequently, twenty vertical electrical soundings were carried out to evaluate aquifer protective capacity/vulnerability in the area. The interpretation shows the area is underlain by four to five geo-electric layers. Total longitudinal conductance values were calculated. Two VES points (14 and 19), representing 10% of the sounding points, showed a weak protective capacity rating; eight VES points (1, 7, 9, 11, 12, 13, and 18), representing 35% of the soundings, showed a moderate protective capacity rating; ten VES points (2, 3, 4, 5, 6, 8, 10, 15, 16, 17, and 20), representing 55% of the total soundings, showed a good protective capacity rating. Three (3) hand-dug wells were sampled with the view to obtaining the groundwater and leachate flow direction within the dump vicinity. An electric water level recorder was used to determine the static water level (SWL) of the three wells, and the leachate flow direction was determined to be north-easterly.

Upper-Cretaceous and Paleocene Biostratigraphy of Nkporo Shales, Calabar Flank, Southern Benue Trough

The present study Biostratigraphic (foraminiferal and palynological), paleoenvironment and paleoecological evaluations are aimed at interpreting the lithology, age, paleoenvironmental as well as the paleoecological condition of the deposited sediments newly exposed along Ikot Okpara Otopy, Southeastern Nigeria. Lithological descriptions of the samples reveal that this section is predominantly shale. This shale is dark grey to light brown, fossiliferous with minor occurrence of silts and sandstones. Foraminiferal analysis reveals a Paleocene interval within the Nkporo Formation for the first time. The sediments have low to moderate number of taxa with 96% benthic and 4% planktics, while a total of 196 microflora were recovered and identified. The microfloral species contain 60% of continental plants with 40% of marine counterparts. Key foraminiferal taxa used in this study include Bolivina afra, Bolivina explicata, Globigerina fringe and Haplophragmoides talokaense, while their microfloral counterparts encountered within the section include Cingulatisporites ornatus, Auriculidites reticulates Ephedripites ambonoides, Retidiporites magdalenensis, Synolocolporites marginatus, Constructipollenites ineffectus, Foveotriletes margaritae, Buttinia andreevi, Proxapertites operculatus, Zlivisporis blanensis and Paleocystodinium sp. These assemblages (Foraminiferal and Palynological) depict the deposition of these sediments during the Maastrichtian Paleocene age. The combination of lithologic and biostratigraphic data reveal paleoenvironment interpretation of the study section to range from marginal - shallow to Middle neritic paleo-water depths, while the paleoecological studies depicts a fluctuation in the salinity from brackish to marine settings deposited within a tropical to subtropical warm and humid climate.

Mineralogical and physico-chemical properties of the Cretaceous shales of the Calabar Flank, south-eastern, Nigeria: Implication for paleo-weathering conditions, provenance and industrial applications

The Physico-chemical and mineralogical properties of the Cretaceous shales of Calabar Flank southeastern Nigeria were examined for their Provenance, Paleo-weathering Conditions and Industrial Applications. Twenty samples of shale from Ekekpon and Nkporo Formations were analysed using X-Ray Fluorescence, X-ray diffraction (XRD), scanning electron microscopy (SEM) and geotechnical techniques. Results from the major oxides of elements revealed that the Nkporo Shale is enriched with SiO2 > Al2O3 > LOI > Fe2O3 > SO3 while the Ekepkon shale is also enriched in SiO2 > Al2O3 > LOI > Fe2O3 > CaO > K2O. The XRD revealed kaolinite as the major clay mineral, while other non-clay minerals are quartz, vallerite, mica, nacaphite, sodalite. The SEM shows that the Ekepkon Shale is enriched in calcium. The correlation matrix revealed SiO2 resides more in the quartz phase of the Nkporo Shales, while in the Ekekpon Shale the SiO2 is associated with the clay. The element ratios and discrimination diagrams revealed that the provenance of the shales is of intermediate to mafic igneous rocks and a tectonic setting of continental to oceanic arcs. The presence of kaolinite in the Nkporo Shale with the chemical index of alteration (CIA) values ranging from 83.58 to 96.93, indicated that the shale is derived from intensive chemical weathering in the source area. The low CIA values (37.90–76.96) in Ekenkpon Shale is attributed to CaO and calcium enrichment in the shale and the shale contains high quartz and kaolinite therefore the shale is suggested to have been derived from an intermediate to intense weathering activities in the source area. The geotechnical properties revealed that both shales are suitable for ceramic and refractory industries. The Ekenkpon Shale will be suitable for use as filling material and as raw material in cement industries. However, the shales do not meet the specifications for paper and rubber production due to the high contents of iron oxide, lime, magnesia, potash and soda.

Assessment of crustal structures by gravity and magnetic methods in the Calabar Flank and adjoining areas of Southeastern Nigeria—a case study

High-resolution potential field data were used to the study of Calabar Flank. The study is aimed at mapping the tectono-sedimentary framework, and determining depth to basement of the area. The smooth magnetic/gravity curves obtained from the 2-D models reflect thick sedimentary series and deeply buried basement rocks with no significant post rift tectonic events. Also, the main basement structures (that is, the horst and graben) and associated normal fault blocks of the Calabar Flank were properly delineated. Thickness of sedimentary series in some locations in the study area was observed to be ~7000 m, and the stacked models showed that the sediment thicknesses dip gently in the southwesterly direction. The models, particularly the joint gravity and magnetic model, validate the extant conceptual geological model for the area.

Assessment of depth to magnetic sources using high resolution aeromagnetic data of some parts of the Lower Benue Trough and adjoining areas, Southeast Nigeria

High resolution airborne magnetic data acquired between 2005 and 2010 were used to determine depth to shallow and deep magnetic sources in some parts of Southeastern Nigeria. Various depth estimation methods such as standard Euler deconvolution (SED), source parameter imaging (SPI), spectral depth analysis (SDA) and two dimensional (2-D) forward modeling were applied. Results obtained from SED, SPI and models of profiles 1 and 2 indicate that the Abakaliki Anticlinorium (AA) and Ikom-Mamfe Rift (IMR) regions are dominated by short wavelength magnetic anomalies caused by extensive tectonic events. The SED map showed depth to shallow and deep magnetic sources ranging from ~ 16.6 to ~ 338.3 m and ~ 394.3 to ~ 5748.1 m respectively. Likewise, depth estimates from the SPI map varies from ~ 147.1 to ~ 554.2 m (shallow magnetic sources) and ~ 644.2 to ~ 6141.6 m (deep magnetic sources). The result obtained from SDA revealed depths to deep magnetic basement in the range of ~ 769 to ~ 6666 m with an average of ~ 3449 m. Also, it showed that depth to shallow magnetic sources vary between ~ 119 and ~ 434 m with mean of ~ 269 m. The 2-D forward modelling showed maximum depth values of ~ 4700, ~4600 and ~ 6500 m in the models of profiles 1, 2 and 3 within the Anambra Basin (AB), Afikpo Syncline (AS) and Calabar Flank (CF) respectively. Generally, from all the various methods applied the results indicate that AB, AS and CF are dominated by long wavelength anomalies. The 2-D models indicated that the basement framework is undulant. Also, depth estimates involving the various methods used in this study correlate strongly with each other in the AB, AS and CF geological regions.

Trace and rare earth element geochemistry of the black and grey shales of the Calabar Flank, Southeastern Nigeria: constraints on the depositional environment and the degree of metal enrichment

This study focuses on the trace and rare earth elements (REE) geochemistry of the Nkporo and Ekenkpon Shales of the Calabar Flank. The main aim is to infer their depositional environment and the degree of their metal enrichment. The shale samples were analyzed using inductively coupled plasma mass spectrometry. The results indicated that the mean concentrations of K, Na, and Fe in Nkporo and Ekenkpon Shales are 1.45, 0.4, and 4.17 wt%, and 1.11, 0.44, and 5.42 wt%; respectively. The Nkporo Shale is enriched with the following trace elements; P > Mn > Sr > Ba > Zn > Ce > Rb > Zr > V>Cr > Ni and depleted in the following trace elements; Ta > Ge > Sb > Bi > Cd > Ag > Te > In > Hg. While the Ekenkpon Shale is enriched with the following trace elements; P > Mn > Ba > Sr > V>Ce > Zr > Rb > Cr > Zn > Ni and depleted in; Sb > Ge > Bi > Ag > Ce > Te > In > Hg. The concentration of redox-sensitive elements such as V, Ni, Mo, U, Cu, Cr, Re, Cd, Sb, Ti, Mn, and their ratio V/Mo and U/Mo in the black and grey shale samples show different patterns. The REE obtained from the Nkporo and Ekenkpon Shales were PAAS normalized. The Nkporo Shale showed a slightly flat light rare-earth element (LREE), middle rare-earth element (MREE), and heavy rare earth element (HREE) pattern enrichment. Ce/Ce* ranges from 0.95 to 1.09 in Nkporo Shale and 0.67 to 1.40 in Ekenkpon Shale. The Ekenkpon Shale showed a slight LREE, MREE enrichment, and depleted HREE patterns. The Mn contents and U/Mo ratio in Nkporo and Ekenkpon Shales suggests a poor oxygen transitional environment. The V/Mo and V/(V + Ni) ratios indicated that the Nkporo shales were deposited in an anoxic to suboxic conditions and Ekenkpon shales were also deposited under an anoxic to suboxic conditions. The V/Ni ratio indicated that the organic matter in the Nkporo shale is terrigenous while that of the Ekenkpon shales are both terrigenous and marine in origin.

Assessment of groundwater potential using geophysical data: a case study in parts of Cross River State, south-eastern Nigeria

Groundwater potential of some parts of Cross River State, Nigeria, was assessed involving vertical electrical sounding (VES) and high-resolution aeromagnetic methods (HRAM). The VES and HRAM dataset were used to delineate the hydro-lithostratigraphic units and map the spatial distributions of geologic structures, respectively. The electro-stratigraphic sections revealed the various hydro-lithostratigraphic units composed of fractured/weathered crystalline basement, sandstones, siltstones, sandy shales, and highly baked and fractured shales occurring at different depths. Generally, the unsaturated top layer is composed of shales, marl, clay, silt, gravel and lateritic materials with resistivity ranging from ~ 3.0 to ~ 550 Ω m. This layer is underlain by various aquifer units like sandstones, siltstones, fractured shales and limestone/marl, and fractured/weathered basement occurring at different depths (~ 30 to ≤ 100 m) as revealed by the electro-stratigraphic sections obtained in the study area. In the Calabar Flank (CF), Oban Massif (OM) and Ikom-Mamfe Embayment (IME), the apparent resistivity for these hydro-lithostratigraphic units varied between ~ 8.50 and ~ 59.50 Ω m, ~ 120.2 and ~ 1562.6 Ω m and ~ 30.8 and ~ 277.2 Ω m, respectively. The enhanced total magnetic intensity maps and source parameter imaging result showed that the OM and IME are characterized by high concentration of short-wavelength anomalies, while the CF is dominated by relatively undisturbed thick sedimentation (~ 6217 m). HRAM results show that such areas are predominated by geologic structures like faults, fractures, fissure, dyke swamps, etc. caused by tectonics. Such geologic structures create secondary porosity and enhance permeability. From all the results obtained, OM and IME represent areas with moderate groundwater potential. The CF dominated by argillites with no significant tectonic activity is observed to have low groundwater potential.

Exploratory mapping of structures controlling mineralization in Southeast Nigeria using high resolution airborne magnetic data

High resolution airborne magnetic data of some regions of Southeast Nigeria were analyzed to map structures controlling mineralization. Such data can be used for mineral assessment programs, surficial geologic boundaries, hydrocarbon exploration at reconnaissance stage, mapping of hydrothermally altered rock zones and geologic structures. First and second vertical derivatives, upward continuation, source edge detection, analytical signal, Centre for Exploration Targeting (CET) and standard Euler deconvolution operations were done to delineate the spatial distributions and depths to the different magnetic sources. The enhanced maps showed major and minor magnetic anomaly centres in the Lower Benue Trough (LBT) and Ikom-Mamfe Rift (IMR) characterized by thin (151–745 m) sedimentation. Also, within these areas there exist some isolated pockets of intermediate depths (745–1634 m) occurring in the neighborhood of these magnetic anomalies. The Calabar Flank (CF) characterized by minor remnants of post-Cretaceous intrusions has sedimentation of over 6126 m in some locations. The 2000 m upward continued TMI map revealed the existence of major deep-seated weak zones believed to have originated during the rifting episode connected with the formation of the Benue Trough. The abundance of intrusive bodies in the LBT and IMR render these parts of the study area unattractive for hydrocarbon exploration. Nevertheless, they possess high base metal mineralization potential while CF is a favorable site for hydrocarbon search.

Ground Magnetic Prospecting in Parts of the Calabar Flank Sedimentary Basin and Environs, South-South Nigeria

Ground Magnetic Prospecting in Parts of the Calabar Flank Sedimentary Basin and Environs, South-South Nigeria

Morphometric Studies of Pebbles from Ewen Area, Calabar Flank, Southeastern Nigeria: Implications for Paleoenvironmental Reconstruction

Morphometric Studies of Pebbles from Ewen Area, Calabar Flank, Southeastern Nigeria: Implications for Paleoenvironmental Reconstruction

Geochemistry of Ekenkpon and Nkporo shales, Calabar flank, SE Nigeria: implications for provenance, transportation history and depositional environment

The Cretaceous Nkporo and Ekenkpon Shales within the Calabar Flank were investigated using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) and Atomic Emission Spectroscopy (ICP-AES) to deduce the provenance, transportation history and depositional environment. The results show the dominance of SiO2 (45.27 – 46.45%; 44.50 – 54.83%), Al2O3 (22.27 – 23.57%; 19.20 – 20.20%) and Fe2O3 (8.30 – 9.04%; 5.64 – 7.30%) constituting the bulk major oxides of Nkporo and Ekenkpon Shales respectively. The Index of Chemical Variation (ICV) ranges from 0.42 – 0.56 and 0.57– 0.68 for Nkporo and Ekenkpon Shales respectively, suggesting moderate and high degree of weathering. The enrichment of Sr (124 – 350ppm; Nkporo Shale and 176 – 856ppm; Ekenkpon Shale) compared to Post Australian Archean Shale (PAAS; 14.6ppm) could be attributed to feldspars in the source area, and is easily incorporated in the clay minerals of the shales. Also the values of Th and U which are 15.00 – 17.20ppm; 14.6- 23.2ppm and 3.5-4.2ppm; 1.9-6.2ppm respectively in Nkporo and Ekenkpon sediments show enrichment compared to PAAS of 14.6ppm and 3.1ppm for respective values of Th and U. The Eu anomaly of 0.04 to 0.07 suggests felsic source rocks for both formations while plots of TiO2 vs. Al2O3 indicate an intermediate to dominantly felsic granodiorite source for both shales, with little input from felsic volcanic provenance plus traces of quartzose sedimentary rocks. The mobility of Na, Ca, and K due to progressive weathering of the shales is evident in the bivariate plots of Na2O wt% vs. PIA, CaOwt% vs. PIA and K2O vs. PIA. Values of Th/U ratios range from 3.37 – 4.91(Nkporo) and 3.10 – 7.68 (Ekenkpon), indicating moderate to high weathering and reworking of sediments. It is envisaged that the area is associated with passive to active continental margin tectonics, where sediments were mainly sourced from felsic rocks of the adjoining terrain and deposited in oxic, continental to transitional marine environment based on Al2O3– K2O +CaO+MgO-Fe2O3+MgO; AKF plot.KEYWORDS: Cretaceous, Calabar Flank, provenance, transportation history, depositional environment.

English

Foraminiferal biostratigraphy and palaeoenvironmental interpretation was carried out on core samples (5 samples between intervals 5-55 m) recovered from borehole ET (BH-ET) located in Etankpini area of the Calabar Flank, south eastern Nigeria. Lithologic description of the borehole samples were carried out and the borehole was sampled at 5 m interval. The samples were later composited at 10 m interval and a total of six samples were subjected to standard micropaleontological preparation procedures. Results from the lithologic analysis show that the basal section of the well (55-60 m) was made up of granite gneiss; overlain by light grey, calcarenite, bioclastic, pisolitic and stylolitic limestones (30-55). Dark grey fissile shales directly overlie the limestone (5-30 m). The foraminiferal recovery was generally low and characterized by planktonic species (Guembelitria harrisi, Hedbergella crassa, Hedbergella delrioensis, Hedbergella simplicissima, Hedbergellid spp., Heterohelix globulosa, Heterohelix planata, Heterohelix reussi, Hedbergella planispira and Hedbergella sigali). The absence of benthonic forms may be an indication of anaerobic bottom conditions. An age of Cenomanian-Early Turonian was assigned to the studied well based on diagnostic foraminiferal species assemblages. The recovered foraminiferal assemblage points to deposition within the Inner Neritic to Middle Neritic depositional setting for the studied well.   Key words: Neritic, Calabar Flank, biostratigraphy, planktonic, anaerobic.

Quality of natural waters in carbonate aquifers at a densely populated Odukpani area of cross river state, Southern Nigeria

The study area, Odukpani is underlain by cretaceous sediments of the Calabar Flank. The main aquifers are fractured black shales that are inter-bedded with calcareous sandstones. The aquifers range...

Quantitative Analysis of Palynomorphs from Neogene Deposits in Calabar Flank: Implication for Paleoenvironmental Interpretation

Quantitative Analysis of Palynomorphs from Neogene Deposits in Calabar Flank: Implication for Paleoenvironmental Interpretation

Potential shale resource plays in southeastern Nigeria: Petroleum system modelling and microfabric perspectives

Nigeria is witnessing significant increase in energy demand as a result of rising population and economic growth; as more focus on clean energy take hold. These challenges have triggered the search for shale gas and shale oil in the inland basins of Nigeria. The aim of the study is to carry out an integrated study that incorporates petroleum systems modelling, field studies and advanced analytical programs in order to define the hydrocarbon prospectivity of Upper Cenomanian-Lower Turonian Eze-Aku Shale and Ekenkpon Shale as potential shale gas/oil plays in southeastern Nigeria. Available subsurface information which includes exploration wells and proprietary Oil Company archive data were used to calibrate and simulate 1-D basin models. Amount of silica content, major clay mineral group and microfabric of the potential shale resource plays were determined using Energy Dispersive X-ray Fluorescence analysis, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy respectively. The simulated models showed that deeply buried Eze-Aku Shale and Ekenkpon Shale have undergone episodic generation of hydrocarbon. Significant amount of silica content (>30%) in Eze-Aku and Ekenkpon Shale samples suggested a brittle nature of the samples and the possibilities of the samples to capture portion of expelled hydrocarbon. Identification of non-swelling clay mineral group in the analyzed shale samples indicated that the samples have the potential for shale gas/oil. The SEM images of analyzed samples showed differences in cementation. This study recommends that deeply buried Eze-Aku Shale and Ekenkpon Shale are potential exploration targets for shale gas/oil in Abakaliki Fold Belt and Calabar Flank of the southeastern Nigeria.

Exploring and Reserve Estimation for Industrial Mineral Potential in Parts of Calabar Area (Ewen/Iwuru/Agbangana Axis) Southern Nigeria

For a developing nation, industrial rocks can be said to be very essential. Limestone and marble are one of the principal raw materials for industrial rocks such as cement manufacture. In Nigeria, Limestone occurs in the sedimentary environment of Benue Trough, Sokoto, Dahomey and Borno (Chad) basins. This Limestone forming environments (shallow coastal marine conditions) appears to have re-occurred several times in the geological history of the basins. The deposits of the Benue trough appear to contain the most economically viable mineral resources including limestone in Nigeria. Nearly all the limestone deposits in the trough are used for industrial purposes such as cement. The Calabar Flank is one the main carbonate province in Nigerian Benue trough. Ibeto Cement Company obtained permit to explore the viability of limestone deposit in some parts of the Calabar flank area for the establishment of a Portland cement production plant. This research evaluated the presence and volumetric analysis of limestone occurrence recovered from core drilling holes in the area on Exploration Licenses (ELs) No. 17373 and part of No. 17374. Prior to subsurface core drilling investigation, surface reconnaissance survey was undertaken. Rockworks 16 software complimented with dilute Hydrochloric acid were used for this evaluation.

Palynostratigraphy of Lemna Road Transect of Benin Formation, Calabar Flank, Nigeria

Palynostratigraphy of Lemna Road Transect of Benin Formation, Calabar Flank, Nigeria