scholarly journals Spectral re-evaluation of sediment thickness within Afikpo Basin and environs, southeastern Nigeria, using high resolution aeromagnetic dataset

2020 ◽  
Vol 9 (1) ◽  
pp. 11
Author(s):  
Stephen Stephen Onyejiuwaka Ibe ◽  
Kevin Uche Iduma
Keyword(s):  
High Resolution ◽  
Analytic Signal ◽  
Data Depth ◽  
Hydrocarbon Accumulation ◽  
Aeromagnetic Data ◽  
Sediment Thickness ◽  
Southeastern Nigeria ◽  
Hydrocarbon Formation ◽  
Tilt Derivative

The discovery of hydrocarbon in the areas bordering Afikpo Basin prompted the re-evaluation of the sedimentary thickness within the basin with high resolution geophysical data. Depth to magnetic sources, sediment thickness, basement topography and structures within it were investigated using spectral analysis, analytic signal and tilt derivative of aeromagnetic data. The results show that the depth to the basement varies between 1.52 and 3.15 km; depth to intermediate magnetic anomaly sources ranges from 0.40 to 1.05 km and depth to the shallow sources varies from 0.10 to 0.34 km. Structures within the basin predominantly have NE-SW trend and the boundary between Afikpo Basin and Southwestern Basement Massif is characterised by NE-SW trending dykes with the longest dyke extending from Amasiri to Abba Omege. The results show that the basin is greatly undulated and the deformation that led to its undulation resulted in the formation of structures which could serve as traps for hydrocarbon accumulation. Sediment thickness greater than 2.3 km associated with some locations within the basin prompted the classification of the places as viable for hydrocarbon formation, if other conditions necessary for its generation are favourable. These places were recommended for further studies for hydrocarbon prospecting on the bases of their sediment structural complexities and thicknesses.  

scholarly journals Analytic Signal Depth from High Resolution Aeromagnetic Data over the Gongola Basin Upper Benue Trough Northeastern Nigeria

2021 ◽  
Vol 25 (4) ◽  
pp. 585-590
Author(s):  
H. Musa ◽  
N.E. Bassey ◽  
R. Bello
Keyword(s):  
High Resolution ◽  
Magnetic Structure ◽  
Horizontal Cylinder ◽  
Analytic Signal ◽  
Aeromagnetic Data ◽  
Polynomial Fitting ◽  
Benue Trough ◽  
Local Maxima ◽  
Depth Determination ◽  
Programming Software

The study of high-resolution aeromagnetic data was carried out over the Gongola basin, upper Benue trough, northeastern Nigeria, for analytic signal depth determination. Total intensity magnetic map obtained from the data using the Oasis Montaj TM programming software was used to get the residual map by polynomial fitting, from where the analytic signal was obtained with the use of anomaly width at half the amplitude (X1/2). This was used to carry out depth estimations over the study area. The results showed that it peaks over the magnetic structure with local maxima over its edges (boundaries or contact), and the amplitude is simply related to magnetization, likewise results also showed that the depth estimates were in the range of 1.2 to 5.9 km and were calculated for contact, dyke/sill and horizontal cylinder respectively. The lowest values are from DD profiles, while the highs are from AA profiles. This work is important in identifying dykes, contacts and intrusives over an area.

scholarly journals Geophysical Investigation of a Fault Zone from Aeromagnetic Data over the Ageva Area of Okene Kogi State, Nigeria

2021 ◽  
pp. 33-43
Author(s):  
Ahmed Lawal ◽  
Adamu Abubakar ◽  
Avazi Victor
Keyword(s):  
Fault Zone ◽  
Analytic Signal ◽  
Aeromagnetic Data ◽  
Geophysical Investigation ◽  
Data Set ◽  
Linear Features ◽  
Qualitative Interpretation ◽  
Residual Correction ◽  
Tilt Derivative ◽  
Depth Extent

High-resolution aeromagnetic data over a part of Ageva fault zone in Nigeria have been analyzed with a view to estimate sedimentary thicknesses within the studied area. The data set of this study area, was subjected to various corrections and interpretation techniques. Regional residual correction was done and the noise level of the data was reduced via upward continuation to a height of 250 m thereby enhancing the reliability of the results obtained. Qualitative interpretation techniques which include: Second Vertical Derivative, Analytic Signal, Tilt derivative were used to delineate the trending pattern of the anomalies in the study area which are in the E-W, NE-SW, NW-SE, and N-S directions. The result suggests that fault zone within Ageva and Owo may be mineralized and also that the faults within Ageva and Ibilo extend by a quarter of their exposed length. The Werner solutions revealed that inferred faults within Owo and Ibilo may have relatively low susceptibilities as compared with others in the study area and the range of the depth extent of linear features is 401.5 m – 982.5 m.

scholarly journals 2-dimensional modeling of high-resolution aeromagnetic data over Yola arm of the upper Benue trough, Northeastern Nigeria

2021 ◽  
Vol 27 (2) ◽  
pp. 133-143
Author(s):  
Musa Hayatudeen ◽  
Nsikak E. Bassey ◽  
Bello Rasaq
Keyword(s):  
High Resolution ◽  
Aeromagnetic Data ◽  
Sediment Thickness ◽  
Benue Trough ◽  
Structural Patterns ◽  
Hydrocarbon Traps ◽  
Dimensional Modeling ◽  
Line Spacing ◽  
Intensity Map ◽  
Tie Line

2-D modeling of high-resolution aeromagnetic data over the area investigated was carried out with the aid of Oasis MontajTM software in order to get the total magnetic intensity map as well as the residual map from where the modeling was carried out. The data was acquired for Nigeria Geological Survey Agency (NGSA) in 2010 by Fugro international of Netherlands. The specifications of the data were terrain clearance of 80 m, flight line spacing of 500 m and a tie line spacing of 5000 m. The area investigated in this work is located between longitude 120 00' - 130 30' E and Latitude 80 00' – 100 00'N. GM-SYS module of the Oasis montaj was used for this research, with depocentres, structural patterns, basement geometry and morphology as well as estimates of the physical character of the cause to an investigated anomaly determined. The models reveal the horst and graben structures of the basement and the various faults that segmented the area into block patterns. The results revealed sediment thickness in the range of 2-5 km for the models which are in agreement with the results obtained by various researchers in the area. Horst and graben were identified in the models which confirmed the rifting nature of the Benue Trough. The authors of this research are of the view that these depocentres, structural patterns and basement geometry may be a promising site for hydrocarbon traps and reservoirs. Keywords: Aeromagnetic Data, GM-SYS, Modeling, Horst, Graben.

scholarly journals Investigation of magnetic anomalies of Abakaliki area, Southeastern Nigeria, using high resolution aeromagnetic data

2018 ◽  
Vol 10 (6) ◽  
pp. 57-71 ◽  
Author(s):  
N. Obiora Daniel ◽  
I. Idike Julius ◽  
I. Oha Andrew ◽  
G. Soronnadi-Ononiwu Chijioke ◽  
A. Okwesili Ngozi ◽  
...  
Keyword(s):  
High Resolution ◽  
Magnetic Anomalies ◽  
Aeromagnetic Data ◽  
Southeastern Nigeria

scholarly journals Application of Aeromagnetic Data to Assess the Structures and Solid Mineral Potentials in Part of North Central Nigeria

2020 ◽  
pp. 11-29
Author(s):  
M. D. Tawey ◽  
D. U. Alhassan ◽  
A. A. Adetona ◽  
K. A. Salako ◽  
A. A. Rafiu ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Signal Amplitude ◽  
Analytic Signal ◽  
Aeromagnetic Data ◽  
Euler Deconvolution ◽  
North Central ◽  
Vertical Derivative ◽  
Magmatic Intrusions ◽  
First Vertical Derivative ◽  
Tilt Derivative

Assessment of the structures and solid minerals was carryout to investigate subsurface structural characteristics and mineralization potential zones within part of north-central Nigeria. The residual magnetic intensity data of the area was reduced to magnetic pole after which several source edge detection/interpretation with depth determination techniques including, analytic signal; tilt derivative; first and second vertical derivatives and Euler deconvolution were applied to the aeromagnetic data. From the analytic signal map, three magnetic zones were delineated. These are: low to relatively low magnetic zone (LM) with amplitude range from 0.003 to 0.009, moderate magnetic zone (MM) with amplitude 0.009 to 0.106 and those with amplitudes above 0.106 were products of later magmatic intrusions into host with fractures, faults and joints. Tilt derivative helped in delineating location and extent of edges of causative sources while Euler deconvolution helps in determination of boundary, depth and geometry of the structures. From first vertical derivative map, structures were found to have high lineament density around the central portion of the area and span toward the western end of the map were delineated. The lineaments mapped trending in the ENE-WSW followed by WNW-ESE with some NE-SW, NNE-SSW and NNW-SSE trends. The second vertical derivative (SVD) map also helped in delineating structures and possible mineralization zones that are pronounced within the study area, around high analytic signal zones. Delineated possible and favorable mineralization zones from second vertical derivative map correlate with portion of the study area with rocks showing high analytic signal amplitude suggesting the rocks to be of later magmatic intrusions where mineralization fluids solidify within the host rocks.

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