Back
 GEP  Vol.5 No.7 , July 2017
Evidence of Some Major Structures Underlying the Douala Sedimentary Sub-Basin: West African Coastal Basin
Abstract: Gravity data have been processed in the Douala sedimentary sub-basin in a section consisting of a set of 116 gravity data points located between latitudes 3°03'N and 4°06'N and longitudes 9°00'E and 10°00'E. The established Bouguer anomaly fields and the Residual anomaly fields, extracted by upward continuation at an optimum height of 30 km, were both characterized by considerably high positive anomalies. These anomalies showed many ring-like positive gravity anomaly contour lines in the study region. Gravity gradients were analysed using the multi-scale horizontal derivative of the vertical derivative (MSHDVD) method, and this excluded the existence of fault lines across this region. Amplitude spectrum was used to estimate the potential field source at a depth of about 4.8 km. The ideal body theory capable of handling sparse data contaminated with noise was applied along a 50.2 km WWS-EEN profile to determine a density contrast of 0.266 g/cm3. Using these results as constraints, 2.5 D modelling carried out along this profile presented two major blocks with density contrast of 0.266 g/cm3. The first block is probably an intrusive igneous body with a density of about 2.77 g/cm3 , having an average thickness of about 26 km with its top and base lying at depths of about 4.25 km and 30.25 km respectively. The second block is likely a pillar of igneous material, located at a depth of about 10.77 km with a density of about 2.77 g/cm3 whose base goes deep down beyond the crust-mantle boundary. These results support previous findings that there are similarities between the Douala sedimentary sub-basin and the coastal sedimentary basin of Mauritania-Senegal and thus foster the suggestions of a more extensive movement that would have affected the whole of the West African coast.
Cite this paper: Ndikum, E. , Tabod, C. , Koumetio, F. , Tatchum, N. , Victor, K. (2017) Evidence of Some Major Structures Underlying the Douala Sedimentary Sub-Basin: West African Coastal Basin. Journal of Geoscience and Environment Protection, 5, 161-172. doi: 10.4236/gep.2017.57013.
References

[1]   Brownfield, M.E. and Charpentier, R.R. (2006) Geology and Total Petroleum Systems of the West-Central Coastal Province (7203), West Africa. U.S. Geological Survey Bulletin 2207-B.
https://pubs.usgs.gov/bul/2207/B/pdf/b2207b_508.pdf

[2]   Tokam, K.A.P., Tabod, C.T., Nyblade, A.A., Julia, J., Wiens, D.A. and Pasyanos, M. (2010) Structure of the Crust beneath Cameroon, West Africa, from the Join Inversion of Rayleigh Wave Group Velocities and Receiver Functions. Geophysical Journal International, 183, 1061-1076.
https://doi.org/10.1111/j.1365-246X.2010.04776.x

[3]   Ndikum, E.N., Tabod, C.T. and Tokam, A.-P.K. (2014) Frequency Time Analysis (FTAN) and Moment Tensor Inversion Solutions from Short Period Surface Waves in Cameroon (Central Africa). Open Journal of Geology, 4, 33-43.
https://doi.org/10.4236/ojg.2014.42004

[4]   Ndikum, E.N., Tabod, C.T., Tokam, A.-P.K. and Essimbi, B.Z. (2014) Fault-Plane Solution of the Earthquake of 19 March 2005 in Monatele (Cameroon). Open Journal of Geology, 4, 289-293.
https://doi.org/10.4236/ojg.2014.46021

[5]   Njike, P.R.N. (1984) Contribution à l’étude Géologique Stratigraphique et Structurale de la Bordure du Basin Atlantique du Cameroun. Thèse de Doctorat 3e Cycle, Université de Yaoundé I, Faculté des Sciences, Cameroun.

[6]   Legeley-Padovani, A., Poudjom-Djomani, Y.H., Boukeke, D-B., Nnange, J.M., Ateba-Bekoa, Albouy, Y. and Fairhead, J.D. (1996) Levés Gravimétriques de Reconnaissance du Cameroun. ORSTOM, Paris.

[7]   Koumetio, F., Tabod, C.T. and Manguelle-Dicoum, E. (2009) Evidence for Upper Mantle Intrusion in the West African Coastal Sedimentary Basins from Gravity Data: The Case of the Southern Part of the Douala Basin, Cameroon. Global Journal of Geological Sciences, 7, 181-187.

[8]   Ndikum, E.N., Tabod, C.T., Essimbi, B.Z., Koumetio, F. and Noutchogwe, C.T. (2014) Gravity Model for an Anomalous Body Located in the NW Protion of the Douala Sedimentary Sub-Basin, Cameroon (Central Africa). Open Journal of Geology, 4, 524-541.
https://doi.org/10.4236/ojg.2014.410039

[9]   Kenfack, P.L., Ngaha, P.R.N., Ekodeck, G.E. and Ngueutchoua, G. (2012) Mineralogic Characterization and Petroleum Potential of Clays (Shales) of the N’Kapa Formation (Paleocene-Eocene) in the Douala Sedimentary Sub-basin (South-West Cameroon). International Journal of Geosciences, 3, 696-709.
https://doi.org/10.4236/ijg.2012.34070

[10]   Kenfack, P.L., Njike, P.R.N., Ekodeck, G.E. and Ngueutchoua, G. (2012) Fossils Dinoflagellates from the Northern Border of the Douala Sedimentary Sub-Basin (South-West Cameroon): Age Assessment and Paleoecological Interpretations. Geosciences, 2, 117-124.

[11]   Reyre, D. (1966) Bassins Sédimentaires du Littoral Africain. Symposium: Littoral Atlantique (New Delhi). Association des services Géologique Africains.

[12]   Hoffman, P. (1971) Aulacogènes and Orthogeosynclines in the Lower Proterozoic of the Northwestern Canadian Shield. Geological Society of America, Abstracts With Programs, 3.

[13]   Nguene, F.R., Tamfu, S., Loule, J.P. and Ngassa, C. (1992) Paleoenvironnements of the Douala and Kribi/Campo Subbasins in Cameroon, West African. Géologie Africaine: Colloque de Géologie Africaine, Libreville, Recueil des Communications, 6-8 May 1991, 129-139.

[14]   Regnoult, J.M. (1986) Synthèse gélogique du Cameroun. D.M.G, Yaoundé, X p.118.

[15]   SNH/UD (2005) Stratigraphie séquentielle et Tectonique des dépots mésozoiques syn-rifts du Bassin de Kribi/Campo. Rapport non publié, X p. 134.

[16]   Ngon, G.F.N., Etame, J., Ntamak-Nida, M.J., Mbog, M.B., Mpondo, A.M.M., Martine, G., Yongue-Fouateu, R. and Bilong, P. (2012) Geological Study of Sedimentary Clayey Materials of the Bomkoul Area in the Douala Region (Douala Sub-Basin, Cameroon) for the Ceramic Industry. Comptes Rendus Geoscience, 344, 366-376.
https://doi.org/10.1016/j.crte.2012.05.004

[17]   Selley, R.C. (1997) African Basins (Sedimentary Basins of the World). Volume 3, Elsevier Science B.V., Amsterdam.

[18]   Pirttijarvi, M. (2009) FOURPOT, University of Oulu, Department of Physics, Geophysics.
https://wiki.oulu.fi/download/attachments/20678098/Fourpot_1.3b.
zip?version=1&modificationDate=1470047813000&api=v2

[19]   Zeng, H., Xu, D. and Tan, H. (2007) A Model Study for Estimating Optimum upward Continuation Height for Gravity Separation with Application to a Bouguer Gravity Anomaly over a Mineral Deposit, Jilin Province, Northeast China. Geophysics, 72, 145-150.
https://doi.org/10.1190/1.2719497

[20]   Koumetio, F., Njomo, D., Tabod, C.T., Noutchogwe T.C. and Manguelle-Dicoum, E. (2012) Structural Interpretation of Gravity Anomalies from the Kribi-Edea Zone, South Cameroon: A Case Study. Journal of Geophysics and Engineering, 9, 664-673.
https://doi.org/10.1088/1742-2132/9/6/664

[21]   Parker, R.L. (1974) Best Bounds on Density and Depth from Gravity Data. Geophysics, 39, 644-649.
https://doi.org/10.1190/1.1440454

[22]   Parker, R.L. (1975) The Theory of Ideal Bodies for Gravity Interpretation. Geophysical Journal International, 42. 315-334.
https://doi.org/10.1111/j.1365-246X.1975.tb05864.x

[23]   Ander, M.E. and Huestis, S.P. (1987) Gravity Ideal Bodies. Geophysics, 52, 1265-1278.
https://doi.org/10.1190/1.1442387

[24]   Huestis, S.P. and Ander, M.E. (1983) IDB2—A FORTRAN Program for Computing Extremal Bounds in Gravity Data Interpretation. Geophysics, 48, 999-1010.
https://doi.org/10.1190/1.1441525

[25]   Cooper, G.R.J. (1998) GRAV2DC for Windows User’s Manual (version 2.05). University of the Witwatersrand, Geophysics Department, Johannesburg.

[26]   Roussel, J. and Lecorce, J.P. (1983) Regional Gravity Trends Associated with the Mauritanides Orogen (West Africa). Reidel Publishing Company, 116, 63-71.
https://doi.org/10.1007/978-94-009-7239-1_8

 
 
Top