INVESTIGATION OF SUBSURFACE GEOLOGY IN THE TANO BASIN OF GHANA USING SEISMIC REFRACTION METHOD

Year 2018, Volume: 7 Issue: 3, 1220 - 1224, 28.12.2018

Hafiz Mohammed Nazıfı

https://doi.org/10.28948/ngumuh.502839

Abstract

2D seismic
refraction data, from seven traverse lines, were used to investigate subsurface
geology in the Appollonian Formation of the onshore Tano Basin of Ghana. Tano
Basin is one of the four basins of Ghana and the most important one when it
comes to oil potential of Ghana. The survey covered approximately a total area
of about 113,000 m². With the exception of one traverse line which had
the length of 60 m, each of the remaining traverse lines had a length of 120m.
The results from the data analysis indicated that, the surveyed area is
underlain by three geological units although results from two traverse lines
revealed two geological units. The P-wave velocity of the first layer ranges
between 335.00 - 468.00 m/s and the average velocity of 391.57 m/s. It has a
thickness range of 5.0 – 27.5 m with an average thickness of 16.25 m. The layer
is interpreted as a weathered layer and consist of soil and dry loose sand
which might be formed as beach deposit. The second layer has P-wave velocity
range of 590.00 – 1133.00 m/s and the average velocity of 881.71 m/s. The layer
thickness ranges between 14.5 – 31.0 m and the average of 25.80 m. The layer
may consist of unconsolidated water- saturated sand and clay. The last layer detected
by this survey has P- wave velocity range of 1068.00 – 2724.00 m/s and the
average of 2074.20 m/s. The layer is interpreted as the bedrock underlining the
surveyed area. The layer may consist of gravel, sandstone and limestone.

Keywords

Ghana, Tano Basin, Appollonian Formation, Seismic Refraction, Subsurface Geology.

References

• [1] AKPAN, A.E., EKWOK, S.E., EBONG, E.D., GEORGE, A.M., OKWUEZE, E.E., “Coupled geophysical characterization of shallow fluvio-clastic sediments in Agwagune, south-eastern Nigeria”, Journal of African Earth Sciences 143, 67-78, 2018.
• [2] POLYMENAKOS, L., TWEETON, D., “Non-invasive characterization of a burial tumulus with use of seismic P-wave velocity and attenuation tomography” Journal of Archaeological Science: Reports, 13 36–48, 2017.
• [3] PEGAH, E., LIU, H., “Application of near-surface seismic refraction tomography and multichannel analysis of surface waves for geotechnical site characterizations: A case study”, Engineering Geology, 208, 100–113, 2016.
• [4] AYOLABI, E.A., ADEOTI, L., OSHINLAJA, N.A., ADEOSUN, I.O., IDOWU. O. I., “Seismic refraction and resistivity studies of part of Igbogbo Township, south west Nigeria”,Journal Sci. Res. Dev., 11, 42 – 61. 2008/2009.
• [5] TELFORD W.M., GELDART L. P, SHERIFF R. E., Applied Geophysics. Cambridge University Press; 1990.
• [6] KEAREY, P., BROOKS, M. & HILL, I., An Introduction to Geophysical Exploration (3rd ed.), Blackwell Science Ltd, Iowa 2002.
• [7] REYNOLDS, J.M., An Introduction to Applied and Environmental Geophysics, John Wiley & Sons Ltd, West Sussex, England, 1997.
• [8] SHARMA, P. V., Environmental and Engineering Geophysics, Cambridge University Press. UK. 1997
• [9] GADALLAH M.R, FISHER R., Exploration Geophysics, Springer, Berlin, Heidelberg, 2009.
• [10] MILSOM J., Field Geophysics, John Wiley and Sons, England, 2007.
• [11] KITSON AE., Provisional Geological Map of the Gold Coast and Western Togoland with Brief Descriptive Notes, Benham & Company UK, 1928.
• [12] ATTA-PETERS D, SALAMİ M.B., “ Late Cretaceous to early tertiary pollen grains from offshore Tano basin, Southwestern Ghana”, Revista Espanola de micropaleontologia,36(3), 451-65 2004.
• [13] PERSİTS F, AHLBRANDT T, TUTTLE T, CHARPENTİER R, BROWNFİELD M, TAKAHASHİ K. Geology, Oil and Gas Fields and Geologic Provinces of Africa, Ver. 2.0. USGS Open File Report. 2002.