Evaluation of Fractured Shale Formations as Aquifers: A Case Study of the Albian–Cenomanian Asu River Group, Southern Benue Trough, Nigeria.

Groundwater is stored within subsurface pores and fractures. Weathering and diagenesis play critical roles in either increasing or reducing rock porosity. In this context, argillaceous rocks (typically regarded as impermeable) can develop fracture porosity, which enhances permeability and allows substantial water storage through interconnected matrix pathways. Alex Ekwueme University Ndufu-Alike and Gregory University Uturu are expanding institutions facing challenges in securing adequate groundwater for domestic and other uses. The study began with preliminary geophysical investigations using electrical resistivity methods across various locations within both campuses. Based on the findings, five drilling points were recommended: three at Ndufu-Alike and two at Uturu. Drilling results indicated that boreholes equipped with small motorized pumps were feasible at Ndufu-Alike, whereas higher-capacity pumps could be utilized at Gregory University if boreholes were sited at Marist Brothers Uturu, approximately one kilometer east of the campus. Very low resistivity values obtained from the survey confirmed that the lithology is predominantly shale with moderate to high plasticity. Pumping tests were conducted following the Cooper–Jacob (1946) method. Transmissivity (T) at Ndufu-Alike ranged from 18.23 m²/day to 37.44 m²/day, while at Uturu it ranged from 22.85 m²/day to 23.04 m²/day. Storativity (S) values ranged between 0.22 and 0.32, indicating an intermediate class associated with confined aquifers. The researchers observed that at Uturu, sandy shales occur within the borehole depth range, resulting in uniform transmissivity. At Ndufu-Alike, however, fractured shales appear sandwiched between two impermeable layers, creating a confined condition. The pumping tests were closely monitored to establish sustainable pumping rates. The study demonstrates that fractured shale aquifers hold promise for domestic water supply and that shales can be considered viable groundwater sources when developed following careful, site specific geophysical investigations.

Groundwater, fractured shale, aquifer, weathering

1. Amah,J.I; Amoke, A.I.; Onuigbo C; and Amah, E. (2025). Assessing the Potentiality of Fractured Shale Deposits as an Aquifer in the Asu-River Group, Southeast Nigeria, Advanced Research Journal, v 6 No. 1, p. 6-16. DOI: 10.71350/3062192522. [Google Scholar] [Crossref]

2. Benkhelil, J; Guirand, M; Ponsard, J.F and Saugy, L (1989). The Bornu-Benue Trough, the Niger Delta and its offshore: Tectono-Sedimentary reconstruction during the Cretaceous and Tertiary From geophysical data and geology. In: C.A Kogbe (ed): Geology of Nigeria. 2nd ed. Rockview, Jos. [Google Scholar] [Crossref]

3. Burke, K; Dessauvegie, T.F.J and Whiteman, A.J (1971). Opening of the Gulf of Guinea and geological History of then Benue depression and Niger Delta. Journal of Natural and physical sci 233 (38), 51-55. [Google Scholar] [Crossref]

4. Ezeh,H.N and Anike, L.O (2009). The preliminary Assessment of the pollution status of streams [Google Scholar] [Crossref]

5. And artificial lakes created by mining district of Enyigba, Southeastern Nigeria and their Consequences. Journal of Environmental Sciences. V. 8(1). [Google Scholar] [Crossref]

6. Murat, R.C (1972). Stratigraphy and paleogeography of the cretaceous and Lower Tertiary in Southern Nigeria, in T.F.J Dessauvegie and A.J Whiteman (eds): Proceedings of the conference on African geology held at Ibadan, Nigeria. Pp. 251-266 [Google Scholar] [Crossref]

7. Nwachukwu, S.O (1972). The tectonic evolution of the southern potion of the Benue Trough, Nigeria. Geological magazine, vol. 109: 411-419 [Google Scholar] [Crossref]

8. Ofoegbu, C.O (1985). A review of the geology of the Benue Trough, Nigeria. Jour of African Earth Sci 3, 283-291 [Google Scholar] [Crossref]

9. Ofoegbu, C.O and Amajor, L.C (1987). A geochemical comparism of the pyroclastic rocks from AbakalikAndEzillo, southern Benue Trough. Journal of mining and Geology, vol 23(1-2): 45-51. [Google Scholar] [Crossref]

10. Okogbue, C.O and Aghamelu, O.P (2010a). comparism of the geotechnical properties of crushed shale From southeastern Nigeria. Bulletin of Engineering Geology and Environment, vol. 69(4): 587-597. [Google Scholar] [Crossref]

11. Reyment, R.A (1965). Aspects of geology of Nigeria. Ibadan University press, 145pp. [Google Scholar] [Crossref]

12. SEG.org (2021). Electric resistivity methods. Retrieved from https://wiki.seg.org/wiki/5tg [Google Scholar] [Crossref]

13. Tijani, M.N; Loehnert, E.P and Uma, K.O (1989). Origin of saline groundwaters in ogoja area, Lower benue Trough Nigeria. Journal of African Earth Science, 23(2), 237-252. [Google Scholar] [Crossref]

14. Telford WM, Geldart LP, Sheriff RE (1990) Applied geophysics. Cambridge Univ. Press 860pWright, J.B (1968). South Atlantic continental Drift and Benue Trough. Tectonophysics, 6, 301-310. [Google Scholar] [Crossref]

• Site Selection to Community Handover: Effective Recharge Shaft Development for Rural Water Security in Shetphal, Maharashtra
• Flood Hazard and Prevention Strategies Towards Sustainable Economic Development and Proper Community Planning in Yenagoa, Bayelsa State, Nigeria
• Lineaments Characterization of Shira Complex, Bauchi State Nigeria
• High-Grade Ore in a Decarbonising World: Simandou, Green Steel and the Strategic Repositioning of India’s Iron Ore Sector
• Mineralogical and Physical Characterization of Some Clayey Soils from Parts of Southwestern Nigeria for Ceramic Application.