Journal of Earth Sciences and Geotechnical Engineering
Identification of a Schist-Micaschist Transition under a Lateralitic Cover of the Bafia Group, Centre Cameroon, using DC Electrical Resistivity Soundings
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Abstract
The shallow subsurface structure along a profile on the Bafia Group in Cameroon has been investigated using data from both DC electric method and pedologic logs. The combination of these approaches aims to resolve the non-uniqueness of solution inherent to inverse problems in geosciences. Results show that the bedrock is located at depth between 11 and 25 m along the line and is overlain from the surface by a thin organo-mineral lateritic cover, an aggregated sandy clay layer, and an altered schistose layer. However, the bedrock displays a change in electrical properties moving from the south (1400 Ům) to the north (2500 Ům) of the profile. This observation is correlated with the presence of mica minerals found in logs of pit 1, located in the south of the profile, and its absence in pit 2 in the north. The change in composition resulting to the variation in electrical propertities of the bedrock could be associated to the shallow effect of the Sanaga Faults, known as a major tectonic structure crossing the region. The sandy-clay layers with thicknesses range 1-5 m is believed to represent a potential thin aquifer, due to the resistivities range 15-100 Ům, common to some aquifers.
