A geomagnetic analysis for lineament detection and lithologic characterization impacting groundwater prospecting: a case study of Buffalo catchment, Eastern Cape, South Africa.

Abstract

A lithostratigraphy analysis commonly adopted for subsurface structures exploration in oil prospecting is deployed for groundwater prognosis, due to the need to address the prevailing water shortage. In this study, the lithology characterization was based on a clustered approach of geomagnetic analysis, geomorphometric analysis, and sequence stratigraphy correlation across the Buffalo catchment, Eastern Cape, South Africa. The result showed the existence of a spatial correlation between the tectonic stress field and the surficial lineaments. Similarly, a significant azimuthal correlation (WNW-ESE) was found between surficial lineaments (203 m–6249 m), subsurface lineaments, and the neotectonic structures. The depth-slicing analysis enables the estimation of the depth of the tectonic stress field, at 382 m, 577 m, 913 m, 1.49 km, and 10.7 km in the subsurface. The sequence stratigraphy correlation based on borehole lithology data enables the identification of the fault system at the contact zones, heterolithic bedding, and the characterization of the hydrostratigraphic domain of the catchment. The study shows that Buffalo hydrostratigraphic structures are dominated by fracture networks, whereby the shallow groundwater resources are possibly hosted by the dolerite-host rock contact zones in the north of the Buffalo catchment. Specific recommendations concerning groundwater management are made to water and environment stakeholders considering the vulnerability of the shallow groundwater system to pollution in the permeable contact zones of dolerite-host rock. The study also recommends the adaptation of surficial lineaments as a morpho-tectonic aid and a hydrostratigraphic analysis tool. The clustered approach demonstrated in this study has important prospects for groundwater exploration in environments with similar geology.