Structural modelling of the deep carbonate aquifer of Jbel Hamra (Northeastern Morocco) using gravity data

In hydrogeological research, the knowledge of the geometry of aquifers is a crucial step to define the groundwater potential areas and assess their productivity. This paper focuses on enhancing our understanding of the deep structure of the Jbel Hamra carbonate aquifer in eastern Morocco by using gravity and borehole data. To analyze gravity anomalies, a thorough array of techniques was utilized, including regional and residual separation, upward continuation, horizontal gradient analysis, spectrum analysis, enhanced logistic filtering, and Euler deconvolution. This study aims to accurately delineate the geological structure of the study area, with a specific focus on identifying and characterizing faults and other pertinent features. The analysis of gravimetric lineaments has enabled the creation of a detailed structural map indicating that the study area's geological configuration is predominantly influenced by three fault systems: NW-SE, ENE-WSW, and NE-SW trends. These fault systems play a crucial role in dividing the bedrock into distinct horst and graben structures. The residual anomalies map shows highs and lows. Gravity highs indicate the uplift of Jurassic carbonate and Palaeozoic rocks, while gravity lows suggest that the carbonate platform is buried under considerable sedimentary cover (Miocene marls). The depth-gravity plot, based on borehole data analysis displayed linear link between the depth of the top of the Jurassic carbonate and the value of the residual gravity anomalies. This relationship is used to generate the first 3D model showing the undulation morphology of the carbonate aquifer of Jbel Hamra. It shows how this morphology governs the groundwater flow, which moves from high areas to low hydraulic head areas. Groundwater storage is notably aligned with depressions (gravity lows), while groundwater divides correspond