Investigating the Structure of a Coastal Karstic Aquifer through the Hydrogeological Characterization of Springs Using Geophysical Methods and Field Investigation, Gökova Bay, SW Turkey

Abstract

The electrical resistivity tomography method has been widely used in geophysics for many purposes such as determining geological structures, water movement, saltwater intrusion, and tectonic regime modeling. Karstic springs are important for water basin management since the karst systems are highly complex and vulnerable to exploitation and contamination. An accurate geophysical model of the subsurface is needed to reveal the spring structure. In this study, several karst springs in the Gökova Bay (SW, Turkey) were investigated to create a 3D subsurface model of the nearby karstic cavities utilizing electrical resistivity measurements. For this approach, 2D resistivity profiles were acquired and interpreted. Stratigraphically, colluvium, conglomerate, and dolomitic-limestone units were located in the field. The resistivity values of these formations were determined considering both the literature and field survey. Then, 2D profiles were interpolated to create a 3D resistivity model of the study area. Medium-large sized cavities were identified as well as their locations relative to the springs. The measured resistivities were also correlated with the corresponding geological units. The results were then used to construct a 3D model that aids to reveal the cavity geometry in the subsurface. Additionally, several faults are detected and their effect on the cavities is interpreted.

Combined analysis of resistivity and induced polarization tomography for 3D modelling and preliminary volume estimation of the possible gold mineralization zones in the Simi locality, Adamawa, Cameroon

“…As the mining sites are located on the flanks and at the foot of the hills, the planning of the geophysical survey carried out in this study is based on the assumption of disseminated mineralization in some of these hills. Although several geophysical methods exist, in this study, the sensitivity of the method (for the detection and location of horizontal and vertical structures or bodies), the type of mineralization sought (metallic sulphides), the depth of the targets (near surface), the geological environment (site constituted by ancient sedimentary deposits) and geomorphological environment (topographic variation), the deposit mode (diffuse or disseminated) and the area of investigation are a set of factors that justify, as in most studies (Gouet et al., 2013; Gündoğdu et al., 2022; Liang et al., 2021; Sağır et al., 2020), the choice of the electrical method as the ideal approach for this study. The choice of using the direct current (DC) and induced polarization (IP) electrical methods over the self‐potential method is not only due to their good accuracy and depth of investigation but also to their affinity in the detection of a particular type of mineralization (clays, metal sulphides, graphite and certain metal oxides such as magnetite) (Chouteau, 2006; Claude et al., 2014; Gouet et al., 2013; Kayode et al., 2022; Lenhare & Moreira, 2020; Martin et al., 2020; Shirazi et al., 2022; Silva et al., 2022; Wang et al., 2022).…”

“…IP and ERT are commonly used in geological and mining prospecting to indicate the presence of metal sulphides, metal oxides, clays and other old buried mine sites in the ground (Bharti et al., 2016; Bharti et al., 2019; Claude et al., 2014; Das et al., 2017; Gündoğdu et al., 2022; Horo et al., 2020; Kayode et al., 2022; Moreira et al., 2019; Shirazi et al., 2022; Silva et al., 2022; Singh et al., 2019; Zaid et al., 2022). Other studies use these methods for the 3D modelling of geoelectric anomalies corresponding to the targets sought (Embeng et al., 2022; Kayode et al., 2022; Lenhare & Moreira, 2020; Martin et al., 2020; Moreira et al., 2019; Sağır et al., 2020; Ya‐wei et al., 2015). This modelling can be done either by 3D inversion of the tomography data using inversion software (Zondres3D, Res3DInv, UBC and others) or by 3D correlation of the interpretation results of the different inverted sections using specific software (Oasis montaj, GeoModeller, RockWorks, GeoScene3D and others).…”

Historic Underground Silver Mine Workings Detection Using 2D Electrical Resistivity Imaging (Durango, Mexico)

“…Electrical resistivity and IP imaging allow the spatial distribution of the low-frequency resistive and capacitive characteristics of subsurface earth materials such as mineral ores, weathered or fresh rock, unconsolidated sediments, and, respectively, uncontaminated and contaminated soils [7][8][9][10][11][12][13]. These methods are extensively utilized in mineral exploration campaigns, engineering and environmental investigations, hydrogeological studies, and archeological prospecting [7,[14][15][16][17][18][19][20][21][22]. Both methods have proven successful in the mineral exploration arena worldwide because of their cost-effective and rapid ability to image natural shallow subsurface geologic structures with mineralization potential [7,8], with a certain degree of resolution dependent on the electrode spacing [23].…”