Porosity Estimation and Geometric Characterization of Fractured and Karstified Carbonate Rocks Using GPR Data in the Salitre Formation, Brazil

Conti, I.; Castro, David Lopes de; Bezerra, Francisco H.R.; Cazarin, Caroline Léssio

doi:10.1007/s00024-018-2032-5

Cited by 13 publications

(9 citation statements)

References 23 publications

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“…The detection of fractures of various scale, from millimetric up to a decametric scale, represents another topic widely researched with GPR, where its geometrical reconstruction capability has made it a valuable tool for characterizing mining sites and rock masses, improving quarries and extraction processes, and determining unstable rock slopes [241][242][243][244]. Another successful application of GPR within this domain is the determination of fracture openings and fillings [245][246][247], crucial for several environmental and engineering applications, including the accessibility of geothermal energy. Fractures and faults represent the primary conduits for the transport of heated fluids needed for geothermal energy, and therefore a detailed knowledge on the fracture network is essential to increase the efficiency of the energy-transition process [248][249][250][251][252].…”

Section: Gpr Applications In Geologymentioning

confidence: 99%

From Its Core to the Niche: Insights from GPR Applications

2022

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Thanks to its non-destructive, high-resolution imaging possibilities and its sensitivity to both conductive and dielectric subsurface structures, Ground-Penetrating Radar (GPR) has become a widely recognized near-surface geophysical tool, routinely adopted in a wide variety of disciplines. Since its first development almost 100 years ago, the domain in which the methodology has been successfully deployed has significantly expanded from ice sounding and environmental studies to precision agriculture and infrastructure monitoring. While such expansion has been clearly supported by the evolution of technology and electronics, the operating principles have always secured GPR a predominant position among alternative inspection approaches. The aim of this contribution is to provide a large-scale survey of the current areas where GPR has emerged as a valuable prospection methodology, highlighting the reasons for such prominence and, at the same time, to suggest where and how it could be enhanced even more.

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Section: Gpr Applications In Geologymentioning

confidence: 99%

From Its Core to the Niche: Insights from GPR Applications

2022

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“…The higher the contrast at the interface of these discontinuities, the higher the amplitudes are, and vice versa. A detailed description of this method and its application of cave studies is presented elsewhere [47][48][49][50][51][52]. Radar stratigraphy was used for the interpretation of reflectors.…”

Section: Ground Penetrating Radar (Gpr)mentioning

confidence: 99%

The Potential Use of Geophysical Methods to Identify Cavities, Sinkholes and Pathways for Water Infiltration

Hussain

Uagoda

Borges

et al. 2020

Water

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The use of geophysical characterization of karst systems can provide an economical and non-invasive alternative for extracting information about cavities, sinkholes, pathways for water infiltration as well as the degree of karstification of underlying carbonate rocks. In the present study, three geophysical techniques, namely, Ground Penetrating Radar (GPR), Electrical Resistivity Tomography (ERT) and Very Low Frequency Electromagnetic (VLFEM) methods were applied at three different locations in relation to fluvial karst, which is listed as an environmentally sensitive area in Rio Vermelho, Mambaí, Goiás, Brazil. In the data acquisition phase, the GPR, direct-current (DC) resistivity and VLFEM profiles were obtained at the three locations in the area. Data were analyzed using commonly adopted processing workflows. The GPR results showed a well-defined lithology of the site based on the amplitude of the signal and radar typologies. On the other hand, the inverted resistivity cross-sections showed a three-layered stratigraphy, pathways of water infiltration and the weathered structures in carbonate (Bambui group). The interpretation of VLFEM as contours of current density resulted from Fraser and Karous–Hjelt filters, indicated the presence of conductive structures (high apparent current density) that might be linked to the weathered carbonate and other conductive and resistive anomalies associated with the water-filled and dry cavities (cave), respectively. The results encourage the integrated application of geophysical techniques such as the reconnaissance for further detailed characterization of the karst areas.

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“…When combined, detailed structural data and isotope geochemistry can help evaluate how hydrothermal fluids expelled from deeper zones may cause carbonate dissolution and hypogenic karstification. These features are observed in seismic‐scale cave systems reaching hundreds of kilometres in length that are observed in carbonates, also including oil fields (Balsamo et al, 2020; Cazarin et al, 2019, 2021; Conti et al, 2018; Eliassen & Talbot, 2005; Ennes‐Silva et al, 2016; Klimchouk et al, 2016).…”

Section: Introductionmentioning

confidence: 96%

Fault zone fluid pathways in the carbonate Irecê basin, NE Brazil

et al. 2022

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We applied field structural data and isotope geochemical (δ13C, δ18O and 87Sr/86Sr) analyses to understand the relationship among calcite veins, fault damage zones and carbonate host rocks in a thrust fault damage zone in the Achado quarry, Irecê Basin in the São Francisco Craton, NE Brazil. Our results reveal three hydrological packages with different rheological behaviours in a stratified carbonate succession. The upper package includes the Achado fault damage zone that is characterised by interlayered dolomitised grainstones and mudstones. These rocks display high positive δ13C values (10‰–13‰), negative δ18O values (mean −6.34‰) and radiogenic (87Sr/86Sr) isotope values (0.70885–0.71519). A second package is marked by a cataclastic brittle shear zone lateral parallel to dolograinstones bedding. These rocks show low to positive δ13C values (−3.41‰ to +8.85‰), more positive δ18O values (mean −3.73‰) and radiogenic (87Sr/86Sr) isotope values (0.71039–0.71373). The lower package is characterised by well‐preserved pristine limestone succession that shows δ13C values ranging between −0.46‰ and +3.17‰, mean δ18O = −5.41‰ and less radiogenic 87Sr/86Sr values (0.70762–0.70818). In contrast to the upper and intermediate packages, rocks from the lower one exhibit very low permeability and behaved as a seal for fluid migration. Fluid flow occurred several times during basin evolution, for example along syn‐rift fault damage zones, bedding‐parallel carbonate breccia, thrust faults, cataclastic shear zones, synorogenic conjugate shear fractures or joints and opening mode I fracture‐fill calcite veins. These fractures allowed pervasive fluid flow in the porous intermediate cataclastic shear zone where fluids flowed and formed veins, as diffuse fluid flow in randomly oriented fracture swarms, or channelised fluid flow in aligned fracture corridors. They record significant centimetre‐scale to km‐scale hydrological behaviour within carbonate layers. Most carbonates that are associated with veins, fault damage zones and hydraulic breccia were formed by fluids of the same origin with low δ13C (−6.0 to −2.0‰) and δ18O (−6.0 to −8.5‰) values, and more radiogenic 87Sr/86Sr values compared to the carbonate host rocks.

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Porosity Estimation and Geometric Characterization of Fractured and Karstified Carbonate Rocks Using GPR Data in the Salitre Formation, Brazil

Cited by 13 publications

References 23 publications

From Its Core to the Niche: Insights from GPR Applications

From Its Core to the Niche: Insights from GPR Applications

The Potential Use of Geophysical Methods to Identify Cavities, Sinkholes and Pathways for Water Infiltration

Fault zone fluid pathways in the carbonate Irecê basin, NE Brazil

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