Characterization of the sedimentary fabrics in ornamental rocks by using GPR

Abstract

In this study, the use of ground-penetrating radar for characterising ornamental sedimentary rocks was tested. Specifically, the ability of this non-invasive geophysical prospecting method to identify fabrics and textures in rocks was investigated. Blocks mined from quarries were analysed, and ornamental rocks with the same lithologies as other widely utilised ornamental rocks with a variety of sedimentary fabrics and textures were selected. Rocks with clastic brechoid, cross-laminated sparitic, massive or layered micritic, and laminar bindstone textures were analysed. Antennas that provided the maximum detail and a sufficient depth of penetration were used. The low electrical conductivity of carbonates permitted the use of high-frequency antennas (800 MHz and 1.6 GHz), which were useful in studying the entire thickness of a boulder (up to 2 m).The cross-laminations in the oolitic limestones, the laminar bindstones of travertines, the differentiation between massive and brecciated fabrics, and the massive and slaty fabrics of the micritic limestones were examined using these two frequencies. In micritic textures without discontinuities (neither sedimentary nor diagenetic), the radargrams could detect facies with few reflections (Crema Marfil). In addition to analysing fabrics and textures, the ground-penetrating radar measurements could identify anisotropy in these rocks, which makes ground-penetrating radar an effective tool for evaluating the mechanical state of a boulder prior to its cutting. stratifications in dunes (Gómez-Ortiz et al. used GPR to detect fractures in carbonate quarries in Greece, Turkey, and Spain, respectively.However, few researchers have attempted to determine the lithology of a rock using GPR. Even fewer researchers have attempted to use GPR to characterise sedimentary textures. Sigurdsson and Overgaard (1998) studied limestone quarries to characterise textural variations between a bryozoan limestone and a coral limestone.In this study, we assess GPR as a non-invasive prospecting method for analysing carbonate rocks and identifying the presence of characteristic fabrics and sedimentary textures. Because of the importance of rocks as construction materials, this study focuses on the lithologies that are most common in ornamental rocks.

A Set of Ground Penetrating Radar Measures from Quarries

“…The AI-COSTSQO project is focused on, among others, the detection and characterization of discontinuities and fractures of the rock mass, affecting ornamental stone production and, consequently, the generation of waste. Previous work in the scientific literature related to fracture detection based on Ground Penetrating Radar (GPR) measurement can be found in [1][2][3][4][5][6][7][8][9][10][11]. The fracture characterization allowed the development and use of optimization algorithms that can reduce the generation of waste for environmental protection, increase economic revenue, and increase the recovery ratio of the quarries.…”

2d Electrical Resistivity Tomography for the Assessment of Minerals’ Occurrences in Ugoneki, Edo State, South-South, Nigeria

“…Alile et al (2016) carried out experimental approach of twodimensional (2D) geoelectrical resistivity imaging in which the resistivity is allowed to vary both laterally along and vertically beneath the survey line, series of 2D apparent resistivity data were generated and the survey revealed lateritic soil, sand, sandstone, shale, limestone, clay, dolomite with resistivity values ranging between 259 Wm to 2159 Wm. Olaseni and Airen (2021) also did research using 3-D ERT to investigate the type of minerals' deposit that can be found in Ugonoba village and the research revealed that at the depth range between 25 m and 33.7 m, the following were found: sand-clay, lateritic sand, sandstone and limestone with high resistivity values ranging from 6001 Ωm to 14376 Ω m. Depending on the chosen geophysical method, operating any method with GPR can achieve high resolution (a few cm) to a depth of a few metres, as attenuation of the electromagnetic waves is comparably small in highly resistive hard rock environments as claimed by Rey et al (2017) and Elkarmoty et al (2017). Here, we consider another potentially useful geophysical exploration technique, electrical resistivity tomography (ERT).…”

Applying Electrical Resistivity Tomography in Ornamental Stone Mining: Challenges and Solutions

“…This includes the use of non-invasive geophysical imaging techniques [5], which have the potential to map subsurface property distributions that are linked to variations in density, porosity, moisture or mineralogy [6]. To-date, the most commonly applied geophysical approach in hard rock exploration is ground penetrating radar (GPR), which employs electromagnetic waves propagating through the rock that are reflected at discontinuities in the electromagnetic properties of the rock, e.g., at fractures or joints [5,[7][8][9][10][11]. Depending on the chosen operating frequency, GPR can achieve high resolution (a few cm) to a depth of a few metres, as attenuation of the electromagnetic waves is comparably small in highly resistive hard rock environments.…”