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Groundwater exploration is increasing in demand, including use in the domestic, industrial and agricultural sectors. The extracted groundwater is an alternative water supply in these sectors. However, there has also been unsuccessful groundwater exploration due to limited subsurface information. Therefore, geophysical methods were applied to obtain subsurface information to determine and classify the subsurface materials using selected geophysical properties. This research aims to evaluate the delineation of potential groundwater zones using 2D electrical resistivity imaging in Universiti Sains Malaysia, Penang Island, Malaysia. Nine resistivity survey lines are conducted within the research area in USM. The geology of the research area is underlain by igneous rock with a centrally located granitic range running in a north-south direction with low-lying elevations ranging from 5 meters to 20 meters above sea level. The electrical resistivity method measures the resistivity distribution by injecting a small current into the ground through two current and potential electrodes, respectively. The voltage reading is measured between two active potential electrodes alternatively. The instrument used for this research is an automated multi-electrode resistivity meter, ABEM Terrameter SAS 4000 system. Apparent resistivity values undergo an inversion process using RES2DINV software to produce the electrical resistivity topography model. The results show the resistivity values ranging from 1Ùm to 20000Ùm. The subsurface materials are classified into four subsurface materials according to the resistivity values ranges: water-saturated zones, topsoil, weathered bedrock, and fresh bedrock. Several anomalies are interpreted as potential water-saturated zones within the project area and suggested as proposed drilling locations for the groundwater drilling program. The extracted groundwater can act as an alternative source for water supplies in Universiti Sains Malaysia. [ABSTRACT FROM AUTHOR]

In central Victoria, inherited zircon in Devonian igneous rocks and detrital zircon in metasedimentary country rocks and an amphibolite-facies xenolith show that Mesoproterozoic parts of the underlying Selwyn Block cannot be the source for all the silicic magmas. Zircon inheritance in S-type samples reveals significant thermal events at 525–425 Ma and 1200–1100 Ma. Both S- and I-type samples have prominent zircon age peaks at 420–410 Ma, which record high-grade metamorphism of the deep crust during the terminal phases of the Benambran and Bindian orogenies. All I-type rocks have 650–500 Ma peaks, suggesting derivation from an arc-related metavolcanic source in the upper Selwyn Block. Protoliths of the greenschist-facies Ordovician metasediments and the amphibolite-facies Cambrian metasedimentary xenolith were deposited in distal backarc settings. Most inherited zircon cores are metamorphic, and the strongest zircon inheritance occurs in hornblende-bearing I-type rocks, highlighting their largely crustal origin. Zircon populations at ca 1400 Ma, thought to signal sediment derivation from East Antarctica and Rodinia-Nuna, are mostly absent in I-type samples and some S-types. The ca 1400 Ma signal probably applies to the upper, metasedimentary Selwyn Block, so Devonian S-type magmas were sourced mainly in the deeper sections. Zircon inheritance in the Devonian igneous rocks was not influenced by the exposed metasedimentary country rocks. Two samples from one of the smaller plutons have contrasting patterns of zircon inheritance, suggesting relatively small-scale source heterogeneity. Many rounded and corroded cores in zircon crystals yield the same ages as the crystallisation dates for the rocks, and thus are antecrysts. Higher whole-rock Zr contents generally correlate with higher proportions of inherited zircon, and differentiation does not affect this relationship. The degree of partial melting of a magma source and the efficiency of crystal entrainment are critical in governing zircon inheritance. Mesoproterozoic sections of the Selwyn Block cannot be the sources for all the Devonian silicic magmas in central Victoria. I-type rocks have 650–500 Ma zircon age peaks, suggesting derivation from arc-related metavolcanic rocks in the upper Selwyn Block. Hornblende-bearing I-type rocks have the strongest zircon inheritance patterns, indicating the largely crustal origins of I-type magmas. Exposed metasedimentary country rocks were not involved in magma genesis. [ABSTRACT FROM AUTHOR]

Dune sands in southeastern Mexico are compositionally and geomorphologically controlled by fluvial input, eastward longshore currents, and the intense winds traveling through the Isthmus of Tehuantepec. Tehuano winds are mainly responsible for the remarkable dune sand entrapment circumscribed to the exposure of volcano‐sedimentary outcrops. Compositionally, the dunes are potentially influenced by granite denudation, volcano‐sedimentary rocks, metamorphic units, and Quaternary sediments besides alluvium. Mono‐ to polycrystalline subangular to angular quartz, K‐feldspar, and schists suggest that granitic‐metamorphic rocks control the river and dune sands composition. Subordinate fractions of mica, Fe–Ti oxide minerals, and reduced amphibole (actinolite) indicate metamorphic‐volcano sedimentary‐granite as the potential parent rock of sand sources. The dune sands compositional framework shows slight flat‐type rare earth elements (REE) trends with a low light rare earth elements (LREE)/heavy rare earth elements (HREE) ratio (e.g., 6.13 ± 6.00), suggesting a significant control of granite rocks. Geochemical signals, CIA and CIW chemical indices support moderate weathering. The petrographic and geochemical analyses indicate little dune sand recycling by aeolian transport despite strong wind systems along the SE coast of Mexico. This provenance study evidences the exhumation of granite, metamorphic, and volcano‐sedimentary materials in the Oaxaca dune sands, confined by the regional geomorphology. [ABSTRACT FROM AUTHOR]

Soil erosion leads to soil loss and affects the hydraulic and mechanical properties of soils, and as a result, the soil fertility, eco-environmental quality, and reliability of engineering facilities will decline. Thus, it is very significant to study the mechanisms of subsurface erosion of granitic under different natural environmental conditions. However, limited studies focus on the effects of combined erosion angles and flow discharges on the subsurface erosion amount. This study self-made a subsurface erosion simulator and designed a series of combinational conditions of different soil column angles (0°, 30°, 60°) and different flow discharges (25 l/h, 50 l/h, 100 l/h) to simulate the subsurface erosion phenomenon and processes of moisture migration within granitic collected from a collapsing erosion area in southern China. Results show that the subsurface erosion development in the soil column is a complex and progressive process with obvious preferential flow, which indicates the transportability of soil particles, and the processes of soil subsurface erosion change markedly along with the change of soil column angle and flow discharge. Moreover, the growth rates of wetting front and subsurface erosion amount will speed up along with the increase of soil column angle of flow discharge. The relations between the advance rate of wetting front and time since the beginning of the test demonstrate bilinear. The erosion amount has obvious fluctuation during the process of subsurface erosion in granitic due to fine particles erosion, reposition, pore clogging, and flushing. [ABSTRACT FROM AUTHOR]

The strength characteristics of a rock is a criterion for its ability to be drilled and fractured. The uniaxial compressive strength (UCS) is the most commonly used strength index in construction industry and in rock engineering projects. Therefore, a comprehensive knowledge on the factors that could influence the value of the compressive strength is essential in any rock engineering project. This paper explores the effects of mineralogical composition on the UCS value of granitic rocks to evaluate its drillability. Samples of granitic rocks were collected from the Interstate Raw Water Transfer Tunnel project. The rock samples were characterized with quantitative Rietveld XRD method to quantify the relative mineral phase compositions in the rock samples. The relationships between mineralogical properties and UCS were investigated by simple regression analysis. The strength of the rock samples increases with higher composition of quartz and decreases with increase in the composition of feldspar and kaolinite. The positive effects of quartz on the strength of the granitic rock is more significant than the negative influence of feldspar and clay content. The drilling rate varies inversely with the UCS. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to provide crystal size distribution (CSD) using photogrammetric and image analysis techniques. A new algorithm is proposed to detect CSDs and a comparison is carried out with conventional watershed segmentation algorithm. Design/methodology/approach – Polished granite plates were prepared to designate the metrics of CSD measurements. There are many important metrics for measurements on CSD. Some of them are orientation, size, position, area, aspect ratio, convexity, circularity, perimeter, convex hull, bounding box, eccentricity, shape, max-min length of CSD's fitted and corrected ellipse, and population density in a per unit area. Prior to image processing stage, camera calibration was performed to remove the image distortion errors. Image processing techniques were applied to corrected images for detecting the CSD parameters. Findings – The proposed algorithm showed the improved preservation of size and shape characteristics of the crystal material when compared to the watershed segmentation. According to the experimental results, proposed algorithm revealed promising results in identifying CSDs more easily and efficiently. Originality/value – This paper describes CSD of granitic rocks by using automated grain boundary detection methods in polished plate images. Some metrics of CSDs were detected by employing a new procedure. A computer-based image analysis technique was developed to measure the CSDs on the granitic rock plates. A validation is done by superimposing digitally detected CSD metrics to original samples. [ABSTRACT FROM AUTHOR]