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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]

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]

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]

The sand, silt, shale and clay fractions soils derived from Maastrichtian sediments in the Afikpo Basin, southeastern Nigeria exhibit unusually high cation-exchange capacities. Smectite was identified by X-ray diffraction in all sample fractions and was selectively dissolved by treatment with 1HCl and 0.5 NaOH. Structural formulae, based on chemical analysis of the dissolved material, suggest that the smectite is intermediate in composition between a di- and a trioctahedral mineral and that the octahedral cation occupancy, together with the number of Mg and Fe atoms per unit cell, decreases with decrease in particle size of the soil fraction examined. The mean formula for the smectite in the clay separate is: [(M+= 0.40, Si = 3.33, Al = 0.67), (Al = 1.07, Fe2+= 0.09, Fe3+= 0.41, Mg = 0.82)] O10(OH)2. Similar analysis of smectite present in clay-size material separate from weathered granitic rock taken from the bases of the soilprofiles showed that it had close to the full trioctahedral inherited from the weathered granites.The clay mineralogy of the soils was affected by inherited smectite, probably of hydrothermal of deuteric origin. This mineral is unstable in the soil environment and, although its alteration products are fairly uniform in composition. Keywords: Dissolution, Granitic, Octahedral, Smectite, Soil

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]

The sand, silt, shale and clay fractions soils derived from Maastrichtian sediments in the Afikpo Basin, southeastern Nigeria exhibit unusually high cation-exchange capacities. Smectite was identified by X-ray diffraction in all sample fractions and was selectively dissolved by treatment with 1HCl and 0.5 NaOH. Structural formulae, based on chemical analysis of the dissolved material, suggest that the smectite is intermediate in composition between a di- and a trioctahedral mineral and that the octahedral cation occupancy, together with the number of Mg and Fe atoms per unit cell, decreases with decrease in particle size of the soil fraction examined. The mean formula for the smectite in the clay separate is: [(M+= 0.40, Si = 3.33, Al = 0.67), (Al = 1.07, Fe2+= 0.09, Fe3+= 0.41, Mg = 0.82)]O10(OH)2. Similar analysis of smectite present in clay-size material separate from weathered granitic rock taken from the bases of the soilprofiles showed that it had close to the full trioctahedral inherited from the weathered granites.The clay mineralogy of the soils was affected by inherited smectite, probably of hydrothermal of deuteric origin. This mineral is unstable in the soil environment and, although its alteration products are fairly uniform in composition. [ABSTRACT FROM AUTHOR]

The Abitibi greenstone belt, Canada, constitutes a segment of a broad volcanic arc that experienced three distinct periods of volcanic activity peaking at 2730–2725, 2718–2714 and 2705–2700 Ma. During all three volcanic episodes, which were generated by subduction-related processes, mantle plume-derived komatiitic volcanic rocks were also added to the composite Abitibi arc. Plume activity resulted in local regional extension, and restricted later volcanism within the belt. North–south shortening produced thrusts and folds, followed by SE-trending dextral strike-slip faults between 2700 and 2692 Ma, the principal belt-wide deformation. Subsequent E–W dextral strike-slip faulting, limited to the major faults, continued to 2690–2680 Ma (Destor–Porcupine fault) and even to 2680–2670 Ma (Cadillac–Larder fault). Extensional structures resulting from the thickened crust developed around 2660 Ma. Granitic intrusions are associated with all the volcanic episodes and phases of deformation, and have been used to constrain the age of many of these events. Their role in stabilizing, and adding to the volcanic crust is perhaps less well appreciated. Large synvolcanic tonalite-dominated intrusions of the tonalite–trondhjemite–granodiorite (TTG) suite are associated with the three major periods of volcanic activity of the Abitibi greenstone belt, and are genetically related to the volcanism. These synvolcanic intrusions occur both as high-level, flat, cauldron subsidence complexes and as batholithic masses at the base of the oceanic crust. Tonalite gneiss, dated from 2714 to 2703 Ma, occurring in structural culminations, is considered to be arc-underplated material. The gneiss crystallized at depth, and, in contrast to the other tonalites, does not appear to have intruded volcanic rocks. The gneisses also record the earliest compressional deformation. Numerous intrusions of island arc affinity, both the TTG and monzodiorite (MZD) suites form stocks and small plutons emplaced during the late phases of major deformation. These are more numerous than voluminous, and most of the tonalite end members of the suites probably intruded deeper within the sequence, retarded by the now-thickened crust. Large tonalite intrusions dominate the uplifted deeper sections adjacent to the Abitibi belt in the Kapuskasing uplift and Grenville Parautochthon, and presumably make up much of the deep crust of the Abitibi belt imaged in Lithoprobe seismic profiles. Small stocks and dyke complexes characterize the late, localized strike-slip deformational phase. These intrusions are porphyritic syenites and related rocks, including some alkaline compositions. Garnetiferous granites of crustal derivation were emplaced in the final period of extensional activity around 2660 Ma. Thus, plutonic rocks are a volumetrically major overall component of the Abitibi belt and were implicated in every phase of its development, from early volcanic arc magmatic activity, through the various stages of deformation, to final stabilization as continental crust. [Copyright &y& Elsevier]

Abstract: The aim of the present study was to investigate a possible correlation between indoor radon and gamma radiation levels in a region of high heat producing rock formations. Since the natural occurring radionuclides are responsible for the major contribution to the total effective dose of the ionizing radiations received by the population, so keeping this in view the indoor radon and gamma radiation levels have been measured in the dwellings of different villages situated in and around the Tusham Ring Complex, Bhiwani district, Haryana, known to be composed of acidic volcanics and the associated granites. The radon concentration levels have not only been found to be varying with the mode of construction of houses and building materials utilized, but also especially on their location with respect to the nearby high heat producing granite rocks. The indoor radon concentration levels at some places, especially those on or close to granite rock formations have been found to be considerably higher and even at some places it also exceeds the upper limit of the proposed action level of the ICRP limits. A better correlation between indoor radon and gamma radiation levels has been observed particularly in case of the dwellings well exposed to the high heat producing granitic rock formations. [Copyright &y& Elsevier]