China
Africa
Explore chapters and articles related to this topic
Neutron Diffraction Studies of Water and Aqueous Solutions
Published in Fausto Martelli, Properties of Water from Numerical and Experimental Perspectives, 2022
Supercritical water and aqueous solutions are important media for greenhouse chemistry and geological research (Franck 2000). The peculiar properties of supercritical water as a solvent, and in particular the tunable solubility of minerals and aromatic complexes at these states have several industrial applications and are of fundamental interest for research in geology. Pressure changes at constant temperature may indeed enable selective precipitation of solutes, opening perspectives for waste treatment, and possibly elucidating the origin and formation of rocks under the Earth’s mantle. On the other hand, curiosity-driven research on water is based on the observation that while the percolating HB network of water at low temperatures is very robust, as demonstrated in previous sections, its characteristics may change at supercritical conditions. Indeed, since the breaking of HBs is an energy activated process (Conde and Teixeira 1984), one could expect that the network can be more easily broken by increasing the temperature. Is it true? At what temperature, may we expect that the network is substantially disrupted? Does the HB network percolate also at supercritical conditions?
Ground/Soil Types and Thermo-Physical Properties
Published in Vasile Minea, Heating and Cooling with Ground-Source Heat Pumps in Cold and Moderate Climates, 2022
According to their formation, the rocks are divided into three major classes (https://www.britannica.com/science/rock-geology, accessed June 6, 2020): (i) igneous (e.g., basalt and obsidian), formed when magma within the earth cooled and hardened; (ii) sedimentary (as conglomerate and limestone), formed from particles of sand, shells, pebbles, and other fragments of material; and (iii) metamorphic (gneiss and marble), formed under the surface of the Earth from the metamorphosis that occurs due to intense heat and pressure. These three classes are subdivided into numerous groups and types (as granite, gneiss, schist, limestone, and silt-stone) on the basis of various factors, the most important being the chemical, mineralogical, and textural properties.
Finite-element analysis as a means of solving geomechanics problems in deep mines
Published in Vladimir Litvinenko, EUROCK2018: Geomechanics and Geodynamics of Rock Masses, 2018
Alexandr Evgenevich Rumyantsev, Andrey Viktorovich Trofimov, Vladislav Borisovich Vilchinsky, Valery Petrovich Marysiuk
In connection with mining at greater depths the problems of the stability of mine workings is particular urgency. At greater depths the natural rock pressure is played a crucial role in the stability of underground structures. With depth for weak rocks, the largest principal stress can reached critical values, even at full observance technology of management the mountain pressure, it can cause processes of cracks formation in rocks – formation of new (induced) cracks under the influence of the redistribution of rock pressure near the workings. Induced fracturing of the rock massive is significantly change the structure of the rock massive near the workings, and changed its reaction to natural and technogenic effects [Odintsev V.N., 1997].
Mid-Devonian basaltic magmatism and associated sedimentation: the Ooloo Hill Formation, central-eastern South Australia
Published in Australian Journal of Earth Sciences, 2023
C. Wade, A. J. Reid, E. A. Jagodzinski, M. J. Sheard
One exception to this is a series of basaltic rocks associated with localised sedimentation that formed in a restricted, intracontinental basin located to the north of the Flinders Ranges, South Australia, defined as the Ooloo Hill Formation (Figure 1). The Ooloo Hill Formation represents a unique composite of siliciclastic and volcaniclastic debris along with shallow submarine basalt flows. In this paper, we present a geochemical and geochronological investigation into these rock packages. The results suggest this area, now entirely buried beneath Mesozoic and Cenozoic successions, contains the remnants of a small volcano-sedimentary basin active in the Devonian. Ooloo Hill Formation volcanic rocks may represent a type of fracture-controlled volcanism formed on continental lithosphere, characterised by low-volume melt production originating in the asthenosphere without a hotspot or mantle plume. We suggest a connection between far-field tectonic forcing at the paleo-Pacific margin coupled with intracontinental deformation that occurred in this region to form this unique volcano-sedimentary basin.
Experiments on the thermally enhanced permeability of tight rocks: A potential thermal stimulation method for Enhanced Geothermal Systems
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Junrong Liu, Zhe Wang, Weixin Shi, Xianfeng Tan
The Chenzhuang area has a porous geothermal reservoir in a shallow formation and a blocky fracture-type geothermal reservoir in the Neo-Archean Taishan formation. The hot dry rock resource is located in the Neo-Archean Taishan formation metamorphic rocks, Precambrian intrusive rocks, and Mesozoic and Cenozoic volcanic rocks. It has poor fissures, no water or very small amounts of water, and no surface heat flow signs. It is a typical heat conducted geothermal reservoir. The top buried depth of the hot dry rock resource in the Chenzhuang area is over 2000 m. The geothermal gradient in the Chenzhuang Uplift area is 4.5–5.5 °C/100 m and that in Chenzhuang Sag area usually is 3.5–4.0 °C/100 m (Figure 2). The rock thermal conductivity, specific heat capacity and thermal diffusivity over 2500 m depth in the area of the exploratory hole are 2.441–3.925 W/(m.K), 0.928–1.930 MJ/(m.K) and 1.576–3.285 mm2/s, respectively. It is a rich and high-temperature geothermal resource. The calculated heat resource reserved in Lijin hot dry rock is about 4.39 × 1020 J. If the temperature difference for heat utilization is 60°C, the total heat resource potential in Lijin hot dry rock is approximately 1.62 × 1020 J (Wang et al. 2016).