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1. Optimal selection of estimator for obtaining an accurate three-dimensional rock fracture orientation distribution

Author:
Huang, Lei; Su, Xuexue; Tang, Huiming
Source:
Engineering geology 2020 v.270 pp. 105575
ISSN:
0013-7952
Subject:
rocks,   etc   ; equations; geometry; models;     Show all 4 Subjects
Abstract:
... Advances in estimating the three-dimensional (3D) orientation distribution include i) the stereology-based Fouché estimator (FE); and ii) its recent modification (MFE), which has one less meshing step and has three modified components compared with the FE. One way to achieve an accurate estimate is by selecting the optimum estimator. Here, we developed a recognizer for the optimum estimator to hel ...
DOI:
10.1016/j.enggeo.2020.105575

2. Deep convolutions for in-depth automated rock typing

Author:
Baraboshkin, Evgeny E.; Ismailova, Leyla S.; Orlov, Denis M.; Zhukovskaya, Elena A.; Kalmykov, Georgy A.; Khotylev, Oleg V.; Baraboshkin, Evgeny Yu.; Koroteev, Dmitry A.
Source:
Computers & geosciences 2020 v.135 pp. 104330
ISSN:
0098-3004
Subject:
rocks,   etc   ; algorithms; automation; neural networks;     Show all 4 Subjects
Abstract:
... The description of rocks is one of the most time-consuming tasks in the everyday work of a geologist, especially when very accurate description is required. We here present a method that reduces the time needed for accurate description of rocks, enabling the geologist to work more efficiently. We describe the application of methods based on color distribution analysis and feature extraction. Then ...
DOI:
10.1016/j.cageo.2019.104330

3. Conditions during the formation of granitic magmas by crustal melting – Hot or cold; drenched, damp or dry?

Author:
Clemens, John D.; Stevens, Gary; Bryan, Scott E.
Source:
Earth-science reviews 2020 v.200 pp. 102982
ISSN:
0012-8252
Subject:
rocks,   etc   ; cold; melting; minerals; temperature;     Show all 5 Subjects
Abstract:
... Granitic magmas extracted from crustal sources can form over a wide variety of P, T and aH₂O conditions. Both fluid-present and effectively fluid-absent conditions can yield granitic magmas, though the majority are formed through high-T, fluid-absent reactions because, in the deep crust, most available H₂O within rock bodies is contained within minerals rather than in free fluids. Fluid-present pa ...
DOI:
10.1016/j.earscirev.2019.102982

4. Raw material procurement as a crucial factor determining knapping technology in the Katta Sai complex of Middle Palaeolithic sites in the western Tian Shan piedmonts of Uzbekistan

Author:
Kot, Małgorzata; Pavlenok, Konstantin; Krajcarz, Maciej T.; Pavlenok, Galina; Shnaider, Svetlana; Khudjanazarov, Mukhiddin; Leloch, Michał; Szymczak, Karol
Source:
Quaternary international 2020
ISSN:
1040-6182
Subject:
rocks,   etc   ; blades; piedmont; raw materials; rivers; Uzbekistan;     Show all 6 Subjects
Abstract:
... This paper presents the results of the study of raw material procurement on two late Middle Paleolithic sites, Katta Sai 1 and Katta Sai 2, located in the western Tian Shan piedmont. The previous studies allowed to identify an unknown Levallois variant of human cultural adaptation in the regional Middle Paleolithic. Predetermined flake technology focused on obtaining the thin triangular flakes or ...
DOI:
10.1016/j.quaint.2020.03.052

5. Microseismic and precursor analysis of high-stress hazards in tunnels: A case comparison of rockburst and fall of ground

Author:
Ma, Chunchi; Li, Tianbin; Zhang, Hang
Source:
Engineering geology 2020 v.265 pp. 105435
ISSN:
0013-7952
Subject:
rocks,   etc   ; case studies; energy; geophysics; monitoring;     Show all 5 Subjects
Abstract:
... In rock engineering, microseismic monitoring technology has been extensively applied for the interpretation and forecast of rockburst hazards. However, highly stressed hard rocks could suffer dynamic geological hazards (rockburst) and gravity-driven geological hazards (fall of ground), both of which have distinct developmental processes and precursory features that await comprehensive exploration. ...
DOI:
10.1016/j.enggeo.2019.105435

6. A statistics-based discrete element modeling method coupled with the strength reduction method for the stability analysis of jointed rock slopes

Author:
Wang, Hanbin; Zhang, Bin; Mei, Gang; Xu, Nengxiong
Source:
Engineering geology 2020 v.264 pp. 105247
ISSN:
0013-7952
Subject:
rocks,   etc   ; shear strength; statistical models; topographic slope;     Show all 4 Subjects
Abstract:
... The stability of jointed rock slopes can be effectively analyzed using the discrete element method (DEM). However, the criteria for terminating the DEM iterative calculation process and determining the factor of safety (FOS) are not well defined. In this paper, a displacement-statistics-based discrete element modeling method (DSDM) is proposed to analyze the stability of jointed rock slopes by cou ...
DOI:
10.1016/j.enggeo.2019.105247

7. Co-effects of bedding planes and parallel flaws on fracture evolution in anisotropic rocks

Author:
Wang, Ding-Jian; Tang, Huiming; Shen, Peiwu; Su, Xuexue; Huang, Lei
Source:
Engineering geology 2020 v.264 pp. 105382
ISSN:
0013-7952
Subject:
rocks,   etc   ; anisotropy; mechanical properties; mechanical stress;     Show all 4 Subjects
Abstract:
... Mechanical and fracturing behaviors of natural rocks largely depend on the pattern of major discontinuities. The focus of this study is to elucidate the co-effects of the bedding planes and parallel structural flaws on the rock rupture and fracture coalescence. Uniaxial compression tests are conducted on the analogue rock specimens with various combinations of bedding inclinations (from 0° to 90°) ...
DOI:
10.1016/j.enggeo.2019.105382

8. Tectonostratigraphy of the Late Archean Dharwar Supergroup, Dharwar Craton, India: Defining a tectonic history from spatially linked but temporally distinct intracontinental and arc-related basins

Author:
Krapež, Bryan; Srinivasa Sarma, D.; Ram Mohan, M.; McNaughton, Neal J.; Rasmussen, Birger; Wilde, Simon A.
Source:
Earth-science reviews 2020 v.201 pp. 102966
ISSN:
0012-8252
Subject:
sedimentary rocks; volcanic rocks,   etc   ; Archean eon; basins; hinterland; provenance; tectonics; India;     Show all 8 Subjects
Abstract:
... The Dharwar Supergroup comprises the unconformity bound Bababudan and Chitradurga groups. The Bababudan Group, which is best preserved in the Western Dharwar Craton, records a divergent margin comprising a basalt-dominant intracontinental rift sequence, a shale-BIF drift sequence, and a sandstone-shale thermal-subsidence sequence. The rift stage evolved from ∼2765 Ma to ∼2720 Ma, whereas the succe ...
DOI:
10.1016/j.earscirev.2019.102966

9. Colloidal Asphaltenes—Non-extinct “Dinosaurs” in Native Petroleum

Author:
Evdokimov, Igor N.
Source:
Energy & fuels 2019 v.33 no.9 pp. 8440-8447
ISSN:
1520-5029
Subject:
rocks,   etc   ; asphaltenes; geochemistry; petroleum;     Show all 4 Subjects
Abstract:
... One of the important paradigms of fundamental petroleum geochemistry has been (and still is) that native asphaltenes in present day crude oils originated in the respective source rocks and are representative of the molecular composition in ancient organic deposits. The survival of “prehistoric” molecular species is enabled by shielding them in complex macromolecular structures of asphaltene nanoco ...
DOI:
10.1021/acs.energyfuels.9b01993

10. A phenomenological modelling of rocks based on the influence of damage initiation

Author:
Zhao, Heng; Zhou, Shuai; Zhang, Ling
Source:
Environmental earth sciences 2019 v.78 no.5 pp. 143
ISSN:
1866-6280
Subject:
rocks,   etc   ; models; prediction; probability;     Show all 4 Subjects
Abstract:
... It is recognized that the stress-induced damage impacts the progressive failure behavior of rocks. A phenomenological model for the compressive failure of rocks is thus presented in this study. The model addresses the progressive growth of damage that leads to the strength weakening on a macroscopic scale. Considering dramatic difference between uniaxial compression and tension strengths for rocks ...
DOI:
10.1007/s12665-019-8172-9

11. Exceptional basal-body preservation in some Early Triassic conodont elements from Oman

Author:
Souquet, Louise; Goudemand, Nicolas
Source:
Palaeogeography, palaeoclimatology, palaeoecology 2020 v.549 pp. 109066
ISSN:
0031-0182
Subject:
rocks,   etc   ; Triassic period; fossils; mineralization; models; prediction; Oman;     Show all 7 Subjects
Abstract:
... Conodont elements are composed of two main parts: the crown and the basal body. The basal body of a conodont element is a laminated structure that is less densely mineralized than the crown and, as a result, is rarely preserved. Elements with preserved basal bodies are found only in exceptional cases in the fossil record. To date, no S or M element with preserved basal body has ever been documente ...
DOI:
10.1016/j.palaeo.2019.01.028

12. In soil radon anomalies and volcanic activity on Mt. Etna (Italy)

Author:
İçhedef, M.; Giammanco, S.; Neri, M.; Catalano, R.; Immé, G.; Morelli, D.; Muré, F.; Giudice, N.
Source:
Journal of environmental radioactivity 2020 v.218 pp. 106267
ISSN:
0265-931X
Subject:
rocks,   etc   ; earthquakes; permeability; radioactivity; radon; soil air; volcanic activity; Italy;     Show all 8 Subjects
Abstract:
... We present here the first attempt to understand the fast dynamics of an active basaltic volcano, namely Mt. Etna using soil gas radon measured in some sites located in strategic places around the volcano. Data were measured continuously from July 2015 to February 2017 and the raw signals were treated in order to filter out all possible periodic components that are normally due to non-volcanic fact ...
DOI:
10.1016/j.jenvrad.2020.106267

13. Applicability of chemical indices to characterize weathering degrees in decomposed volcanic rocks

Author:
Okewale, Ismail Adeniyi
Source:
Catena 2020 v.189 pp. 104475
ISSN:
0341-8162
Subject:
volcanic rocks,   etc   ; cations; leaching; oxides; statistical analysis; water content; weathering;     Show all 7 Subjects
Abstract:
... Among the useful tools in characterizing weathering degrees are chemical indices, which combines bulk major elemental oxides into a single metric value and commonly presented along a vertical profile. However, characterizing geomaterials of diverse nature using chemical indices may be problematic. In this study, chemical indices were evaluated to characterize weathering degrees in decomposed volca ...
DOI:
10.1016/j.catena.2020.104475

14. The magmatic and magmatic-hydrothermal evolution of felsic igneous rocks as seen through Nb-Ta geochemical fractionation, with implications for the origins of rare-metal mineralizations

Author:
Ballouard, Christophe; Massuyeau, Malcolm; Elburg, Marlina A.; Tappe, Sebastian; Viljoen, Fanus; Brandenburg, Jean-Tristan
Source:
Earth-science reviews 2020 v.203 pp. 103115
ISSN:
0012-8252
Subject:
igneous rocks,   etc   ; biotite; crystallization; fractionation; mineralization; partition coefficients; regression analysis;     Show all 7 Subjects
Abstract:
... Despite Nb and Ta being considered as ‘geochemical twins’, most Ta mineral deposits are associated with muscovite-bearing peraluminous granites and related pegmatites (MPG), whereas significant Nb deposits are related to peralkaline to metaluminous A1-type granites and syenites as well as nepheline syenites. Metaluminous to peraluminous A2-type granites and syenites have a lower potential for rare ...
DOI:
10.1016/j.earscirev.2020.103115

15. Influences of test method and loading history on permeability of tight reservoir rocks

Author:
Zhang, Decheng; Ranjith, P.G.; Perera, M.S.A.; Zhang, C.P.
Source:
Energy 2020 v.195 pp. 116902
ISSN:
0360-5442
Subject:
rocks,   etc   ; gases; permeability; soil air; soil pore system; water reservoirs;     Show all 6 Subjects
Abstract:
... Steady-state and unsteady-state (downstream pressure build-up) gas permeability tests were conducted on low permeability siltstone at a series of upstream pressures during the loading and unloading processes. The characteristics of downstream pressure build-up curves are analysed in detail, and the permeability is calculated based on the data in the stabilization stage. Analysing approaches with a ...
DOI:
10.1016/j.energy.2020.116902

16. Mechanism of microbial dissolution and oxidation of antimony in stibnite under ambient conditions

Author:
Loni, Prakash C.; Wu, Mengxiaojun; Wang, Weiqi; Wang, Hongmei; Ma, Liyuan; Liu, Chaoyang; Song, Yuyang; H Tuovinen, Olli
Source:
Journal of hazardous materials 2020 v.385 pp. 121561
ISSN:
0304-3894
Subject:
rocks,   etc   ; antimony; biodegradation; environmental factors; mining; oxidation; sulfide minerals;     Show all 7 Subjects
Abstract:
... In this study, we demonstrate that a bacterial isolate Paraccocus versutus XT0.6 from the Xikuangshan antimony mine, the world largest antimony deposit, is capable of stibnite dissolution, oxidation of Sb(III), and formation of secondary Sb(V) bearing mineral. The isolate could oxidize dissolved Sb(III) aerobically and anaerobically. It was able to dissolve Sb(III) in solid minerals, which was sub ...
DOI:
10.1016/j.jhazmat.2019.121561

17. Combined steam based high-temperature heat and power storage with an Organic Rankine Cycle, an efficient mechanical electricity storage technology

Author:
Arabkoohsar, A.
Source:
Journal of cleaner production 2020 v.247 pp. 119098
ISSN:
0959-6526
Subject:
rocks,   etc   ; electricity; energy; heat; heating systems; steam; storage technology;     Show all 7 Subjects
Abstract:
... Today, mechanical energy storages are getting more important than before as the share of fluctuating renewable energies are dramatically increasing in the global energy matrix. Steam-based high-temperature heat and power storage is one of the very recent mechanical energy storage technologies introduced. This system stores electricity as heat in a packed bed of rocks and then, co-generates heat an ...
DOI:
10.1016/j.jclepro.2019.119098

18. A revised classification scheme of pyrite in the Witwatersrand Basin and application to placer gold deposits

Author:
da Costa, Giuliana; Hofmann, Axel; Agangi, Andrea
Source:
Earth-science reviews 2020 v.201 pp. 103064
ISSN:
0012-8252
Subject:
sedimentary rocks,   etc   ; anaerobic conditions; basins; gold; mineralization; pyrite; quartz; weathering;     Show all 8 Subjects
Abstract:
... Pyrite is the most abundant ore mineral in gold-bearing quartz pebble conglomerates (QPCs) of the Witwatersrand Basin and similar Archaean sedimentary units. Much of the pyrite in Archaean conglomerates is detrital in origin, implying that it survived weathering, transport, and reworking under anoxic conditions. Detrital pyrite is generally found together with authigenic pyrite formed in situ as a ...
DOI:
10.1016/j.earscirev.2019.103064

19. Estimation of potential arsenic leaching from its phases in excavated sedimentary and metamorphic rocks

Author:
Suzuki, Shoji; Katoh, Masahiko
Source:
Environmental geochemistry and health 2020 v.42 no.2 pp. 407-418
ISSN:
0269-4042
Subject:
metamorphic rocks,   etc   ; arsenic; clay; leaching; sediments; water solubility;     Show all 6 Subjects
Abstract:
... It is important that hazardous excavated sedimentary and metamorphic rocks are treated appropriately and reused without posing an environmental risk. Up-flow column leaching tests were conducted to examine whether arsenic leaching behavior varied among five hazardous excavated sedimentary and metamorphic rocks (two mudstones, clay sediment of marine origin, slate, and black schist) and to determin ...
DOI:
10.1007/s10653-019-00371-x

20. Evolution of pore-shape and its impact on pore conductivity during CO2 injection in calcite: Single pore simulations and microfluidic experiments

Author:
Agrawal, Priyanka; Raoof, Amir; Iliev, Oleg; Wolthers, Mariëtte
Source:
Advances in water resources 2020 v.136 pp. 103480
ISSN:
0309-1708
Subject:
carbonate rocks,   etc   ; calcite; carbon dioxide; models; permeability; water resources;     Show all 6 Subjects
Abstract:
... Injection of CO₂ into carbonate rocks causes dissolution and alters rock transport properties. The extent of the permeability increases, due to the increased pore volume and connectivity, strongly depends on the regimes of transport and dissolution reactions. Identification of these regimes and their parametrization at the microscopic scale is required for an understanding of the injection process ...
DOI:
10.1016/j.advwatres.2019.103480