Статті в журналах з теми "Quartz grain characteristics"
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1
Wu, Chao, Peng Qian, Xiangmin Zheng, Limin Zhou, Hui Wang, and Hongyang Xu. "Quartz grain characteristics of the late Pleistocene hard clay in the Yangtze River delta and implications for sedimentary environment and provenance." Quaternary Research 97 (June 9, 2020): 199–215. http://dx.doi.org/10.1017/qua.2020.31.
Повний текст джерелаАнотація:
AbstractThe sedimentologic fingerprinting in detrital deposit is vital to reconstruct sedimentary environments and discriminate sources. In this study, grain size and microtextural characteristics of quartz from the late Pleistocene hard clay in the Yangtze River delta (YRD) were analyzed by using a laser particle size analyzer and a scanning electron microscope. Subaqueous quartz from the Yangtze River and Yellow River sediments and eolian quartz from the Chinese Loess Plateau loess were also analyzed by scanning electron microscopy to obtain the microtextural characteristics. Quartz grains of the hard clay were characterized by poor sorting, fine skew, bimodal grain-size distributions, and numerous eolian microtextures. The comparison of the quartz grain characteristics of the hard clay with these in eolian loess indicated that the hard clay belonged to an eolian deposition. Moreover, the fine quartz grains of the hard clay were dominated by eolian microtextural characteristics, representing long-distance transportation. The coarse quartz grains of the hard clay exhibited more subaqueous microtextural characteristics, which indicated that the coarse fraction of the hard clay was derived from the proximal source regions in the YRD. The determination of buried eolian deposition with multiple sources in the YRD implies a southward westerly jet stream, strengthened eolian dust transportation, and extensive aridification in the YRD due to the increased Northern Hemisphere ice sheets in Marine Oxygen Isotope Stage 2.
2
Hu, Yue, Bo Li, and Zenobia Jacobs. "Single-Grain Quartz OSL Characteristics: Testing for Correlations within and between Sites in Asia, Europe and Africa." Methods and Protocols 3, no. 1 (December 26, 2019): 2. http://dx.doi.org/10.3390/mps3010002.
Повний текст джерелаАнотація:
We studied the characteristics of the optically stimulated luminescence (OSL) signal of single-grain quartz from three sites in China, Italy, and Libya, including the brightness, decay curve and dose response curve (DRC) shapes, recuperation, and reproducibility. We demonstrate the large variation in OSL behaviors for individual quartz grains of different samples from different regions, and show that recuperation, sensitivity change, and reproducibility are independent of the brightness and decay curve shape of the OSL signals. The single-grain DRCs can be divided into at least eight groups with different characteristic saturation doses (D0), and a standardized growth curve (SGC) can be established for each of the DRC groups. There is no distinctive difference in the shape of OSL decay curves among different DRC groups, but samples from different regions have a difference in the OSL sensitivities and decay shapes for different groups. Many of the quartz grains have low D0 values (30–50 Gy), and more than 99% of the grains have D0 values of <200 Gy. Our results raise caution against the dating of samples with equivalent dose values higher than 100 Gy, if there are many low-D0 and ‘saturated’ grains.
3
Kalińska-Nartiša, Edyta, Kristaps Lamsters, Jānis Karušs, Māris Krievāns, Agnis Rečs, and Raimonds Meija. "Quartz grain features in modern glacial and proglacial environments: A microscopic study from the Russell Glacier, southwest Greenland." Polish Polar Research 38, no. 3 (September 1, 2017): 265–89. http://dx.doi.org/10.1515/popore-2017-0018.
Повний текст джерелаАнотація:
Abstract It is assumed that close to the margins of ice-sheets, glacial, fluvial and aeolian processes overlap, and combined with weathering processes, produce numerous sediments, in which quartz is a common mineral. Quartz grains, if available, may serve as a powerful tool in determining the depositional history, transportation mode and postdepositional processes. However, quartz grain studies in some modern glacial areas are still sparse. In this study, we examine for the first time quartz grains sampled from the modern glacial and proglacial environments of the Russell Glacier, southwest Greenland in binocular microscope and scanning electron microscope, to analyze their shape, character of surface and microtextures. We debate whether the investigated quartz grains reveal glacial characteristics and to what extent they carry a signal of another transportation and sedimentary processes. Although glacial fracturing and abrasion occur in grain suites, most mechanical origin features are not of a high frequency or freshness, potentially suggesting a reduced shear stress in the glacier from its limited thickness and influence of the pressurized water at the ice-bed. In contrast, the signal that originates from the fluvial environment is much stronger derived by numerous aqueous-induced features present on quartz grain surfaces. Aeolian-induced microtextures on grain surfaces increase among the samples the closest to the ice margin, which may be due to enhanced aeolian activity, but are practically absent in sediments taken from the small scale aeolian landforms. In contrast, aeolian grains have been found in the bigger-size (1.0–2.0 mm) investigated fraction. These grains gained the strongest aeolian abrasion, possibly due to changes in transportation mode.
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Poernomo, Herry. "SORPTION AND DISPERSION OF STRONTIUM RADIONUCLIDE IN THE BENTONITE-QUARTZ-CLAY AS BACKFILL MATERIAL CANDIDATE ON RADIOACTIVE WASTE REPOSITORY." Indonesian Journal of Chemistry 10, no. 3 (December 14, 2010): 276–84. http://dx.doi.org/10.22146/ijc.21430.
Повний текст джерелаАнотація:
The experiment of sorption and dispersion characteristics of strontium in the mixture of bentonite-quartz, clay-quartz, bentonite-clay-quartz as candidate of raw material for backfill material in the radioactive waste repository has been performed. The objective of this research is to know the grain size effect of bentonite, clay, and quartz on the weight percent ratio of bentonite to quartz, clay to quartz, bentonite to clay to-quartz can be gives physical characteristics of best such as bulk density (rb), effective porosity (e), permeability (K), best sorption characteristic such as distribution coefficient (Kd), and best dispersion characteristics such as dispersivity (a) and effective dispersion coefficient (De) of strontium in the backfill material candidate. The experiment was carried out in the column filled by the mixture of bentonite-quartz, clay-quartz, bentonite-clay-quartz with the weight percent ratio of bentonite to quartz, clay to quartz, bentonite to clay to quartz of 100/0, 80/20, 60/40, 40/60, 20/80, 0/100 respectively at saturated condition of water, then flowed 0.1 N Sr(NO3)2 as buffer solution with tracer of 0.05 Ci/cm3 90Sr as strontium radionuclide simulation was leached from immobilized radioactive waste in the radioactive waste repository. The concentration of 90Sr in the effluents represented as Ct were analyzed by Ortec b counter every 30 min, then by using profile concentration of Co and Ct, values of Kd, a and De of 90Sr in the backfill material was determined. The experiment data showed that the best results were -80+120 mesh grain size of bentonite, clay, quartz respectively on the weight percent ratio of bentonite to clay to quartz of 70/10/20 with physical characteristics of rb = 0.658 g/cm3, e = 0.666 cm3/cm3, and K = 1.680x10-2 cm/sec, sorption characteristic of Kd = 46.108 cm3/g, dispersion characteristics of a = 5.443 cm, and De = 1.808x10-03 cm2/sec can be proposed as candidate of raw material of backfill material in the radioactive waste repository.
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Křížová, Lenka, Marek Křížek, and Lenka Lisá. "Applicability of quartz grains surface analysis to the study of the genesis of unlithified sediments." Geografie 116, no. 1 (2011): 59–78. http://dx.doi.org/10.37040/geografie2011116010059.
Повний текст джерелаАнотація:
This paper deals with genetic types of unlithified sediments and their characteristics with an emphasis on quartz grain surface microrelief. There are various physical-geographic agents in different sedimentary environments which play an important role in the origin of certain marks on the surface of sedimentary grains. As a result, studying the features of quartz grain surfaces enables us to determine the possible origin of sediments and landforms. Reference samples were chosen from geomorphological landforms of known origin: a moraine in the Labský Důl Valley, a debris flow in the Důl Bílého Labe Valley, a flood accumulation and deluvium from the Důl Bílého Labe Valley in the Krkonoše Mountains and eolian sediment from Klárov in Prague. Significant differences in surface micromorphology were found among these samples.
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Shimada, Aiko, Masashi Takada, and Shin Toyoda. "Characteristics of ESR signals and TLCLs of quartz included in various source rocks and sediments in Japan: A clue to sediment provenance." Geochronometria 40, no. 4 (December 1, 2013): 334–40. http://dx.doi.org/10.2478/s13386-013-0111-z.
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AbstractThe variation of electron spin resonance (ESR) signal intensities and thermoluminescence colour images (TLCIs) of quartz was investigated in the present study for various rocks and sediments in Japan, to discuss the possibilities of identifying the sediment provenance. The ESR signal intensity of the E1’ centre in the same grain size in granitic quartz varies from sample to sample, except for that in Quaternary samples of volcanic sediment, which is very low, close to the noise level. It was found that the diagram, ESR intensities of Al versus Ti-Li centre signal intensities, distinguish volcanic from the same grain size in granitic quartz as well as distinguish individual tephra from another. The TLCIs from volcanic quartz and some granitic quartz samples is almost red and that from the rest of granitic and metamudstone quartz is blue as results of TLCIs although the emission intensities are different. Our results suggest that examining the multiple-centre signal intensities of ESR and the TLCIs are effective to identify the source of quartz and to estimate the sediment provenance.
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Ma, Zhao, Lichao Nie, Zhaoyang Deng, Xiaobin Xu, Xin Yin, Junfeng Shen, Kai Wang, and Ningbo Li. "Relationship between Induced Polarization Relaxation Time and Hydraulic Characteristics of Water-Bearing Sand." Applied Sciences 12, no. 11 (June 5, 2022): 5735. http://dx.doi.org/10.3390/app12115735.
Повний текст джерелаАнотація:
The induced polarization method has become a popular method for evaluating formation permeability characteristics in recent years because of its sensitivity to water and water-bearing porous media. In particular, the induced polarization relaxation time can reflect the macroscopic characteristics of the porous media of rock and soil. Therefore, in order to study the relationship between relaxation time and permeability, eight quartz sand samples of different grain sizes were used to simulate water-bearing sand layers under different geological conditions, and the induced polarization experiment and the Darcy seepage experiment were carried out on the same sand sample. The experimental results show that relaxation time and permeability are closely correlated with the grain size of quartz sand samples. According to the experimental data, the power function equation is a better fit for describing the relationship between permeability and relaxation time. It is worth noting that the equations obtained are only empirical equations for quartz sand samples, and they may not be applicable to all geological conditions.
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Hathon, Lori A., Michael T. Myers, and Abhishek Arya. "Pore Volume Compressibility of Unconsolidated Sand Reservoirs: Insights Gained Using Laboratory-Created Sand Pack Analogs." Petrophysics – The SPWLA Journal of Formation Evaluation and Reservoir Description 62, no. 5 (October 1, 2021): 516–36. http://dx.doi.org/10.30632/pjv62n5-2020a6.
Повний текст джерелаАнотація:
Pore volume compressibility is a fundamental driver of production for unconsolidated sand reservoirs. Prediction of compressibility is desirable when direct measurements on core are not available. Many characteristics of reservoir sands change simultaneously. For this reason, the controls on compressibility are difficult to isolate and interpret. We present the results of compaction experiments using laboratory-created, unconsolidated sands. In these analog sands, we change one textural or mineralogical parameter at a time to investigate the influence of that parameter on the measured compaction properties. Initially, simple quartz grain packs of varying grain sizes were used. Subsequently, additional parameters were investigated, including grain packing, angularity, sorting, feldspar content, ductile grain content, small volumes of dispersed clay, and initial sample preconditioning at stress. Multiple samples of each type were created and tested. This allowed the testing to be halted at several intermediate stresses and the samples to be examined using 2D and 3D imaging and image analysis techniques. For monomineralic quartz sand packs, grain size is a principal control on compressibility. As mean size increases from 150 to 450 μm, peak compressibility increases from 6 to 24 microsips. The depletion stress at which peak compressibility occurs decreases from 8,000 to 2,500 psi. Increasing grain angularity also increases compressibility but with smaller effect. For 150-μm quartz sands, increasing the angularity resulted in an increase in compressibility from 6 microsips for round quartz to 10 microsips for angular quartz and decreased the depletion stress required to achieve peak compressibility from 8,000 to 7,000 psi. As sorting varies from well to moderately poorly sorted, compressibility decreases, and the curve broadens as a function of depletion stress. Adding small volumes of feldspar (or other minerals that cleave) increases the compressibility more than the change resulting from changes in grain size, illustrating the importance of framework grain composition. Adding similar volumes of ductile grains results in a similar increase in compressibility to that observed for feldspar. However, when the size of the ductile grains is larger than that of the associated quartz (e.g., locally derived rip-up clasts), the increase in compressibility is significantly larger. To validate the experimental work, we compare the results of uniaxial pore volume compressibility tests on laboratory-created sands with measurements made on subsurface samples of similar texture and mineralogy. Both the shape of the compressibility curves as well as the magnitude of the compressibility are successfully reproduced. We conclude that laboratory-created sands can provide reasonable proxies for estimating the compressibility of subsurface reservoirs when intact subsurface samples are not available for measurement (e.g., only percussion sidewall samples are acquired) as long as mineralogy and texture are known.
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Zheng, Xinxin, Ruichen Chen, Jian Chen, Song Chen, and Lulu Shi. "Breakage Characteristics of Quartz Sand Based on Ring Shear Tests: Implications for the Fragmentation Processes of Rock Avalanches." Advances in Civil Engineering 2022 (January 13, 2022): 1–12. http://dx.doi.org/10.1155/2022/7879067.
Повний текст джерелаАнотація:
To investigate the effects of internal shear fragmentation on dry granular flow, in this study a series of ring shear tests were performed on quartz sand samples under different normal stresses (100 kPa, 200 kPa, and 300 kPa), shear displacements (3 m, 5 m, 10m, 15 m, and 20 m), and shear rates (30 deg min−1, 60 deg min−1, and 90 deg min−1). Next, the grain-size distributions, fractal dimensions, and microcharacteristics of the quartz sand before and after the experiments were compared and analyzed. The study results show that grain breakage under shearing preferentially occurs at the edges of the particles and forms a bimodal distribution in frequency grain-size distribution curves, which is consistent with observations of rock avalanches. The fine particles prevent the coarse particles from breaking, in turn leading to the ultimate grain-size distribution and stable fractal dimension (2.61) of quartz sand at relatively small shear displacements compared with the travel distance of rock avalanches. The results of this study suggest that the fragmentation of rock avalanches during the shear spread stage may be far less significant than previously believed. Therefore, the fragmentation effect is not considered to be a major factor of the hypermobility in the late stage of rock avalanches.
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He, Shao-Heng, Zhi Ding, Hai-Bo Hu, and Min Gao. "Effect of Grain Size on Microscopic Pore Structure and Fractal Characteristics of Carbonate-Based Sand and Silicate-Based Sand." Fractal and Fractional 5, no. 4 (October 4, 2021): 152. http://dx.doi.org/10.3390/fractalfract5040152.
Повний текст джерелаАнотація:
In this study, a series of nuclear magnetic resonance (NMR) tests was conducted on calcareous sand, quartz sand, and glass bead with a wide range of grain sizes, to understand the effect of grain size on the micro-pore structure and fractal characteristics of the carbonate-based sand and silicate-based sand. The pore size distribution (PSD) of the tested materials were obtained from the NMR T2 spectra, and fractal theory was introduced to describe the fractal properties of PSD. Results demonstrate that grain size has a significant effect on the PSD of carbonate-based sand and silicate-based sand. As grain size increases, the PSD of sands evolves from a binary structure with two peaks to a ternary structure with three peaks. The increase in the grain size can cause a remarkable increase in the maximum pore size. It is also found that the more irregular the particle shape, the better the continuity between the large and medium pores. In addition, grain size has a considerable effect on the fractal dimension of the micro-pore structure. The increase of grain size can lead to a significant increase in the heterogeneity and fractal dimension in PSD for calcareous sand, quartz sand and glass bead.
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Stella, Giuseppe, Dorotea Fontana, Anna Gueli, and Sebastiano Troja. "Different approaches to date bricks from historical buildings." Geochronometria 41, no. 3 (September 1, 2014): 256–64. http://dx.doi.org/10.2478/s13386-013-0157-y.
Повний текст джерелаАнотація:
Abstract The application of Thermally (TL) and Optically (OSL) Stimulated Luminescence on bricks used as building material has allowed solving an chronological issue in the field of historical building dating. The possibility to use one or more methodologies of dating is closely related to the luminescent and granulometric characteristics of the sample. Using some brick samples collected in the church of Sain Seurin in Bordeaux (France), this paper discusses the implications and the possibility to use different approaches and techniques for dating. With this aim luminescence measurements were performed on both polymineral fine grain and quartz inclusion phases extracted from each brick. For Equivalent Dose (ED) and consequently age determination, TL on mixed fine grain fraction (FG), OSL on quartz inclusions (QI) and on mixed fine grain (FG*) fraction, were used. The results obtained suggest the advantage of using OSL technique on fine grain fraction cleaned up by IR stimulation (FG*), but the use of quartz inclusion represents indeed a good alternative.
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Hentschel, Felix, Claudia A. Trepmann, and Emilie Janots. "Deformation of feldspar at greenschist facies conditions – the record of mylonitic pegmatites from the Pfunderer Mountains, Eastern Alps." Solid Earth 10, no. 1 (January 17, 2019): 95–116. http://dx.doi.org/10.5194/se-10-95-2019.
Повний текст джерелаАнотація:
Abstract. Deformation microstructures of albitic plagioclase and K-feldspar were investigated in mylonitic pegmatites from the Austroalpine basement south of the western Tauern Window by polarized light microscopy, electron microscopy and electron backscatter diffraction to evaluate feldspar deformation mechanisms at greenschist facies conditions. The main mylonitic characteristics are alternating almost monophase quartz and albite layers, surrounding porphyroclasts of deformed feldspar and tourmaline. The dominant deformation microstructures of K-feldspar porphyroclasts are intragranular fractures at a high angle to the stretching lineation. The fractures are healed or sealed by polyphase aggregates of albite, K-feldspar, quartz and mica, which also occur along intragranular fractures of tourmaline and strain shadows around other porphyroclasts. These polyphase aggregates indicate dissolution–precipitation creep. K-feldspar porphyroclasts are partly replaced by albite characterized by a cuspate interface. This replacement is interpreted to take place by interface-coupled dissolution–precipitation driven by a solubility difference between K-feldspar and albite. Albite porphyroclasts are replaced at boundaries parallel to the foliation by fine-grained monophase albite aggregates of small strain-free new grains mixed with deformed fragments. Dislocation glide is indicated by bent and twinned albite porphyroclasts with internal misorientation. An indication of effective dislocation climb with dynamic recovery, for example, by the presence of subgrains, is systematically missing. We interpret the grain size reduction of albite to be the result of coupled dislocation glide and fracturing (low-temperature plasticity). Subsequent growth is by a combination of strain-induced grain boundary migration and formation of growth rims, resulting in an aspect ratio of albite with the long axis within the foliation. This strain-induced replacement by nucleation (associated dislocation glide and microfracturing) and subsequent growth is suggested to result in the observed monophase albite layers, probably together with granular flow. The associated quartz layers show characteristics of dislocation creep by the presence of subgrains, undulatory extinction and sutured grain boundaries. We identified two endmember matrix microstructures: (i) alternating layers of a few hundred micrometres' width, with isometric, fine-grained feldspar (on average 15 µm in diameter) and coarse-grained quartz (a few hundred micrometres in diameter), representing lower strain compared to (ii) alternating thin layers of some tens of micrometres' width composed of fine-grained quartz (<20 µm in diameter) and coarse elongated albite grains (long axis of a few tens of micrometres) defining the foliation, respectively. Our observations indicate that grain size reduction by strain-induced replacement of albite (associated dislocation glide and microfracturing) followed by growth and granular flow simultaneous with dislocation creep of quartz are playing the dominating role in formation of the mylonitic microstructure.
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Mao, Song, and Qin Zhang. "Mineralogical Characteristics of Phosphate Tailings for Comprehensive Utilization." Advances in Civil Engineering 2021 (March 31, 2021): 1–13. http://dx.doi.org/10.1155/2021/5529021.
Повний текст джерелаАнотація:
The mineralogical characteristics of a phosphate tailing were studied, and the occurrence state, mineral types, and embedded characteristics of phosphorus in the phosphate tailings were ascertained. The results show that the main minerals in the phosphate tailings are collophane. The main gangue minerals are quartz, dolomite, calcite, a small amount of potassium feldspar, plagioclase, chlorite, etc. Monazite was found in phosphate tailings. In addition, the coarse grain size of quartz and feldspar and fine embedded particle size of calcite and dolomite are also the main factors affecting the mineral processing of phosphate tailings. According to the analysis of mineralogical characteristics, the physical and chemical properties of phosphate tailings provided the basis for comprehensive utilization of phosphorus resources.
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Mills, Stephanie G., Christopher Gerbi, Jeffrey H. Marsh, Martin G. Yates, Sheila J. Seaman, and Joseph C. White. "Tectonic and chemical implications of cathodoluminescent microstructures in quartz, Parry Sound domain, Ontario, Canada." Canadian Journal of Earth Sciences 54, no. 6 (June 2017): 677–92. http://dx.doi.org/10.1139/cjes-2016-0168.
Повний текст джерелаАнотація:
Cathodoluminescence (CL) imaging of quartz in orthogneiss of the Parry Sound domain, Grenville Province, Ontario, Canada, reveals four dark microstructures—medium-dark grains, mantles, sinuous lines, and straight lines. The Parry Sound domain experienced granulite-facies deformation and metamorphism followed by variable degrees of amphibolite-facies retrogression associated with the development of retrograde shear zones. We integrate our observations of CL-visible quartz microstructures with structures observable with optical and scanning transmission electron microscopy, analyses of water species concentration, and trace element distribution in quartz, as well as with microstructures in plagioclase, to determine their characteristics and elucidate their timing and mechanisms of formation relative to the deformational history. Medium-dark grains are primarily located in and near kilometer-scale shear zones at the margins of the Parry Sound domain, have notably darker cores than most samples in the interior, and may have higher water contents than other samples in the interior. These grains formed during late shearing, at a lower temperature than CL-bright grains; they thus provide evidence that the large shear system narrowed with time. Dark mantles occur at grain boundaries and correlate with higher concentrations of Fe. They formed after the first shearing event, but while still at amphibolite facies, and they provide evidence for post-kinematic alteration at grain boundaries. Dark sinuous lines correspond to subgrain boundaries that formed after retrograde shearing, but while still at amphibolite facies. Dark straight lines correspond to fluid inclusion trails and most likely formed at low temperatures and pressures during exhumation.
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Islam, Md Shofiqul, Md Hasibul Hasan Shijan, Md Samin Saif, Pradip Kumar Biswas, and Muhammad Omar Faruk. "Petrophysical and petrographic characteristics of Barail Sandstone of the Surma Basin, Bangladesh." Journal of Petroleum Exploration and Production Technology 11, no. 8 (May 31, 2021): 3149–61. http://dx.doi.org/10.1007/s13202-021-01196-0.
Повний текст джерелаАнотація:
AbstractThe Barail sandstone in the Surma Basin is a medium- to coarse-grained pinkish-colored rock exposed near the northeastern margin of Bangladesh. In this study, we evaluated the reservoir quality of the Barail sandstone based on its petrophysical and petrographic characteristics. Petrophysical analyses of outcropped samples showed that sandstones are made up of 16.48% porosity and 132.48 mD permeability. Sandstone density ranges from 1.94 g/cm3 to 2.37 g/cm3, with a mean value of 2.12 g/cm3, shown as moderately compacted sandstone. Integrated data such as bulk density, porosity, permeability, Rock Quality Index (RQI), Normalized Porosity Index (NPI), Flow Zone Indicator (FZI), compressive strength, etc. with their relationships indicate that Barail sandstone owing characters to become a good petroleum reservoir. The rock samples consisted mainly of quartz with an insignificant amount of rock fragments and plagioclase feldspar and are categorized as sub-arkose to sub-litharenite. The rock samples also contains lithic (andesine, microcline, muscovite, biotite, etc.) of granitic and gneissic fabric and some volcanic product like aguite, albite, andesine, garnet, spinel and ulvo-spinel indicating the source of nearby orogeny. The euhedral to subhedral shape of the quartz grain in a porphyritic texture, moderately sorted with a smaller amount of clay minerals indicating the moderately mature rock type. The iron oxide border around the quartz grain also indicates that the Barail sandstone was deposited under dry climatic condition.
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Zhao, Dajun, Shulei Zhang, and Meiyan Wang. "Microcrack Growth Properties of Granite under Ultrasonic High-Frequency Excitation." Advances in Civil Engineering 2019 (June 18, 2019): 1–11. http://dx.doi.org/10.1155/2019/3069029.
Повний текст джерелаАнотація:
The failure of most rock materials is essentially a process of crack initiation and propagation. It is of great significance to study the microcrack growth characteristics of granite under ultrasonic high-frequency excitation for understanding the failure mechanism of rock under ultrasonic vibration. In this paper, the experimental and numerical simulation methods are used to study the propagation characteristics of rock cracks under ultrasonic vibration. Scanning electron microscopy (SEM) was used to observe the growth of microcracks in granite samples after ultrasonic vibration for 0 min, 2 min, and 4 min. A discrete element software PFC2D was used to simulate and solve the cracking mechanism of rock cracks under ultrasonic vibration. Also, it is found that the action of ultrasonic vibration can effectively promote the development of microcracks in the granite samples. The main three cracks causing the failure of quartz under the ultrasonic high frequency are intragranular cracks, transgranular cracks, and grain boundary cracks. The breakage of transgranular cracks usually contributes a shell-like fracture, that is, a regular curved surface with a concentric circular pattern appears on the fracture surface, which is a typical quartz brittle fracture mode. In addition, the feldspar grain failure is mainly caused by intragranular crack and transgranular crack. Microcracks are wavy expansion in feldspar grain. Mica failure is mainly caused by grain boundary crack, and the effect of lamellar cleavage on the failure of mica is significant. Moreover, it is also found that the mechanism of microcrack propagation is tensile failure. The failure of feldspar grains is mainly contributed to the failure of granite.
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Ngo, Chi Kim Thi, Long Van Hoang, Binh Van Phan, Tinh Nguyen Trinh, Trung Tu Do, Hiep Huu Nguyen, and Nghiem Van Dao. "The characteristics of the surface sediments in Co To island." Journal of Mining and Earth Sciences 61, no. 2 (April 29, 2020): 33–40. http://dx.doi.org/10.46326/jmes.2020.61(2).04.
Повний текст джерелаАнотація:
552 grain size samples and 33 mineral quality defined samples have been collected in the Co To island, Tonkin Bay of Vietnam, to study the distribution and the sediment provenance. The field investigation method, the grain analysis, and the detrital composition examination method have been used to study the characteristics of the surface sediments in Co To island. The obtained results show that the surface sediments in the area consist of ten different fields, namely: sandy gravel, gravelly sand, sand, gravelly muddy sand, sand mixed gravel, muddy sand, gravelly mud mixed sand, silty sand, muddy sandy gravel, and sandy mud. The mineral component method shows that quartz is the main contain of the surface sediment (72,0÷90,6%), less rock detritus, felspat, mica, and very few of the shells. It is to confirm that the continent is the main primary material source of the study area. The distribution of the sediment is complicated. As the East-Southeast side of the research area, the sediment distribution following gravity way, coarse grain near the shore (gravel, sandy gravel,…), finer grain far off the shore (gravelly muddy sand, silty sand,…), choice level is very low. Which This is saying that the movement of sediment in the area is dominant, ; the flow energy is governed by the topography near the island and seafloor. In tMhe meanwhile, the west-northwest side, the topography of seafloor is the complicated, coarse sediment grains (gravel, sand), ); the roundness is bad, which is saying that the hydrodynamic flow there plays an important role in the sediment distribution.
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Lubis, I. F., A. D. Titisari, and N. S. Irsani. "Textural and mineralogical characteristics of sand grains of Oyo River Deposit at Yogyakarta, Indonesia: implications on sedimentation and origin." IOP Conference Series: Earth and Environmental Science 851, no. 1 (October 1, 2021): 012030. http://dx.doi.org/10.1088/1755-1315/851/1/012030.
Повний текст джерелаАнотація:
Abstract Oyo river deposit is one of the potential resources for small scale sand mining in Yogyakarta. The deposit extends along the upstream to downstream area of the river. A detailed study on textural and mineralogical characterization is aimed for better understanding of Oyo River sedimentation and provenance. Ten sediment samples were analyzed by using granulometry method, these include grain size, morphological and mineralogical analysis. The result shows that the average of grain size changes from coarse sand (0.88 mm) in the upstream to medium sand (0.37 mm) in the downstream. Sorting value is dominated by moderately sorted (0.7lφ - 0.94φ), skewness is dominated by very fine skewed (0.3φ - l.l0φ), and kurtosis is dominated by extremely leptokurtic (2.8φ - 6.5φ). Meanwhile for the grain shape is dominated by oblate and bladed, sphericity changes from elongate to subequant, roundness is dominated by subangular and subequant. Mineralogical composition consists of magnetite, hematite, pyroxene, amphibole, quartz, feldspar, and lithic fragment. Plotting result on triangular QFL (Quartz Feldspar Lithic-fragment) diagram shows that the provenance of Oyo River sand deposit is coming from dissected arc tectonic setting.
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Liu, Guanlin, Youliang Chen, Xi Du, Suran Wang, and Tomás Manuel Fernández-Steeger. "Evolutionary Analysis of Heterogeneous Granite Microcracks Based on Digital Image Processing in Grain-Block Model." Materials 15, no. 5 (March 5, 2022): 1941. http://dx.doi.org/10.3390/ma15051941.
Повний текст джерелаАнотація:
Rocks are natural materials with a heterogeneous microstructure, and the heterogeneity of the microstructure plays a crucial role in the evolution of microcracks during the compression process. A numerical model of a rock with a heterogeneous structure under compression is developed by digital image processing techniques and the discrete element method. On the grain scale, the damage mechanism and microcrack characteristics of a heterogeneous Biotite granite under compression fracture are investigated. First, the process of constructing a digital image-based heterogeneous grain model is described. The microscopic characteristics of geometric heterogeneity, elastic heterogeneity, and contact heterogeneity are all considered in the numerical model. Then, the model is calibrated according to the macroscopic properties of biotite granite obtained in the laboratory, and the numerically simulated microcrack cracking processes and damage modes are obtained with a high degree of agreement compared to the experiments. Numerical simulations have shown the following: (1) Microcracking occurs first at the weak side of the grain boundaries, and the appearance of intragranular shear cracks indicates that the rock has reached its peak strength. (2) The stress concentration caused by the heterogeneity of the microstructure is an essential factor that causes rock cracks and induces rupture. Intragranular cracks occur successively in quartz, feldspar (plagioclase), and biotite, with far more intragranular cracks in quartz and feldspar (plagioclase) than in biotite. (3) Microcracking in quartz occurs as clusters, fork and fracture features, and in feldspar (plagioclase) it tends to cause penetration microcracking, which usually surrounds or terminates at the biotite. (4) As the confining pressure increases, the tensile break between the grains is suppressed and the number of shear cracks increases. At the macro level, the rock failure mode of the numerical model changes from split damage to shear destruction, which is consistent with the law shown in laboratory experiments.
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Bello, Abdulwahab Muhammad, Stuart J. Jones, Jon Gluyas, and Khalid Al-Ramadan. "Impact of Grain-Coating Clays on Porosity Preservation in Paleocene Turbidite Channel Sandstones: Nelson Oil Field, UK Central North Sea." Minerals 12, no. 5 (April 29, 2022): 555. http://dx.doi.org/10.3390/min12050555.
Повний текст джерелаАнотація:
The Forties Sandstone Member is an important deep-water reservoir in the Central North Sea. The role of depositional characteristics, grain-coating clays, and diagenesis in controlling the reservoir quality of the sandstones is poorly understood. The main aim of the study is to understand the role of depositional characteristics, grain-coating and pore-filling clays, and diagenesis in controlling the reservoir quality evolution of turbidite-channel sandstones. The study employed a multi-disciplinary technique involving thin section petrography and scanning electron microscopy (SEM) to investigate the impact of grain size, clay matrix content, mode of occurrence of grain-coating chlorite and illite, and their impact in arresting quartz cementation and overall reservoir quality in the sandstones. Results of our study reveal that porosity evolution in the sandstones has been influenced by both primary depositional characteristics and diagenesis. Sandstones with coarser grain size and lower pore-filling clay content have the best reservoir porosity (up to 28%) compared to those with finer grain size and higher pore-filling clay content. Quartz cement volume decreases with increasing clay-coating coverage. Clay coating coverage of >40% is effective in arresting quartz cementation. Total clay volume of as low as 10% could have a deleterious impact on reservoir quality. The Forties Sandstone Member could potentially be a suitable candidate for physical and mineralogical storage of CO2. However, because of its high proportion (>20%) of chemically unstable minerals (feldspar, carbonates, and clays), their dissolution due to CO2 injection and storage could potentially increase reservoir permeability by an order of magnitude, thereby affecting the geomechanical and tensile strength of the sandstones. Therefore, an experimental study investigating the amount of CO2 to be injected (and at what pressure) is required to maintain and preserve borehole integrity. The findings of our study can be applied in other reservoirs with similar depositional environments to improve their reservoir quality prediction.
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Shoukat, Noureen, Numair Ahmed Siddiqui, M. Suhaili B. Ismail, and Syed Haroon Ali. "Depositional environment and diagenesis of early Miocene Nyalau Formation, Sarawak, Malaysia." IOP Conference Series: Earth and Environmental Science 1003, no. 1 (April 1, 2022): 012044. http://dx.doi.org/10.1088/1755-1315/1003/1/012044.
Повний текст джерелаАнотація:
Abstract Diagenetic understandings tied to depositional sequences that developed over the past decades help to predict the reservoir quality in oil and gas exploration. Understanding the lithologic characteristics and diagenetic alterations is key to decipher the various complex controls on its porosity and permeability. This diagenetic heterogeneity is a product of a complex history of diagenetic modifications, however, there are not many studies addressing this problem. The results show that the exposed sections around Bintulu town comprise of massive sandstones intervals, laminated clays, and brackish-shales and lignite. Five main types of lithologies are identified in the stratigraphic sections: sandstones, shales, coal, siltstones, and mudstones. These rock types are further sub-divided into fifteen lithofacies based on sedimentary structures and other characteristics. Petrographic studies revealed that the sandstones are well-sorted quartz arenite, with fine to medium grained sand. The diagenetic processes recognized include compaction, dissolution and cementation. The early, middle, and late diagenetic stages are present in the lithostratigraphy. Bioturbation marks the start of post-depositional changes, and allowed rapid exchange of pore waters with overlying depositional water. Iron oxide occurred in early diagenesis rapidly after the sediments were buried. However, later grain dissolution provided the secondary porosity and permeability. Compaction rates were high in muddy sediments. Sandstone samples with high mud content have less diagenetic signatures. Later, quartz and calcite cement stabilizes the grains and decreases porosity generated by early dissolution. Middle stages of diagenesis involved the growth of chlorite perpendicular to quartz grains. The late diagenetic changes involved the growth of pyrite crystals associated with chemical composition of deep burial pore fluids. The cement types that have been observed in this formation include clay, calcite, quartz overgrowth and iron oxides whereas, the later phases destroyed the early generated porosity. The calcite cement in the early stage of diagenesis, though, resisted the compaction of sediments and aids to preserve the porosity. Dominant porosity is interparticle porosity that is present depositionally and later enhanced by secondary grain dissolution.
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Fitzsimmons, Kathryn. "An assessment of the luminescence sensitivity of Australian quartz with respect to sediment history." Geochronometria 38, no. 3 (September 1, 2011): 199–208. http://dx.doi.org/10.2478/s13386-011-0030-9.
Повний текст джерелаАнотація:
Abstract This study provides a preliminary systematic characterisation of OSL sensitivity, with respect to sediment history, of single grains of Australian quartz from a variety of source rocks and depositional contexts. Samples from two distinct lithologies and with relatively short modern sedimentary histories were compared in an examination of the influence of rock type on OSL sensitivity. Sediments derived from weathered sandstone were found to be brighter than those from metamorphosed schists, suggesting that sensitivity may be inherited from the source rock and its earlier sedimentary history. Secondly, quartz from the same source, but different modes of deposition, was compared to assess the effect on sensitivity of nature of exposure to light during the most recent bleaching event. Quartz grain sensitivity appears not to vary depending on the mode of sediment deposition, suggesting that the nature of exposure to light during deposition is less important in the sensitisation process. This study highlights the complexity and variety of natural sedimentary quartz, demonstrating the limitations of an investigation based solely on OSL sensitivity. Further systematic investigation into the physical, geological and geomorphological characteristics of sediments is proposed to better understand the mechanisms of luminescence sensitisation in quartz.
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Cook, Jennie E., Laurel B. Goodwin, David F. Boutt, and Harold J. Tobin. "The effect of systematic diagenetic changes on the mechanical behavior of a quartz-cemented sandstone." GEOPHYSICS 80, no. 2 (March 1, 2015): D145—D160. http://dx.doi.org/10.1190/geo2014-0026.1.
Повний текст джерелаАнотація:
A key goal of petrophysical studies of sandstones is to relate common field measurements, particularly seismic or sonic velocities, to parameters defining the rock’s mechanical and hydrologic characteristics. These include elastic and inelastic mechanical properties, porosity, and permeability. We explored relationships among these properties in variably quartz-cemented, mature arenites of the St. Peter Sandstone with porosities ranging from 9% to 25%. In a previous paper, we described microstructural changes accompanying progressive quartz cementation and related porosity and permeability reduction in this sample suite. Here, we report ultrasonic velocities ultrasonic velocities, dynamic and static elastic properties, confined compressive strength, and tensile strength. Analyses of these data demonstrated that factors controlling permeability also fundamentally determined the elastic and inelastic mechanical properties. We found that the number of grain contacts, or bonds, per number of grains viewed in the thin section (bond-to-grain ratio [BGR]) was a key predictive parameter of the mechanical and hydrologic properties. Although the contact length and number of contacts correlated well with the mechanical behavior, statistical analyses showed that BGR was a better predictor of strength, elastic stiffness, and fluid transport properties than was the contact length. The BGR provided a measure of the pore throat occlusion that reduced permeability and the connectivity of the grain framework that stiffened and strengthened the rock. Because porosity and BGR were typically well correlated, porosity was a more quickly and easily measured proxy for BGR in this case. However, our analysis showed that it was the microstructural changes associated with porosity loss rather than porosity loss per se that largely controlled the properties of interest. Thus, consideration of BGR as well as the relative strengths of grains and bond type (cement, pressure solution) for different compositions of sandstone and cement may constructively form the basis for comparative studies of other more complex sandstones.
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Solongo, Saran, Daniel Richter, Tuguldur Begzjav, and Jean-Jacques Hublin. "OSL and TL characteristics of fine grain quartz from Mongolian prehistoric pottery used for dating." Geochronometria 41, no. 1 (March 1, 2014): 15–23. http://dx.doi.org/10.2478/s13386-013-0119-4.
Повний текст джерелаАнотація:
Abstract The OSL, post-IR OSL and pulsed post-IR OSL applied to polymineral grains and calculated by fitting to the data the contributions from fast, medium and slow components revealed that the polymineral samples under study are dominated by the medium component. An increase in De’s with increasing integration intervals was observed, which is considered as an indication of increasing medium and decayed fast component; and the equivalent doses obtained using different components or minerals reflect also the shape of the dose distributions. The identified fast component in polymineral sample has photoionization cross section of 1.2±0.02 × 10−17 cm2. The present study shows the usefulness of the application of different luminescence techniques combined with fitting procedures as a check which should be adopted in dating protocols. Based on luminescence ages obtained on poly-mineral grains from prehistoric pottery samples from the Boroo settlement, Mongolia, which are in agreement with independent age control by 14C on charcoal material, it is argued that the manufacturing of Xiongnu — pottery at this site lasted until ca. 130±75 AD.
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Koch, Kristof, André Revil, and Klaus Holliger. "Relating the permeability of quartz sands to their grain size and spectral induced polarization characteristics." Geophysical Journal International 190, no. 1 (May 21, 2012): 230–42. http://dx.doi.org/10.1111/j.1365-246x.2012.05510.x.
Повний текст джерела
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Poernomo, Herry, and Noor Anis Kundari. "DISPERSION AND SORPTION CHARACTERISTICS OF URANIUM IN THE ZEOLITE-QUARTZ MIXTURE AS BACKFILL MATERIAL IN THE RADIOACTIVE WASTE REPOSITORY." Indonesian Journal of Chemistry 6, no. 3 (June 15, 2010): 261–67. http://dx.doi.org/10.22146/ijc.21729.
Повний текст джерелаАнотація:
The experiment of sorption and dispersion characteristics of uranium in the zeolite-quartz mixture as candidate of raw material of backfill material in the radioactive waste repository has been performed. The objective is to know the effect of zeolite and quartz grain size on the zeolite-to-quartz weight ratio that gives porosity (ε), permeability (K), and dispersivity (α) of uranium in the zeolite-quartz mixture as backfill material. The experiment was carried out by fixed bed method in the column filled by the zeolite-quartz mixture with zeolite-to-quartz weight percent ratio of 100/0, 80/20, 60/40, 40/60, 20/80, 0/100 wt. % in the water saturated condition flowed by uranyl nitrate solution of 500 ppm concentration (Co) as uranium simulation which was leached from immobilized radioactive waste in the repository. The concentration of uranium in the effluents represented as Ct were analyzed by spectrophotometer Corning Colorimeter 253 every 15 minutes, then using Co and Ct uranium dispersivity (α) in the backfill material was determined. The experiment data shown that 0.196 mm particle size of zeolite and 0.116 mm particle size of quartz on the zeolite-to-quartz weight ratio of 60/40 wt. % with ε = 0.678, K = 3.345x10-4 cm/second, and α = 0.759 cm can be proposed as candidate of raw material of backfill material in the radioactive waste repository. Keywords: backfill material, quartz, radioactive waste, zeolite
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Ilevbare, M., and O. I. Imasuen. "Sedimentology and maturity of Ajali formation, Benin flank Anambra basin, Nigeria." Ife Journal of Science 22, no. 1 (May 26, 2020): 123–36. http://dx.doi.org/10.4314/ijs.v22i1.13.
Повний текст джерелаАнотація:
The Ajali Sandstone, western flank, Anambra Basin, was studied for textural characteristics and maturity of the sediments. Grain size analysis (51 samples), thin section and heavy mineral analysis (15 samples each) and XRF fusion for metallic oxides (15 samples) were analyzed. The textural parameters show that the Ajali Sandstone are medium sand, poorly to moderately sorted, coarse to strongly coarse skewed with mesokurtic to leptokurtic grains. The thin section analysis reveals grains that are sub-angular to sub-rounded (this typifies grains that have travelled fairly long distance to the deposition site), of moderate to well sorted grains, with both monocrystalline and polycrystalline quarts-grains type, with a modal composition of Q F and L . A mineralogical maturity 90.4, 2.3 2.9 index (MMI) of 17.04, SiO /Al O ratio of 180.24, and a ZTR index of 67.96% were obtained. The values for the 2 2 3 MMI and SiO /Al O indicates mineralogical matured sediments, the ZTR index shows a chemically immature 2 2 3 to sub-mature sandstone, and the modal composition values are consistent with a texturally and compositionally matured sands. The mineralogical maturity is indicative of high degree of chemical weathering of source area. Furthermore, the high quartz and silica content make the sandstone prospective for glass and glassware production.
Key words: Anambra Basin, Maturity, Mineralogical maturity index, Textural characteristics, Glass
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Trauerstein, Mareike, Sally E. Lowick, Frank Preusser, and Heinz Veit. "Testing the suitability of dim sedimentary quartz from northern Switzerland for OSL burial dose estimation." Geochronometria 44, no. 1 (April 12, 2017): 66–76. http://dx.doi.org/10.1515/geochr-2015-0058.
Повний текст джерелаАнотація:
Abstract We investigate the suitability of sedimentary quartz associated with former glacial advances in northern Switzerland to provide reliable burial dose estimates using Optically Stimulated Luminescence (OSL). Previous studies on northern alpine quartz show that its signal characteristics can be poor and potentially problematic. We analyse quartz signals of small aliquots, which reveal the presence of a prominent medium or slow component in the initial part of some signals. Nonetheless, rejection of aliquots with unfavourable signal composition does not alter the burial dose estimates, but significantly reduces the data set for De determination. Signal lifetimes from isothermal decay measurements cover a wide range of values, yet the lowest lifetimes are high enough to guarantee a reliable burial dose estimate for samples of < 400 ka. Comparison of small aliquot and single grain burial dose distributions reveals that signal averaging masks partial bleaching in some of the samples. We therefore strongly recommend single grain measurements for samples from this setting and area, in order to exclude age overestimation due to partial bleaching.
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Carranza-Edwards, Arturo, and Leticia Rosales-Hoz. "Grain-size trends and provenance of southwestern Gulf of Mexico beach sands." Canadian Journal of Earth Sciences 32, no. 12 (December 1, 1995): 2009–14. http://dx.doi.org/10.1139/e95-153.
Повний текст джерелаАнотація:
Sand samples from 30 beach locations of the southwestern Gulf of Mexico littoral zone were texturally and mineralogically investigated. Based on their source lithology and fluvial network, they were subdivided into two groups: (1) sands with volcanic rocks in the source region and (2) sands with a nonvolcanic source. Sands from foreshore and backshore areas exhibit similar textural characteristics, with less rock fragments than those from the inshore zone, where the high energy of breaking waves and littoral currents is present. A quartz–feldspar–rock fragment triangular diagram indicates that the proximity of volcanic sources is responsible for the enrichment of rock fragment content in the beach sands. Beach sands associated with Tampico and Veracruz embayments have greater quartz content, caused by a greater transport distance. Mineralogical maturity and provenance indexes used in a binary diagram are helpful in discriminating sand samples from volcanic and nonvolcanic domains.
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D'Orsay, A. Murray, and H. W. van de Poll. "Quartz-grain surface textures: evidence for a tropical climate during the Middle Pennsylvanian in eastern Canada." Canadian Journal of Earth Sciences 22, no. 5 (May 1, 1985): 786–90. http://dx.doi.org/10.1139/e85-084.
Повний текст джерелаАнотація:
Scanning electron microscope examination of quartz grains separated from conglomerates in an alluvial fan sequence within the Pennsylvanian Fowler Head Formation of Nova Scotia revealed surface characteristics that are typical of those obtained from modern tropical environments. This evidence suggests that a similar tropical climate may have existed in eastern Canada during Middle Pennsylvanian time.
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Klevakina, K., J. Renner, N. Doltsinis, and W. Adeagbo. "Transport processes at quartz-water interfaces: constraints from hydrothermal grooving experiments." Solid Earth Discussions 5, no. 1 (April 22, 2013): 609–54. http://dx.doi.org/10.5194/sed-5-609-2013.
Повний текст джерелаАнотація:
Abstract. We performed hydrothermal annealing experiments on quartzite at temperatures of 392 to 568 °C and fluid pressures of 63 to 399 MPa for up to 120 h during which hydrothermal grooves developed on the free surfaces of the samples. Analysis of surface topology and groove characteristics with an atomic force microscope revealed a range of surface features associated with the simultaneous and successive operation of several processes partly depending on crystal orientation during the various stages of an experiment. Initially, dissolution at the quartzite-sample surface occurs to saturate the fluid in the capsule with SiO2. Subsequently, grooving controlled by diffusion processes takes place parallel to dissolution and precipitation due to local differences in solubility. Finally, quench products develop on grain surfaces during the termination of experiments. Average groove-root angle amounts to about 80° and slightly depends on temperature, run duration, and misorientation between neighboring grains. The grooving is thermally activated, i.e., groove depth ranging from 5 nm to several micrometers for the entire suite of experiments generally increases with temperature and/or run time. We use Mullins' classical theories to constrain kinetics parameters for the transport processes controlling the grooving. In the light of previous measurements of various diffusion coefficients in the system SiO2-H2O, interface diffusion of Si is identified as the most plausible rate-controlling process. Grooving could potentially proceed faster if the fluid were not convecting in the capsule. Characteristic times of healing of microfractures in hydrous environments constrained from these kinetics parameters are consistent with the order of magnitude of time scales over which healing occurs in-situ according to geophysical surveys and of recurrence intervals of earthquakes.
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Groza-Săcaciu, Ștefana-M., Cristian Panaiotu, and Alida Timar-Gabor. "Single Aliquot Regeneration (SAR) Optically Stimulated Luminescence Dating Protocols Using Different Grain-Sizes of Quartz: Revisiting the Chronology of Mircea Vodă Loess-Paleosol Master Section (Romania)." Methods and Protocols 3, no. 1 (February 27, 2020): 19. http://dx.doi.org/10.3390/mps3010019.
Повний текст джерелаАнотація:
The loess-paleosol archive from Mircea Vodă (Romania) represents one of the most studied sections in Europe. We are applying here the current state of the art luminescence dating protocols for revisiting the chronology of this section. Analysis were performed on fine (4–11 µm) and coarse (63–90 µm) quartz extracts using the single aliquot regenerative (SAR) optically stimulated luminescence (OSL) dating protocol. Laboratory generated SAR dose response curves in the high dose range (5 kGy for fine quartz and 2 kGy for coarse quartz) were investigated by employing a test dose of either 17 or 170 Gy. The results confirm the previously reported different saturation characteristics of the two quartz fractions, with no evident dependency of the equivalent dose (De) on the size of the test dose. The OSL SAR ages are discussed and compared to the previously obtained results on quartz and feldspars. The previous reports regarding the chronological discrepancy between the two quartz fractions are confirmed. However, while previous investigations on other sites concluded that this discrepancy appears only above equivalent doses of about 100 Gy, here fine grain quartz ages underestimate coarse quartz ages starting with equivalent doses as low as around 50 Gy.
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Fitzsimmons, Kathryn E., Zoran Perić, Maike Nowatzki, Susanne Lindauer, Mathias Vinnepand, Charlotte Prud’homme, Aditi K. Dave, Andreas Vött, and Peter Fischer. "Luminescence Sensitivity of Rhine Valley Loess: Indicators of Source Variability?" Quaternary 5, no. 1 (December 21, 2021): 1. http://dx.doi.org/10.3390/quat5010001.
Повний текст джерелаАнотація:
Loess provides a valuable terrestrial record of past environmental conditions, including the dynamics and trajectories of air mass circulation responsible for dust transport. Here we explore variations in the luminescence sensitivity characteristics of sedimentary quartz and feldspar as possible tools for identifying changes in source down a loess-palaeosol sequence (LPS). Luminescence sensitivity is a rapidly measurable index which is the product of interplay between source lithology and the history of the quartz or feldspar clasts. Variations in sensitivity of down profile may therefore reflect changes in sediment provenance as well as other factors such as weathering through pedogenesis. We undertake an empirical investigation of the luminescence sensitivity of quartz and feldspar from different grain-size fractions from the Schwalbenberg LPS in the German Rhine valley. We compare samples from a 30 m core spanning the last full glacial cycle with samples of oxygen isotope stage (OIS) 3–2 age exposed within nearby profile. We find an overall inverse relationship between quartz and feldspar sensitivity, as well as variability in sensitivity between different quartz grain sizes. Statistical analyses yield a significant correlation between IR50 sensitivity from unprocessed sediments and clay content, and feldspar sensitivity and Si/Al ratios down the core. Since Si/Al ratios may indicate changes in provenance, the latter correlation suggests that IR50 measurements on unprocessed samples may be used to provide a reliable, rapid scan of source variability over millennial timescales.
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Chen, Yong, Yongsheng Song, Wenjuan Li, and Liulu Cai. "Mineralogical Characteristics of a Micro-Fine and Low Grade Refractory Gold Ore." MATEC Web of Conferences 142 (2018): 02011. http://dx.doi.org/10.1051/matecconf/201814202011.
Повний текст джерелаАнотація:
Detailed characterization of a micro-fine, low-grade refractory gold ore from a beneficiation plant in Yunnan Province, China, was investigated. Different analytical techniques, such as videlicet size analysis, scanning electron microscopy, and mineral analysis by a Mineral Liberation Analyser, were used for mineralogical characterization of the ore. The results show that the most valuable metal is gold. Grain size of pyrites and arsenian pyrites, which are main gold carrying minerals, are mostly 1 ~ 30 μ m. The gangue mineral is composed of quartz, mica, dolomite and feldspar, while the content of easy-to-float and clay gangue minerals is up to 33%.
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Klevakina, K., J. Renner, N. Doltsinis, and W. Adeagbo. "Transport processes at quartz–water interfaces: constraints from hydrothermal grooving experiments." Solid Earth 5, no. 2 (August 27, 2014): 883–99. http://dx.doi.org/10.5194/se-5-883-2014.
Повний текст джерелаАнотація:
Abstract. We performed hydrothermal annealing experiments on quartzite samples at temperatures of 392 to 568 °C and fluid pressures of 63 to 399 MPa for up to 120 h, during which hydrothermal grooves developed on the free surfaces of the samples. An analysis of surface topology and groove characteristics with an atomic force microscope revealed a range of surface features associated with the simultaneous and successive operation of several processes partly depending on crystal orientation during the various stages of an experiment. Initially, dissolution at the quartzite-sample surface occurs to saturate the fluid in the capsule with SiO2. Subsequently, grooving controlled by diffusion processes takes place parallel to dissolution and precipitation due to local differences in solubility. Finally, quench products develop on grain surfaces during the termination of experiments. The average groove-root angle amounts to about 160°, varying systematically with misorientation between neighboring grains and depending slightly on temperature and run duration. The grooving is thermally activated, i.e., groove depth ranging from 5 nm to several micrometers for the entire suite of experiments generally increases with temperature and/or run time. We use Mullins' classical theories to constrain kinetic parameters for the transport processes controlling the grooving. In the light of previous measurements of various diffusion coefficients in the system SiO2–H2O, interface diffusion of Si is identified as the most plausible rate-controlling process. Grooving could potentially proceed faster by diffusion through the liquid if the fluid were not convecting in the capsule. Characteristic times of healing of microfractures in hydrous environments constrained from these kinetic parameters are consistent with the order of magnitude of timescales over which postseismic healing occurs in situ according to geophysical surveys and recurrence intervals of earthquakes.
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Ke, Ganpan, Merrick Johnston, and Hefeng Dong. "Rock-physics models for bitumen-saturated sands: Fractional gradient model and Hashin-Shtrikman iterative model." GEOPHYSICS 77, no. 2 (March 2012): D7—D15. http://dx.doi.org/10.1190/geo2011-0338.1.
Повний текст джерелаАнотація:
Rock-physics modeling of heavy-oil-saturated sands requires adjustments and new approaches to the available fluid-substitution schemes used on conventional reservoirs. This paper introduces two models: the fractional-gradient model (FGM) for simulating the frequency dispersion of the shear modulus of pure bitumen and the Hashin-Shtrikman iterative model (HSIM) for modeling the moduli of bitumen-saturated sands as a function of frequency and temperature. Taylor expansion shows that the first-order FGM has higher resolution than the Maxwell model and lower complexity than the Cole-Cole model. In addition, FGM is superior to Maxwell and Cole-Cole models in that viscosity modeling does not need to be done prior to shear-modulus modeling. The building of HSIM is based on observations of the microstructure of the bitumen-saturated sands. Three main characteristics in the sands are observed in the simplified model, producing a range of stiff, medium, and soft effective matrices. Bitumen can dominate the matrix as if the quartz grains were suspended in it (soft); quartz grains can surround the bitumen (stiff); and a bitumen layer can form around the quartz grain (medium). The quartz grains are assumed to be statistically spherical. HSIM is obtained by iteratively calculating the HS bounds of the stiff and soft parts of the sands. The measured shear modulus of pure bitumen and bitumen-saturated sands at different frequencies and temperatures verify the validity of these two models. The combination of these two models gives a novel fluid-substitution routine for modeling the time-lapse response during steam-assist gravity draining thermal production of bitumen. The limitations of the two models also are discussed.
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Gabryś, Katarzyna, Emil Soból, Wojciech Sas, Raimondas Šadzevičius, and Rytis Skominas. "Warsaw Glacial Quartz Sand with Different Grain-Size Characteristics and Its Shear Wave Velocity from Various Interpretation Methods of BET." Materials 14, no. 3 (January 23, 2021): 544. http://dx.doi.org/10.3390/ma14030544.
Повний текст джерелаАнотація:
After obtaining the value of shear wave velocity (VS) from the bender elements test (BET), the shear modulus of soils at small strains (Gmax) can be estimated. Shear wave velocity is an important parameter in the design of geo-structures subjected to static and dynamic loading. While bender elements are increasingly used in both academic and commercial laboratory test systems, there remains a lack of agreement when interpreting the shear wave travel time from these tests. Based on the test data of 12 Warsaw glacial quartz samples of sand, primarily two different approaches were examined for determining VS. They are both related to the observation of the source and received BE signal, namely, the first time of arrival and the peak-to-peak method. These methods were performed through visual analysis of BET data by the authors, so that subjective travel time estimates were produced. Subsequently, automated analysis methods from the GDS Bender Element Analysis Tool (BEAT) were applied. Here, three techniques in the time-domain (TD) were selected, namely, the peak-to-peak, the zero-crossing, and the cross-correlation function. Additionally, a cross-power spectrum calculation of the signals was completed, viewed as a frequency-domain (FD) method. Final comparisons between subjective observational analyses and automated interpretations of BET results showed good agreement. There is compatibility especially between the two methods: the first time of arrival and the cross-correlation, which the authors considered the best interpreting techniques for their soils. Moreover, the laboratory tests were performed on compact, medium, and well-grained sand samples with different curvature coefficient and mean grain size. Investigation of the influence of the grain-size characteristics of quartz sand on shear wave velocity demonstrated that VS is larger for higher values of the uniformity coefficient, while it is rather independent of the curvature coefficient and the mean grain size.
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Pantopoulos, George, Gustavo Kenji Lacerda Orita, Garibaldi Armelenti, Camila Eliza Althaus, Juliano Kuchle, Claiton Marlon dos Santos Scherer, Amanda Goulart Rodrigues, and Luiz Fernando De Ros. "Depositional conditions at the Aptian pre-salt margins: evidence from quantitative petrography and textural analysis of the Mucuri Member, Espírito Santo Basin, Brazil." Petroleum Geoscience 27, no. 4 (May 4, 2021): petgeo2020–112. http://dx.doi.org/10.1144/petgeo2020-112.
Повний текст джерелаАнотація:
Aptian siliciclastic onshore deposits of the Mucuri Member are important reservoirs in the Espírito Santo Basin (eastern Brazil). A detailed quantitative petrographical and textural analysis of well core samples was performed in order to unravel their depositional processes and conditions, in relation to previously proposed depositional models. The results allowed differentiation between two groups of sandstone samples, characterized by different textural characteristics associated to different depositional processes and environments within the Mucuri depositional system. Fluvial sandstones are represented by medium- to coarse-grained, poorly sorted arkoses, rich in plutonic rock fragments and feldspar grains, mainly transported by traction. Coastal-lacustrine sandstones correspond to very fine- to fine-grained, moderately sorted micaceous arkoses, mainly transported in suspension. The application of a discriminant function based on grain-size parameters validated previously proposed depositional settings for the studied sample groups. The combination of grain-size and shape data revealed differences in hydraulic equivalence and shape between grains from different depositional settings. In terms of hydraulic equivalence, micas in the fluvial sediments present lower settling velocity values, in contrast to the relatively large mica grains in the coastal sediments, which are hydraulically equivalent with the associated quartz and feldspar grains. The results of this study provide key information regarding depositional conditions (transportation mechanisms, grain-settling velocity and mineral hydraulic fractionation) at the margins of the Aptian pre-salt system, which can constrain the hydrological conditions and the sediment type available for distal lacustrine areas.
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Irvani, Irvani, and Elsha Delvi Artasari. "Studi Karakteristik Tailing Pada Lokasi Eks Penambangan Timah di Bukit Sambung Giri Kecamatan Merawang Kabupaten Bangka." PROMINE 6, no. 2 (December 25, 2018): 31–36. http://dx.doi.org/10.33019/promine.v6i2.1086.
Повний текст джерелаАнотація:
Tailing deposits at ex-tin mining area in Bangka and Belitung Island has a large number of economical
residual minerals. This study is to identify tailing characteristic and its potential mineralogy and
elements based on shallow hand boring (Auger) samples, along stream line in west part of Sambung
Giri Hill. Every coordinate sample plotted on base map. Loboratory analisys using Strereo
Mikroscope for identify minerals characteristics, and geochemical analysis using XRF for identification
the presence of elements. The tailing deposits has laterally grain size gradation to down stream,
composed above 94% sand fraction, and small amount of shale and granule fraction. Quartz mineral
presence more then 90%, followed by iron oxide (hematite), clay, zircon, cassiterite, ilmenite, monazite
and tourmaline minerals, showed low consistency in lateral spatial exept quartz, with its Rare Earth
Elementh (REE) composition is Cerium (Ce), Lanthanum (La), Yttrium (Y), Neodymium (Nd) and
Samarium (Sm).
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Aini, H. N., N. I. Setiawan, M. N. Haq, C. A. Mahardika, S. Nugroho, and R. Setiawan. "Characteristics of Mengger Formation’s volcaniclastic in Cisaat River, Brebes, Central Java, Indonesia." IOP Conference Series: Earth and Environmental Science 1071, no. 1 (August 1, 2022): 012014. http://dx.doi.org/10.1088/1755-1315/1071/1/012014.
Повний текст джерелаАнотація:
Abstract The Cisaat River in Brebes Regency, Central Java, is one of the sites on Java Island where vertebrate fossils were found. Mengger Formation, composed of volcaniclastics material such as tuff and pumice fragments, contains these fossils. The presence of vertebrate fossils along with volcanic deposits has remained unclear of its deposition history. This research characterizes the volcaniclastic rocks in Mengger Formation based on geological field observation and petrography analysis. The study aims to identify and distinguish its primary and secondary volcaniclastic depositional processes. The measured stratigraphic sections reveal that the formation has 7 lithofacies from older to younger, namely grain-supported conglomerate, sandstone, siltstone, sandy mudstone, matrix-supported conglomerate, tuffaceous sandstone, and tuffaceous conglomerate. The primary volcaniclastic materials comprise pumice clast, plagioclase, pyroxene, hornblende, quartz, biotite, lithic fragments, and volcanic glass. In contrast, secondary volcaniclastic or epiclastic-sedimentary materials contain lithic fragments, quartz, plagioclase, pumice clast, and clay matrix. The origin of the resedimented volcaniclastic material was probably derived from a large volume of ignimbrite near the volcano. From the deposit and measurement section, it can be concluded that the type of the Mengger volcaniclastic.
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Górniak, K., T. Szydłak, A. Gaweł, A. Klimek, A. Tomczyk, B. Sulikowski, Z. Olejniczak, J. Motyka, E. M. Serwicka, and K. Bahranowski. "Commercial bentonite from the Kopernica deposit (Tertiary, Slovakia): a petrographic and mineralogical approach." Clay Minerals 51, no. 1 (March 2016): 97–122. http://dx.doi.org/10.1180/claymin.2016.051.1.09.
Повний текст джерелаАнотація:
AbstractCommercial bentonite from the Kopernica deposit, Slovakia, is currently mined by the CERTECH Company, Poland, to produce materials intended for animal-care applications and other industrial purposes. The present study aimed to assess the mineralogical, petrographic and physicochemical characteristics of three bentonite varieties from Kopernica used by the company. The X-ray diffraction, optical microscopy, field emission scanning electron microscopy (FESEM), nuclear magnetic resonance, thermal analysis, infrared spectroscopy and chemical analyses showed that the main component of the rocks is montmorillonite with the average structural formula Ca0.31K0.08Na0.04(Al3.23Mg0.54Fe0.23)[(Si7.80Al0.20)O20](OH)4. In addition, opal-C/CT, biotite, potassium feldspar and plagioclase, quartz, clinoptilolite and kaolinite are present. Key information about the textural relationships between the mineral components identified was obtained from detailed thin-section petrography and FESEM studies. The rocks studied have fragmented, eutaxitic texture. They are composed of pumice fragments collapsed into lenticular masses (fiamme) which were strongly deformed and altered, though the shard structures were retained. The compressed glass shards were moulded around pyroclastic grains such as crystal fragments of quartz, biotite and zoned plagioclases, and clasts of volcanic rocks. Observations by FESEM showed that the axes of shards and the walls of the flattened vacuoles are outlined by the inward-growing microlites of silica (axiolitic texture), whilst the interiors of shards are altered to clay. Grain-size distribution, textural properties and microscope observations of grain-size fractions reveal that the Kopernica bentonite contains montmorillonite-opal aggregates difficult to disperse in water.
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Sesikashvili, Otari, Elene Gamkrelidze, Nodari Mardaleishvili, Gia Dadunashvili, Shalva Tsagareishvili, and George Pkhakadze. "The biochemical changes in legumes during high-temperature micronization." Potravinarstvo Slovak Journal of Food Sciences 15 (June 28, 2021): 555–65. http://dx.doi.org/10.5219/1629.
Повний текст джерелаАнотація:
The article considers the change in chemical and biological characteristics in some legumes grains, under conditions of high-temperature micronization with different moisture contents during heat treatment with infrared rays. The heat treatment of grains was carried out on a laboratory apparatus with a quartz radiant infrared panel. The temperature variation in the heat treatment zone occurred due to changing the distance between the panel and the surface of grains. The grain temperature was determined using a laser thermometer, and with a timer. To determine chemical and biological characteristics, we used a special optical density metering device. We have studied: 1. The dependence of starch content on the temperature in the changing initial moisture content. We found that after 30 seconds of high-temperature micronization of, “Tsanava“ beans at a grain moisture content of 12.7%, the starch content in the grain increases from 39.65% to 40.12%, then gradually decreases, and at 18.3% moisture content, it increases from 38.71% to 41.2%, with a moisture content of 28.6% it increases from 37.36% to 42.42%. Similar processes are also observed for the beans “field red“ and “white lupine“; 2. The dependence of glucose content on the temperature in the changing initial moisture content. As the mass fraction of starch decreases, the percentage of sugar (in terms of the equivalent amount of glucose) at a moisture content of 12.7% at the initial stage increases from 1.36% to 1.46%, and then the percentage of sugar increases relatively quickly to 1.64%, at a moisture content of 18.3% it increases from 1.3% to 1.38%, and then increases to 1.51, with a moisture content of 28.6%, it increases from 1.28% to 1.35% and then increases to 1.54. Similar processes are also observed for the beans “field red“ and “white lupine“.
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Wang, Zhenkang, Jiangfeng Chen, Wenping Li, Qiqing Wang, Qinghe Niu, Shiliang Liu, and Yanbo Hu. "Relationship between petrographic parameters and physical-mechanical properties of weakly cemented sandstones." Quarterly Journal of Engineering Geology and Hydrogeology 54, no. 1 (April 3, 2020): qjegh2018–168. http://dx.doi.org/10.1144/qjegh2018-168.
Повний текст джерелаАнотація:
Petrographic characteristics (textural properties and modal compositions) have an intrinsic influence on the physical and mechanical (PM) properties of weakly cemented sandstones. Sixteen sandstone samples were tested to determine the PM parameters and then thin sections from those samples were used to measure the petrographic parameters. Petrographic parameters were analysed statistically to establish quantitative relationships between the petrographic characteristics and PM properties. Based on multiple linear regression (MLRA) and stepwise multiple regression analyses (SMRA), several multiple regression equations with significant petrographic variables were established for estimating the PM parameters of the sandstone. Results indicated that uniaxial compressive strength (UCS) and Young's modulus (E) were closely related to mean grain size (Mz) (φ-value), non-uniform coefficient (Cu), fractal dimension (Fd), Riley sphericity (Ψp), packing proximity (Pp), floating contacts (Fl), grain-to-grain contacts (G-G), feldspar content and organic matter content. An increased percentage of grain-to-cement contacts (G-C) and reduced percentages of grain-to-matrix contacts (G-M) and organic matter content indicated a high value of Poisson's ratio (POISS). In addition, Mz, Cu, Fd, Ψp, quartz, feldspar, and organic matter contents were found to be significant parameters for density and P-wave velocity (Vp). Furthermore, density and POISS could be predicted using the results from the MLRA and Fd was a good predictor for density, Vp and UCS using the results from the SMRA. Additionally, it was noted that the petrographic characteristics of roof sandstones had significant influence on the overburden pressure characteristics within the coal faces in the Shendong mining area.
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Mamedov, Natig Khankishi, Babek Zakir Salmanov, Gabil Balakishi Mamedov, and Urfan Tofig Taghiyev. "Opimization of the main design and operating parameters of the micronization device." Agrarian Scientific Journal, no. 8 (September 10, 2021): 100–103. http://dx.doi.org/10.28983/asj.y2021i8pp100-103.
Повний текст джерелаАнотація:
The article substantiates the main characteristics of the studied device of micronization in the processing of grain feed by the method of micronization. Here, an experimental micronizer that micronizes feed grain was taken as the object of research. A multi-factor experiment was also conducted to determine the optimal distance of the infrared lamp from the quartz glass and the optimal power of the light flux. The experiments were carried out on an experimental installation equipped with a “Legrand” dimmer, which allowed changing the radiation power of the lamps. For the experiments, a symmetrical Box-Bench plan was selected from a rotatable, composite second tier. The studies were conducted on wheat, barley and velamir.
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Kalvoda, Ladislav, Martin Dráb, Monika Kučeráková, and Stanislav Vratislav. "Freezing and Thawing of D2O/Sand Mixtures Investigated by Neutron Diffraction." Crystals 11, no. 8 (August 16, 2021): 961. http://dx.doi.org/10.3390/cryst11080961.
Повний текст джерелаАнотація:
Evolution ice diffraction patterns in mixtures of D2O with quartz sand of three different grain coarseness (100–600, 300–800 and 600–1200 μm) were studied under various temperature regimes by means of neutron diffraction method. The studied structural parameters and characteristics involved the phase composition of specimens, Ih D2O ice lattice parameters, and crystallographic texture of the present phases. Variations in the ice crystallographic texture during the repeated freezing and thawing were observed for all tested sample types, showing an intermittent enhancement of ice and quartz texture indices accompanying the start of specimens cooling. Formation of radial internal stresses is demonstrated by the observed split of (002) and (100) diffraction maxima of ice. Estimated mean internal radial stress values are calculated.
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Rahimzadeh, Neda, Tobias Sprafke, Christine Thiel, Birgit Terhorst, and Manfred Frechen. "A comparison of polymineral and K-feldspar post-infrared infrared stimulated luminescence ages of loess from Franconia, southern Germany." E&G Quaternary Science Journal 70, no. 1 (February 8, 2021): 53–71. http://dx.doi.org/10.5194/egqsj-70-53-2021.
Повний текст джерелаАнотація:
Abstract. Loess-paleosol sequences (LPSs) are essential records for reconstructing Quaternary paleoenvironments. No previous study has provided numerical chronologies of loess in Lower Franconia, southern Germany; their chronostratigraphic assumptions have relied mainly on German (pedo)stratigraphic schemes. In this study, we provide for the first time a chronology for LPSs in Lower Franconia based on optically stimulated luminescence (OSL) dating using quartz and a comparison of K-feldspar (63–100 µm) and the polymineral fraction (4–11 µm). Our results show that all obtained ages are in stratigraphic order, ranging from Holocene to late Pleistocene, and in general confirm the former stratigraphical interpretations. A good agreement of the obtained ages is observed between both feldspar grain size fractions; they also agree well with the quartz OSL ages up to ∼50 ka. However, a marked difference between the growth pattern of the dose response curves and consequently different saturation characteristics of fine and coarse grains is found. Even though in our samples the discrepancy in ages is not very significant, we suggest the use of coarse-grained K-feldspar whenever possible in order to not be confronted with unknowns such as the mineral composition of the polymineral fraction.
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Tsodoulos, I., K. C. Stamoulis, C. Papachristodoulou, PS Pavlides, and K. G. Ioannides. "APPLICATION OF OSL METHOD IN DATING PAST EARTHQUAKES." Bulletin of the Geological Society of Greece 50, no. 1 (July 27, 2017): 392. http://dx.doi.org/10.12681/bgsg.11740.
Повний текст джерелаАнотація:
The aim of this study was to establish a chronological frame of paleoseismic events of Gyrtoni Fault, (Thessaly, Central Greece), with the use of OSL dating method. The Gyrtoni Fault, defines the north-eastern boundary of the Middle-Late Quaternary Tyrnavos Basin, and was previously investigated with geological methods. Twenty five fluvial-colluvial sediment and pottery samples were collected from two paleoseismological trenches, excavated along the Gyrtoni Fault, from both the upthrown and the downthrown fault blocks. Optically Stimulated Luminescence (OSL) dating was applied to coarse grain quartz using the single-aliquot regenerative-dose (SAR) protocol. Investigations of luminescence characteristics using various tests confirmed the suitability of the material for OSL dating using the SAR protocol. Radioactivity measurements were performed in order to estimate the annual dose rateof the surrounding soils to which the quartz grains were submitted during the burial period of the collected samples. The estimated OSL ages agreed well with the available stratigraphical data, and archaeological evidence. The occurrence of three surface faulting events in a time span between 1.42 ± 0.06 ka and 5.59 ± 0.13 ka was revealed while an earlier faulting event (fourth) was also recognized to be older than 5.59 ± 0.13 ka.
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Sokic, Miroslav, Jovica Stojanovic, Branislav Markovic, Mladen Bugarcic, Nada Strbac, Zeljko Kamberovic, and Vaso Manojlovic. "Effects of structural and textural grain characteristics on leaching of sulphide minerals from a polymetallic concentrate by sodium nitrate and sulphuric acid solution." Chemical Industry 71, no. 6 (2017): 461–69. http://dx.doi.org/10.2298/hemind161130006s.
Повний текст джерелаАнотація:
In this paper, the influence of structural and textural characteristics of sulfide minerals on their leaching from a polymetallic concentrate by sulfuric acid and sodium nitrate solution is presented. The starting material was Pb?Zn?Cu sulphide polymetallic concentrate enriched during the flotation of a polymetallic ore in the "Rudnik" flotation plant (Rudnik ? Serbia). Leaching experiments were carried out in a closed glass reactor, which provides stable hermetic conditions and allows heating at constant temperature. Chemical, XRD, qualitative and quantitative microscopic and SEM/EDX analyses were used to characterizes samples of the polymetallic concentrate and leach residue. It was determined that chalcopyrite, sphalerite, galena, pyrrhotite and quartz were present in the polymetallic concentrate. The content of sulphide minerals was 69.5%, of which 60.9% occurred as liberated grains: 88.3% of chalcopyrite, 59.3% of sphalerite, 25.1% of galena and 51.6% of pirrhotite. The rest of chalcopyrite, sphalerite, galena and pirrhotite grains were in the forms of inclusions, impregnations, and simple and complex intergrowths. During the leaching process by sodium nitrate and sulphuric acid solution, it was shown previously that the leaching rate of sulphide minerals decreased with time while a part of the sulphide minerals remained in the leach residue. After leaching at 80?C for 120 min, the yields were 69.8, 82.7 and 67.1% for Cu, Zn and Fe, respectively. Lead, in the form of insoluble anglesite, remained in the leach residue. In addition to the anglesite, unleached sulfide minerals and quartz, elemental sulfur was found in the solid residue. The content of sulphide minerals was 35% of which 33.7% minerals occur independently. In specific, 54.7% of chalcopyrite, 31.9% of sphalerite, 8.2% of galena and 37.6% of pyrrhotite appear as separate grains with highly corroded surfaces. Therefore, the structural assembly of sulphide grains in the polymetallic concentrate is favourable and it is not the reason for the observed decrease in the leaching rate in the final process stages. The obtained findings may be explained by the presence of elemental sulphur that is formed during the reaction and precipitated at the grain surfaces, thus creating a diffusion barrier for the leach solution.
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Jiu, Bo, Wenhui Huang, Jing Shi, and Mingqian He. "Growth Mechanism of Siliceous Cement in Tight Sandstone and Its Influence on Reservoir Physical Properties." Energies 11, no. 11 (November 13, 2018): 3133. http://dx.doi.org/10.3390/en11113133.
Повний текст джерелаАнотація:
To investigate the effect of siliceous cementation on the densification of sandstone and the forming process of tight sandstone, based on cathodoluminescence, scanning electron microscopy and thin section analysis, the growth mechanism and characteristics of quartz particles in tight sandstone formations are explored. Meanwhile, combined with conventional core analysis and X-ray diffraction experiments, the factors affecting the crystallization of quartz particles, including the chlorite content, grain size and clay mineral, are analyzed, respectively. The entire siliceous cementation is divided into two processes. The first part is the process in which the weathered and rounded particles in the formation are restored to the hexagonal dipyramid crystal by siliceous cementation. The second part is the process of coaxial growth that the hexagonal dipyramid crystal continues to increase with the form of micro-quartz film. As siliceous cements continue to increase, the petrological characteristics of sandstones are constantly changing. The tight sandstone developed in the study area is composed of lithic sandstone and quartz lithic sandstone. Based on the analysis results, 2D and 3D evolution models are established for densification of two different lithic sandstones. When the content of siliceous cement in the study area is less than 17%, the porosity of tight sandstone increases with the increase of cement. When the content of cement is more than 17%, the porosity of tight sandstone is negatively correlated with the content of cement. When the cement content is greater than 10%, the reservoir permeability is negatively correlated with it. Furthermore, the particle size mainly affects the permeability of reservoir, and the particle size is negatively correlated with the permeability of tight sandstone. The most high-quality tight sandstone reservoir in the study area is in the first cementation stage when siliceous cements are distributed in porphyritic texture with the content of 10–15% and a grain size of 0.2–0.3 mm. In addition, the relatively high-quality reservoir is the one developing clay mineral film with a content of cementation about 5–12%.
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Skripnikova, N. K., V. A. Vlasov, M. A. Semenovykh, G. G. Volokitin, and V. V. Shekhovtsov. "CARBON-CONTAINING TECHNOGENIC RAW MATERIALS IN CERAMIC PRODUCT PRODUCTION." Vestnik Tomskogo gosudarstvennogo arkhitekturno-stroitel'nogo universiteta. JOURNAL of Construction and Architecture, no. 6 (December 29, 2019): 115–21. http://dx.doi.org/10.31675/1607-1859-2019-21-6-115-121.
Повний текст джерелаАнотація:
The paper explores the possibility of using carbon-containing waste produced by a metallurgical plant. The physico-mechanical characteristics of the obtained products are studied depending on the compositions and the grain size of the feedstock. It is found that the use of carbon-containing waste allows producing ceramic bricks with the following parameters: ρ ~ 2150 kg/m3, Rsg ~ 42 MPa, W ~ 3.4 %, and the frost resistance of over 50 cycles. The results of phase formation in ceramic products are presented. It is shown that the use of carbon-containing waste allows to obtain alumi-nosilicate compounds, such as anorthites and quartz-containing compounds, which give strength characteristics to finished products.