The ferricrete was formed directly from the saprolitic layer of the argillaceous sandstone, preserving the pre-existing structure. The processes of deep weathering, the original enrichment in kaolinite of the sandstone, the age of the plateau, and the paleoclimatic changes have been favorable to the formation of clayey Ferralsol.The mouth bar is characterized as inverse grading. The lithology is mainly fine sandstone and medium sandstone, with the sorting coefficient between 1.23 and 1.45. The roundness is good, with the particle size lying between 0.15 and 0.32 mm. Argillaceous content is slightly higher, ranging from 5% to 10%.The mouth bar is characterized as inverse grading. The lithology is mainly fine sandstone and medium sandstone, with the sorting coefficient between 1.23 and 1.45. The roundness is good, with the particle size lying between 0.15 and 0.32 mm. Argillaceous content is slightly higher, ranging from 5% to 10%.Freshwater-lake cycles average 5.2 m (17 ft) thick. They consist of basal, transgressive, fluvial to lake-margin deposits that are argillaceous, very fine grained sandstone to coarse siltstone with indistinct lamination, planar or cross lamination, or are disrupted by convolute bedding, desiccation cracks, root casts, soil-ped casts, and tubes.Oct 20, 2023 · Argillaceous definition: (of sedimentary rocks and deposits ) composed of very fine-grained material, such as clay... | Meaning, pronunciation, translations and examples Argillaceous sandstone synonyms, Argillaceous sandstone pronunciation, Argillaceous sandstone translation, English dictionary definition of Argillaceous sandstone. a sandstone containing much clay. See also: Argillaceous Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co For argillaceous sandstone in this paper, the Mogi–Coulomb can better reflect the strength characteristics of argillaceous sandstone than the Mohr–Coulomb and Drucker–Prager. From the six height characteristic parameters and two texture parameters of the fracture surface topography, it can be seen that the undulation, fluctuation and ...Compared with the triaxial loading test, the strength, peak strain and residual strength of argillaceous sandstone with the same confining pressure under unloading conditions all decrease, and the ...Argillaceous rocks. Argillaceous rocks are those in which clay minerals are a significant component. For example, argillaceous limestones are limestones consisting predominantly of calcium carbonate, but including 10-40% of clay minerals: such limestones, when soft, are often called marls. Oct 31, 2021 · Red sandstone is a major component of the bank slope in the Three Gorges Reservoir area. However, because of seasonal variations in reservoir water level and precipitation, red sandstone often experiences cyclic cycles of wetting and drying. The mechanical characteristics of the rock are highly susceptible to deterioration under the influence ... A sandstone with siliceous cement is, for example, much more resistant to weathering than an argillaceous sandstone with clay minerals in its matrix. Of major importance are the macroscopic and microscopic structural anisotropies in a rock, such as bedding, foliation, schistosity or jointing as they provide pathways for infiltration of ...Pisha sandstone is composed of different constituencies and thickness of sandstone, sandy shale, and argillaceous sandstone. The particle size in argillaceous sandstone is relatively small (less than 0.05 mm), with a specific surface area, and the surface effect is strong, so it is vulnerable to be weathered in the conditions of hydration ...Mar 30, 2022 · Through macro- and microanalysis, it is found that the compression failure form of argillaceous red sandstone belongs to x-shaped conjugate inclined plane shear failure. After saturation, the internal pores of argillaceous red sandstone become larger, and the cementation ability decreases, resulting in the decrease of rock sample strength. 1. Sep 27, 2022 ... Failure characteristics of argillaceous sandstone: (a) triaxial loading test, (b) triaxial unloading test. Shear strength parameters analysis.The upper unit (8056–8112 ft) is composed of burrowed and foraminiferal laminated mudstone and argillaceous limestone (Fig. 5) deposited in open marine environment followed downward by fine- to coarse-grained sandstone interbedded in the lower unit (8112–8180 ft) with some calcite-rich mudstone and dolomitic limestone …This facies association is composed of reddish-brown or greenish-grey siltstone, mudstone, and argillaceous sandstone, with localized anhydrite nodules and insect burrows filled with clay or coarser siliciclastic sediment. The quartz grains are mainly fine or slit size, and their content is lower than 40%.“Volumetric digital image correlation applied to X-ray microtomography images from triaxial compression tests on argillaceous rock.” Strain, Vol. 43, No. 3 ... Ni, H. M., and Wen, S. (2014). “Spatial acoustic emission evolution of red sandstone during multi-stage triaxial deformation.” Journal of Central South University, Vol. 21, No ...... sandstone DO 3 Argillaceous sandstone. This problem has been solved! You'll get a detailed solution from a subject matter expert that helps you learn core ...Arches National Park is an incredible geological wonderland located in Utah. The park covers 76,518 acres, with more than 2,000 sandstone arches. Pinnacles, balancing rock formations, Canyonlands and the Colorado River are some of the natur...This shows the permeability coefficient k of argillaceous sandstone decreases with increasing confining pressure P c (Duda and Renner, 2013;Ngai et al., 2013;Alam Badrul et al., 2014; Nazanin ...Sep 27, 2022 · Test methodology. The selected argillaceous sandstone is the surrounding rock of the tunnel, the maximum burial depth is about 500 m, and the maximum in-situ stress level is about 15 MPa, so the ... Jul 26, 2019 ... The largest group is classified as argillaceous sandstone where fine clay particles that are interspersed with the sand grains are compacted by ...Apr 1, 2022 · This facies association is composed of reddish-brown or greenish-grey siltstone, mudstone, and argillaceous sandstone, with localized anhydrite nodules and insect burrows filled with clay or coarser siliciclastic sediment. The quartz grains are mainly fine or slit size, and their content is lower than 40%. The adsorption of polymer KA on oil sands is in line with the Langmuir isotherm law. The adsorption amount is different for polymer KA on four types of oil sands. For equilibrium adsorption, the maximum value is from argillaceous sandstone, followed by conglomeratic sandstone. The third is argillaceous gravel, and the minimum is sand gravel.Request PDF | On Dec 1, 2022, Ying Xu and others published Experimental study on the permeability evolution of argillaceous sandstone under elevated temperatures | Find, read and cite all the ...Sporadic thin beds of argillaceous sandstone and silty dolomite occur in the lower part of the formation. Beds of thinly interlaminated, dark grey-green mudstone and dolomitic siltstone occur locally towards the top of the formation (formerly separated in the East Midlands as the Glen Parva Formation, Warrington et al., 1980). Halite is ...The drilling depths of HB-95-01 and HB-95-02 are 250 m and 350 m, respectively. The principal lithologic units for HB-95-01 are sandstone, argillaceous sandstone, and sandy mudstone. The principal lithologic units for HB-95-02 are sandstone, argillaceous sandstone, and sandstone mixed with some mudstone.The mechanical behaviors including the triaxial strength, yield and peak strains of the argillaceous sandstone are less correlated to the temperature level from …Argillaceous definition: (of sedimentary rocks and deposits ) composed of very fine-grained material, such as clay... | Meaning, pronunciation, translations and examplesAs a whole the formation is a large body of red calcareous and argillaceous sandstone and shale. "History and Comprehensive Description of Loudoun County, Virginia" by James W. Head. The cliffs at Foul Point and Point Cunningham unite the sandstone and argillaceous formation. "Discoveries in Australia, Volume 1." by J Lort StokesMar 15, 2021 ... Moreover, when it contains a considerable amount of clay or silt, we call it argillaceous sandstone. The colour of sandstone varies depending on ...The argillaceous sandstone is mainly damaged by compression shear when triaxially loaded. Since the unloading of the confining pressure will form a tensile-shear crack perpendicular to the unloading direction, the tensile-shear failure is the main damage during triaxial unloading.From a CU setting Barker et al. (2008) document the increasing thickness of argillaceous sandstone at the expense of underlying co-genetic relatively clean sandstone within the same bed towards a laterally confining basin margin; they interpret such a depositional trend to record increasing turbulence suppression due to flow …Flemming Formation and Oakville Sandstone, undivided; Crossbedded sandstone and sandy shale; partly oolitic; some beds contain abundant oysters and bivalves. Unit lies disconformably on Oligocene units, and disconformably below Pliocene units. ... Kiamichi, La Pena, and Taraises are mostly argillaceous limestone and calcareous, silty shale. Jlc:Sandstone is composed of sand-sized mineral grains, rock fragments, or pieces of fossils that are held together by a mineral cement. The definition of sandstone is based on the size of the grains: It grades into siltstone, shale, or mudstone (grains less than 0.0625 mm in diameter) and conglomerate ( if the grain size exceeds 2 mm1).The permeability and mechanical tests of sandstone under the deviatoric stress cyclic loading-unloading were conducted on the triaxial rock mechanics test system produced by GCTS Company, as shown in Fig. 1.The system can be used for permeability test and the dynamic mechanical properties of rock materials under complex stress paths …Argillaceous rocks break down into five groups. This includes argillite, claystone, shale, siltstone, and mudstone. If a rock contains mainly clay minerals, then more than likely, it's an argillaceous rock. But, to know the full details of rocks, you will have to examine them under a microscope to tell the difference.... sandstone DO 3 Argillaceous sandstone. This problem has been solved! You'll get a detailed solution from a subject matter expert that helps you learn core ...Argillaceous rocks can display a wide range of durability behavior after excavation and in cut slopes. In this paper, we propose a classification of argillaceous rocks based on their textural characteristics. Three main components of the classification scheme are the clastic framework, the fine-grained matrix, and the cementing agent. Unlike other schemes, the unlithified argillaceous ...In this paper, we propose a rock physics template to diagnose the distribution of the clay for argillaceous sandstone. First, we investigate the effect of different types of clay distributions on the elastic properties of argillaceous sandstone based on rock physics models.the tunnel is mainly composed of sandstone with argillaceous sandstone. The tunnel lithology of the section near Lianhua stream is thick and massive pure limestone, which is easily corroded. A large karst cave is found on the ground surface about 100m north of the tunnel line, and a small amount of water is produced in dry season. The localMay 18, 2020 · The clastic rocks mainly include claystone, siltstone, argillaceous siltstone, fine sandstone and gravel-bearing fine sandstone. 3. The best physical properties among the mixed siliciclastic-carbonate rocks are observed in sandy dolomite, followed by grey siltstone and grey mudstone. Mar 27, 2023 · Calcareous Cement – It has calcites, and forms in patches leaving gaps open, so it makes sandstone porous. Argillaceous Cement – It has clay particles, and forms softer types of sandstone. Ferruginous Cement – It has ferrous content. So, it also is known as Hematite cement and gives reddish hues. Matrix of Sandstone. It is fine material. These sediments are dominantly calcareous and argillaceous sandstone deposited by mixed processes of slumps and debris flow. Some areas have intercalated red shales at the base. In the outcrops, the Miocene sediments are mainly non-marine sandstone, while in subsurface the limestone are well developed, with alternation of siltstone and ...Section snippets Experiments and method. An overview of the experimental program and equipment is shown in Fig. 1. Two types of experiments were carried out; One is the mechanical and SEM test on intact 3D printed sandstone specimens after heating at different temperatures (Experiment Ⅰ), and the other is the mechanical and CT test on printed sandstone specimens containing prefabricated ...Effect of Arenite, Calcareous, Argillaceous, and Ferruginous Sandstone Cuttings on Filter Cake and Drilling Fluid Properties in Horizontal Wells. Geofluids 2019-04-16 | Journal article DOI: 10.1155/2019/1956715 Part of ISSN: 1468-8115 Part of ISSN: 1468-8123 Contributors ...Oct 15, 2020 · The mesostructures of rocks determine their macromechanical properties. These rock mesostructures may be altered by the freeze-thaw cycles in cold regions. In this regard, this paper proposes a quantitative evaluation method based on computed tomography (CT) scanning technology for investigating the mesostructure and damage characteristics of sandstone subjected to freeze-thaw conditions. CT ... The objective of this work is to investigate the permeability evolution characteristic of an argillaceous sandstone subjected to coupled triaxial stress and real …Blocky or cylindrical log patterns exhibit relatively little vertical variation in argillaceous content and are typical of siliciclastic rocks that have low overall argillaceous content. ... Sandstone bodies in these systems tend to form well-developed sand bars at the mouths of distributary channels. River-dominated systems periodically ...In this paper, the effect of different sandstone formation cuttings, including arenite (quartz rich), calcareous (calcite rich), argillaceous (clay rich), and ferruginous (iron rich) sandstones, on the filter cake and drilling fluid properties was investigated. Aug 25, 2006 · The soft red sandstone 6 to 20 feet above the dolomite is very fine-grained and highly calcareous, but the associated white sandstones are essentially noncalcareous and more argillaceous. Norton's thin maroon shale must be classed here as a red (2.5YR5/6) slightly calcareous very argillaceous siltstone; the clay fraction seemingly is ... Photomicrographs of feldspathic (L) and lithic (R) greywacke. The top images are in plane-polarized light; the bottom images are in cross-polarized light.Cements fill the pore spaces. Closeup of Pharaoh Menkaure's greywacke statue, 25th century BCE, from the Egyptian Museum in Cairo. Greywacke or graywacke (German grauwacke, signifying a grey, …Through macro- and microanalysis, it is found that the compression failure form of argillaceous red sandstone belongs to x-shaped conjugate inclined plane shear failure. After saturation, the internal pores of argillaceous red sandstone become larger, and the cementation ability decreases, resulting in the decrease of rock sample strength. 1.Blocky or cylindrical log patterns exhibit relatively little vertical variation in argillaceous content and are typical of siliciclastic rocks that have low overall argillaceous content. ... Sandstone bodies in these systems tend to form well-developed sand bars at the mouths of distributary channels. River-dominated systems periodically ...ÐÏ à¡± á> þÿ i ...Quartzose sandstones are mainly classified as RRTI and RRTII rocks; and RRTIII and RRTIV mostly host the glauconitic and argillaceous sandstone microfacies. …Oct 1, 2023 · The bedding space of argillaceous sandstone (i.e. matrix) has a tensile-dominant AE events source corresponding to the cracking pattern (Fig. 8), with a larger AE events magnitude, but the bedding structure has a shear-dominant AE events source in a smaller magnitude. The implosive mechanism is mainly concentrated on the upper and bottom flaws ... Arenite. Arenite (Latin: arena, "sand") is a sedimentary clastic rock with sand grain size between 0.0625 mm (0.00246 in) and 2 mm (0.08 in) and contain less than 15% matrix. The related adjective is arenaceous.The equivalent Greek-derived term is psammite, though this is more commonly used for metamorphosed sediments.. Since it refers to grain size …hi ⋯hi+n is the thickness of each stratum. γi ⋯γi+n is the density of each stratum; i=1,2,3⋯ When ðqi+n+1Þi <ðqi+nÞi, that is, ðqi+nÞi as the load applied to the i stratum, the result of equation (1) is used as the load on the i stratum to calculate its caving step length. The data in Table 1 is put into equation (1), and the load on each stratum is calculated.May 18, 2020 · The clastic rocks mainly include claystone, siltstone, argillaceous siltstone, fine sandstone and gravel-bearing fine sandstone. 3. The best physical properties among the mixed siliciclastic-carbonate rocks are observed in sandy dolomite, followed by grey siltstone and grey mudstone. The White House’s exterior walls are made of white painted Aquia Creek sandstone that was quarried by slaves. This is the same stone that was used to build the Capitol building.One of the most stunning rock formations at Vermilion Cliffs National Monument is called White Pocket. Here's how to get there. Located in Arizona, the Vermilion Cliffs National Monument consists of sandstone patterned with striking natural...Pennington Formation - Medium-gray shale, containing interbedded limestone, dolomite, argillaceous sandstone, dusky-red and grayish-olive mudstone, and minor shaly coal. Mainly restricted to northeastern AL and part of the Sequatchie anticline. Where less than 100 feet thick the formation is included in the Bangor Limestone.It consists of greenish-gray siltstone intercalated with quartzitic sandstone, argillaceous sandstone and occasional shale. Bioturbation and cross-bedding are common. It has a depositional environment with a shallow-marine shelf. Upper Quartzite Member (1,677 m, …Sandstone that contains more than 90% quartz is called quartzose sandstone. When the sandstone contains more than 25% feldspar, it is called arkose or arkosic sandstone. When there is a significant amount of clay or silt, geologists refer to the rock as argillaceous sandstone. The color of sandstone varies, depending on its composition.Microstructural variation of red sandstone under a high humidity environment is the main reason for its deterioration of macroscopic mechanical properties. Aiming at the tensile failure of weakly cemented soft rock in high humidity environment, five kinds of red argillaceous siltstone disc samples with different water contents were obtained ...Sandstone is a sedimentary rock made up of sand-size grains of minerals and organic particles. Most sandstones contain silicates like quartz and feldspar but ...Jun 1, 2023 · The prepared AASS and schematic view of the apparatus: (a) the prepared artificial argillaceous sandstone samples; (b) schematic view of the apparatus for the stress dependent PPR experiment. During the tests, for each sample, under various effective stresses, porosity and the corresponding permeability will be simultaneously measured by the ... The repeated wetting–drying (WD) cycles can cause the deterioration of rock and thus affect the service performance of the related rock engineering, e.g., the crushed-rock embankment and the reservoir. The study comprehensively investigated the deterioration mechanism of sandstone under the WD cycles based on a series of multi-scale experiments, including the microstructure, the meso–micro ...Argillaceous rocks make up 50 to 95% of the section and play a key role in the formation of lithologic, mineralogic, geochemical, and thermobaric characteristics of the basin ( Buryakovsky, 1974a, 1993c, 1993d ). Following are the results of a study of argillaceous-rock cores recovered from deep onshore and offshore exploratory and producing ...The elastic properties of argillaceous sandstones are significantly controlled, however, by the perplexing distribution of dispersed, cemented and matrix (including structural and …Mar 26, 2022 · The well and mud logging data, core samples, and the well-tie sections indicated that the bottom of the Qingshuihe Formation contained pebbly sandstone, gritstone, medium sandstone, fine sandstone, siltstone, argillaceous sandstone, mudstone, and claystone (Fig. 3 and Fig. 11c–d). The above sand bodies are collectively called massive ... Feb 1, 2023 · According to the geological data (Wu et al., 2021b), the average effective thickness of the reservoir is about 22.5 m and the reservoir rock is tight argillaceous sandstone with average porosity of 9.33% and average permeability of 0.26 mD, suggesting that Zhongjiang Gas Field is a typical ultra low-porosity and low-permeability tight sandstone ... Assuming that each layer of soil is continuous and isotropic, the influence of permeability on the deformation property of the foundation soil is ignored. The upper structure adopts the Mohr–Coulomb primary structure , and the argillaceous sandstone adopts the Burgers creep primary structure . The effects of static loads on the roadbed and ...Feb 1, 2023 · The objective of this work is to investigate the permeability evolution characteristic of an argillaceous sandstone subjected to coupled triaxial stress and real-time elevated temperature conditions. A series of triaxial compression seepage tests were carried out at four constant temperature levels (20 °C, 40 °C, 80 °C and 100 °C). This paper is based on the condition where layered argillaceous cemented sandstone as an engineering background is met by the No. 207 fully mechanized working face open-off cut (Wanli No. 1 Coal Mine). Through mechanical theory analysis and field practice, the engineering safety problem of the large-span argillaceous cemented …Similarly, argillaceous sandstones are sandstones consisting primarily of quartz grains, with the interstitial spaces filled with clay minerals. Category ...Argillaceous rocks break down into five groups. This includes argillite, claystone, shale, siltstone, and mudstone. If a rock contains mainly clay minerals, then more than likely, it’s an argillaceous rock. But, to know the full details of rocks, you will have to examine them under a microscope to tell the difference.Request PDF | On Dec 1, 2022, Ying Xu and others published Experimental study on the permeability evolution of argillaceous sandstone under elevated temperatures | Find, read and cite all the ...deterioration of mechanical properties of argillaceous sandstone specimen. 1.Introduction e mining of deep mineral resources would inevitably encounter the problem that the ground temperature in-The sandstone of the Silurian Xiaoheba Formation in the Sichuan Basin is poorly understood and the exploration prospect is unclear. The geological characteristics of oil and gas from the aspects of sedimentation, reservoir and accumulation of the sandstone of the Xiaoheba Formation in the Sichuan Basin, as well as evaluating its exploration potential and prospect, were made possible using the ...The elastic properties of argillaceous sandstones are significantly controlled, however, by the perplexing distribution of dispersed, cemented, and matrix (including structural and layered) clay....Surrounding rock pressure is an important factor to be considered during designing tunnel structures. In this research, the on-site surrounding rock pressure of a large diameter shield tunnel in argillaceous sandstone stratum was tested, and the evolution process of surrounding rock pressure was analyzed, based on which the variation law of …Discriminating the argillaceous sandstone reservoirs into several hydraulic flow units (HFUs) is a useful reservoir zonation technique. This study introduces a statistical method for analyzing ... Mar 27, 2023 · Calcareous Cement – It has calcites, and forms in patches leaving gaps open, so it makes sandstone porous. Argillaceous Cement – It has clay particles, and forms softer types of sandstone. Ferruginous Cement – It has ferrous content. So, it also is known as Hematite cement and gives reddish hues. Matrix of Sandstone. It is fine material.
The argillaceous sandstone is mainly damaged by compression shear when triaxially loaded. Since the unloading of the confining pressure will form a tensile-shear crack perpendicular to the unloading direction, the tensile-shear failure is the main damage during triaxial unloading.. What game is jay bilas calling today
The ferricrete was formed directly from the saprolitic layer of the argillaceous sandstone, preserving the pre-existing structure. The processes of deep weathering, the original enrichment in kaolinite of the sandstone, the age of the plateau, and the paleoclimatic changes have been favorable to the formation of clayey Ferralsol.Bioturbated sandstone (Sg-bio) (Fig. 2e) and argillaceous sandstone (Sd) (Fig. 2c,f) are particularly common in the upper intervals of FA1. Parallel-laminated shale (Fig. 2 g) is locally observed ...Jan 11, 2017 ... ... Sandstone and underlying the glauconitic, argillaceous sandstone of the Franconia Formation. Extent and thickness. The Ironton Sandstone ...Pores are well developed and are mainly intergranular. Calcite cement and argillaceous matrix are evenly distributed between grains. E 2 w, Tongyhouluk. D Fine-grained lithic sandstone, well sorted, moderately rounded, with weak overgrowth of quartz. Pores are well developed, which are primary intergranular pores and intergranular …For the quantitative analysis, the linear M-C criterion is also used to describe the peak strength of argillaceous sandstone after relaxation, and the fitting result is shown in Fig. 6 (b). The correlation coefficient is up to 0.92, which implies that the M-C criterion can also fit the peak strength of argillaceous sandstone after relaxation well.Argillaceous rocks make up 50 to 95% of the section and play a key role in the formation of lithologic, mineralogic, geochemical, and thermobaric characteristics of the basin ( Buryakovsky, 1974a, 1993c, 1993d ). Following are the results of a study of argillaceous-rock cores recovered from deep onshore and offshore exploratory and producing ...Apr 2, 2017 ... Nuclear magnetic resonance (NMR) procedure typically minimizes the effects of external magnetic field gradients on the transverse relaxation ...Sep 27, 2022 · Test methodology. The selected argillaceous sandstone is the surrounding rock of the tunnel, the maximum burial depth is about 500 m, and the maximum in-situ stress level is about 15 MPa, so the ... It is important to identify the location of gravelly sandstone in Taoerhe Sag, an oil target area in the Chezhen Depression. To date, most attention has focused on sedimentary characteristics; hence, information regarding a clear sensitivity analysis of seismic attributes is incomplete. To address this, we used well analysis and seismic …With increasing drying-wetting cycles, the peak stress of argillaceous sandstone decreased exponentially, and the T2 spectrum area and porosity showed exponential increase. The internal pore of ...Sandstone is a sedimentary rock made up of sand-size grains of minerals and organic particles. Most sandstones contain silicates like quartz and feldspar but ...Oct 1, 2023 · The bedding space of argillaceous sandstone (i.e. matrix) has a tensile-dominant AE events source corresponding to the cracking pattern (Fig. 8), with a larger AE events magnitude, but the bedding structure has a shear-dominant AE events source in a smaller magnitude. The implosive mechanism is mainly concentrated on the upper and bottom flaws ... Oct 7, 2018 ... ... sandstone lens (= relatively thin, gray, clay-rich interval with sandy-silty grains); occasional coarsely-crystalline/coarse-grained ...The elastic properties of argillaceous sandstones are significantly controlled, however, by the perplexing distribution of dispersed, cemented, and matrix (including structural and layered) clay....Sandstone is a sedimentary rock formed from cemented sand-sized clasts. The cement that binds the clasts can vary from clay minerals to calcite, silica or iron oxides. Sandstone can be further divided according to: Clast size - fine (0.06-0.2mm), medium (0.2-0.6mm), coarse (0.6-2mm); Sorting - a sandstone comprising a mixture of clast sizes is ....