Figure 1 - uploaded by Adam D Switzer
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-A grain-size comparator chart (to scale). The chart shows the different size fractions from silt (63 µm) through to large cobbles (128256 mm). Such charts are useful for field comparisons.
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Measuring the particle-size distribution of sediments is a fundamental tool in geomorphology. Boulder- and cobble-size material is generally measured by direct measurement whereas a wide variety of techniques are available to determine grain-size distributions for sand- to clay-dominated sediments. Commonly, a combination of methods is needed and n...
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... any site of sediment mobility the PSD varies considerably through space (e.g., bedforms and landforms) and time, thereby exerting control over physical transport and sedimentation processes ( Warrick et al., 2009). The variety of grain sizes (Figure 1) encountered by geologists, geomorphologists, and archeologists means that no one technique can be applied to all environments and their associated landform components. It is generally desirable to have a convenient, repeatable, precise, accurate, and representative means by which to assess sediment grain sizes when reconstructing palaeoenvironments or investigating processes (see discussions of Syvitski et al., 1991a, Syvitski et al., 1991b, Cheetham et al., 2008and Donato et al., 2009. ...
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... Second, the largest sieve size particles remain on the sieve and cannot pass ( ). As the number of sieves increases, the number of size divisions and the relative level of analytical details increase (Switzer 2013). By weighing each sieve's remaining sediment, one can obtain such information like the sieve mesh sizes, raw weights, weight percentages, and cumulative percentages, finer or coarser than the specific sieve (Switzer 2013). ...
loods are among the adverse natural events with the possibility of turning into a disaster, causing economic losses and casualties. Flood events can become even more dangerous with the presence of intense sediment transport since the morphologic response of a river can determine erosion and deposition in different areas. In-bed structures can be undermined in erosional reaches, while the riverbed elevation increases in a depositional reach and, consequently, the conveyance of the river decreases. The dynamics of the morphologic processes may be different in lowland and upland reaches due to different sediment, slopes, and flow properties. The aim of the thesis is to study, experimentally and numerically, the bed aggradation process in an overloaded channel with a supercritical flow regime. The aggradation experiments of the study are executed in the Mountain Hydraulics Laboratory of the Politecnico di Milano, located in the Lecco campus. These experiments are characterized by an inflow discharge of sediment material that is larger than the sediment transport capacity, resulting in the deposition of sediment in the studied channel. A series of aggradation experiments are realized varying the water discharge and the inflow sediment discharge. Beyond the observation of the phenomenon in progress, the experiments provide quantitative information. For the purpose of experimental data acquisition, different parts of the experimental system are monitored with different cameras, and measurements are done through some image processing methods, appropriately devised. The experimental campaign is completed by experiments specifically devoted to determining the sediment transport capacity of the flow at the initial condition. The time scales of a considered scenario are of great importance for the goal of emergency planning. For the present experiments, this consideration stimulates a study of the propagation of a sediment aggradation wave, for which a front can be identified and its celerity can be determined. The runs performed in this thesis enable preliminary considerations to be made on how a front celerity may depend on the control parameters of the system. The aggradation process studied by the experimental tests is also reproduced with a numerical simulation. The software used to implement the numerical model is BASEMENT, provided by ETH Zurich. In order to obtain a good correspondence between numerical and experimental results, two parameters are calibrated: the Manning coefficient and a bedload factor for the computation of the sediment transport capacity. Depending on the water discharge, different values for calibration factors are obtained.
... The variability of precipitation and changes in hydro-geomorphic conditions in the study area results in the characteristics of the deposits, particularly in the grain size distribution of the sediments. On the other side, particle size is a fundamental factor that controls erosion, transport, and deposition of sediments, [15], [16]. The erodability of soils increases in case of large sand fraction and low clay and silt contents, [17]. ...
... Sampling in June 2022 shows a very platykurtic curve (0.49). Considering that kurtosis is a second indicator of sorting, these values indicate poorly to very poorly sorted materials, [15]. ...
Erosion processes, triggered by water, occur and propagate on sloping surfaces and have a significant negative impact on the soil quality and vegetation, as well as cause a change of the topographic surface. In the long term, they can lead to an increase in sediment transport, siltation of dams, and higher flood hazard. The development of water erosion reflects on the slope profile and the specific landforms like rills and gullies. In this regard, the geomorphological features of the areas can be considered indicators of the spatial distribution of erosion and accumulation. The sediment properties give information about the conditions of the transport and the intensity of the hydrogeomorphic processes. The current study aims to analyse the short-term changes in erosion and deposition by application of morphometry and grain size analysis. Topographic wetness index (TWI) and cross-section profiles of two small gullies were analysed based on high-resolution digital terrain models (DTMs), generated from unmanned aerial system (UAS) data. Remote sensing was combined with field geomorphological research and sediment sampling. The results of the research show about average 2 cm change in erosion and deposition for the period October 2021 – November 2022. Despite TWI and cross-section profiles depending on the DTMs resolution, they are reliable indicators for erosion and deposition. The grain size analysis supports the morphometric analysis. Coarse to very fine sands are predominant in most cases of sediment sampling. The sorting coefficient shows very poorly to moderately sorted deposits which indicates transport in a more dynamic environment and temporary flow.
... A proper investigation of the sedimentary grain-size characteristics of a reservoir, and their relationship with depositional environment can provide better understanding of sorting processes, lateral continuity, and reservoir quality. [5,16,18] Moreover, through the analysis of sedimentary environments, it can assist the stratigraphic correlation of sediment and their mode of deposition mechanism. [11,12,15] Statistical parameters of grain size distribution such as graphic mean, standard deviation or sorting, skewness, mode, and kurtosis, can indicate sediment diagenesis, transportation mechanism, and depositional setting. ...
Brunei Darussalam has a complex petroleum system with transitional deposition environment of deltaic and estuarine sandstone. Grain-size analyses by sieve method was performed on more than 200 samples of semi-consolidated to unconsolidated sandstone mostly Belait and Seria Formation outcrops with different sedimentary environments. There are 6 identified facies group: Channel Sand (CS), Coastal Plain (CP), Upper Shoreface (US) Lower Shoreface (LS), Offshore Transition Zone (OTZ) and Offshore Sand (OS). Grain size analysis and statistical parameters such as mean, standard deviation, skewness and kurtosis was used to obtain graphical representation of sandstone characteristics. Overall results suggest that Bruneian sandstone outcrops composed of fine to medium grain size sand, poorly to moderately sorted, grain size distribution is mostly very fine to finely skewed and leptokurtic in nature. This paper aimed to predict the relation of unconsolidated sandstones reservoir with grain size distribution and depositional environment.
... Samples were sieved through a series of screens with mesh openings from 500 μm to 63 μm. After sieving, each sediment fraction was dried at 60 • C and weighed, and the weight percentage was calculated (Hsieh and Chang 1991;Switzer 2013). To measure bulk density, certain volumes of sediment were dried at 60 °C and weighed. ...
The assemblage structure of brachyuran crabs and their relationships with environmental parameters of water and sediment were assessed in the mangrove ecosystem of the northern Persian Gulf. In this study, the spatial distribution and diversity of crabs within two different habitats were studied through four seasons in 2018. A total of 11 species were identified, of which nine species were found in un-vegetated (mudflats) and eleven species in vegetated (mangrove) habitats. Opusia indica, Manningis arabicum, and Nasima dotilliformis were the dominant species in un-vegetated habitats, while O. indica, M. arabicum, and Parasesarma persicum were dominant in vegetated habitats. Nonmetric multidimensional scaling ordinations (nMDS) and a three-way factor PERMANOVA indicated that the crab species assemblage differed significantly between the two habitats, but not among seasons. The vegetated habitats showed higher species richness and Shannon-Weiner diversity index than un-vegetated habitats. However, the species evenness index showed no difference between the habitats. The result of redundancy analysis (RDA), indicated that the sediment grain size and organic matter (OM) content were responsible for the distribution of brachyuran crabs between these two habitats. The results of this study will be useful in the management and conservation of mangrove forests and in understanding the ecological patterns of brachyuran crabs in the Persian Gulf.
... Sedimentary structures, unconformities, grain size, sorting and rounding were recorded by visual and tactile means. For particles larger than silt, grain size was visually estimated, aided by auxiliary classification sheets [38], following the Wentworth division [39]. Sorting and rounding degrees for sand particles were described by visual and microscopic analyses, also aided by classification auxiliary sheets [40,41]. ...
The study presents SEM-based automated mineralogy to distinguish between natural sediments and iron ore tailings deposits from the Paraopeba River, after the failure of B1 Dam in Brumadinho, Minas Gerais, Brazil. Samples were obtained from borehole cores drilled over channel bars and banks eight months after the failure. After preliminary facies description, sediments from 54 chosen intervals were subjected to density measurement, X-ray diffraction (XRD), SEM-based automated mineralogy (QEMSCAN) analysis and determination of geochemical major components. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) revealed six main mineral associations governed by different contents and ratios of quartz, kaolinite and hematite. Natural sediments are predominantly composed of mineral associations containing kaolinite, quartz and quartz + hematite with density values ranging from 2.5 to 3.3 g/cm3. Tailings deposits have density values higher than 3.5 g/cm3 and are mainly composed of hematite with occasional occurrences of kaolinite + hematite. Because of geological complexity and historical terrain occupation and usage, geochemical anomalies are common in the Paraopeba River sediments. Our data suggests that mineralogical oriented studies should precede detailed geochemical investigations, to enhance the understanding of the source of such anomalies and the environmental jeopardy associated to the occurrence. In this sense, SEM-based mineralogy has an enormous potential in environment studies.
... Natural sand is usually used as a fine aggregate. Although particles are three-dimensional, most particlesizing techniques assume that the material holds a spherical shape, and particle-size analysis is measured accordingly (Figure 3.1) (Switzer, 2013). ...
Architecture and site have been linked since the dawn of civilization, as early societies adapted their environments using found materials and developed custom tools towards construction. However, the tradition of sourcing local materials diminished dramatically with the advent of industrialization and the ease of transporting materials to construction sites. In the past decade, robotic tools have been permeating the field of architecture, reconnecting makers and matter. The advent of in situ robotic tools offers to further deepen this connection by performing fabrication on-site. This critical capacity provides the possibility to transform terrains and modulate native matter into architectural grounds and structures.
Under the environmental imperative to reconsider material sourcing, and with the pressing need to develop alternatives to the rapidly depleting construction sand, architects are assuming a resource-conscious approach. The thesis seeks to advance this approach and forwards a vision for post-Anthropocene, large-scale, architectural, and landscape construction – territorial-based digital fabrication. This vision seeks to shift the focus of digital fabrication in architecture from an object-oriented process to an environment-directed endeavor.
To this end, the thesis explores four aspects: Informing Grounds – the capacity to embed information in sand and soil; Customizing Territories – the modulation of terrains into performa- tive grounds and structures; Reconstituting Geomaterials – the transformation of geomaterials into architectural elements and systems using additive manufacturing; and Contextualizing Ad- ditive Construction – the tailoring of the production process to the site. These issues bridge disparate research avenues – the automation of earthworks, the robotic forming of landscapes, in situ resource utilization, and on-site robotic construction. The thesis contributes conceptual, theoretical, and methodological foundations for performing territorial-based robotic fabrication. Based on the experimental investigation of the presented case studies, it develops, demonstrates, and discusses territorial-based strategies. These include experimental frameworks, workflows, methods, protocols, technical setups, and expanded terminology. The thesis concludes with the notion of Matter-to-Structure, anchoring digital fabrication in the territory it is situated in and linking terrains, found matter, and the architecture they nurture.
... After the treatment, the sediment samples were wet sieved through 230 mesh (0.0625 mm) followed by American Standard Test Sieve Series (ASTM) for the separation. The size analysis of very fine particles (silt and clay) was carried out by the pipette analysis method (Krumbein and Pettijohn, 1961;Switzer, 2013). For the organic carbon (OC) estimation some parts of the sediment samples were oven-dried at 60 °C and powdered with the grinder (Retsch, RM100) followed by Walkley and Black method (Krishan et al., 2009). ...
The Mahanadi River, surrounding estuaries along the coastal water are important to understand the relationship between heavy metals, ecosystem and human health, as the region being used largely by fisher communities for the potential fishing ground and agriculture. The study evaluates the ecological risk index of heavy metals in the surface sediments along the coastal environment of the Bay of Bengal between 2011 and 2012. The metals concentrations were varied from a maximum in Manganese (4,137 mg/kg) to a minimum in Cadmium (17 mg/kg). The factor analysis result shows that higher concentration of cadmium (Cd), chromium (Cr), Nickel (Ni), lead (Pb), and Zinc (Zn) were significant environmental risk in the study region. The cluster analysis indicated that the creek sediment is heavily polluted than the estuary ecosystem of the coastal environment. Enrichment factor and Geo-accumulation Index of the surface sediment resulted that, the Cd was high enrichment and was moderate to severe in the study region. Pollution load index denoted that the sampling sites in the creek sediment were more polluted than coastal due to the influence of agricultural runoff, industrial and anthropo-genic. The Cr, Cu, Ni, Pb, and Cd concentrations result in the potential toxicity to the aquatic organisms based on the comparison with the SQGs. Indicates the average magnitude of the metals in the study period in the decreasing order of Mn, Cr, Cu, Ni, Pb, and Cd which were alarming except iron (Fe) in the estuary and coastal ecosystem of the Bay of Bengal. The present investigation would be a first-hand informant to understand the impact of heavy metals in the ecosystem in the region. The result inputs need to be monitored further in the long term basis for isotopic sediment dating to reconstruct the contamination history for the ecosystem modeling, sustainable ecosystem, and coastal zone management.
... The laser diffraction grain size analyzer of Counter LS 13320 (Beckman Coulter Co. Ltd) of Shinshu University was used for grain size analysis of collected samples after treated with 10% hydrogen peroxide (H 2 O 2 ) solution to remove the organic carbon (Switzer, 2013;Switzer and Pile, 2015;Haque and Hoyanagi, 2021). The machine can determine the grain size ranges between 0.04 μm and 2000 μm. ...
... The color coding for the sediment is shown in Fig. 4. Fig. 10. Bivariate plot of mean grain size and standard deviation of grain showing distinct clusters on sediments of unit A-C and modern beach sand (modified after Switzer et al., 2005;Switzer, 2013). Shigeno and Nanayama (2016) inundation height and roughness of depositional surface. ...
This study examines the sedimentary characteristics, provenance, and depositional processes of the storm deposits from 2007 Cyclone Sidr that have been identified on the southern coast of Bangladesh. Three sedimentary units up to 70 cm thick have been identified in fifteen geological core collected at a distance of 135–277 m from the coast. Laboratory analyses of grain size, TOC, TN, δ13C, and diatom assemblages were carried out to characterize the deposits. Massive to parallel laminated bluish gray mud underlies the storm overwash deposits. White to light gray, massive to parallel laminated, normal graded 1–17 cm thick sand overlies the mud unit with sharp to erosional contact. The mean grain size and thickness of this sand unit decrease landward with increasing sorting value, where grain size distribution of sand is comparable with modern beach sand. The unimodal sand that dominated the base of the storm deposits grades into bimodal olive-gray sandy silt in the upper part of the deposits. The grain size implies that the sand carried from the beaches and mud likely sourced from the suspended, nearshore sediment of the bay and adjacent rivers. TOC/TN, δ13C values and the presence of brackish mudflat origin diatoms with silty sand laminae in bluish gray mud indicate a tide-influenced environment. Post-storm sand and sandy silt sediments unit contain freshwater and marine-brackish diatoms that have likely been deposited from flooding caused by storm surge water from the bay and overbank flooded river water due to subsequent heavy rainfall. These sediments were sorted according to storm waves and settled over the study area. This study indicates that the low-lying delta coast gets the influences of high water levels both from the bay and the river during a storm. The modern storm deposit will help to characterize the paleo/prehistoric tropical cyclone in geological time for future studies in this area.
... Samples were treated with 15% hydrogen peroxide (H 2 O 2 ) to remove organics and 10% hydrochloric acid (HCl) to remove carbonate fragments. The samples were rinsed in distilled water before introducing to the Malvern Mastersizer 2000 for grain size analyses using laser diffraction following procedures outlined by Switzer (2013). ...
Typhoon Durian in November 2006 was most notable for a series of devastating lahars that buried communities at the base of Mayon volcano in Bicol, Philippines. Typhoon Durian delivered extreme rainfall that remobilized volcanic debris that caused more than ~1200 deaths and extensive property damage. Although not as deadly as the lahar, Typhoon Durian also generated a storm surge that caused localized dune breaching on Malinao barrier sand spit in Lagonoy Gulf. In the absence of instrumental data of the storm surge, we used the geomorphical and sedimentary imprints including erosion scarps, washover fans and terraces to infer the inundation heights on the barrier spit. The surface elevations of washover fans, terraces and relic dunes indicate inundation heights above 1.5 m but not exceeding 3 m. Typhoon Durian's overwash deposit is characterized by typical washover fan stratigraphy, and exhibits horizontal to sub-horizontal lamination on the front to mid-fan and foreset stratification near the fan terminus. Subsurface stratigraphy using shore-normal ground penetrating radar (GPR) imaging reveals at least two buried erosional surfaces farther inland from the erosional surface of Typhoon Durian. Similar to Durian, the older erosional surfaces were probably sustained from previous typhoons. We infer that episodic erosional events most likely have repeatedly disrupted the prograding development of the Malinao barrier spit. Typhoon Durian highlights the exposure of volcanic landscapes to multiple hazards from cyclone landfall.
... To overcome the ubiquitous irregularity of particle geometry, in many cases an equivalent sphere is assumed based on some physical property measured by the adopted technique (Switzer, 2013); examples include: equivalent sphere on the same measured particle volume, sphere based on the same surface area, sphere passing through the same sieve opening. ...
Transport processes of plastic particles in freshwater and marine environments are one of the relevant advances of knowledge in predicting the fate of plastic in the environment. Here, we investigated the effect of different shapes on the settling velocity, finding a representative reference diameter which encompasses three-dimensional shapes like pellets or spherules, two-dimensional shapes like fragments or disks, and one-dimensional shapes like filaments or fibers. The new method is able to predict the settling velocity of plastic and natural particles given the representative size and the Corey shape factor coefficient, over the entire range of viscous to turbulent flow regime.
The calibration of the method with experimental data, and the validation with an independent dataset, support its application in a wide range of hydraulic conditions.
