Size Analysis Of Sediments Research Articles

Grain Size Analysis of Sediments from the Northern Andaman Sea: Comparison of Laser Diffraction and Sieve-Pipette Techniques

A comparison has been made of sand, silt, and clay percentage of 118 samples from the Ayeyarwady continental shelf, northern Andaman Sea, measured by the sieve–laser diffraction technique and by classical sieve-pipette methods. Clay and silt percentages determined by Malvern Mastersizer 2000 Laser Particle Size Analyzer are 37% and 157% of pipette clay and pipette silt percentages, respectively. Clay particles separated by the settling technique and having an apparent size of less than 2 µm when measured with laser diffraction show that 99% of the particles have an upper size range between 4.8 and 7.7 µm. A calibration relationship between pipette and laser diffraction techniques has been developed for the northern Andaman Sea. A clay particle size of 2 µm defined by the pipette technique corresponds best to a size of 6.2 µm defined by laser diffraction. For the laser data, when 6.2 µm is taken as the boundary between silt and clay, the results are comparable to pipette analysis. Use of the calibration relationship enables one to make use of the rapid laser diffraction size analysis technique for routine sediment texture analysis with high precision.

Variability in sediment supply, transfer and deposition in an upland torrent system: Iron Crag, northern England

AbstractResearch into torrent erosion has focused on bedload transport dynamics, debris flow propagation during flood events, and fan sedimentation. Studies have frequently been biased towards specific events and have not considered sediment delivery in the catchment as a whole. The aim of this study is to examine spatial variations and process controls on sediment transfer in an upland torrent system (hillslopes, channel and fan).The study site is Iron Crag, a small torrent system (catchment area 2·4 ha) situated in the northern Lake District, UK. Particle size analysis of hillslope sediments trapped during transport suggests sediment calibre is controlled primarily by sediment source. Freeze–thaw and rainfall processes impart a weak but recognizable size sorting signature on the trapped sediments. However, these variations are less significant in determining sediment supply to the basal fan, than those operating in the channel system. Channel sediment movement is strongly influenced by storm events, the type of flow process (debris flow or fluvial flow), the sediment characteristics, and the local channel topography. The importance of the channel–fan coupling is clearly demonstrated in that more than 90 per cent of fan sedimentation is derived from channel sediment sources. Copyright © 2006 John Wiley & Sons, Ltd.

Using Grain Size Analysis as the Basis for a Research Project in an Undergraduate Sedimentology Course

Multi-week, research style projects within the context of a one-semester undergraduate course provide scope to explore topics in depth and build student skills. I developed a research-style project for an undergraduate sedimentology course using grain size analysis of sediments that combines developing field and laboratory skills, improving writing ability, exploring statistical techniques and encouraging critical thinking. The project asks students to consider the hypothesis that the grain size distribution of sediment samples can be successfully used as fingerprints to identify sediment transport processes and depositional environments. To do this groups of students work together collecting sediment from beach environments, analyzing the grain size distribution of these samples and use statistical analyses such as histograms and log-probability graphs to help interpret their data. The use of log-probability graphs, which are a somewhat controversial technique in sediment grain size analysis, is chosen to introduce students to contentious issues in scientific research and to encourage critical thinking. Success of the project is dependent on providing students with sufficient time and feedback and to re-write reports, analyze data and contribute to classroom presentations and discussions. Development of such projects requires thoughtful selection of a topic that will meet desired pedagogical objectives and careful structure so that time is managed effectively.

Salinity episodes and their reversal in the late Pliocene of south-western Australia

Fossil pollen and grain size analysis of sediments from Yallalie in south-western Australia is used to reconstruct the history of salinization and aridity of the region between 2.63 and 2.56 Ma. Three well-defined episodes of aridity are defined by a reduction in humid woodland and expansion of chenopod shrubland around 2.59, 2.56 and 2.558 Ma. Each episode lasted an estimated 2–3000 years. The grain size data supports the general aridity conclusion but also demonstrates there was a large amount of environmental variability, especially between about 2.59 and 2.56 Ma, which included short term wetting and drying cycles. These cycles are at sub-Milankovitch time scales and suggest that the vegetation patterns show much more inertia to change than do the sediment dynamics. The general pattern of change at Yallalie is similar to that revealed in the Chinese Loess and Red Clay sequence but the detail of change is much greater in the lake sediment than revealed for the aeolian sediment of central Asia.

Particle size analysis of sediments, soils and related particulate materials for forensic purposes using laser granulometry

Particle size is a fundamental property of any sediment, soil or dust deposit which can provide important clues to nature and provenance. For forensic work, the particle size distribution of sometimes very small samples requires precise determination using a rapid and reliable method with a high resolution. The Coulter™ LS230 laser granulometer offers rapid and accurate sizing of particles in the range 0.04–2000 μm for a variety of sample types, including soils, unconsolidated sediments, dusts, powders and other particulate materials. Reliable results are possible for sample weights of just 50 mg. Discrimination between samples is performed on the basis of the shape of the particle size curves and statistical measures of the size distributions. In routine forensic work laser granulometry data can rarely be used in isolation and should be considered in combination with results from other techniques to reach an overall conclusion.

Morphological and Sedimentological Changes on an Artificially Nourished Beach, Lincolnshire, UK

Beach nourishment is increasingly seen as an appropriate management solution in areas which are experiencing beach erosion. Such a scheme has been implemented along the Lincolnshire coast between Skegness and Mablethorpe, on the east coast of England, since 1994. Poorly sorted, gravelly sandy sediment has been placed on the beaches in a gently sloping seaward profile to raise beach levels and protect the hard defences from wave attack. Grain size analysis of beach sediments, topographic profiling and remote sensing have been used to monitor the beach response. After nourishment, wave reworking caused a rapid redistribution of sediment over the beach profile during the succeeding weeks. Coarse sediment has remained on the beach berm, while finer sediment has migrated to the lower beach and sub-tidal zone. The berm face has correspondingly become steeper, producing more wave reflectance, and further scour and erosion of lower beach sediment, although there appears to have been little alongshore sediment transport. The most severe sediment loss has occurred around promontories and on the central portion of the convex-shaped coast which experiences greatest wave exposure. While the nourishment scheme has improved the standard of defence, further sediment losses could be reduced by nourishing the beach with a more natural size grading, promoting a flatter beach profile and increasing the dissipation of wave energy. Unless stabilization of the beach profile can be achieved, further periodic renourishment will be required to maintain relatively high beach levels.

Study of a debris torrent in the Dolomites, Italy

The Dolomites are situated in a region characterised by the presence of widespread debris flows, which originate at the foot of sub-vertical rocky walls and involve the underlying debris talus. These flows are characterised by the scantiness of the planimetric surface in the watershed and, when they are not channelled, by the variability of the courses from one event to another. This paper describes the study of a channelled debris flow or debris torrent, which periodically jeopardises the built-up area of San Vigilio di Marebbe (Bolzano). This town is located on a large alluvial fan formed by the torrents Ermo and Fojed6ra. The beds of both torrents are constantly full of debris, which is partly contained by many dams and mostly carried away by the water that undercuts the banks. The Fojedora, in particular, which until 1971 ran through the town carrying with it considerable amounts of debris, regularly damaged the town. As a result of these incidents, the last part of the course of the Fojed6ra was artificially diverted into the Ermo by the construction of a 4 m high and 320 m long dyke. In this way the flows, which continued to run through the torrent in the following years, were confined in the channel, and the only danger was that posed by the damming of the main channel into which the torrent Fojed6ra-Ermo flows.
 The last important event took place on 27 July 1995 following a short but bad cloud burst in the upper reaches. It mobilised a considerable amount of debris and gave rise to a flow, which was contained by the dyke, and temporarily obstructed the main torrent and the valley floor.
 The aim of the study was to reveal the mechanisms that might trigger off the flows, to analyse the morphometry of the deposits in order to characterise these deposits in terms of grain size, and to assess the possibility of damage to the infrastructure. The work was carried out in the following phases:
 - a historical reconstruction of past events from both historical documents and the "memories" of the oldest inhabitant s of the town:
 - a study of the precipitation records of two meteorological stations located near the landslide area; and
 - a topographical reconstruction of the flow route in order to map the main morphological elements , such as channels, scarps, banks, and lobes, and to carry out the grain size analysis of sediments.
 Detailed mapping of the alluvial fan by mean s of overlaying slope and land use maps was aimed at evaluating whether a possible flow that was not contained by the dyke might reach San Vigilio di Marebbe.

Characterization of Energy Gradient in Enclosed Bays of Ubatuba Region, South-eastern Brazil

This paper deals with the characterization of the energy gradient of the sedimentary dynamics of enclosed bays of south-eastern Brazil through the utilization of coarse fraction analysisIn the Ubatuba coastal region, south-eastern Brazil, the use of traditional sedimentological techniques, such as grain size and compositional analysis of surface sediments revealed little information on the spatial variability of the bottom dynamics.Many advances in the comprehension of the sedimentary processes were obtained with the utilization of coarse fraction analysis, which allowed the identification of the sectors of marine and continental influence. The utilization of a multivariate technique, the correspondence analysis, on coarse fraction analysis data reveals, through a plot of the two first factors produced by the multivariate technique, the existence of an energy gradient acting over the area, inside and between the bays, leading to the deposition of different constituents.

Heavy Metal Levels in Marine Sediments of Singapore

Marine environmental levels of the metals copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd) were measured from sediments collected around 20 coastal locations around Singapore, over a 2-year period. Sediment-size analysis was conducted on sediment samples, and Atomic Absorption Spectrophotometry was used in the analyses of sediment heavy metal concentrations. The levels of heavy metals in marine sediment was largely dependant on sediment particle size, as illustrated by the correlation of sediment size with Multidimensional Scaling (MDS) configurations of sediment metal concentrations. In addition, the proximity to shipping activity, and the release of anti-fouling paint from boats also influence heavy metal concentrations in marine sediments of Singapore.

Trace metals and lanthanides in a tropical river environment

The river Periyar in the State of Kerala, India is subjected to pollution from a number of industrial units such as zinc smelter, rare earth plant, phosphatic fertilizer unit etc. The levels of Zn and Cd in water and sediments in the river have in recent years increased ten fold as compared to a study conducted earlier during 1970. The levels of these trace metals in water increase at the backwater zone under high salinity in summer due to solubilisation from the sediments. Among the lanthanides Ce is the most predominant in water. Elements such as Ce, La, Sm, Gd and Y show a concentration factor of 103 in sediments. The trace metals show maximum concentration at the top layer of sediment column extending up to 20 cm from the surface. Particle size analysis of river sediments in the industrial outfall area shows a mass median diameter of 11 μm with a geometric standard deviation of 2.4 for Zn and Cd.

Using a Laser Particle Counter to Enhance Sedimentology Laboratory Exercises

Traditional size determination of fine-grained sediments by the pipette or hydrometer methods is tedious, very time consuming, and frequently not accurate. Using a laser particle counter is more accurate and the method can be used to quickly and accurately determine the size distribution of the less than 100μm fraction of very small samples. This paper describes the operation of the Spectrex Laser Particle Counter and its use in sedimentology laboratory exercises. In addition to doing size analysis of bottom sediments, the laser particle counter can be used to determine size distributions of suspended particles in saline water. It is not necessary to disaggregate or slake the flocculated particles prior to analyses. In the settling scan mode the laser counter can monitor particles in suspension at preset times and determine the settling rates of the sediment. The results are printed out in both tabular and graphical form.

Assessment of analytical techniques for the size analysis of fine grained sediments : Singer, J K; Anderson, J B; Ledbetter, M T; McCave, I N Jones, K P N; Wright, R J Sediment PetrolV58, N3, May 1988, P534–543

Assessment of analytical techniques for the size analysis of fine grained sediments : Singer, J K; Anderson, J B; Ledbetter, M T; McCave, I N Jones, K P N; Wright, R J Sediment PetrolV58, N3, May 1988, P534–543

An Assessment of Analytical Techniques For The Size Analysis of Fine-Grained Sediments

ABSTRACT An evaluation of techniques for the size analysis of fine-grained sediments revealed that the Malvern Laser Sizer (E3600), Electrozone Particle Counter (Model 112), Micromeritics SediGraph (5000E), and hydrophotometer work well for the analysis of sorted silt. Differences in results may be attributed to the particle property being measured by each instrument. The Malvern Laser Sizer and Electrozone Particle Counter are sizing techniques; the hydrophotometer and SediGraph determine sedimentation diameter through particle settling. There was less agreement among these instruments for unsorted natural sediments containing greater than 15 percent clay by weight. Clay content of less than or equal to 8 percent does not appear to decrease the resolution of silt-sized particles.

A comparison of four methods of size analysis of fine-grained sediments

Abstract Four established methods of analysing particle sizes finer than 63 μm are compared: pipette, hydrometer, SediGraph, and hydrophoto-meter. Four samples were analysed: a high plasticity mud, a p-layer loess, a highly micaceous silt, and a synthetic pure quartz mud. All results of pipette and hydrometer analysis are close throughout the entire size range. SediGraph results compare closely with pipette results at sizes finer than 16 μm (6φ))) but indicate a markedly coarser distribution at larger diameters. The hydrophotometer gives anomalously coarse results throughout the size range. No general conversion factor could be devised to adjust hydrophotometer results to those of the pipette and hydrometer methods. Reproducibility is excellent for pipette and hydrometer, good for hydrophotometer, and fair for SediGraph. Instrument precision of the SediGraph and hydrophotometer is excellent; imprecision arises mainly through the subsampling process.

Phi and Sediment Size Analysis: DISCUSSION

Phi and Sediment Size Analysis: DISCUSSION

SEDIMENT TRANSPORT DURING A CONTROLLED RESERVOIR RELEASE1

ABSTRACTThe transport of bedload and suspended sediments and particulate organic matter was evaluated in Huntington Creek, Utah, during a controlled release of water from Electric Lake Reservoir from August 7–10, 1979. Effects of the release on channel geometry and riffle composition also were assessed. Bedload transport rates increased from zero to 1,650 and 1,500 kg/hr at two cross sections as discharge was increased from 0.4 to 4.9 m3/s; transport rates then decreased erratically as discharge was held constant. Cross section measurements and sediment size analysis indicate that flows were insufficient to transport riffle sediments. Rapid increases in the transport rates of suspended sediments and particulate organic matter also occurred during rising discharge and again decayed when discharge became constant. Suspended sediment concentrations for samples obtained with an automatic pumping sampler were generally less than those found for samples obtained with a DH‐48 sampler. Biological measurements still are needed to determine if such a release can improve fisheries habitat by removing fine sediments.

Comparison of the bottom nepheloid layer and late Holocene deposition on Nitinat Fan: Implications for lutite dispersal and deposition

A study of 56 sediment cores and 121 nephelometer profiles from Nitinat deep-sea fan shows variations in late Holocene accumulation rates and sediment texture which parallel variations in thickness and suspended sediment load of the bottom nepheloid layer. Furthermore, accumulation rates, sediment texture, and nepheloid layer variables all show a substantial degree of correlation with fan topography. In general, the nepheloid layer thickens (>100 m) and suspended sediment loads increase (>100 µg/cm 2 ) above Cascadia Channel (the major channel crossing the fan) as well as above the northern flank of the fan. Over levees and the western portion of the fan, the nepheloid layer thins to 2 . Cascadia Channel and the northern flank of the fan have been loci of rapid sedimentation, with accumulation rates ranging from approximately 5 to greater than 12 mg/cm 2 /yr. In contrast, the apex and western reaches of the fan have significantly lower accumulation rates: 1 to 5 mg/cm 2 /yr. Detailed size analysis of bottom sediments shows that areas characterized by rapid sedimentation and a thick, heavily loaded nepheloid layer have more medium to fine silt (5 to 7 ϕ) than the clay-rich (>8 ϕ) sediments from interchannel areas with low accumulation rates and a thin, lightly loaded nepheloid layer. The data suggest that turbid water moves continuously down Cascadia Channel and the northern flank. The transport mechanism is size-selective and topographically controlled, concentrating silt-sized detritus in topographic lows. The data also suggest a positive downward flux of sediment particles within the nepheloid layer, at least when averaged over a significant period of time.

On the grain size analysis of sediments by Visher's method and its application to ecological study for benthos

On the grain size analysis of sediments by Visher's method and its application to ecological study for benthos

The Logarithmic Spiral: Definition and Expression of a New Graphical Representation of Results in Sedimentological Analysis

ABSTRACT To avoid the loss of information in the coarser and the smaller fraction, results of size analysis of sample can be plotted in three-component diagrams, also called ternary diagrams or triangular diagrams, the sample being represented by a single point. A particular disposition of triangular diagrams called a sequence of triangular diagrams can be formed by considering the grade scale (10 10) as the successive boundaries of each diagram. In this system, a sample is represented by a curve which is a logarithmical spiral, the equation being: = a e-K. Geometric and trigonometric relationships give and . Study of the variations of the K coefficient permits one to obtain the mathematical position of truncation points of log-probability curves. In this graphical representation of samples, the straight lines, which join truncation points, correspond to sedimentary populations (Visher, 1969). A spiral curve is formed by several arches of which we know the equations. These arches are homologues of the straight lines of sedimentary populations in log-probability curves. The logarithmic spiral gives: first, an equation fo the size analysis of sediments, and secondly, greater accuracy in determination and study of sedimentary populations which depend on the different modes of transport and deposit of sediment.

A Rapid Method for Size Analysis of Coarse Sediments

ABSTRACT A photographic method for size analysis of coarse sediments is proposed. The operator must be provided with a camera and two rods divided into segments of suitable length. The rods are plated at both sides of the sampling area and a picture is taken. The clasts are counted in the picture by comparison of their minor visible axis with straight lines drawn between the rods.