Grain Size Distribution Characteristics Research Articles

Provenance of soil parent materials in relation to regional environmental changes in the Songnen Plain, Northeast China

Parent materials have a strong control on soil formation process and soil properties, understanding their provenance can provide important information for soil genesis, classification, and regionalization. The Songnen Plain in northeast China has large areas of Phaeozems and Chernozems, popularly known as “black soils”, but their parent material provenance and sedimentary processes are still unclear. Therefore, this paper analyzes the types and formation process of soil parent materials in the context of regional environmental changes. This analysis is based on the characteristics of grain size distribution and quartz particle morphology at the regional and profile scales. The results indicate that aeolian loess is the predominant parent material. For instance, the surface of quartz particles exhibits characteristics indicative of mechanical impact, which is produced during the process of wind transportation. The particle size distribution curve displays a bimodal pattern, and the soil particle size tends to become finer from west to east. However, in some areas, the soil is influenced by river or lake sediments. The main source areas of aeolian deposits are likely the Gobi and sandy land in the upwind direction of the study area, while the Songhua River alluvial deposits only provide source material in local areas. High-resolution grain size analysis and K-feldspar single-particle OSL chronology show that from the Last Glacial Maximum to the Early Holocene, far-source materials dominated the deposition process. In the Middle Holocene, climate warming increased the frequency of dust activities and accelerated the deposition process. In the late Holocene, climate fluctuations and intensified human activities led to more intense dust storms in the provenance area, which in turn promoted the continuous accumulation of parent materials for soils that developed into Phaeozems and Chernozems.

Grain-size distribution characteristics of sediments in coastal shallow waters from Van Don to Tien Yen - Ha Coi, Northwest Gulf of Tonkin, Vietnam, according to End-member modelling analysis

The study involved the collection of eighteen surface sediment samples from the coastal shallow water area from Van Don to Tien Yen - Ha Coi in the Northwestern section of the Gulf of Tonkin to analyze their particle size composition. Utilizing the EMMAgeo end-member analysis model, four characteristic particle sizes (4EM) of 0.34, 7.7, 130, and 230 µm, corresponding to clay, fine silt, and fine sand of varying sizes were identified. In conjunction with the sedimentary environment, the spatial distribution analysis of these end members allowed a detailed determination of the formation conditions and distribution of the sediment components. Clay deposits (EM1) are primarily intercalated between the islands. At the same time, fine silt (EM2) is concentrated in the northern part of the study area, transported by flows, and deposited in a low-energy environment. Fine sand sediments (EM3 and EM4) are distributed along the coast of the Van Don peninsula in the Southern part of the study area and likely formed in association with tidal-wave processes under higher energy conditions compared to the North.

Response of Grain-Size Distribution Characteristics of a Gravel Bar to Topographic and Hydraulic Conditions: A Case Study from the Upper Yangtze River in China

Response of Grain-Size Distribution Characteristics of a Gravel Bar to Topographic and Hydraulic Conditions: A Case Study from the Upper Yangtze River in China

Validation of appropriate estimation criteria for the number of components for separating a polymodal grain-size distribution into lognormal distributions

Polymodal particle size distributions are generally analyzed by separating them into lognormal distributions, but estimating the precise number of lognormal components required remains a considerable problem. In the present study, appropriate evaluation criteria for the estimation of the number of components were examined by using artificial data for which the true number of components was known. The characteristics of estimations of the number of components by four evaluation criteria, the mean square error (MSE), Akaike information criterion (AIC), Bayesian information criterion (BIC), and adjusted R-squared (ARS), were investigated. The results showed that the MSE and ARS were less sensitive to the true number of components and tended to overestimate the number of components. By contrast, the AIC and BIC tended to underestimate the number of components, and their correct answer rates decreased as the true number of components increased. The BIC tended to include the true number of components among its higher ranked models. The present evaluation results suggest that the MSE, although frequently used, is not necessarily the most appropriate evaluation criterion, and that the AIC and ARS may be more appropriate criteria. Furthermore, checking whether the number of components estimated by the AIC or ARS is included among higher ranked BIC models might prevent overestimation and thereby allow for more valid estimation of the number of components. When the criteria were applied to grain-size distributions of lacustrine sediments, it was possible to estimate the number of components that reflected differences in grain-size distribution characteristics.

Fractal features of soil grain-size distribution in a typical Tamarix cones in the Taklimakan Desert, China

Tamarix cones play key roles in preventing sand erosion and maintaining regional ecosystem stability. This study aimed to explore the characteristics of soil grain size distribution (GSD) in Tamarix cones across the Taklimakan Desert, verify the relationships between soil grain composition and the fractal dimension, and analyze the relationships between soil GSD and environmental factors. Soils of the Tamarix cones from 0 to 500 cm soil depth were sampled every 20 cm at four sites (Qiemo, Qira, Aral, and Tazhong) along the periphery to the hinterland of the Taklimakan Desert. A total of 300 soil samples were collected to measure soil grain sizes and soil properties. Soil grain size composition was dominated by silt and very fine sand, and the fraction of fine particles decreased and that of the coarse particles increased with soil depth, except for at Tazhong. This suggested that suspension-size particles are the main component of the soil GSD and decrease with the increasing depth in the profiles at the Tamarix cones. The soils were poorly and moderately poorly sorted. Kurtosis generally showed a mesokurtic peak, and the GSD was negatively skewed towards the coarser particles. The fractal dimensions of GSD decreased in the following order Qiemo (2.30) > Qira (2.07) > Aral (1.99) > Tazhong (1.96) because of the increase of coarse particles. The fractal dimension had a strong positive correlation with the clay and silt fractions, and a strong negative correlation with the sand fraction, indicating that the fractal dimension can reflect the characteristics of the soil GSD. The strong relationships between the fractal dimensions and selected soil properties indicate that the fractal dimension can not only quantify changes in soil properties, but also reflect the degree of desertification and degradation in the desert region. Considering the strong wind activities and different deposition sources in the Taklimakan Desert, this study provides a deep insight into the soil formation processes of Tamarix cones within extreme arid desert ecosystems.

Insight into the environmental significance of grain-size fractal and pedogenesis of a typical loess and paleosol sequence

The loess-paleosol sequence contains rich climate change information during formation process. A typical loess-paleosol sequence was selected to analyze the grain-size, magnetic susceptibility and element intensity of samples. Fractal method was used to describe the characteristics of grain-size distribution and evaluate the relationship between fractal dimension and pedogenesis process. Based on the results of the mass balance and soil reconstruction model, the relationship between loess deposition and pedogenesis was studied. Change of unary fractal dimensions was consistent with the changing trend of climate indicators, and average fractal dimensions of paleosol (2.246) was greater than that of loess (2.201). The fractal dimension can evaluate the fragmentation degree of particles and magnitude of energy events. Results of piecewise linear regression analysis showed that there were two different fragmentation mechanisms in the process of particle fragmentation. DF1 was close to 3, and the energy dissipation in the process of coarse particles breaking into fine particles was mainly manifested in volume; DF2 was close to 2, and the energy in the process of breaking fine particles into clay particles mainly proceeded along a two-dimensional plane. The volume changes of loess and paleosol were simultaneously affected by pedogenesis, formation pressure and global climate. The mass loss or gain shown by the different size-fraction components and element intensity indicated that the loess deposition and pedogenesis were simultaneous. During the prevailing summer monsoon, strong pedogenesis was dominant and formed paleosol. While the cold-dry climate during the prevailing winter monsoon promoted the loess deposition. The fractal and reconstruction model respectively quantitatively calculated the degree of particle fragmentation and the amount and process of material change during the formation process of loess-paleosol. Their combined application can enrich the theory of soil genesis and help to understand the origin of loess-paleosol sequence and its relationship with climate change.

Recrystallization mechanisms, grain refinement, and texture evolution during ECAE processing of Mg and its alloys

This article presents key findings from a study of the microstructural evolution and grain size refinement of equal-channel angular extrusion (ECAE)-processed Mg and Mg-based alloys. Firstly, we delineate the experimental trends and material characteristics of grain size distribution and texture of as-cast pure Mg and rolled AZ31B which were processed via ECAE. We then identify and describe the primary controlling mechanisms of dynamic recrystallization (DRX) and twinning and how their interaction affects the overall refinement process. Secondly, using preliminary results from ongoing studies of other Mg-based model binary and ternary systems, with access to precipitation hardening mechanisms, we present new opportunities and beneficial outcomes that could affect and control the material's microstructural properties. Thirdly, we provide a summary of prior and concurrent modeling and simulation efforts that capture and emulate the experimentally observed trends of DRX and illustrate their predictive capability. We then, within a Materials-by-Design and Optimization framework, conclude with implications for future developments in Mg alloy research.

Particle breakage of sand subjected to friction and collision in drum tests

This paper presents a laboratory experimental study on particle breakage of sand subjected to friction and collision, by a number of drum tests on granular materials (silica sand No. 3 and ceramic balls) to investigate the characteristics of particle breakage and its effect on the characteristics of grain size distribution of sand. Particle breakage increased in up convexity with increasing duration of drum tests, but increased linearly with increasing number of balls. Particle breakage showed an increase, followed by a decrease while increasing the amount of sand. There may be existence of a characteristic amount of sand causing a maximum particle breakage. Friction tests caused much less particle breakage than collision tests did. Friction and collision resulted in different mechanisms of particle breakage, mainly by abrasion for friction and by splitting for collision. The fines content increased with increasing relative breakage. Particle breakage in the friction tests (abrasion) resulted in a sharper increase but with a smaller total amount of fines content in comparison with that in the collision tests (splitting). For the collision tests, the fines content showed a decrease followed by an increase as the amount of sand increased, whereas it increased in up convexity with increasing number of balls. The characteristic grain sizes D 10 and D 30 decreased in down convexity with increasing relative breakage, which could be described by a natural exponential function. However, the characteristic grain sizes D 50 and D 60 decreased linearly while increasing the relative breakage. In addition, the coefficients of uniformity and curvature of sand showed an increase followed by a decrease while increasing the relative breakage.

Characteristics of Grain Size Distribution of River Flooding Sediments in Ibang-myeon, Changnyeong and their Meaning

Characteristics of Grain Size Distribution of River Flooding Sediments in Ibang-myeon, Changnyeong and their Meaning

Seasonal variations of textural and heavy minerals of the Karamana river sediments and beach sediments of Trivandrum, Southern Kerala

Kerala, south western state of India is known for its abundant heavy mineral deposits along the coast. Beach placer deposits in Kerala is known for ilmenite, rutile, zircon, monazite, sillimanite and garnet. The grain size study of the sediments from Karamana river, flowing in the southern part of Kerala. Sediments from different parts of the river basin is studied, which enabled to understand the grain size variations with course of the river from the Peppara dam to Thiruvallam, very near to coast. Mineralogy of the river vary from one place to another depending different factors like host rocks in the province, climate conditions of the area, agents of transport and hydraulic condition during deposition, also can predict the actual source area associated with heavy mineral. Textural and heavy mineral studies of the placers of beach and Karamana river basins indicating the river is one of the important contributors of sediments to the western coast of the southern part of Kerala. Samples from various parts of the river indicate that the sediment is medium sand, moderately sorted, fine skewed and platykurtic. The characteristics of grain size distribution are related to the source rocks, process of weathering, and different sorting processes during transportation and deposition. The total heavy mineral percentage shows it is prominently enrichment in fine sand and very fine sands.

Grain-size and microstructure of the loess from closed depressions in the Nałęczów Plateau (East Poland)

<p>The investigation was conducted in the eastern part of the Nałęczów Plateau, a region of the Lublin Upland, in eastern Poland. The loess cover of this region was formed mainly during the last glaciation, and loess accumulation lasted until 15,000–12,000 BP. The undulating loess plateau with numerous oval-shaped closed depressions (CDs) is the main landform in the study area. Particle size distribution and SEM analyses were conducted for loess profiles under the bottoms and on the slopes of 4 CDs. Grain-size distribution characteristics as well as qualitative and quantitative micromorphological characteristics of the the loess forming the bottoms and slopes of the depressions were compared and discussed. It was documented that the differences between the loess forming the bottoms and slopes of the depressions are insignificant in the case of clay fraction content, but are considerable in the case of microstructure characteristics. The differences documented result from the impact of syn- and post-depositional diagenetic processes related mainly to suffosion and hydroconsolidation occurring under the influence of water. A quantitative assessment of the morphological effects of these processes was carried out in the context of the origin of closed depressions. The morphological effect of Holocene diagenetic processes was manifested in the deepening of the initial closed depressions formed previously under the influence of primary morphogenetic processes.</p>

Characteristics of grain size distribution and the shear strength analysis of Chenjiaba long runout coseismic landslide

Study on the grain size distribution characteristics and the frictional strength behavior of the slide deposits are helpful to disclose the landslide runout process and understand the mechanism of a long runout landslide. We performed grain size distribution analysis on samples collected from Chenjiaba landslide induced by Wenchuan earthquake. The grain size distribution of samples from the landslide sections quantitatively depicts a gradual coarsening upward grading from shear zone to the top section. Then a multistage - multiphase ring shearing approach was used to determine a comparative shear strength behavior of samples from each landslide section. In this method, a sample was sheared continuously for large displacement and fast rate on different normal stress conditions. The multiphase shear mode with a maximum of 105 mm/min rate has allowed observing the qualitative change and patterns of the frictional resistance behaviors of soils under different normal stresses. The results of coefficient of friction values under multiphase shear mode have shown substantial post peak shear weakening behaviors after large shear displacement that can be narrated with long runout processes. The shear strength test results indicate that the shear zone samples have developed higher friction angle values compared to overlying section samples, on the last phase of shear process, which may be very important to understand the braking mechanism of a long runout landslide.

The integration of grain-size distribution and plasticity parameters for characterizing and classifying unconsolidated fine-grained sediments

Grain-size distribution (GSD) characteristics are often used to classify different types of sediment and to understand how variations in depositional processes affect mechanical behavior. However, the current grain-size-based classification systems have not been able to distinguish fine-grained sediments with varying silt and clay content. In addition, the current classification systems do not consider mineralogy in the classification scheme or the subsequent implication of mineralogy in the mechanical behavior of the sediment. This study proposes a new grain-size-based scheme to classify unconsolidated inorganic sediments that cover a wide range of natural depositional environments with a special emphasis on fine-grained deposits. The proposed classification assumes a linear relationship between percent fines and the silt fraction. This relation describes the behavior of the GSD curve, which analysis showed to be controlled by the ratio of the clay fraction to the silt fraction. The proposed scheme allows the clay mineral composition to be included, and allows the mechanical behavior to be inferred as well. The classification scheme shows that plasticity indices (i.e. liquid limit and plasticity index) are reliable proxies for clay mineralogy. In addition, the study uses the activity of clay as a quantifiable factor that discriminates between the major clay-mineral groups. By combining grain-size characteristics and plasticity, the proposed classification extends the utility of the scheme beyond simply classifying the sediment class, towards inferring the potential mechanical behavior of sediments having various GSD characteristics and mineralogy.

Characteristics of Grain Size Distribution on Beaches Sediment of Sumba Island, Nusa Tenggara Timur Based on Grainsize and Geochemical Data

Study of beaches sediment characteristics were conducted on three beaches on Sumba Island, East Nusa Tenggara.The research is a part of Widya Nusantara Expedition which conducted by using Research Vessel of Baruna Jaya VIII. The aim of this study is to determine the characteristics of coastal deposits through the observation of grain size by using the grain size trend analysis approach (Grain Size Trend Analysis, commonly abbreviated as GSTA) and geochemical analysis. A total of 36 samples were taken on each coast representing high tide, transition and low tide along the coast. A grain size analysis was performed using a Malvern Mastersizer 2000 that was processed with Gradistat 4.0 software. Geochemical analysis was carried out using X-ray fluorescence spectrometry (XRF). The distribution of beach sediments is dominated by moderate sand - coarse sand and differences on content of geochemical elements (Ca, Sr, Fe, K, and Ti). The coastal conditions that are connected to the Indian Ocean (B1) have different characteristics from the beach that connected to the Sumba strait (B5 and B7). GSTA analysis showed sediment of Laboya Beach finer than sediment on Waikelo and Melolo Beach. Geochemical elements on Laboya Beach indicates different values than others. It indicates there are differences in the provenance and composition of sediment on the all three beaches. The supply of coastal deposits on these three beaches is influenced by the mechanism of precipitation of the walls and the processes of waves and rivers.Keywords: distribution, sediment, grainsize, geochemical, XRF, beach sediment.

Characteristics of Grain Size Distribution on Beaches Sediment of Sumba Island, Nusa Tenggara Timur Based on Grainsize and Geochemical Data

Study of beaches sediment characteristics were conducted on three beaches on Sumba Island, East Nusa Tenggara.The research is a part of Widya Nusantara Expedition which conducted by using Research Vessel of Baruna Jaya VIII. The aim of this study is to determine the characteristics of coastal deposits through the observation of grain size by using the grain size trend analysis approach (Grain Size Trend Analysis, commonly abbreviated as GSTA) and geochemical analysis. A total of 36 samples were taken on each coast representing high tide, transition and low tide along the coast. A grain size analysis was performed using a Malvern Mastersizer 2000 that was processed with Gradistat 4.0 software. Geochemical analysis was carried out using X-ray fluorescence spectrometry (XRF). The distribution of beach sediments is dominated by moderate sand - coarse sand and differences on content of geochemical elements (Ca, Sr, Fe, K, and Ti). The coastal conditions that are connected to the Indian Ocean (B1) have different characteristics from the beach that connected to the Sumba strait (B5 and B7). GSTA analysis showed sediment of Laboya Beach finer than sediment on Waikelo and Melolo Beach. Geochemical elements on Laboya Beach indicates different values than others. It indicates there are differences in the provenance and composition of sediment on the all three beaches. The supply of coastal deposits on these three beaches is influenced by the mechanism of precipitation of the walls and the processes of waves and rivers.Keywords: distribution, sediment, grainsize, geochemical, XRF, beach sediment.

Soil erosion in relation to climate change and vegetation cover over the past 2000 years as inferred from the Tianchi lake in the Chinese Loess Plateau

Understanding the response of past soil erosion to climate change and human disturbances is quite essential for managing and preventing soil erosion in the future. Here, we report a high-resolution soil erosion sequence during the past 2000 years based on grain-size data from a sediment core GS07A in Tianchi Lake in the Chinese Loess Plateau. These grain-size data are analysed by end-member modelling and further deciphered by detailed modern investigations of surface sediments, surface soils, and modern dust samples aided by published grain-size distribution characteristics of different depositional provenances and processes. Six strong soil erosion periods, including more than 20 serious soil erosion events, are inferred at 150–300 CE, 450–750 CE, 900–1100 CE, 1200–1400 CE, 1650–1800 CE, and 1950–2000 CE. These soil erosion records correspond well with intensive flood events in downstream rivers and the neighbouring Longxi area documented from the historical literature, suggesting that regional high-intensity rainfall or flood events are the main cause of soil erosion. Vegetation cover in the catchment also influenced soil erosion: light vegetation cover aggravated soil erosion even in the periods with a low frequency of flooding, while heavy cover reduced soil erosion even in the periods with a high frequency of flooding. Our results highlight the role of sustainable land use and vegetation restoration around the catchment in controlling soil erosion in the Chinese Loess Plateau.

A discontinuous dynamic recrystallization model incorporating characteristics of initial microstructure

Abstract In order to describe and predict the kinetic process of discontinuous dynamic recrystallization (DDRX) during hot working for metals with low to medium stacking fault energies quantitatively, a new physically-based model was proposed by considering the characteristics of grain size distribution, capillary effect of initial grain boundaries (GBs) and continuous consumption of GBs. Using Incoloy 028 alloy as a model system, experiments aiming to provide kinetic data (e.g., the size and volume fraction of recrystallized grain) and the associated microstructure were performed. Good agreement is obtained between model predictions and experimental results, regarding flow stress, recrystallized fraction and grain size evolution. On this basis, a thermo-kinetic relationship upon the growth of recrystallized grain was elucidated, i.e., with increasing thermodynamic driving force, the activation energy barrier decreases.

PARTICLE SIZE CHARACTERISTICS OF RIVERBED SEDIMENTS TRANSPORTED BY TIDAL BORE ‘BONO’ IN KAMPAR ESTUARY, RIAU-INDONESIA

The presence of tidal bore in the Kampar River (locally known as ‘bono’) may influence sedimentation in the Kampar River and its estuary. Understanding sedimentation mechanisms (e.g., erosion, deposition) is important to communities along the Kampar River, which can be studied by analyzing characteristics of grain size distribution. Here, we study riverbed sediment samples collected from 17 stations using an Ekman grab sampler, accompanied by bathymetry and acoustic Doppler current profiler (ADCP) measurements. Grain size data show that the sediments are coarser upstream and gradually finer downstream. Silty sands are predominant in the upstream section of the river, sands in its river body and sandy silts in the downstream. The results indicate the influence of undular bores on grain size characteristics. We also found that the propagation of bono and Kampar River’s funnelshaped morphology cause intense scouring events of riverbed sediments. Sortation values that range between 0.332.14 suggest unstable currents that result in randomly deposited sediments. The sediment mass transfer per area is positively towards downstream at the low tidal condition. However, after the passage of the bores, the sediment mass transfer area becomes negatively towards upstream.

Determination of grain-size characteristics from electromagnetic seabed mapping data: A NW Iberian shelf study

The electric conductivity and magnetic susceptibility of sediments are fundamental parameters in environmental geophysics. Both can be derived from marine electromagnetic profiling, a novel, fast and non-invasive seafloor mapping technique. Here we present statistical evidence that electric conductivity and magnetic susceptibility can help to determine physical grain-size characteristics (size, sorting and mud content) of marine surficial sediments. Electromagnetic data acquired with the bottom-towed electromagnetic profiler MARUM NERIDIS III were analysed and compared with grain size data from 33 samples across the NW Iberian continental shelf. A negative correlation between mean grain size and conductivity (R=−0.79) as well as mean grain size and susceptibility (R=−0.78) was found. Simple and multiple linear regression analyses were carried out to predict mean grain size, mud content and the standard deviation of the grain-size distribution from conductivity and susceptibility. The comparison of both methods showed that multiple linear regression models predict the grain-size distribution characteristics better than the simple models. This exemplary study demonstrates that electromagnetic benthic profiling is capable to estimate mean grain size, sorting and mud content of marine surficial sediments at a very high significance level. Transfer functions can be calibrated using grains-size data from a few reference samples and extrapolated along shelf-wide survey lines. This study suggests that electromagnetic benthic profiling should play a larger role for coastal zone management, seafloor contamination and sediment provenance studies in worldwide continental shelf systems.

Reconsideration at field scale of the relationship between hydraulic conductivity and porosity: the case of a sandy aquifer in South Italy.

To describe flow or transport phenomena in porous media, relations between aquifer hydraulic conductivity and effective porosity can prove useful, avoiding the need to perform expensive and time consuming measurements. The practical applications generally require the determination of this parameter at field scale, while most of the empirical and semiempirical formulas, based on grain size analysis and allowing determination of the hydraulic conductivity from the porosity, are related to the laboratory scale and thus are not representative of the aquifer volumes to which one refers. Therefore, following the grain size distribution methodology, a new experimental relation between hydraulic conductivity and effective porosity, representative of aquifer volumes at field scale, is given for a confined aquifer. The experimental values used to determine this law were obtained for both parameters using only field measurements methods. The experimental results found, also if in the strict sense valid only for the investigated aquifer, can give useful suggestions for other alluvial aquifers with analogous characteristics of grain-size distribution. Limited to the investigated range, a useful comparison with the best known empirical formulas based on grain size analysis was carried out. The experimental data allowed also investigation of the existence of a scaling behaviour for both parameters considered.