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Understanding the development and spatial distribution of alluvial patches in mixed bedrock‐alluvial rivers is necessary to predict the mechanisms of the interactions between sediment transport, alluvial cover, and bedrock erosion. This study aims to analyze bedrock alluviation patterns using a 2D morphodynamic model, and to use the model results to better understand the mechanisms responsible for alluvial patterns observed experimentally. A series of simulations are conducted to explore how alluvial patterns in mixed bedrock‐alluvial channels form and evolve for different channel slopes and antecedent sediment layer thicknesses. In initially bare bedrock low‐slope channels, sediment cover increases with increasing sediment supply because areas of Froude‐subcritical flow enable sediment deposition, while in steep‐slope channels the flow remains fully supercritical and the model predicts so‐called runaway alluviation. For channels initially covered with sediment, the model predicts a slope‐dependent sediment supply threshold above which sediment cover increases with increasing sediment supply, and below which the bedrock becomes fully exposed. For a given sediment supply, the fraction of bedrock exposure and average alluvial thickness converge toward the equilibrium value regardless of the initial cover thickness as long as it exceeds a minimum threshold. Steep channels are able to maintain a continuous strip of sediment under sub‐capacity sediment supply conditions by achieving a balance between increased form drag as bedforms develop and reduced surface roughness as the portion of alluvial cover decreases. In lower‐slope channels, alluvial patches are distributed sporadically in regions of the subcritical flow. Plain Language Summary: Bedrock rivers may have patches of alluvial sediment that cover some or all of the underlying bedrock. The amount of this sediment cover can change dynamically over time depending on the flow, upstream sediment supply, channel morphology, and antecedent sediment conditions. Here, we use a numerical model to simulate flow and sediment transport so that we may better understand what controls sediment cover in mixed bedrock‐alluvial rivers. We used the model to simulate channels of varying slopes, sediment supplies, and initial sediment cover, and we analyze the model's output to gain insight into how alluvial patches form and what controls their extent and dynamics. Our numerical model results produce phenomena that have been observed in physical experiments, and they show that the channel slope and initial sediment thickness play an important role in determining whether and how much sediment can be deposited. Our results also show that flow transitions provide critical locations where sediment deposits can start to form. Persistent sediment cover in bedrock channels can develop when a delicate equilibrium is reached between sediment roughness and the flow field. Key Points: Numerical simulations are conducted in mixed bedrock‐alluvial channels to analyze controls on alluvial patternsPartial alluvial cover over steep slopes requires roughness from bedforms and sediment transport to prevent sediment washoutTranscritical flow produces zones of deposition over otherwise exposed bedrock beds [ABSTRACT FROM AUTHOR]

Mixed bedrock‐alluvial rivers can exhibit partial alluvial cover, which plays an important role in controlling bedrock erosion rates and landscape evolution. However, numerical morphodynamic models are generally unable to predict quasi‐steady persistent patches of depositional alluvial features under conditions where the sediment supply is less than the sediment transport capacity of the channel. Hence, we present a new two‐dimensional depth‐averaged morphodynamic model that can be applied to both fully alluvial and mixed bedrock‐alluvial channels, and we use the model to gain insight into the mechanisms responsible for the development of sediment patches and patterns of bedrock alluviation. The model computes hydrodynamics, sediment transport, and bed evolution using a roughness partitioning that accounts for differential roughness of sediment and bedrock, roughness due to sediment transport, and form drag. The model successfully replicates observations of bar development and migration from a fully alluvial flume experiment, and it models persistent sediment patches observed in a mixed bedrock‐alluvial flume experiment. Numerical experiments in which the form drag, sediment transport roughness, and bedform stress correction were neglected did not successfully reproduce the observed persistent sediment cover in the mixed bedrock‐alluvial case, suggesting that accounting for these different roughness components is critical to successfully model sediment dynamics in bedrock channels. Plain Language Summary: Some rivers have patches of sediment intermittently distributed among areas of bare bedrock. These sediment patches can influence flow conditions and patterns of bedrock erosion in these channels. Flume experiments and field studies have shown that the amount of sediment cover and the pattern of sediment patches in mixed bedrock‐alluvial rivers can sometimes stabilize over time, but numerical models have been largely unable to replicate those observations. Here, we present a new numerical model for mixed bedrock‐alluvial rivers that explicitly accounts for how the bedrock and sediment affect the flow. We show that the model can successfully simulate observations from flume experiments conducted with and without exposed bedrock, and it is able to simulate persistent partial sediment cover. These conditions develop because of the way the bedrock and sediment interact with the flow, which we demonstrate through simulations where some of those feedback are "turned off," resulting in completely exposed bedrock without sediment cover. Key Points: A new model is developed to predict the dynamics of alluvial patterns in mixed bedrock‐alluvial channelsModel‐predicted alluvial patterns are similar to those observed in fully alluvial and semi‐alluvial flume experimentsAccounting for differential roughness and shear stress correction are important for model prediction of the degree of exposed bedrock [ABSTRACT FROM AUTHOR]

The deformation behavior of deep excavations is affected by many factors, among which the geological conditions are greatly affected. Hangzhou Bay is affected by marine siltation and river alluvium, and the geological conditions within the urban area of Hangzhou are quite different. In this paper, the geological and deformation data of 79 deep excavation cases in the Hangzhou urban area were collected, and the statistical analysis showed that the deformation control of excavations in the silt area was poor. The average maximum lateral wall displacement of deep excavations of the Hangzhou urban area was 0.41%H (H was the depth of the excavation), the average value of the alluvial area was 0.22%H, and the average value of the silted area was 0.55%H. The influence of geological conditions, wall type, and construction period on the deformation of excavations was compared, and the deformation behavior of excavations in the silted area was clearly affected by various factors. [ABSTRACT FROM AUTHOR]

Silty alluvial soils are highly compressible. Deep soil mixing is being increasingly used for remediating such ground conditions, which produces artificially cemented soil columns that gain strength with curing. This study investigated the one-dimensional compression and shear stiffness degradation behaviour of an alluvium in its reconstituted, undisturbed and artificially cemented states. The binder used to stabilise the soil was a low-carbon alkali-activated blast-furnace slag. Oedometer and triaxial data indicated that the nature of the soil structure evolved from being chiefly meta-stable when undisturbed to dominantly stable in its cemented state after 28 days of curing. A new framework has been presented to quantify continuous changes in structure within the alluvium during one-dimensional compression in its undisturbed and cemented states, with respect to its intrinsic properties. This better captured structure degradation during earlier stages of compression compared with previous frameworks and provided insights into defining the limits of meta-stable and stable components of structure within materials of higher strength. A new formulation has been developed for predicting shear stiffness degradation of samples with strain under triaxial conditions. This showed efficiency and good performance in modelling experimental data and was successfully used to quantify initial structure and degradation of structure within the undisturbed and cemented alluvium. [ABSTRACT FROM AUTHOR]

A column experiment at a laboratory level was carried out to assess the effect of the application of nanotechnology in the decontamination of soils and alluvial deposits with high levels of potentially toxic elements (PTEs). A suspension of zero-valent iron nanoparticles (nZVI) was injected at three different concentrations in selected samples (two sediments, one soil). For most of the elements, the retention by nZVI was proportional to the concentration of the suspension and the trend was similar. Metals were immobilized by adsorption on the surface layer of the nanoparticles and/or by complexation, co-precipitation, and chemical reduction. By day 60 following injection, the nZVI lost reactivity and the retained species were desorbed and back into the soluble phase. The definition of spatial patterns for PTEs' distribution allowed for the construction of contamination risk maps using a geostatistical simulation approach. The analysis obtained from the extractable contents of five target elements (Zn, Cu, Cd, Pb, As) was cross-checked with the estimated map network to assess their retention efficiency. Data from the analysis of these elements, in the extractable phase and in the porewater of the sediments/soils, indicate the nZVI injection as a suitable technique for reducing the risk level of PTEs in contaminated Fe-rich tropical environments. [ABSTRACT FROM AUTHOR]

Alluvial soils cover about 5% territory of Poland and they are an important part of the environment of floodplains and river valleys. These soils have long been studied by soil scientists around the world. The high school students also have a relatively high knowledge of them in comparison with other soil types. Information about them is readily available in textbooks and on the internet. Is this enough to make alluvial soils the driving force behind efforts to popularize soil science? The aim of this paper is to diagnose the state of knowledge about these soils among high school students of Kuyavian-Pomeranian region as well as the assessment of their suitability in the soil awareness raising. Querying geography textbooks and internet sources as well as a survey method were used as the main research methods. Information on alluvial soils is commonly found in geography textbooks and websites. The awareness of soil distribution within Kuyavian-Pomeranian voivodship is the highest for alluvial soils among all studied types of soils. Respondents correctly assess the value of these soils and can identify ways to increase soil awareness among the public. Among the respondents there is a conviction that there is a need for changes in soil science education, especially in the field of extracurricular activities. Suggestions for such activities are included in this publication. The Year of Alluvial Soils is a good opportunity to introduce new solutions in the popularization of soil science on a regional and national scale. [ABSTRACT FROM AUTHOR]

The Soil Science Society of Poland has elected alluvial soils (Polish: mady) to be the Soils of the Year 2022. Although alluvial soils cover less than 5% of Poland, they have high importance for agriculture and forestry due to their specific location in river valleys, moisture status and high potential productivity. Moreover, alluvial soils play crucial role for functioning of many protected natural and semi-natural ecosystems in river valleys. Stratified alluvial soils, commonly involving buried topsoil horizons, are also important for the reconstruction of natural environmental changes (in particular climatic and hydrological ones) and human impact on the landscape. This paper presents: (a) a concept of alluvial soils in Poland; (b) a review of the development and transformation of alluvial soils in relation to river valley dynamics and human influences, (c) historical and present classification schemes for alluvial soils in Poland and their correlation with international classification systems (WRB and Soil Taxonomy); and (d) utility of alluvial soils for agriculture and forestry based on their physicochemical properties and water regime. [ABSTRACT FROM AUTHOR]

Jiaodong stands out among three global provinces boasting gold reserves surpassing 5000 tons. As geological exploration in the region continues to rise, the significance of deep and covered areas in Jiaodong for ore prospecting becomes increasingly evident. In this study, a Fine-grained soil prospecting method was employed in the Qujia hidden gold deposit and its surrounding region, situated in Yantai City, Shandong Province, and concealed by alluvial soil. The gold (Au) content exhibited a high enrichment level, and the range of Au and silver (Ag) geochemical anomalies demonstrated a robust correlation with known hidden orebodies. Furthermore, transmission electron microscopy and nano-CT were utilized to identify nano-micron metal particles and micro-fractures in the wall rock. A hereditary relationship between the nano-micron metal particles of ore-forming elements present in surface media and the deep orebody was observed. A migration model detailing the movement of deep ore-forming materials in the form of nano-micron metal particles, governed by a multi-agent relay dominated by ascending geogas flow, was established in the Qujia gold deposit in Jiaodong. These findings contribute theoretical support for the fine-grained soil prospecting method in geochemical exploration within alluvial soil covered areas. • The fine-grained soil prospecting method was employed in the Qujia gold deposit. • The surface geochemical anomalies corresponded to known ore bodies. • The nano-micron metal particles and micro-fractures were identified. • The migration model was established. [ABSTRACT FROM AUTHOR]

Plaxis is a software program widely used in Singapore for the analysis of excavation problems in the Kallang Formation and the Old Alluvium. The present study showed that the soft soil creep model was the most appropriate for excavation study of a retaining wall with a stabilizing berm in the estuarine deposit and the upper and lower marine clays of the Kallang Formation, and the hardening soil model was the most appropriate for the fill, fluvial deposits, and Old Alluvium in Singapore using Plaxis. The appropriate values of soil parameters of the estuarine deposits, fluvial deposits, Kallang Formation, and Old Alluvium for excavation study required by the hardening soil and the soft soil creep models will be summarized based on the summary of design parameters of a detailed geotechnical study and a literature review of the appropriate values reported in the literature for each soil layer. The validity of using such values for Plaxis analysis will be confirmed by a comparison of the predicted deflection of a diaphragm wall with the field measurement. The appropriate values of soil parameters of the estuarine deposits, fluvial deposits, Kallang Formation, and Old Alluvium for excavation study required by the hardening soil and the soft soil creep models will be very useful for practicing engineers. [ABSTRACT FROM AUTHOR]

Support crushing and roof fall accidents frequently occur in the large mining height stope covered by the thin bedrock and large-thick alluvium (TBLA). A comprehensive method including field monitoring, numerical modelling, and theory analysis was performed to investigate the strata movement and its induced ground behaviors of a deep-buried stope under TBLA. The filed measurement results indicated that strong roof periodic weighting phenomenon occurred regularly at an interval of 18–23 m during panel 3301 retreating. During weighting period, dynamic characteristics of hydraulic supports are prominent and characterized by high safety valve opening rate and poor working conditions including tilt down operation and excessive end distance. Additionally, numerical modelling results revealed that the thickness of bedrock affects the movement behaviors of the roof strata and its generated spatial structure significantly. Based on the above results, an integrated control measure was proposed and successfully applied to the test site. [ABSTRACT FROM AUTHOR]

The Standard Penetration Test (SPT) is the most common in-situ tests for soil investigations. On the other hand, the Cone Penetration Test (CPT) is considered one of the best investigation tools. Many CPT-SPT correlation relationships have been proposed worldwide to estimate soil parameter from the other's available data. However, unfortunately, no available SPT-CPT correlations are established for the alluvial soil of Dhaka city. This paper aims at presenting correlations among the SPT-N value, cone tip resistance (qc), sleeve friction resistance (fs), soil behavior index (Ic) and mean particle size (D50) for an alluvial soil deposit of Dhaka city. It is found that for the relationship between equivalent SPT N60-value and SPT N60-value the coarser soil layers As1 and As2 show the coefficient of correlation (R2) is 0.7106 and 0.534 respectively, which indicate a reliable relationship. In addition, the correlation between cone tip resistance (qc) and SPT N60-value shows very strong relationship which is very similar to proposed Meyerhof correlation. Furthermore, the relations between other mentioned parametres also shows a valid correlations similar to other authors. [ABSTRACT FROM AUTHOR]

Soil cohesion is one of the main parameters in designing mitigation methods for shoring to support deep excavation. Therefore, construction cost of tall buildings with deep excavation in large cities is greatly dependent of cohesion. Because of problems encountered with undisturbed sampling, in-situ testing has an important role in determining soil parameters. Cementation generally increases soil cohesion. On the other hand, new geotechnical design codes propose statistical methods as the rational method for analysis and representation of soil data in order to capture soil parameters uncertainties. This paper aims to explore the characteristic values of coarse-grained alluvium based on experimental results of in-situ direct shear and plate load at the edge of trench tests. The site location in in Tehran, capital of Iran, with coarse-grained soil consisting of gravely sand to sandy gravel with some cobbles and boulders, mostly cemented by carbonaceous materials. Statistical analysis has been done between cohesion and angle of internal friction. Also, probability distribution functions have been fitted to soil parameters. The obtained results indicate that friction angle has a truncated normal distribution but cohesion can be presented with lognormal distribution. The sample test show correlation coefficient of 0.45 between c′ and φ′ stating a positive correlation. Furthermore, characteristic values of these parameters are determined based on different methods and the results have been compared with each other. The characteristic value of cohesion and friction angle calculated in the range of 25 to 50 kPa and 30 to 35°, respectively. Global stability analyses with different calculated characteristic values are also performed. It is presented that characteristic value evaluation is an important step in geotechnical practices. [ABSTRACT FROM AUTHOR]

Deep excavation supported by vertical retaining walls together with strutting system is commonly used in Singapore for the construction of underground infrastructure. In this paper, a series of numerical scenarios simulated by PLAXIS software are carried out to study the influence of different design parameters such as pre-auger loosening effect, the embedded depth of retaining wall into the stiff soil layer, and the elastic modulus of the ground improvement layer on excavation design especially on strut force, retaining wall deflection, and bending moment. The results show that there is high risk if only a single set of parameters are used as input to predict the performance of the retaining system. Sensitivity analysis shall be carried out to evaluate the effects of these parameter variations within a reasonable range on strut force, retaining wall deflection, and bending moment. [ABSTRACT FROM AUTHOR]

The results of the field radiometric survey of the mined monazite Vasil'evka placer in southern Yakutia are presented. It is shown that the natural background radioactivity of soils of the surveyed area mainly depends on the features of its geological structure and, to some extent, on landscape-geocryological conditions. The rate of equivalent dose of gamma radiation on the soil surface of the studied plot varies in a wide range (from 0.04 to 0.50 µSv/h or more), depending on changes in the concentrations of 40K, 238U, and 232Th in soils. Radiogeochemical features of soils in the studied area are well displayed on radiometric maps by isolines of the dose rate and radionuclide contents. The concentrations of 40K, 238U, and 232Th are minimal in a peat-bog soil and a high moor on the interfluves composed of crystalline schists and gneisses and are maximal in podburs and alluvial soils formed on the products of weathering of granitoid rocks and monazite-bearing alluvial deposits in the Vasil'evka River valley. The studied soils are characterized by low mean concentrations of 40K and 238U, corresponding to their background values in soils of Yakutia. The mean concentration of 232Th in the studied soils is increased as compared to the geochemical background. In addition to the composition of soil-forming rocks, the content and distribution of radionuclides in soils are significantly affected by soil-forming processes, chemical properties of elements, and technogenic impact. According to the effective specific activity of radionuclides, the studied soils correspond to the first, second, and third classes of building materials. Soils and enriched sands in some parts of technogenic landscapes are assigned to low-radioactive industrial waste according to the specific activity of thorium and require disposal. Their use as building materials from the identified areas of natural thorium concentration in alluvial deposits has serious limitations. [ABSTRACT FROM AUTHOR]

The present study aims to assess groundwater potential in the Telidjene Basin located in the semi-arid part of eastern Algeria, applying an innovative approach combining both remote sensing and hydrogeophysics methods. A re-interpretation of geophysical data and vertical electrical sounding (VES) measurements were applied and calibrated with the borehole data to map the deep structures that may control the presence of groundwater and identify the geological and hydrogeological setting. Morphometric factors affecting recharge were mapped using several types of remote sensing data (SRTM DEM, Landsat-8). Thematic maps were overlaid using the multicriteria method and GIS to detect potential recharge areas. The results show that the main factors influencing recharge are fracturing and drainage density. Four potential recharge areas were identified over a 547 km2 area of the basin. 20% of the area falls in the weakest class, 32% in the weak class, 3% in the moderate, and 16% in the strongest. Furthermore, the study reveals that an alluvial aquifer with a thickness of up to 60m, spreading over the surface, along the Wadi Telijene and the alluvial soil, is deposited unconformably on Cretaceous terrain containing aquifer horizons of varying thickness and different electrical resistivities (10-150 Ωm), drawing an anticlinal structure with lithostratigraphy interrupted by a series of faults and spurs of Aptian and Triassic age. The south-western part of the basin has a high to moderate recharge and storage capacity. Its alluvial cover is directly fed by precipitation and fractured limestones deposited in a syncline outcropping on the edges forming an alluvial and carbonate bilayer aquifer. This study concluded that an integrated approach, involving recent, efficient, and inexpensive technology, such as remote sensing and conventional geophysical method, can be successfully used to identify groundwater potential in the study area. [ABSTRACT FROM AUTHOR]

In 2000, Tim Church published an excellent examination of the secondarily deposited obsidian in Rio Grande Quaternary alluvium for a relatively small section of the Rio Grande in southern New Mexico. Here, the goal is to complement Church's study to include six secondary deposits of a portion of the Rio Grande hydrological basin nearly 400 km in length, coupled with a comparison to 11 archaeological sites on or near the river basin. Additionally, the compositional and metric data on obsidian sources from the Jemez Lineament sources have also improved since 2000, providing useful data on nodule dimension as well as compositional data at the primary sources. By recording both nodule sizes against source provenance at these points along the Rio Grande, scholars can compare the results of nearby archaeological contexts and the source obsidian available at various points along the Rio Grande. It is often difficult to determine whether the raw material used to produce a chipped stone tool was originally procured at the source or in secondary contexts. That, however, can never be achieved anywhere in the world without firm secondary depositional data. This issue is the focus of this study. [ABSTRACT FROM AUTHOR]

The study investigates the measurement of radon concentration in soils and rocks as a natural tracer for exploring uranium mineralization, first of its kind in Bangladesh. The range of radon concentration was measured as 8–4360 Bq/m3 with an average of 851.41 Bq/m3. Among the measured values, 2120–4360 Bq/m3 was observed in the Tertiary sediments whereas 8–584 Bq/m3 was found in the Recent alluvial soil of different bils and haors. These high radon concentrations are explained by geogenic factors such as mineral content in rocks, alluvium cover, sufficient porosity, probable subsurface fault, and flooding by water streamed through adjacent uranium-rich areas in India. The radon values indicate that the rock formations are promising for uranium mineralization. The radon concentration in rocks and soils are well comparable to the similar studies of the other parts of the world. The results are in good agreement with the previous radiometric survey results, suggestive to extensive exploration activities to confirm uranium mineralization in the area. Moreover, the average annual effective dose of 0.008092 mSv/y in the region calculated from the radon values is within the WHO and ICRP safety limits. [ABSTRACT FROM AUTHOR]

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Due to tool, time and budget limitations, 2-dimensional analyses of deep excavation are often adopted for engineering practice; thus, the 3-dimensional behaviour is ignored. Because conducting 3-dimensional analyses is very time-consuming and costly, the "plane strain ratio (PSR)" indicator is defined to assist in understanding the 3-dimensional behaviour of deep excavations via the results of 2-dimensional analyses. However, previous works of the impacts on PSR have focused on only the excavation geometry and distance from the excavation corner. In this paper, additional factors that may affect the PSR for excavations in both drained and undrained materials are examined, and it is concluded that not only excavation geometry and distance to the corner but also the ratio of the wall embedded depth to the excavation depth and the wall thickness have comparatively significant influences compared to other factors, whether excavating drained or undrained materials. Lastly, multiple regression is used to modify the value of the PSR from empirical PSR charts for sand and clay considering the impacts of these abovementioned factors. [ABSTRACT FROM AUTHOR]

Vrgada Island is situated in the central part of the eastern Adriatic coast. Upper Cretaceous limestones crop out on the surface and Pleistocene sediments cover them in some parts of the island. This study focused on a coastal cliff trending N - S on the northern part of the island. Aeolian-alluvial deposits, which are 12.5 m thick were analysed and three different facies in this succession described. The lowermost facies A highlights a strong aeolian influence marked by an increased silt percentage and was deposited during colder climate conditions. Sand and gravel in facies B were deposited by streams of dense, cold water formed by melting snow and ice from the nearby Dinaric mountains. The bioturbated sandy facies C was probably formed during a warmer climate. An unusually high percentage of augite in the lowermost part of facies A can be explained by the input of volcanic dust, most likely from the Roman or Campanian volcanoes in Italy. This, combined with the surface textures on quartz grains detected from SEM photographs indicates a short distance transport for the sediment, no matter which mechanism was dominant. The sediments from Vrgada Island represent a transitional zone between the north Adriatic islands, where aeolian sediments dominate and the South - Eastern Adriatic archipelago, where mixed alluvial and aeolian sediments were observed. [ABSTRACT FROM AUTHOR]

In this study, liquefaction potential of the alluvial soils consisting of clay, silt, and sand sized materials in Sahilkent (Bafra, Samsun) area was investigated using CPT data. Within the scope of the study, 20 boreholes each having a depth of 15 meters were drilled throughout Bafra district, and one undisturbed soil sample were obtained per meter from 5 of these boreholes located in Sahilkent area. Wet sieve, hydrometer, plastic limit, liquid limit, and natural water content determinations were conducted on 20 samples with high silt and sand content. In the preliminary evaluation, it was determined that there is a liquefaction potential in some regions at different depths, and in order to perform detailed liquefaction analyses, 15-meter-deep CPTu were carried out in 1 meter distance from those 5 borehole locations. In CPTu tests, data including cone tip resistance, sleeve friction, effective stress, relative stiffness, etc. were recorded every 5 cm, and average values of these data for each meter depth were used in the liquefaction analysis. Liquefaction analyses was conducted for an earthquake scenario of Mw = 7.2 and the liquefaction potential of the 15-meter soil layer in the study area was determined. As a result of the analyses, it was determined that no liquefaction will occur for an earthquake scenario of Mw = 7.2 in Sahilkent region. It is thought that high fine-grained content of the alluvium, and the fact that existing clean sand levels are located between fine-grained soil layers increase the resistance of the soil against liquefaction. [ABSTRACT FROM AUTHOR]

Longwall extraction of coal seam disturbs the whole overburden strata, from the coal seam to the surface, and forms a subsidence basin. This paper investigated the mechanism of the overburden strata bending deformation, the alluvium mechanical parameters, and their effect on surface subsidence by the theoretical analysis and numerical simulation analysis. The dynamic processes of overburden failure and surface subsidence due to longwall mining was analyzed by a novel two-dimensional trapezoidal-area method. A "π-shaped" model was first developed to reveal that surface subsidence consists of the overburden strata bending deformation and the subsidence of the alluvium. The process and mechanism of the overburden strata bending transfer were analyzed, and two mechanical models of the strata bending deformation were established, i.e., the strata suspended bending model and the strata overhanging bending model. The maximum subsidence equation of the overburden strata bending basin was derived based on the theoretical analysis. Also, the effect of the alluvium mechanical parameters on the surface subsidence was investigated by numerical simulation analysis. The rationalities of the numerical simulation were validated by the field measurements. The results show that surface subsidence increases logarithmically during increased alluvium thickness and decreases exponentially and logarithmically during increased internal friction angles and increased cohesions, respectively. [ABSTRACT FROM AUTHOR]

Underground mining will lead to deformation and failure of overburden and frequently associated with water inrush. In view of the special situation of No.8 mining area in Baodian Coal Mine (thin bedrock and thick alluvium). According to geological engineering characteristics and overlying lithified strata, different bedrock height models were established using physical and numerical simulation. The deformation and failure of overburden, mining-induced stress, and height of the caving zone are then studied using these models. The results show that mining-induced stress is different in overburden and clay, with a large variation near the rock and clay layers. Findings also illustrate that the clay layer has an inhibitory effect on mining-induced stress. The height of the caving zone increases with the height of the bedrock, and the height of the caving zone obtained by physical and numerical simulation are similar. Through the comprehensive comparison of the height of the caving zone, it can be inferred that the height of the caving zone does not reach the thinnest position of the bedrock and no large water inrush will occur. The results obtained in this study provide an important framework for the study of coal mining safety under similar geological conditions in other locations. [ABSTRACT FROM AUTHOR]

Natural or artificial cementation strongly affects stiffness and damping characteristics of soil deposits. In this paper, it is tried to figure out cementation effects on the spectral response using one-dimensional ground response analysis. A constitutive model is applied which is based on separating the mechanical behavior of cemented soil into two distinct parts, soil matrix and cemented bonds. A non-recursive algorithm was used to calculate the nonlinear behavior of horizontally multilayered soil in frequency domain. The model was verified based on recorded acceleration time histories at sites with cemented alluviums and the results showed good consistency. [ABSTRACT FROM AUTHOR]

Some accidents of dams are attributed to suffusion around open-framework gravel (OFG) in sandy gravel alluvium. However, whether OFG can be really an internal seepage exit of fine particle migration in the field or not? How much the effect of OFG on suffusion is? These problems have not been investigated yet. This paper presented a list of flume-scale suffusion tests to investigate suffusion at the tip of a cutoff wall in sandy gravel alluvium with OFG. The results indicate that suffusion first initiates at the downstream side of the tip of the cutoff wall in the test without OFG, while in the tests with OFG, it initiates at the upstream side of OFG, and then both mainly progress backward to the upstream side. OFG significantly decreases the hydraulic gradients at the initiation of suffusion and at blowout. In addition, the experimental results also confirm that OFG is likely to be an internal seepage exit of fine particle migration in the field. A large number of fine particles and some coarse particles in the sandy gravel are eroded into OFGs in the tests, and OFG significantly increases the settlement induced by blowout; meanwhile, it makes the settlement unstable after blowout. [ABSTRACT FROM AUTHOR]

We investigate processes of bedrock‐core bar and island development in a bedrock‐influenced anastomosed reach of the Sabie River, Kruger National Park, eastern South Africa. For sites subject to alluvial stripping during an extreme flood event (~4,470–5,630 m3 s−1) in 2012, preflood and postflood aerial photographs and LiDAR data, 2‐D morphodynamic simulations, and field observations reveal that the thickest surviving alluvial deposits tend to be located over bedrock topographic lows. At a simulated peak discharge (~4,500 m3 s−1), most sediment (sand, fine gravel) is mobile but localized deposition on bedrock topographic highs is possible. At lower simulated discharges (<1,000 m3 s−1), topographic highs are not submerged, and deposition occurs in lower elevation areas, particularly in areas disconnected from the main channels during falling stage. Field observations suggest that in addition to discharge, rainwash between floods may redistribute sediments from bedrock topographic highs to lower elevation areas, and also highlight the critical role of vegetation colonization in bar stability, and in trapping of additional sediment and organics. These findings challenge the assumptions of preferential deposition on topographic highs that underpin previous analyses of Kruger National Park river dynamics, and are synthesized in a new conceptual model that demonstrates how initial bedrock topographic lows become topographic highs (bedrock‐core bars and islands) in the latter stages of sediment accumulation. The model provides particular insight into the development of mixed bedrock‐alluvial anastomosing along the Kruger National Park rivers, but similar processes of bar/island development likely occur along numerous other bedrock‐influenced rivers across dryland southern Africa and farther afield. Key Points: Flood deposition along bedrock‐influenced anastomosed channels is preferentially initiated over topographic lows on exposed bedrockVegetation succession on developing bars and islands increases erosional resistance, and captures additional sediment and organicsBedrock topographic lows become topographic highs (bedrock‐core bars and islands) in the latter stages of sediment accumulation [ABSTRACT FROM AUTHOR]

The paper presents results of landscape planning and investigation on Fluvisols. The object is "Kubratovo 1" sand and gravel deposit, Bulgaria. Soil samples were taken from twentyone soil profiles at a depth of 0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm, and 80-100 cm. The changes in physicochemical properties were investigated at different soil depths and the relationships between different soil characteristics were tested. There are statistically significant positive or negative regressions. There are regression relationships between the soil texture fractions and bulk density, total porosity, soil organic matter, total Kjeldahl nitrogen, available phosphorus and available potassium. [ABSTRACT FROM AUTHOR]

The experience of previous earthquakes in the world shows that the structural damage due to the earthquakes is highly influenced by the site condition, which is known as site effects. Since most cities are built on alluviums, studying the seismic response of alluvial basin, which are the site of many structures, is very important. This study investigates the seismic response of 2D trapezoidal alluvial valleys with slope angles of 31ᵒ, 45ᵒ, and 71.5ᵒ, against P and SV vertically propagating incident waves in middle and lateral areas of the valleys. Then the effect of changes in Poisson’s ratio and specific weight of alluvial materials on the seismic response of the valley in the mentioned areas is investigated. Numerical modeling is done using QUAKE/W finite element software, based on the equivalent linear analysis. According to the results, by increasing the slope angle of the valley, the vertical acceleration and displacement response spectrum in the middle and lateral areas of the alluvial valley decrease and increase, respectively. Moreover, by increasing the Poisson’s ratio and specific weight of alluvial materials, the vertical acceleration and displacement response spectrum in the middle area of the valley decrease, but do not undergo tangible changes in the lateral areas of the valley. [ABSTRACT FROM AUTHOR]

This paper describes the performance of the Moroccan high-speed railway embankment over alluvial soft ground treated with prefabricated vertical drains. For analyzing soil behavior, numerical analyses were performed under 2D finite element Plaxis code. The authors undertook Class-B prediction at first, using two different constitutive models, soft soil and soft soil creep (SSC) models. Class-C prediction was then performed using only SSC. By comparing the predictions with field measurement, it was concluded that the time-dependent model (SSC) produced acceptable results. However, reasonable modification for the SSC model input parameters in Class-C prediction led to obtain accurate matches with field measurements. [ABSTRACT FROM AUTHOR]

The activities carried out by preindustrial agricultural societies are not usually considered as important factors of soil degradation. Nonetheless, repetitive human daily activities for hundreds of years can substantially transform the natural properties of the soils. At the site of La Playa, Mexico, the activities of early farmers modified the landscape and had an important role in the physical transformations of the natural soil features. This paper depicts the characteristics of La Playa paleosols, which were the living surface of the Early Agriculture Period community (4000 - 1800 cal BP) and we discuss the influence of daily subsistence activities on the soil. The soil features (structuring, differentiation of horizons, texture-in field and laboratory, color, porosity, stoniness, magnetic properties, organic carbon content, carbonation, presence of cutans, nodules and/or concretions, among other pedological features) of three profiles with pedosediments (paleosols interbedded with sediments) formed during late Holocene are discussed. Our study suggests that La Playa Fluvisols are poorly developed and were formed with alluvial deposits (largely composed of reworked soils). The pedogenic properties indicate that overlapping developed during short time periods of stability, under arid conditions of the last 4000 years. The uniformity of the features in all the studied profiles indicate similar pedogenetic conditions across the site. The micromorphological and magnetic properties clearly show that the soil was deeply disturbed by human activities, mainly by roasting features to process food, crematories and grave digging to bury the dead, and removing soil for several agricultural activities. [ABSTRACT FROM AUTHOR]

The permanent ground deformation during the earthquake faulting induces moderate to severe damages to the underground tunnels. The majority of the investigations on the behavior of the tunnels against fault offset were in the rock medium. There is very little available in the literature about the fault-tunnel interaction in alluvial soil. This paper has studied the interaction between a continuous tunnel and reverse faulting within a dense sandy alluvial deposit. An experimental centrifuge test, alongside the numerical modelling, has been utilized for this purpose. It has been shown that the longitudinal strains of an infinite tunnel were much higher than that of a finite length tunnel. The results have also displayed that there are critical cross-sections along the tunnel's length that maximum curvatures, moments, shears, and axial forces occur in them. The numerical parametric study on the variation of the Fault Zone Width (FZW) and reinforcement content (ρs ) have shown that higher ρs values would be more useful in tunnel resistance against faulting. Besides, smaller FZW will make higher deformations, moments, and forces in the concrete lining. The optimum rs value has been obtained as 4%. [ABSTRACT FROM AUTHOR]

The role of fluvial sedimentary areas as organic carbon sinks remains largely unquantified. Little is known about mechanisms of organic carbon (OC) stabilization in alluvial sediments in semiarid and subhumid catchments where those mechanisms are quite complex because sediments are often redistributed and exposed to a range of environmental conditions in intermittent and perennial fluvial courses within the same catchment. The main goal of this study was to evaluate the contribution of transport and depositional areas as sources or sinks of CO2 at the catchment scale. We used physical and chemical organic matter fractionation techniques and basal respiration rates in samples representative of the three phases of the erosion process within the catchment: (i) detachment, representing the main sediment sources from forests and agricultural upland soils, as well as fluvial lateral banks; (ii) transport, representing suspended load and bedload in the main channel; and (iii) depositional areas along the channel, downstream in alluvial wedges, and in the reservoir at the outlet of the catchment, representative of medium- and long-term residence deposits, respectively. Our results show that most of the sediments transported and deposited downstream come from agricultural upland soils and fluvial lateral bank sources, where the physicochemical protection of OC is much lower than that of the forest soils, which are less sensitive to erosion. The protection of OC in forest soils and alluvial wedges (medium-term depositional areas) was mainly driven by physical protection (OC within aggregates), while chemical protection of OC (OC adhesion to soil mineral particles) was observed in the fluvial lateral banks. However, in the remaining sediment sources, in sediments during transport, and after deposition in the reservoir (long-term deposit), both mechanisms are equally relevant. Mineralization of the most labile OC (the intra-aggregate particulate organic matter (Mpom) was predominant during transport. Aggregate formation and OC accumulation, mainly associated with macroaggregates and occluded microaggregates within macroaggregates, were predominant in the upper layer of depositional areas. However, OC was highly protected and stabilized at the deeper layers, mainly in the long-term deposits (reservoir), being even more protected than the OC from the most eroding sources (agricultural soils and fluvial lateral banks). Altogether our results show that both medium- and long-term depositional areas can play an important role in erosive areas within catchments, compensating for OC losses from the eroded sources and functioning as C sinks. [ABSTRACT FROM AUTHOR]

Harsit Creek which is one of the major rivers of the Eastern Black Sea region in terms of both volumetric flow rate and length formed a small delta in east of the Giresun province and Tirebolu town centre by depositing the carried alluvium in the mouth portion. Floods caused by Harsit Creek and consisting partially covered with swamp prevents the use of delta as agricultural and residential area until 1950s. The rehabilitation of the Harsit Creek after 1950 and with the drainage of delta began to turn into first the agricultural field, after 1980 a residential area. These changes are today continuing by accelerating. In addition, the coastal road which is one of the country's major transportation projects and completed in 2000s is located in the coastal areas of the delta. The sand extraction is performed from down ground of Valley of Harsit Creek since the 1990s. Also in the years of 2000s ponds were built on Harsit Creek to produce electricity. These developments lead to a reduction the alluvial soils that are reached by Harsit Creek and it is threatening human facilities on delta. In the present study, aerial photographs belong to 1950, 1973, and 1984 and high-resolution satellite imagery belong to 2007 and 2014 have been analysed; field observations were made; it is focused on both futures of delta and changes in the delta by doing face to face interviews with local residents. In addition, measures to be taken were highlighted. [ABSTRACT FROM AUTHOR]

Abstract: Wetlands are the largest source of methane (CH4) globally, yet our understanding of how process‐level controls scale to ecosystem fluxes remains limited. It is particularly uncertain how variable soil properties influence ecosystem CH4 emissions on annual time scales. We measured ecosystem carbon dioxide (CO2) and CH4 fluxes by eddy covariance from two wetlands recently restored on peat and alluvium soils within the Sacramento–San Joaquin Delta of California. Annual CH4 fluxes from the alluvium wetland were significantly lower than the peat site for multiple years following restoration, but these differences were not explained by variation in dominant climate drivers or productivity across wetlands. Soil iron (Fe) concentrations were significantly higher in alluvium soils, and alluvium CH4 fluxes were decoupled from plant processes compared with the peat site, as expected when Fe reduction inhibits CH4 production in the rhizosphere. Soil carbon content and CO2 uptake rates did not vary across wetlands and, thus, could also be ruled out as drivers of initial CH4 flux differences. Differences in wetland CH4 fluxes across soil types were transient; alluvium wetland fluxes were similar to peat wetland fluxes 3 years after restoration. Changing alluvium CH4 emissions with time could not be explained by an empirical model based on dominant CH4 flux biophysical drivers, suggesting that other factors, not measured by our eddy covariance towers, were responsible for these changes. Recently accreted alluvium soils were less acidic and contained more reduced Fe compared with the pre‐restoration parent soils, suggesting that CH4 emissions increased as conditions became more favorable to methanogenesis within wetland sediments. This study suggests that alluvium soil properties, likely Fe content, are capable of inhibiting ecosystem‐scale wetland CH4 flux, but these effects appear to be transient without continued input of alluvium to wetland sediments. [ABSTRACT FROM AUTHOR]

The main objective of this study was to provide a methodological insight in the archaeometric field of ceramic provenance and technology, through the identification of the scale of representative differences in terms of clay composition. For this purpose, a total of 78 clay specimens-representative of the three types of Daunian clayey raw materials (Sub-Apennine clays, alluvial deposits and terraced alluvial deposits)- was collected and geochemically investigated, with the aim of determining up to which geographical scale, the exclusive application of geochemical analyses can provide reliable results for the reconstruction of clayey raw materials supply. For the Daunian territory, the scale has been identified with that of a ‘riverine province’, i.e. between the local and the regional extension of the north Apulian fluvial courses. In practice, the Sub-Apennine clays can be chemically distinguished into a northern group, including the Salsola, Vulgano, Celone and Lorenzo streams and a southern group, including the Carapelle stream and the Ofanto river. Moreover, the comparison between the geochemical composition of the clay samples and that of local ceramic productions (previously investigated) has shown that the Sub-Apennine clays were either used as received (Clay 1 group) or refined through decantation (Clay 2 group), before being shaped into fine wares or building materials; conversely, both the alluvial and the terraced alluvial deposits were used “as received” for the production of coarse wares. Furthermore, for the first time, the geospatial network analysis was further applied to the investigation of ancient raw materials exploitation. This analysis was performed in order to reach a reasonable reconstruction of both routes and travel times linking supply areas with production and distribution sites. Surprisingly, the results have shown that, at small distances, the transportation of clayey raw materials is not only reliable but rather highly likely, especially in those sites where Sub-Apennine clays are not readily available. [ABSTRACT FROM AUTHOR]

Alluvial soils derived from sediments of Piedmont origin occur in the Atlantic Coastal Plain of the southeastern U.S. In South Carolina, high-order rivers receiving sediment are Savannah (SV), Congaree (CN), Wateree (WA), Santee (ST), Lynches (LY), and Great Pee Dee (PD). This study investigated distribution of soil properties on natural levee, valley flat, and backswamp landforms within and among the six river floodplains and compared results to the taxonomic classifications used historically during soil survey production. This study also investigated the contribution of sediment sources to soil characteristics. Data were compiled for 65 soil pedons sampled from 16 soil survey areas during a 41-year time period. Pedons were located in three Major Land Resource Areas (MLRAs), and the results should aid in development of both land resource area and ecological site concepts. Data analyses centered on clay and silt contents, mineralogy, base saturation (BS), and cation exchange activity (CEA) classes. Evaluation of data from the six river floodplains revealed common properties among soils on fluvial landscapes across multiple MLRAs. Four soil systems, each derived from a predominant rock type, composed the Piedmont drainage basin of each river. The absolute area of each soil system differed between rivers, but sediment supplied typically did not result in great soil texture variation per landform. The land area proportion of the Carolina Slate Belt soil system had a close relationship to silt contents of the alluvial soils. On the valley flat landform of five floodplains, particle-size control section (PSCS) median clay content ranged only between 302 g kg − 1 and 405 g kg − 1 . Among all valley flats median PSCS silt content ranged between 361 g kg − 1 and 511 g kg − 1 . Slight positive downriver trends for clay were observed on SV, WA, and PD and for silt on SV and WA. Although local BS variation could be high between pedons, slight positive downriver BS trends on valley flats were observed on SV, WA, and ST. Negative BS trends were seen on LY and PD. Kaolinite was the dominant clay mineral in soils of all landforms on the six floodplains. Weatherable primary minerals in sand and silt fractions resulted in higher BS except for the LY soils, where resistant minerals composed sand and silt fractions. The semiactive CEA class occurred predominantly on all three landforms. Taxonomic analysis supported soil assignment to the suborders Aquepts or Udepts on all floodplains. Great group level Eutrudepts in South Carolina are first reported here, and they occur extensively enough on SV, CN, WA, and PD to warrant recognition in soil map units. Because most soil properties showed little variability for soils occurring in floodplains for all six rivers, botanical assessments will be needed to determine the magnitude of the role the properties have toward defining ecological sites. Ultimately, the alluvial systems may be aggregated as a single land resource area within the Coastal Plain. [ABSTRACT FROM AUTHOR]

The Ganga River is a major river of North India and is known for its fertile alluvium deposits formed due to floods throughout the Indo-Gangetic plains. Flood frequency analysis has been carried out through various approaches for the Ganga River by many scientists. With changes in river bed brought out by anthropogenic changes the intensity of flood has also changed in the last decade, which calls for further study. The present study is in a part of the Upper Indo-Ganga plains subzone 1(e). Statistical distributions applied on the discharge data at two stations found that for Haridwar lognormal and for Garhmukteshwar Gumbel EV1 is applicable. The importance of this study lies in its ability to predict the discharge for a return period after a suitable distribution is found for an area. [ABSTRACT FROM AUTHOR]

Along low gradient rivers in northern Australia, there is widespread gully erosion into unconfined alluvial deposits of active and inactive floodplains. On the Mitchell River fluvial megafan in northern Queensland, river incision and fan-head trenching into Pleistocene and Holocene megafan units with sodic soils created the potential energy for a secondary cycle of erosion. In this study, rates of alluvial gully erosion into incipiently-unstable channel banks and/or pre-existing floodplain features were quantified to assess the influence of land use change following European settlement. Alluvial gully scarp retreat rates were quantified at 18 sites across the megafan using recent GPS surveys and historic air photos, demonstrating rapid increases in gully area of 1.2 to 10 times their 1949 values. Extrapolation of gully area growth trends backward in time suggested that the current widespread phase of gullying initiated between 1880 and 1950, which is post-European settlement. This is supported by young optically stimulated luminescence (OSL) dates of gully inset-floodplain deposits, LiDAR terrain analysis, historic explorer accounts of earlier gully types, and archival records of cattle numbers and land management. It is deduced that intense cattle grazing and associated disturbance concentrated in the riparian zones during the dry season promoted gully erosion in the wet season along steep banks, adjacent floodplain hollows and precursor gullies. This is a result of reduced native grass cover, increased physical disturbance of soils, and the concentration of water runoff along cattle tracks, in addition to fire regime modifications, episodic drought, and the establishment of exotic weed and grass species. Geomorphic processes operating over geologic time across the fluvial megafan predisposed the landscape to being pushed by land used change across an intrinsically close geomorphic threshold towards instability. The evolution of these alluvial gullies is discussed in terms of their initiation, development, future growth, and stabilisation, and the numerous natural and anthropogenic factors influencing their erosion. [ABSTRACT FROM AUTHOR]

River regulation since the 17th century, large-scale drainage, and intensive farming have seriously transformed soils in the river valleys of Poland. Flood suppression and groundwater lowering have created oxidizing conditions in topsoil and allowed biological activity and plant rooting, which has retarded original stratification of the alluvial substratum. However, ploughing has led to the development of thick humus horizons. In particular, soils with organic topsoil horizons have been changed, i.e. they have lost their initial swampy nature and have undergone an anthropogenic transformation to mineral soils. Despite the long-term agricultural land use, it is still possible to recognize the peaty character of organic matter in some soils and this allows reconstruction of their origin. This study investigated a sequence of soils in the valley of the river Barycz: (i) occasionally flooded, very moist Fluvic Histic Gleysols, with a Murshic organic layer, (ii) weakly drained soils with a high groundwater table, deeply ploughed, where the sandy plough layer contains easily recognizable peat-derived organic material, weakly bound to the mineral fraction (Fluvic Anthromollic Gleysols), and (iii) deeply drained soils, deeply ploughed, where organic carbon content in the plough layer is below 10%, but peat-derived particles of organic matter are still recognizable and are weakly bound to the mineral fractions [(Endogleyic Phaeozems (Anthric) or Endogleyic Umbrisols (Anthric)]. None of the thick plough layers, although intentionally created by humans by mixing the organic layer with underlying sandy material, fulfill the requirements of the anthropogenic diagnostic horizons. Therefore, two new qualifiers are proposed to the WRB classification in relation to the recent addition of the “Murshic” qualifier, namely “Anmooric” and “Atric”, to allow accurately naming the postswampy soils at subsequent stages of their transformation. [ABSTRACT FROM AUTHOR]

The article presents an analysis of geotechnical parameters of the alluvial deposit (the areas of the Vistula and Warta river valleys) with a view to using the soil as an earth construction material and as a foundation for buildings constructed on the grounds tested. Strength and deformation parameters of the subsoil tested were identified by the CPTU (cone penetration test) and DMT (flat dilatometer test) methods, as well as by the vane test (VT). The article includes the analysis of overconsolidation process of the soil tested and a formula for the identification of the overconsolidation ratio OCR. Equation 4 reflects the relation between the undrained shear strength and plasticity of the silts analyzed and the OCR value. The analysis resulted in the determination of the Nkt coefficient, which might be used to identify the undrained shear strength of both sediments tested. On the basis of a detailed analysis of changes in terms of the constrained oedometric modulus M0, the relations between the said modulus, the liquidity index and the OCR value were identified. Mayne's formula (1995) was used to determine the M0 modulus from the CPTU test. The usefulness of the alluvial deposit as an earth construction material was analysed after their structure had been destroyed and compacted with a Proctor apparatus. In cases of samples characterized by different water content and soil particle density, the analysis of changes in terms of cohesion and the internal friction angle proved that these parameters are influenced by the soil phase composition. On the basis of the tests, it was concluded that the most desirable shear strength parameters are achieved when the silt is compacted below the optimum water content. [ABSTRACT FROM AUTHOR]

The radiocesium distribution coefficient between the suspended matter and water in river systems in the Fukushima-1 Daiichi NPP accident zone was estimated from the data of the radiation monitoring of aquatic systems. The radiocesium distribution coefficient in rivers of the Fukushima region appeared to be higher by 1-2 orders of magnitude than that in rivers of the Chernobyl zone in the first years after the accident (1987-1990). The possible materials responsible for radiocesium binding by the alluvium are both micaceous clay minerals (vermiculite, muscovite, etc.), present in soils and alluvium of the Fukushima region, and water-insoluble glassy particles containing radiocesium, uranium, and other elements from the structure of the damaged reactors, present in the accidental fallout. [ABSTRACT FROM AUTHOR]

Deposition of mercury (Hg) from the atmosphere is an important source of this contaminant to terrestrial ecosystems. Once deposited, all forms of Hg can be retained or emitted back to the atmosphere. Distinguishing between volatilization of geogenic or indigenous Hg and that deposited from the atmosphere is difficult. Field flux measurements in the general area of two industrial scale gold mining operations, showed local deposition of Hg emitted from point and nonpoint sources, and subsequent re-emission. The work presented in this paper investigated deposition/emission of elemental Hg to and from alluvium and two mine materials before, during, and after exposure to high air concentrations, for both wet and dry conditions, using a laboratory gas exchange chamber and a Hg permeation source. In general, results showed a range in mean elemental Hg deposition velocities ranging from 0.13 to 0.46 cm s −1 that varied with material. A significant influence of atmospheric ozone (O 3 ) on flux was observed that depended on the material and whether wet or dry. A synergistic relationship existed between O 3 and light promoting Hg flux, and flux was also influenced by material grain size, chemistry, and primary mineralogy. [ABSTRACT FROM AUTHOR]

The ~200-m-thick riverlaid Bullhead Alluvium along the lower Colorado River downstream of Grand Canyon records massive early Pliocene sediment aggradation following the integration of the upper and lower Colorado River basins. The distribution and extent of the aggraded sediments record (1) evolving longitudinal profi les of the river valley with implications for changing positions of the river's mouth and delta; (2) a pulse of rapid early drainage-basin erosion and sediment supply; and (3) constraints on regional and local deformation. The Bullhead Alluvium is inset into the Hualapai and Bouse Formations along a basal erosional unconformity. Its base defines a longitudinal profile interpreted as the incised end result after the Colorado River integrated through lake basins. Subsequent Bullhead aggradation, at ca. 4.5- 3.5 Ma, built up braid plains as wide as 50 km as it raised the Colorado River's grade. We interpret the aggradation to record a spike in sediment supply when river integration and base-level fall destabilized and eroded relict landscapes and Tertiary bedrock in the Colorado River's huge catchment. Longitudinal profiles of the Bullhead Alluvium suggest ⩾200 m post-Bullhead relative fault uplifts in the upper Lake Mead area, >100 m local subsidence in the Blythe Basin, and deeper subsidence of correlative deltaic sequences in the Salton Trough along the Pacific-North American plate boundary. However, regionally, for >500 km along the river corridor from Yuma, Arizona, to Lake Mead, Arizona and Nevada, the top of the Bullhead Alluvium appears to be neither uplifted nor tilted, sloping 0.5-0.6 m/km downstream like the gradient of a smaller late Pleistocene aggradation sequence. Perched outcrops tentatively assigned to the Bullhead Alluvium near the San Andreas fault system project toward a Pliocene seashore or bayline twice as distant (300-450 km) as either the modern river's mouth or a tectonically restored 4.25 Ma paleoshore. We conclude that Bullhead aggradation peaked after 4.25 Ma, having lengthened the delta plain seaward by outpacing both 2 mm/yr delta subsidence and 43-45 mm/yr transform-fault offset of the delta. Post-Bullhead degradation started before 3.3 Ma and implies that the river profile lowered and shortened because sediment supply declined, and progradation was unable to keep up with subsidence and plate motion in the delta. [ABSTRACT FROM AUTHOR]

Developed by a geological structure similar asymmetric horst, Anieş's morph-hydrographic basin presents through its relief forms, a complex geographical unit, in terms of morphometric indicators respectively altitude, slope, depth of fragmentation and slope exposition for the entire landscape. At a taxonomic level, we can distinguish a variety of soil types and subtypes, mainly due to the physical and chemical properties and mineralogical soil deposits. This article aims to interpret some morphometric indicators and correlations supported by a GIS raster and vector database integrated in spatial analysis modules, discover quantitative and qualitative features of various types of surfaces and define morphometric parameters. The morphometric study of: slope, slope exposition and energy relief correlated with altitude by indirect mapping, have identified the following types of zone soils: luvisols, eutric cambosols distric cambosols, podzols, prepodzols, criptopodzols and humosiosols and intra-zone soils: rendzins, lithosols, hystosols and fluvisols. The indirect maping reflect the variety and complexity of soil types in Anieş's basin, each with varying surfaces, lithological substrates and specific properties The necessity of this article is important in the achievement of studies concerning the land usefulness, in order to implement essential measures such as: correcting the soil's acidity and monitoring the lands affected by soil erosion. [ABSTRACT FROM AUTHOR]

A soil column simulation experiment was conducted to study the effect of different nitrogen intensity in nitrogen fertilizer leaching loss characteristics in anthropogenic-alluvial soil. There were 5 treatments in this experiment, no nitrogen fertilizer treatment (N0), conventional fertilization treatment (N300), optimized fertilization treatment (N240), double conventional fertilization treatment (N600) and double optimized fertilization treatment (N480). The results showed that with different nitrogen intensity treatments, nitrate nitrogen concentration increased firstly and then decreased and leaching concentration peak appeared delay with nitrogen rates increasing. Nitrate nitrogen was the predominant nitrogen leaching form, increase of nitrogen application could postpone nitrogen peak appear time and lead to leaching risk. Ammonium nitrogen leaching loss occurred in the earlier period. Total N leaching losses were 94.53, 128.02, 222.06 kg·hm-2 and 268.6 kg·hm-2 in treatments N240, N300, N480 and N600, which accounted for nitrogen leaching losses rates by 39.38%, 42.67%, 46.26% and 44.77%, respectively. Applied nitrogen fertilizer was very easily leaching to 100 cm soil depth, indicating that nitrogen fertilizer leaching could be a pollution source for underground water. About 39.38%～46.26% of fertilizer nitrogen applied in soil was lost by leaching. The accumulative total N leaching amount was in accordance with logarithmic equation of Yt=a+blnt. [ABSTRACT FROM AUTHOR]