Quaternary Soils Research Articles

Source apportionment of Cd in karst soil based on the delayed geochemical hazard model.

Soil Cd contamination has become increasingly prominent in karst regions. Studies have generally elucidated the natural sources of Cd in high-background areas and analyzed their migration and enrichment mechanisms. This study comprehensively analyzed the total content and speciation of Cd in high-background areas using the delayed geochemical hazard (DGH) model to identify the sources of Cd in the region. The results indicated that Cd in the research area followed a pattern of gradual geochemical disasters. In Quaternary soil, brick-red soil, and submergenic paddy soil with hydromorphic characteristics, 32%, 7.69%, and 30% of soil Cd samples exceeded the critical threshold of the releasable total amount, respectively. Based on the DGH model, it was concluded that Cd in this region was mainly influenced by human activities. Field investigations corroborated this conclusion and aligned with the findings. Compared with the traditional source apportionment receptor models (mainly PCA and PMF), the DGH model not only saved considerable time and cost, but also avoided uncertainty associated with the results and complex and varied data processing and computational analysis processes. Moreover, the DGH model was able to identify the factors having the greatest impact on the ecological risk of Cd in the research area, thus facilitating targeted prevention and management planning based on the characteristics or chemical properties of their elements.

Evaluation of watertightness and slope stability analysis of Upper Guder dam, West Showa, Central Ethiopia

Ethiopia is currently emphasizing the construction of micro dams to enhance agricultural productivity and assure food security. The Upper Guder Dam, situated in the West Shoa Zone, Central Ethiopia, is one such project. However, the dam faces challenges due to complex geological and structural conditions, including leakage and slope instability. Hence, this study focuses on addressing the abutment slope stability and watertightness condition of this dam. Accordingly, the study employed discontinuity surveying, Seismic Refraction Tomography (SRT), Rock Quality Designation (RQD), and Lugeon testing to assess the water tightness. Additionally, kinematic analysis and the Limit Equilibrium Method (LEM) were used to evaluate abutment slope stability. Results from surface geological mapping and core drilling showed that the dam site is constituted by quaternary soil, tuff, and basalt. The Lugeon test results indicate that the left abutment of the dam is susceptible to leakage down to a depth of 40 m, which suggests that the permeable zone extends deeper than the results revealed by the SRT. Furthermore, this test demonstrated that the dam's right and central foundations are susceptible to leakage to the drilled depths. The SRT revealed that the central foundation, right, and left abutments of the dam are susceptible to leakage to the depth of 35 m, 30 m, and 34 m, respectively. Moreover, the kinematic analysis revealed that a section of the left abutment of the dam is susceptible to wedge mode of failure due to the intersection of JS1 and JS2. The LEM modeling of the right abutment of the dam also depicted that this section of the dam is unstable under saturated conditions which illustrates the importance of precipitation as the major slope destabilizing factor in the study area. Based on the study findings, this study recommended the use of curtain grouting to address the water tightness issue and slope angle reduction to mitigate the slope instability problem.

Assessing foundation characteristics at the war dam site, lake tana basin, Ethiopia: A geophysical and geotechnical perspective

An integrated geophysical and geotechnical study evaluated the foundation conditions at the War dam site in northwest Ethiopia. This investigation included the classification of rock quality, shallow seismic refraction, and magnetic approaches. The dam's location comprises quaternary soil deposits and rhyolite rock units that have undergone varied weathering and fracturing. The shallow seismic refraction method distinguishes three layers of p-wave velocities that are less than 1.5 km per second with a depth range of 2–6 m, 1.5–2.5 km per second at a depth range of 15–20 m, and 2.5–3.5 km per second ranging from 20 to 40 m, respectively. Magnetic data were used to identify lineaments, and the RQD value acquired from boreholes ranged from extremely poor to excellent. Lineaments were recognized using the tilt angle approach. The results of the permeability tests demonstrated that the rock mass that serves as the dam's foundation had characteristics that are resistant to low permeability. The maximum and minimum lugeon values obtained from the testing were 9Lu and 0.81Lu, respectively. There are weak zones at and below the surface of the dam site, according to the overall findings acquired from seismic refraction, magnetic, and discontinuity surveying. These results were obtained from monitoring the dam site. These significant structures are directed towards a SW-NE, NE-SW, NNW-SSE, and SSW-NNE orientation. The study assessed the geological suitability of a proposed dam site using seismic refraction and magnetic survey methods. Significant geological variations were observed, particularly in the right abutment and valley floor, indicating the need for targeted grouting. The findings suggest that while the site is generally suitable for dam construction, specific areas require further ground improvement to ensure stability.

Internal heat source in the vadose zone: A comprehensive exploration through theoretical spectral analysis and practical application into thermal diffusivity and hydraulic flux in a Quaternary soil water layer

AbstractThis groundbreaking study introduces a scientifically robust method for assessing internal heat generation in shallow, unsaturated aquifers, highlighting the intricate interplay between internal heat, thermal diffusivity, and hydraulic flux. The research pioneers a novel approach employing time‐frequency spectral analysis to address challenges posed by conventional methods that rely solely on prescribed thermal diffusivity and hydraulic flux for evaluating internal heat over time. Rooted in a solid theoretical framework supported by meticulous temperature and heat flux observations, the method adeptly incorporates the concept of an unknown internal heat. The study systematically explores three distinct boundary conditions, showcasing versatility: one with fixed temperatures at the inlet and outlet, another with known temperature at the inlet and no heat flux at the outlet, and a third with a prescribed inlet temperature and constrained outlet heat flux. The estimation of internal heat, coupled with prescribed thermal diffusivity and hydraulic flux, harnesses in‐situ temperature and heat flux spectra through an innovative inverse stochastic spectral approach. A notable feature of this research lies in its ability to strategically handle various parameters, including prescribed thermal diffusivity, hydraulic flux, variations in target depth, significant frequency components, and boundary conditions. The variation assessment findings emphasize the diverse range when predicting internal heat generation based on prescribed thermal diffusivity and hydraulic flux. This study facilitates the determination of potential internal heat magnitudes at different depths and provides profound insights into in‐situ conditions within the vadose zone.

Sediments of an underwater tunnel constructed by the immersed sections method

In St. Petersburg there is a necessity to build a large number of underwater tunnels for various purposes. The construction of tunnels using the method of immersed sections is the most complex and high-tech, but at the same time competitive construction method, requiring the solution of a non-standard engineering task at each stage. The aim of the study is to analyze the sediment of the immersed tunnel section depending on the deformation characteristics of the underlying sand covering and the different depth of the bedrock of the Proterozoic clays. The calculations were completed using mathematical 3D models in the MIDAS GTS NX software package based on the finite element method. The reliability of the mathematical modeling results was confirmed by high convergence with the results of field observations of section precipitation during the construction of the Kanonersky Tunnel. The obtained results were statistically processed by methods of correlation and regression analysis with the construction of functional dependence. The greatest contribution to the change in the sediment of the tunnel section was made by the thickness of the Quaternary soils at the base of the section – the depth of the Proterozoic clays, with significantly less influence of the stiffness of the underlying sand covering. The obtained functional dependence makes it possible to predict the precipitation of the section with a high degree of probability in the geological conditions of St. Petersburg. It is established that with any combination of the considered parameters, the amount of precipitation of the section of the underwater tunnel with these characteristics does not exceed the values requiring expensive additional fixing of the foundation soils.

STATISTICAL METHOD FOR ESTIMATING SELECTED GEOTECHNICAL PROPERTIES OF QUATERNARY SEDIMENT

Quaternary sediments have characteristics that distinguish them from older soils. In engineering practice, these sediments are of particular interest to engineering geologists and geotechnical engineers because many engineering constructions have to be founded on, or in, them. This paper describes a method for rapidly estimating selected geotechnical properties of some Quaternary soil from the Mesopotamian Plain using statistical correlation equations. The paper explored an expedient statistical method to estimate some geotechnical properties (including total and dry unit weights, void ratio, porosity, Atterberg limits, and compression index) rapidly without running time-consuming and expensive laboratory tests. It was found that the selected properties showed a relatively moderate to high correlation with independent properties. Both the unit weight and void ratio depicted a high correlation with initial water content. while a moderate correlation existed between compression index and initial water content. Also, the plasticity index has a strong correlation with liquid limit values. The results of this study accord an additional usage as facultative engineering tools for geotechnical engineers to utilize for any preliminary engineering design.

Palynological data confirm the occurrence of forest on the Loess Plateau of central China during the Middle Quaternary (MIS13)

The Loess paleosol sequence S5SS1 (top layer of S5 paleosol layers; marine isotope stage (MIS) 13) has been extensively studied because it is the most developed paleosol layer among all Quaternary soils in the China loess and represents the greatest humidity since the past 2.5 Ma. The question of whether forests occurred on the Loess Plateau tablelands when these paleosols were deposited is still a controversial scientific issue. This research provides a quantitative reconstruction of the past climate and forest cover between 544 and 480 ka based on a high-resolution pollen record together with magnetic susceptibility (χfd) and L*a*b* color parameters. Results suggest that the Luochuan area (central Loess Plateau) was sparsely covered by temperate deciduous forest under warm and humid conditions with a strong East Asian summer monsoon. The precipitation and woody cover during 544 and 531 ka were similar to those today and much greater than modern from 531 to 480 ka. Our findings are supported by paleosol profile research and modern vegetation studies. This study confirms that MIS 13 was a warm and humid period and that sparse forest developed on the tablelands of the central Loess Plateau, which provides new thinking on the ecosystem restoration program of the Loess Plateau.

Formation of Loads on the Interstation Tunnels at Deep Grounding Subway Stations in the Geotechnical Conditions of St. Petersburg

One of the unresolved issues in the design of subway structures is the formation of loads on the interstation tunnels near subway stations on deep ground. There are three ways to determine the pattern of load changes from the full weight of the uppers soil above the station tunnel to the weight of the soil in the collapse vault above the interstation tunnel: mathematical modeling, full-scale field experiment or physical modeling. In the article, the authors analyze this problem and propose to solve it by physical modeling using the method of equivalent materials. The laboratory bench simulates the massif of the Upper Kotlin hard clays, the interface section of the station tunnel and the interstation tunnel, as well as the load from the overlying quaternary soils. In the next stages of the experiment, it is planned to simulate tunneling and take readings from the contact pressure sensors on the tunnel lining. The results of the research will allow us to proceed to a reasonable mathematical modeling of the law of distribution of loads, as well as perform adequate verification of the subsequent mathematical models.

Mineralogy and geochemistry of modern Red River sediments (North Vietnam): Provenance and weathering implications

Abstract This study illustrates the clay mineralogy and sedimentary geochemistry of the Red River and its major tributaries and distributaries in northern Vietnam and shows how these methods can be used to unravel grain size, provenance, hydraulic-sorting, and chemical weathering effects. All sand samples are SiO2-rich and consequently depleted in most chemical elements (but Sn and Pb) relative to the upper continental crust (UCC). The order of element mobility indicated by αAlE values, which estimate the degree of depletion in mobile element E relative to the UCC standard, is Ca ≥ Na > Sr > Mg > Ba ≥ K ≥ Rb. In mud fractions, SiO2 decreases, and other elements consequently increase. The grain size-dependent intrasample chemical variability of fluvial sediments reflects the grain size distribution of detrital minerals, which is strictly controlled in turn by the settling-equivalence principle. The 87Sr/86Sr ratio in Red River sands varies widely between 0.716 and 0.748, and εNd ranges from −8.5 to −13.8. The negative εNd values and high 87Sr/86Sr ratios point at a significant contribution from Precambrian crystalline basement, directly or through recycling of Triassic siliciclastic strata. Clay-mineral assemblages, dominated by illite and smectite with subordinate kaolinite and minor chlorite, suggest largely physical erosion in the upper catchment and stronger weathering in the monsoon-drenched lower catchment. Extremely intense weathering is demonstrated by a Quaternary soil sample from the Red River valley in northernmost Vietnam, which is a pure quartzose sand yielding a tourmaline-dominated heavy-mineral suite and a kaolinite-dominated clay-mineral assemblage. In the humid landscapes of northern Vietnam, no detrital mineral, excepting quartz, muscovite, tourmaline, prismatic sillimanite, anatase, and zircon, can resist even shallow early pedogenesis.

Microbial features of mature and abandoned soils in refractory clay deposits

Processes of soil restoration in anthropogenically disturbed soils is an urgent topic in modern ecology and nature management. Being mediator between mineral soil composition and plant vegetation, soil microbial community is important factor of soil restoration processes. Analysis of main soil nutrition components followed by 16S amplicon sequencing are sufficient methods for primary analysis of novel locations. Here is the primary analysis in a novel location in Northwest Europe (Russia). Main nutrition parameters (pH, P, Na and NH4+) and 16S rDNA Illumina amplicons were explored in abandoned soils from sandy pit quarry (2 sites) and refractory clay mining dumps (4 sites).Microbial communities of mature soils and dumps are variable and different in terms both nutritional and microbial components. pH, N and TOC are strong predictors for microbial composition. Dumps of refractory clays pQ_2 are non-developed soils, highly acidic and form specific microbial community. Differences between dumps and mature soils in both pre-quaternary and quaternary soils are connected with specific bacterial taxa. Those taxa are connected more with plant composition, not the soil properties themselves. The exact changes in microbial community are unique for different soils and areas.Graphical

Utility of visible and near-infrared spectroscopy to predict base neutralizing capacity and lime requirement of quaternary soils

Detailed knowledge of a soil’s lime requirement (LR) is a prerequisite for a demand-based lime fertilization to achieve the optimum soil pH and thus sustainably increasing soil fertility and crop yields. LR can be directly determined by the base neutralizing capacity (BNC) obtained by soil-base titration. For a site-specific soil acidity management, detailed information on the within-field variation of BNC is required. However, soil-base titrations for BNC determination are too laborious to be extensively applied in routine soil testing. In contrast, visible and near-infrared spectroscopy (visNIRS) is a time and cost-effective alternative that can analyze several soil characteristics within a single spectrum. VisNIRS was tested in the laboratory on 170 air-dried and sieved soil samples of nine agricultural fields of a quaternary landscape in North-east Germany predicting the soil’s BNC and the corresponding lime requirement (LRBNC) at a target pH of 6.5. Seven spectral pre-processing methods were tested including a new technique based on normalized differences (ND). Furthermore, six multivariate regression methods were conducted including a new method combining a forward stagewise subset selection algorithm with PLSR (FS-PLSR). The models were validated using an independent sample set. The best regression model for most target variables was FS-PLSR combined with the second Savitzky-Golay derivation as pre-processing method achieving R2s from 0.68 to 0.82. Finally, the performance of the direct prediction of LRBNC (R2 = 0.68) was compared with an indirect prediction that was calculated by the predicted BNC parameters. This resulted in slightly higher correlation coefficients for the indirect method with R2 = 0.75.

Organic carbon rich-soils in the brazilian semiarid region and paleoenvironmental implications

Soil organic carbon (SOC) contents are commonly high in the mountainous tropical soils with wet climates in Southeastern and Southern Brazil, but high SOC soils in the Brazilian semiarid zone are poorly known. The Borborema Plateau represent a complex core of folded and uplifted crystalline rocks with the highest altitudes in the Brazilian semiarid. The present study objetived to describe unusual SOC-rich soils from the semiarid Borborema Plateau, discussing past and present, soil-forming processes, and landscape evolution. We described and characterized 11 Late Quaternary soils in the Borborema Plateau, emphasizing chemical and physical properties, soil carbon stock, and water behavior, allowing us to know about the soil diversity of the semiarid highlands. Five Umbrisols and one Cambisol were described in concave slopes and summits above 1,000 m, under relicts of semideciduous forest and Rupestrian Grassland vegetation; downslope, we found Planosols, Leptosols, Regosols, Luvisols, and Arenosols in partially dissected pediments below 600 m, representing typical soils of the Caatinga (Dry forest). Borborema highland soils with high SOC are acidic, dystrophic, moderately developed, whereas soils from the Caatinga range from moderately acid to moderately alkaline, hypereutrophic, and poorly to moderately developed. The Umbrisols and Cambisols have a mean SOC content of up to 94% higher than typical Caatinga soils. Water retention and availability are similar between acidic soils with high SOC and typical dry forest soils. Radiocarbon analysis of humic fraction of soil indicated the dominance of C3 plants since the start of pedogenesis of Umbrisols, at ∼ 6,900 cal yr BP. The stabilization of high amounts of organic carbon in highland semiarid soils was attributed to P, acidity, and fine particles. These small relicts of soils with high SOC represent hotspots of SOC stocks in the Brazilian semiarid, and they protect “islands” of relict vegetation from past wetter Late Quaternary paleoenvironments.

Study on Correlation of Physical and Mechanical Properties Indexex of Cohesive Soil in Hilly and Plain Region along the Yangtze River in Anhui Province

In this paper, a large number of geotechnical engineering survey data are collected in hilly and plain region along the Yangtze River in Anhui Province. Based on the statistical analysis and calculation of the experimental data of physical and mechanical properties of cohesive soils (the main quaternary soil layers in the area), the correlation between the liquidity index and water content and other physical and mechanical properties indexes are analyzed, and the fitting regression is carried out respectively. The results show that the liquidity index (IL)) and water content (w) are highly correlated with cohesion (C), compression modulus (Es), compression coefficient (α), natural density (ρ), void ratio (e), and the regression equations have high goodness of fit and good fitting effect; In addition, the fitting regression equations of water content, void ratio and natural density are compared with the theoretical calculation formula, it is found that the calculation results are close, which proves that the fitting regression equations are reliable and can be used in engineering practice.

Soil-chronosequence and Quaternary landscape evolution at the marine terraces of Harmony Point, Nelson Island, Maritime Antarctica.

This study characterized the physical, chemical, macro- and micromorphological soil properties from three successive marine terrace levels from Harmony Point (Nelson Island, Maritime Antarctica) in order to understand the pedological signatures of Quaternary coastal landscape evolution of Maritime Antarctica. Soils were sampled on the Late Holocene beach (current beach) and Mid Holocene marine terraces higher up, at 3, 8, and 12 m a.s.l. At the lower levels, the predominant soils were Gelorthents, whereas Haplogelepts dominate the higher terraces. Soil properties are mostly influenced by parent material and faunal activity, in which cryoclastic (thermal weathering) and phosphatization are the main soil-forming processes. Soils from the upper levels are more developed, deeper with reddish colors, granular structures and incipient formation B horizon. These horizonation features highlight that soils vary according with age of glacier-isostatic terrace uplift, representing a Quaternary soil chronosequence. All marine terrace levels are Ornithogenic soils, at varying degrees. However, the presence of old bird nesting sites for long periods led to formation of phosphatic horizons, stable Fe-phosphate minerals and abundant vegetation in the highest terraces of this part of Maritime Antarctica.

О влиянии подземных горных выработок на инженерно-геологические условия Прикамья

The article is devoted to the current engineering and geological topic - the impact of underground workings on the conditions of construction and engineering structures operation at territory of urban agglomerations. The example of the city of Perm shows the need to take into account their presence and influence on the bearing capacity of the base rocks, especially of the cover quaternary soils. The design method proposes the possibility of using the bedrock as a base, taking into account the depth of workings, the load on their roof and strength characteristics, as well as the type of foundation used in this case.

Feasibility of Artificial Slope Hazards Identification in Regional Mountainous Highway Using SBAS-InSAR Technique: A Case Study in Lishui, Zhejiang

Safety status of artificial slopes is significant for the operation and maintenance of highway to mitigate the risk; thus, slope hazard identification is necessary. In order to realize large-area and low-cost application for regional highway, taking the Longqing Highway (length of 55 km) as a case study, the SBAS-InSAR (Small Baseline Subset-Interferometric Synthetic Aperture Radar) technique is adopted to detect the ground deformation and conduct hazard identification based on slope dip, aspect, geological data and historical hazard record. Field survey is carried out to verify the identified potential hazards. Results show that the detected potential hazards are distributed mainly in the areas consisting of granite residual and the Quaternary soil. Six potential hazards identified by the SBAS-InSAR-based method are roughly in accordance with the on-site verification. It is suggested that the SBAS-InSAR technique has the ability to obtain the slope deformation accurately and reveal the safe condition of the slopes. The SBAS-InSAR technique can be suitable for assistance in regional highway slope inspection.

A multidisciplinary approach in cover-collapse sinkhole analyses in the mantle karst from Guangzhou City (SE China)

Mantled karst is characterized by solution processes in underground conditions, where karst evidence can be masked. In mantled karst environments, cover-collapse sinkhole can be considered one of the most hazardous elements. This study seeks to develop a methodological framework utilizing different techniques and approaches to understand cover-collapse sinkhole genesis and its likely evolution. The study area is located in the Conghua district of Guangzhou city, Guangdong Province, in the south-eastern region of China. A mapping procedure was introduced to combine data from aerial photographs and intensive field investigations. In addition, data interpretations from borehole drilling activities and different geophysical approaches were performed to reconstruct the Quaternary deposit features, rock head morphology, and karst features. During these investigations, the detailed typology, morphometry, and chronology inventory of 49 cover-collapse sinkholes were analysed, and three karst fissure zones covered by Quaternary soil were observed. In the study, the hydrogeological data suggested that karst aquifer pumping triggered the drop in groundwater levels. Cover-collapse sinkholes might be ascribed to erosion of the soil layers due to the groundwater level decline.

Dynamic compaction of the Baltic basin silty Sand - quality assurance with CPT, DPM, DMT and PLT

Post-glacial evolution of the Baltic basin sedimented Quaternary soils at the great thickness (up to 30 m) in Riga, Latvia. There are present zones of different combinations of postglacial, alluvial, limnological and dune formations within the metropolitan area of Riga. The geomorphological evolution of this territory is dominated by the Baltic sea former stages, distinguishing these areas as rather complicated. The dynamic compaction was proposed below the warehouse floor of area about 40K m2 in Baltic basin silty Sand. The effect of compaction was evaluated to the depth of 10 m and extensive quality assurance using cone penetration and piezocone tests (CPT(U)), dynamic probing (DP) tests, flat dilatometer tests (DMT) and plate loading tests (PLT), was introduced. CPT(U) and DMT results were compared in terms of soil stiffness parameter evaluation prior and after dynamic compaction. The limitation of DP tests were investigated and finally also warehouse test embankment verified by PLT evaluating shallow compaction rates.

Engineering Characterization of Quaternary Sandy Soil in the Mesopotamia Plain

The Quaternary sandy soil from Mesopotamia Plain and its engineering characteristics are one of the main objects of this paper, where the depositional environment, source material information, and chemical and physical factors have been provided by the characterization of the quaternary sandy soil. The influence of shape, mineral composition, and roundness of the soil grains has been studied with the assistance of sieve analysis, X-ray analysis, and scanning electron microscope. The main engineering properties of the soil (compressibility (no lateral strain), and shear strength) have been included in this paper. These properties have been determined under different compaction efforts, with unsoaked and soaked conditions. It has been found out that quaternary soil grains exhibit all about the same size, which indicates well-sorting sediment. The particles of the soil have been bulky, they have been almost sub-angular to a slightly rounded shape, which has reflected the mechanical weathering of the source minerals that formed quaternary sandy soil, and this may influence the compressibility and shear strength parameters. Mineralogically, the main assemblage of the soil has consisted of two minerals types (quartz, and calcite); such variety is chemically stable. It has been noted that, for the soaking conditions under different pressures, the axial deformation, the compression index, and the swelling index of the soil are low. This has been attributed to grain regularity. Under confined compression, the mechanism of deformation for such grains includes "contact slippage". Finally, increasing the compaction effort has impeded the shearing of the soil particles and the sliding between the grains of soil.

The SHRIMP U-Pb isotope dating of Mesozoic volcanic from Zhangwu-Heishan Area, West Liaoning Province, China

The Zhangwu-Heishan area is located in the east of the Fuxin-Yixian basin. Besides the Quaternary soil, the study area is mostly covered with volcanic rock. The horizon and age of volcanic rock play an essential role in understanding fossil beds, structures, and sedimentary evolution of West Liaoning Province and coal seeking. During this work, 11 volcanic rock samples were measured by SHRIMP U-Pb isotope analysis. Based on the reported data on the age of the Mesozoic volcanic rock in West Liaoning Province, in combination with new measurement data, Cretaceous volcanic activities in West Liaoning Province can be divided into five stages, namely 132±1 Ma, 126±1 Ma, 122±2 Ma, 115±2 Ma, and 100±5 Ma. Based on statistical results, this paper concluded that the thinning time of the crust in Northeast China is from 132±1 Ma to 115±2 Ma.