Karst Depressions Research Articles

Morphometric and geological features of potential karst depressions in Kanthan limestone formation, Malaysia

In Malaysia, limestones extensively outcrops in the northern half of Peninsular Malaysia, such as in Langkawi Islands, northern Perlis, Kinta Valley in Perak, southern Kelantan and Kuala Lumpur Valley in Selangor. Although these limestone formations vary considerably in geological age and tectonic setting they are very similar in chemical composition; being dense, recrystallized, and massive varieties of limestone with little impurity; these are more likely to develop large caverns within them. Currently, most of these limestones are continuously quarrying for the production of dimension stone, aggregate resources, and raw materials for cement industries, part of urban development infrastructure and could be foreseen as future potential reservoirs of high-quality groundwater. Nonetheless, the fragility of karst environments makes it highly vulnerable to a variety of different geological hazards. The aim of this study is to determine the geohazard susceptibility of karst depressions in Kinta Valley, Ipoh using morphometric measurement and joints properties calculations. The joint properties calculate include spacing, roughness, aperture, persistence, infilling and weathering. This study describes the field data measurements of few quarries in Kinta Valley, Ipoh to examine the morphometric and geological features of limestone karst in the area. The effect of geologic evolution, structural properties and hydrogeologic variables on the geomorphologic and spatial distribution of karst depressions are discussed in this study.

Nitrate distribution and dynamics as indicators to characterize karst groundwater flow in a mined mineral deposit in southwestern China

Groundwater recharge source and flowpaths, along with aquifer medium characteristics, are identified based on nitrate distribution and dynamics. These are significant factors in long-term water-resources management of the Sichuan-Yunnan-Guizhou lead-zinc mining deposits, southwestern China. The results show that high nitrate concentration correlates with lower temperature and heavy isotope enrichment, indicating groundwater recharge from the eastern karst depression area (situated at higher elevation), which has intensive agriculture. Higher NO3- concentration corresponds to higher Ca/Mg ratio in the Carboniferous karst aquifer, both indicating the preferential groundwater flowpath, while the lateral nitrate distribution signifies hydraulic connection with the northern Devonian aquifer passing through the aquitard via NE–SW and N–S trending faults. Nitrate pollution has reached deep sections of the karst aquifers and generated a wide vertical distribution, with the lowest elevation of significant nitrate concentration at –28 m relative to sea level, far lower than the recharge area by over 1,500 m. The variations in groundwater temperature, electrical conductivity and partial pressure of CO2 in the early rainy season are associated with enhanced dissolution capacity of the carbonate minerals, controlled by the soil CO2 effect, hence characterizing the mining area as a fissure-dominant karst groundwater system. Under such conditions, nitrate concentration rises and recedes subsequent to recharge events, and these processes characterize nitrate leaching. Overall, the current nitrate distribution is the result of increased agricultural productivity, intensive mine dewatering works and intrinsic media heterogeneity. Nitrate functions as an artificial, stable and cost-effective tracer for groundwater-system characterization in this mining area.

Analysis of the soil and microclimate relationship in two dolines of Carso Huasteco, Mexico

Dolines are karst depressions whose environmental and climatic characteristics in tropical regions are not well known. By measuring and analyzing different components of the microclimate in two dolines located in Tamasopo, Mexico, we aim to contribute to the understanding of the climatic conditions in these formations. The variables analyzed include temperature, solar radiation, soil and air humidity, as well as their relationship to physical and chemical characteristics of the soil such as pH, conductivity, texture, and the content of organic matter, carbon, nitrogen, phosphorus, calcium, potassium, sodium and magnesium. Measurements and soil samples were taken in three strata: bottom, slope and exterior. The results show a gradient in the climatic variables along the three strata, as well as higher concentrations of all elements, except phosphorus, in soil from the dolines, with respect to the exterior. Furthermore, statistical analysis shows a high correlation between the environmental conditions and edaphic properties. The micro climatic factors of the dolines generate a different environment, rich in humidity and with temperatures commonly lower than those present in tropical regions. These conditions cause abrupt changes in the physical and chemical composition of the soil, which present high concentrations of nutrients.

Comportamento hídrico das depressões cársticas da região de Lagoa Santa, MG

As depressões cársticas se configuram como importantes feições dissolutivas presentes principalmente em regiões calcárias. À luz da típica geomorfologia e hidrogeologia cárstica, este trabalho apresenta as investigações realizadas nas depressões cársticas situadas sobre as rochas pelito carbonáticas do Grupo Bambuí, localizadas nos arredores da Área de Proteção Ambiental (APA) Carste Lagoa Santa (MG). As investigações tiveram como principal objetivo a compreensão do comportamento e desempenho hídrico das 393 depressões cársticas detectadas a partir de Modelo Digital de Elevação (MDE) derivado de uma imagem do satélite ALOS PALSAR. As etapas se constituíram fundamentalmente de geoprocessamento em ambiente SIG, foto observação através de imagens do Google Earth Pro, classificação supervisionada em imagens multiespectrais dos satélites Landsat registradas em quatro períodos hidrológicos distintos (ano com índice pluviométrico normal e ano atipicamente seco). O coeficiente de Kappa e acurácia geral indicaram que as classificações supervisionadas realizadas obtiveram resultados excelentes. As análises estatísticas multivariadas revelaram que a presença de lagoas no interior das depressões cársticas após o período de estiagem em ano hidrológico normal ou em ano de excepcional stress hídrico está relacionada com a morfologia e morfoestrutural. Isto é, as depressões maiores, com grandes profundidades, altos índices de eixos de alongamento e grandes áreas de maciços calcários em seus interiores são aquelas mais favoráveis a possuírem água em seus interiores.

A New GIS-Based Model for Karst Dolines Mapping Using LiDAR; Application of a Multidepth Threshold Approach in the Yucatan Karst, Mexico

Dolines are important features strongly influencing the outcomes of groundwater vulnerability maps, subsidence risk and land use studies. Their relationship with subsurface features like epikarst, stresses the importance of doline mapping for environmental and hydrological management strategies. Current methodologies to map dolines from elevation models apply morphometric attributes on depressions, including a depth threshold, to filter depressed areas and to define dolines. However, the use of a single threshold tends to overlook dolines located in already depressed areas. In this work a new geographic information systems (GIS)-based methodology is proposed to identify karst depressions within digital elevation models, applying a multidepth threshold approach. The method statistically classifies depression intervals to identify dolines at variable depths. The method was tested in the Yucatan karst, displaying a final accuracy of 63% after testing different parameters. The results are affected by false positives due to the impossibility of verifying by imagery 190 possible dolines in areas of dense vegetation. Nevertheless, out of 655 estimated dolines, 464 match those located by imagery giving sensitivity and precision values of 85% and 71%, respectively. Comparing this methodology against single threshold outcomes, improvement is evident in doline mapping. Notwithstanding, its application and performance with lower and higher resolution elevation models must be investigated.

Revealing the scale-specific influence of meteorological controls on soil water content in a karst depression using wavelet coherency

Temporal soil water content (SWC) patterns are affected by meteorological factors that operate at different intensities at different scales. Pearson’s correlation analysis can only identify linear correlations at the measurement scale, therefore we examined the relationships between SWC and meteorological factors at different scales and occasions in a karst landscape using wavelet coherency analysis. SWC was measured at five soil depths using time domain reflectometry in two land uses over 242 d in a karst depression, southwest China. The results showed that the temporal SWC dynamics were influenced mainly by precipitation and land use. The temporal SWC patterns in farmland differed from those in grassland. The relationships between SWC and meteorological factors varied with scale, and a significant correlation was generally observed at large scales. Information on variation of scale for SWC improved the performance of soil moisture prediction. Soil depth had a greater impact on wavelet coherency at large scales than land use. Positive and negative correlations were detected between SWC and meteorological factors using wavelet coherency analysis. This study indicated that wavelet coherency analysis has potential to reveal the scale-specific dependence of SWC on controls.

Urbanization-induced acid rain causes leaching loss of calcium from limestone-derived soil in South China

Acid rain events in Yuebei, a region of northern Guangdong Province, China, have been increasing due to rapid urbanization in recent years. A three-year study was conducted to assess the effect of rainfall on losses of dissolved calcium (Ca2+) from limestone soils in a karst area in Yuebei. Soil leachate was collected from 61 events that produced more than 100 ml leachate per event during a 3-year period. Each rainfall event caused on average a loss of 8.5 × 10−4 g Ca2+ kg−1 soil with a Ca2+ loss of 2.16 × 10−5 g kg−1 per mm of rain. Cumulative net Ca2+ loss from the soil for the 61 events monitored was 0.05 g kg−1. In terms of Ca-loss per mm rain, the largest net Ca2+ loss from the soil occurred with mild acid rain (pH 4.5–5.6), followed by non-acid rain (pH 5.6–6.29) and severe acid rain (pH < 4.5). Net Ca2+ losses through natural rainfall were significantly larger than those induced by simulated rainfall with distilled water (control) or rainwater from the karst depression area of an adjacent talus slope. Total water soluble Ca2+ content in the soil continuously decreased due to acid rain, with a total reduction of 0.36 g kg−1 during the three-year experimental period. Net Ca2+ losses from the soil were positively correlated with leachate Ca2+ concentration and rainfall and negatively correlated with rainwater pH. The losses of Ca2+ from the soil can increase the risk of acidifying soils in the flat karst area in Yuebei, which may also affect the adjacent regions through changing the chemistry of groundwater and surface water.

Relict drainage effects on distribution and morphometry of karst depressions: a casestudy from central Taurus (Turkey)

Relict drainage effects on distribution and morphometry of karst depressions: a casestudy from central Taurus (Turkey)

Lithogenesis on peneplaned сontinented platform of Kazakhstan and Siberia during the Cretaceous-Paleogene boundary epoch

Research subject. The inner structure, composition, and genesis of the poorly studied formation of weathering crusts are studied with reference to peneplaned platform territories in Kazakhstan and Siberia during the Cretaceous-Paleogene boundary epoch. This formation hosts many valuable minerals, such as bauxite, iron ores, refractory clays, etc., thereby attracting much research attention. Materials and methods. The results were obtained following a series of long-term studies and a review of available data recently obtained on the weathering crust formation in the territories of Kazakhstan and Siberia. The methods of lithological facies and formation analysis were used, along with the separate studies of the eluvial material – weathering crusts in erosion areas and intra-formation weathering horizons in accumulation areas. Results. The weathering crust formation in the study area is shown to comprise two kinds of rock mass: siliceous-kaolinite ones forming erosion-tectonic depressions and kaolinite-bauxite ones forming karst depressions. The inner structure, composition, and genesis of both rock mass units are studied in detail, with all their sedimentation stages being analyzed. The sedimentation process is traced from the preparation of the material in weathering crusts at erosion areas to the deposition of this material and its post-sedimentation transformations (mostly with the involvement of subaerial diagenesis) in depressions. Detailed information is presented on subaerial diagenesis, which deserves further studies. Conclusions. This publication is the frst to present detailed information on the inner structure, composition and genesis of the ancient formation of weathering crusts produced in hot humid climate on peneplaned land territories. It is confrmed that the processes underpinning this formation – starting with the preparation of the material and ending with its accumulation in depressions – were different from those typical of modern orogenic environments. This conclusion extends the current understanding of the forms and nature of ancient lithogenetic processes.

Evaluation of the impact of karst depression-type impoundments on the underlying karst water systems in the Gejiu mining district, southern Yunnan, China

The influence of mining activities on groundwater quality is a growing concern due to highly toxic metals in the tailings. Carbonate rocks are common in the surrounding rocks of ore deposits. But such mining districts generally do not have the conditions to construct traditional tailings impoundments due to the different degrees of karstification. This paper utilises field investigations, chemical analyses, and permeability tests, etc. to study the effect of tailings impoundments on the underlying karst water systems in the Gejiu world-class Sn-polymetallic mine located in a typical karst region in southern China, with samples collected from both karst springs deriving from the mining area and tailings porewater. Because of the abundance of sulphide minerals in the ores, acid mine drainage is expected to pose a high risk. However, the results indicate that the tailings porewater is moderately neutral and is characterized by the SO4–Ca–Mg hydrochemical type. This can be attributed to the substantial buffering capacity of carbonate minerals. Pollution elements in the tailings porewater mainly include SO42− and toxic metals including As, Cd, Mn, Pb, and Hg. The type of pollution factors and the degree of contamination are not consistent in the different tailings impoundments. The hydrochemical classification of four karst springs distributed in the south of the mining area is HCO3–Ca–Mg. The concentrations of SO42− and the toxic constituents in the springs are far below the national standards for drinking water. The spring water not being contaminated may be attributed to the operation mode of the tailings impoundments (peripheral discharge and reuse of ponded water), the residual clay between the tailings impoundments and the carbonate bedrocks and the sufficient buffering capacity of the underlying karst systems. The tailings disposal at the Gejiu tin mine within the natural karst depressions is able to provide a reference for the operation of karst mines in China and elsewhere.

A review of fractals in karst

Many features of a karst massif can either be modelled using fractal geometry or have a fractal distribution. For the exokarst, typical examples include the geometry of the landscape and the spatial location and size-distribution of karst depressions. Typical examples for the endokarst are the geometry of the three-dimensional network of karst conduits and the length-distribution of caves. In addition, the hydrogeological parameters of the karst massif, such as hydraulic conductivity, and karst spring hydrographs may also exhibit fractal behaviour. In this work we review the karst features that exhibit fractal behaviour, we review the literature in which they are described, and we propose hypotheses and conjectures about the origin of such behaviour. From the review and analysis, we conclude that fractal behaviour is exhibited at all scales in karst systems.

Black carbon air pollution

The paper presents a study of air pollution caused by black carbon (BC) and fine particulate matter (PM) carried out in the rural area of the municipality of Loški Potok in the winter season of 2017/2018. Measurements of pollutants were performed at two different locations, one at Retje, a village at the bottom of a karst depression, and the other on the top of the Tabor hill in settlement Hrib. The measurement results exposed the main sources of black carbon air pollution in this area: domestic heating with biomass (almost 80% of all black carbon emissions) and unfavorable meteorological conditions for dilution of pollutants during temperature inversions. Three times higher concentrations were measured at Retje during temperature inversions than in the days of mixed atmosphere. In the winter of 2017/18, the average concentrations in the Retje hollow were even higher than those of Ljubljana, which calls attention to the problem of polluted air in rural areas too.

Isotope Compositions (δ13C, δ18O) of Manganese Carbonates of the Porozhinsk Deposit (Yenisei Ridge, Krasnoyarsk Region)

New carbon and oxygen isotope data are reported on carbonate ores and host dolomites (upper Pod”emsk subformation) of the Porozhinsk manganese deposit. Manganese carbonates filling the karst depression of the Porozhinsk area are characterized by low δ13C (–14.6…–9.5‰, PDB) and δ18O (18.8…22.1‰, SMOW). These data indicate that the carbonate formation was contributed by the isotopically light carbon, which was released during the decomposition of organic matter, while waters of the ore-precipitating solutions were presumably of meteoric origin. Host dolomites (Porozhinsk and Mokhovoi areas) are characterized by the heavier carbon (–1.9…2.0‰) and oxygen (23.3…27.7‰) isotope compositions, which are presumably typical of carbonate sediments of the Late Neoproterozoic sea basin.

Paleokarstic water tables and their control on reservoirs in Ordovician Yingshan Formation, Tazhong Area, Tarim Basin, NW China

Abstract Based on cores, well logging and karstic paleogeomorphology, the identification method of multi-period paleokarstic water tables and their distribution and control on reservoirs were researched of Yingshan Formation in Tazhong Area, Tarim Basin. Three periods' water tables numbered 1 to 3 have been identified from bottom to top of Yingshan Formation in Tazhong Area. The corresponding typical horizontal undercurrent zones are characterized by single karst fabrics such as sack-like dissolved vugs or subhorizontal channels, combination of various karst fabrics like pre-existing high-angle fractures intersected by small caves and subhorizontal channels, and combination of multi-layered caves and different karst fabrics of large pores. On the plane, periodical rising sea levels caused the development of No.1, No.1 and 2, No.1, 2 and 3 water tables in karst depressions, slopes and highlands respectively. As the result of the nearly horizontal occurrence of Yingshan Formation, submembers of Yingshan Formation had tiny angles with fracture-cave bodies of each period's water table, so the karst reservoirs are characterized by “crossed strata regionally and developed along the stratum locally”. The distance between water table and unconformity, thickness of horizontal undercurrent zone and average thickness of reservoir all tended to increase with the rise of karst landforms. The karst highland and slope had 2-3 periods' water tables and thicker horizontal undercurrent zones, so they had thicker and better quality reservoirs, making them favorable exploration areas.

Современный химический состав вод озер Мазуевской карстовой депрессии

An analysis of the current hydrochemical state of the waters of the Mazuevskaya karst depression located in the Kusherstko-Suksunskiy karst region was carried out. The area is a zone of discharge of karst waters of the Ufimskiy Swell (brachiantikline). The obtained data provided an opportunity to trace changes in the chemical composition of karst lakes in time, as well as to supplement the hydrochemical model of this region

Reconstructing recent changes in sediment yields from a typical karst watershed in southwest China

Southwest China is characterized by shallow soils with low soil loss tolerance (30–68 t km−2 yr-1), and this region is one of the largest contiguous karst areas in the world, notorious for its highly eroded landscapes. However, reliable information on soil erosion rates in these karst watersheds is limited due to the highly heterogonous landscape. Karst depressions are a unique geomorphologic pattern in southwest China which can trap eroded sediment similar to a reservoir or dam, and may provide a great opportunity for sediment yield estimation if the sediment chronology can be properly determined. This study used karst depression sediment deposits to reconstruct the changes in sediment yields over the past 60 years from a typical karst watershed in southwest China. Three sediment cores were collected from the depression to measure the changes in 137Cs and 210Pbex, clay, silt, and sand contents, and soil organic carbon at different depths. The results indicated that the three common 210Pbex dating models - Constant Sedimentation (CFCS), Constant Initial Concentration (CIC), and Constant Rate of Supply (CRS) - were not applicable to karst depressions, while a modified CRS model that used 137Cs age marker as reference improved determination of the sediment chronology. From 1949 to 2015, the sediment yields initially increased and then sharply decreased to a low value, which might represent a general trend of soil erosion dynamics in karst watershed of southwest China. It was noteworthy that the mean soil erosion rate after the “Grain for Green” project of 1999 was only 80 t km−2 yr-1, which also is greater than the soil loss tolerance in karst regions. This study demonstrates the potential for use of 137Cs and 210Pbex to evaluate the temporal variation in sediment yield in a typical karst watershed of southwest China and may improve karst watershed management.

Anomalous spontaneous electrical potential characteristics of epi-karst in the Longrui Depression, Southern Guangxi Province, China

This paper examines the use of the temporal and spatial distribution of natural electric fields in karst depressions to detect shallow groundwater resources. Under specific osmotic pressures, vadose water is filtered through the soil layer, and supplies deep karst water through pipes or underground rivers along the carbonate dissolution fracture network. As a result, a natural electric field is generated by ions at the interface between conductive soil and rock layers. Detecting this natural electric field can be used as a research method for shallow karst water exploration. This method has been applied to a karst depression in Longrui, China, and the results show that an anomalous zone with electric potential values of − 60 mV to − 80 mV occurs in the center of the depression. The anomalous zone has an S-shaped, north-to-south distribution, with a width of about 40 m. Changes in the plane of the anomalous zone indicate differences in shallow karst development in depressions, and hydrogeological drilling reveals shallow caves, sags and fault zones that correspond with the natural potential anomalies at different depths in the Longrui Depression. Additionally, advancement of boreholes reveals a water yield of 60 m3/h. This highlights the effectiveness of using the natural electric field method to detect karst water in epi-karst areas.

Prediction of profile soil moisture for one land use using measurements at a soil depth of other land uses in a karst depression

Information on root-zone soil water content (SWC) is essential for vegetation restoration, irrigation scheduling, and hydrological modeling. However, measurements of SWC within a variety of land uses may be time-consuming and labor-costing. This study tested whether SWC at a depth of a land use can be used to predict profile SWC of other land uses in terms of temporal stability analysis at a karst depression area in southwest China. A total of 30 datasets of root-zone SWC from 0.1- to 0.5-m depths were collected by time domain reflectometry probes for three typical land uses from March 12 to November 8, 2015. Results showed that the profile mean SWC and its associated standard deviation (SDP) and coefficient of variation (CVP) differed significantly (P < 0.05) among the grassland, farmland, and forestland. The profile SWC was more temporally stable according to the apparently lower CVT in comparison with CVP. The similarities of the vertical patterns of SWC were strong for the same land uses, while were relatively weak between the different land uses. The SWC measurements of the most temporally stable depth can be used to accurately predict profile SWC for both the same land use and other land uses. This study further expands the application of the temporal stability analysis and can aid water resource management in areas with diverse land uses.

Margin for error: Anthropogenic geomorphology of Bajo edges in the Maya Lowlands

Many early Maya cities developed along the edges of large structural or karst depressions (bajos). This topographic position aided growing populations to more effectively capture and store rainwater, a necessity for year-round occupation of interior portions of the Maya Lowlands of Mexico and Central America. Ancient Maya forest clearance on sloping terrain led to accelerated soil loss and the aggradation of the bajo margins. These newly created margins of colluvial lands became a focus of subsequent intensive agriculture and helped underwrite further urban expansion. We document this long-term landscape transformation with data derived principally from field investigations at Tikal, Guatemala, and Yaxnohcah, Mexico, but with reference to other Maya centers in the Elevated Interior Region (EIR). Data are derived from field investigations, interpretation of lidar imagery, and laboratory analyses. We present a model of three variants of bajo margin landscape change with differences attributable to topography, lithology, hydrology, and cultural processes. We present preliminary data on crops that were cultivated on bajo-margin soils. We further describe how agriculture was adapted to evolving bajo margins as evidenced by systems of field walls, terraces, and ditches.

Human‐induced land degradation and biodiversity of Classical Karst landscape: On the example of enclosed karst depressions (dolines)

AbstractIn the karst landscape of the Kras Plateau (south‐west Slovenia), we studied the impact of historical human‐induced land degradation on biodiversity by studying the characteristics and changes in vegetation of degraded and nondegraded karst depressions (dolines). Intensive human‐induced land degradation began as a consequence of the abandonment of traditional land use; thus, many dolines have disappeared by being completely filled with waste material and overgrowth. The study is based on a chronosequence approach and assesses whether vegetation (e.g., community succession stages) can be used as a (bio)indicator of land degradation to estimate approximately the duration of degradation on the basis of the stage of succession. The locations and duration of degradation of dolines were identified in advance by analysing a time series of historical aerial photographs, topographical maps, and digital elevation models. Ecological evaluation was based on sampling the floristic composition and the topsoil. In this study, three vegetation measures were established as indicative of degradation: (a) the appearance of ruderal species, (b) hemeroby, and (c) alien and invasive species. A succession model of degraded karst landscape was produced on the basis of identified chronosequences to assess the long‐term spatial impact of doline degradation on karst biodiversity. The model is showing the tendency towards the vegetation homogenization of karst landscape.