Polygonal Karst Research Articles

Geomorfologi Tanah Pada Transisi Geologi Formasi Wonosari dan Nglanggran di Kecamatan Purwosari Gunungkidul Yogyakarta

The transition zone of the Wonosari and Nglanggran Formation in Purwosari District has the characteristics of thick soil, steep slopes, and no outcrops. The different characteristics found in the Wonosari Formation Zone are characterized by polygonal karst formations with thin soil and limestone rocks, and the Nglanggran Formation in the form of thick soil, andesite rock outcrops, and steep slopes. Geomorphological mapping of the Nglanggran and Wonosari Formation can be done easily through morphological approaches and outcrops. Geomorphological mapping is quite difficult to do in the transition of the Wonosari and Nglanggran Formation because it does not have outcrops and is difficult to interpret from morphology. Soil geomorphological approach needs to be done to define landform units for areas that do not have outcrops dan difficult to interpret through morphology. The purpose of this study was to map the geomorphological distribution of soil characteristics in the geological transition zone. The methods used to identify landform units are morphological delineation and soil survey. The morphological delineation for landform units was obtained from aerial photographs. The results of the delineation of landforms from aerial photographs are detailed by soil surveys. The results of the delineation of landforms using aerial photography produce high resolution, smooth, and firm compared to other sources. The results of the delineation of landforms from aerial photos obtained two units of landforms, limestone karst hills, Wonosari formation and andesitic rocky hills, Nglanggran formation. There is a transitional transition zone in the TP7 soil sample with the color change from dark brown (karst) to light brown (old volcanic). The thickness of the soil in the old volcanic is more than 1 meter and deeper than the karst soil (< 60 cm). The transition zone has three soil horizons A, B, and B/C which are classified as more developed than the karst region (A and B horizons). The soil texture in old volcanic is clay and silt, while the dominant karst area is clay.

Sinkhole development in the Sivas gypsum karst, Turkey

The extensive gypsum karst of Sivas, Turkey is one of the most outstanding examples of bare gypsum karst in the world. It displays a number of remarkable geomorphic features, including: (1) two stepped planation surfaces cut-across folded gypsum developed during an initial phase of slow base level deepening punctuated by periods of stability; (2) unusual deeply entrenched gypsum canyons related to a subsequent phase of rapid fluvial incision and water table lowering; (3) a polygonal karst of superlative quality mainly developed in the upper surface; (4) relict valleys disrupted by sinkholes in the lower erosional surface; (5) a large number of bedrock collapse sinkholes mostly associated with the lower surface; and (6) numerous cover subsidence sinkholes developed in the valley floors. This work analyses the spatial distribution, characteristics and evolution of the sinkholes within the broad Plio-Quaternary geomorphological and paleohydrological evolution of the epigene karst system dominated by autogenic recharge. A cartographic sinkhole inventory has been produced in an area covering 2820 km2 with morphometric data and including 295 bedrock collapse sinkholes and 302 cover subsidence sinkholes. The different sinkhole types show a general spatial zonation controlled by the hydrogeological functioning of the different sectors: (1) solution sinkholes (polygonal karst) in the upper recharge area; (2) bedrock collapse sinkholes in the lower denudation surface and close to the base level, where well developed caves are inferred; and (3) cover subsidence sinkholes, with high densities probably associated with areas of preferred groundwater discharge. The morphology of the bedrock collapse sinkholes, varying from small cylindrical holes to large and deep tronco-conical depressions with gentle slopes reflect to geomorphic evolution of these sinkholes that reach exceptionally large hectometre-scale diameters. Their evolution, involving substantial enlargement and deepening, is attributed to the solutional removal as solute load of large volumes of gypsum by downward vadose flow. This type of morphological evolution with significant post-collapse solutional denudation differs from that observed in carbonate rocks characterised by lower solubility and erodibility. The analysis of historical imagery reveals that bedrock collapse sinkholes currently have a very low probability of occurrence and that buried cover subsidence sinkholes are used for urban development creating risk situations.

Karst Morphology of Karangbolong Area, Java-Indonesia

The Karangbolong karst is situated in the southern zone of Java where Miocene limestone has been uplifted and has experienced karstification since the late Pliocene. The research documented here aims at exploring morphological characteristic of the area. Special interest is attributed to differentiation of valley or depression morphology, conical karst morphology, and the roles of jointing system and uplift history in their development. The morphology investigation was mostly undertaken using aerial photograph visual interpretation of panchromatic aerial photograph and analytically shaded DEM, as well as field observations. The results show that the general morphological features of Karangbolong karst are characterized by aligned valleys and aligned enclosed depression with three different patterns. The orientation of the valleys and enclosed depressions coincide with the structural pattern of the area, indicating that the formation of aligned valleys and aligned enclosed depressions is preferential dissolution through jointing. The residual hills are typified by conical karst morphology with sharp peaks. It is found that tight joint spacing appears to be the main reason for the sharp peak of the conical hills. Asides from jointing system, morphology of the area is likely governed also by topographical position and gravity sliding of the limestone bed during the uplift. Uplift history has important control on the differentiation of morphology between plateau part and sloping part. Limitation of this research is that the aerial photograph was not rectified well, because the analyses in this research were more on pattern identification. More accurate rectification is needed for better morphometric analyses. Key words: Southern Java, Karangbolong karst, polygonal karst, tropical geomorphology.

Morphometric and geological features of karstic depressions in gypsum (Sivas, Turkey)

Gypsum covers an area of approximately 5 % in Turkey and is mainly found in Sivas basin. Gypsum in the Sivas basin includes many karst structures with various sizes and has a variety of forms that present different conditions offering different morphometric features. Two basic shapes of karstic terrain are reflected in this area offering a wide variety of gypsum karst. The first of these are dissolution dolines which constitute the polygonal karst areas, and the second one is collapse dolines which is deeper karst depressions formed by roof collapse and the accompanying of solutions. The aim of this study was to determine and identify general characteristics of doline in the study area using morphometric measurements and calculations. Density of dolin is very high in study area. The source of the dolines data included 1/25,000 scale digital maps containing elevation and several cartographic attribute interpretations, a very demanding field work and satellite images. The parameters calculated for the study area include depression length, width, orientation, area, perimeter, depth, circularity index, depression density, circularity index, length/width ratio and major axis orientation. This study describes an application of geographic information systems to examine the morphometric and geological features of gypsum karst in Sivas basin. The effect of geologic, structural, and hydrogeologic variables on the morphometry and spatial distribution of depressions are discussed in the study.

Submerged karst landforms observed by multibeam bathymetric survey in Nagura Bay, Ishigaki Island, southwestern Japan

Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the southern Ryukyu Islands, Japan. The coastal seafloor at depths shallower than ~130m has been subjected to repeated and alternating subaerial erosion and sedimentation during periods of Quaternary sea-level lowstands. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85×2.7km) and visualized the high-resolution bathymetric results over a depth range of 1.6–58.5m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. Although these submerged karst landforms are covered by thick postglacial reef and reef sediments, their shapes and sizes are distinct from those associated with coral reef geomorphology. The submerged landscape of Nagura Bay likely formed during multiple glacial and interglacial periods. According to our bathymetric results and the aerial photographs of the coastal area, this submerged karst landscape appears to have developed throughout Nagura Bay (i.e., over an area of approximately 6×5km) and represents the largest submerged karst in Japan.

Análise comparativa da extração automatizada de dolinas a partir de modelos digitais de terreno

As cartas topográficas de semidetalhe e detalhe (escalas 1:50.000 e 1:10.000) não representam adequadamente a complexidade da rede de drenagem e das feições morfológicas de áreas cársticas. O presente trabalho avalia a extração automatizada de dolinas, feições morfológicas típicas do carste poligonal, a partir de modelos digitais de terreno gerados de pares estereoscópicos de fotografias aéreas na escala 1:25.000 e de dados do sensor SRTM (Shuttle Radar Topography Mission/NASA) com resolução de 30 e 90 m. A área de estudo corresponde aos planaltos cársticos do Vale do Rio Ribeira de Iguape, sul do Estado de São Paulo, que compreende remanescentes importantes da Mata Atlântica e rico patrimônio espeleológico. O modelo digital de terreno obtido a partir de fotografias aéreas foi gerado pelo programa Geomatica (Módulo Ortho-Engine), utilizando parâmetros de calibração interna de câmera e pontos de controle extraídos de cartas topográficas nas escalas 1:50.000 e 1:10.000 e de GPS (Sistema de Posicionamento Global). A extração automatizada das dolinas dos modelos derivados de fotografias aéreas e dos dados SRTM foi feita em ambiente SIG (Sistema de Informação Geográfica). Baseado na análise morfométrica das dolinas, os resultados foram comparados com cartas topográficos nas escalas 1:10.000 e 1:50.000 e fotointerpretação convencional. Os modelos gerados com o programa Geomatica e SRTM de 30 m de resolução detectaram várias dolinas não representadas nas cartas topográficas e no modelo SRTM de 90 m de resolução. Desse modo, quanto maior a resolução do modelo, maior a sensibilidade do método para a extração de dolinas. Comparando-se os parâmetros de área e perímetro das dolinas, os valores obtidos pelo Geomatica ficaram muito próximos aos do fotointerpretado. A utilização dos diferentes modelos mostrou-se uma importante ferramenta, que pode auxiliar nos trabalhos de fotointerpretação convencional, principalmente em regiões onde inexistem informações cartográficas de detalhe.

Assessment of sediment and erosion rates by using the caesium-137 technique in a Chinese polygonal karst depression

Karst depressions comprise geomorphologically important sources and sinks for sediments and associated pollutants; yet the sedimentology of many depressions is not well understood in the world. In this paper, the 137Cs technique was employed to estimate recent sedimentation rates in a Chinese polygonal karst depression. The results indicate that the sediment deposition rates ranged from 0.91 to 1.97 mm year−1 from 1963 to 2007, and the average sediment deposition rate and specific deposit yield were estimated to be 1.47 mm year−1 and 20 t km−2 year−1, respectively. These results are consistent with the local monitoring data of runoff fields, which confirms the validity of the overall approach. This shows that the soil loss rate is very low in some karst areas of Southwest China. Above all, the approach appears to offer valuable potential to study surface erosion by estimating sediment deposition rates of karst depressions, rather than the assessment of complicated soil erosion in stony soils of carbonate rock slopes. In addition, the space distribution of surface soil and 137Cs inventories are affected remarkably by the inhomogeneous dissolution of limestone under the soil. It may be an important phenomenon, which exists widely in karst areas, and it is significantly different from other places.

The application of caesium-137 measurements to estimate recent sedimentation rates in a typical karst depression of Guizhou Plateau, China

The existing traditional methods of assessing the rates of soil loss have many limitations and are difficult to apply in the karst areas of Southwest China. Karst depressions comprise geomorphologically important sources and sinks for sediments and associated pollutants, yet the sedimentology of many depressions is not well understood. In this paper, the 137Cs technique was employed to investigate recent sedimentation rates in a Chinese polygonal karst depression. The results indicated that the sediment deposition rates ranged from 0.91 to 1.97 mm·a−1 in the period from 1963 to 2007, and the average sediment deposition rate and specific deposit yield of the catchment were estimated to be 1.47 mm·a−1 and 20 t·km−2·a−1, respectively. The results obtained were consistent with the local monitoring data of runoff plots, confirming the validity of the overall approach. It was shown that soil loss rates were very low in some karst areas of Southwest China. Above all, the approach appears to offer valuable potential to study surface erosion by estimating sediment deposition rates of karst depressions, rather than the assessment of complicated soil erosion in stony soils of carbonate rock slopes. In addition, the spacial distribution of surface soil and 137Cs inventories was affected remarkably by the inhomogeneous dissolution of limestone under the soil. It may be an important phenomenon which exists widely in the karst areas and is significantly different from other places.

Geomorphological map of the Serra da Bodoquena karst, west-central Brazil

Please click here to download the map associated with this article. The Serra da Bodoquena is a karst area situated on the southern edge of the Pantanal wetland region in the states of Mato Grosso and Mato Grosso do Sul, central-western Brazil. Morphological analysis, on a scale of 1:60,000, made it possible to identify such various karst features as dolines, caves, sinks and springs, as well as karst cones and corridors, among others, compartmentalized into six morphological units. To the west of the Serra, the labyrinth karst that was identified reflects a situation of extreme flattening and diffuse infiltration via vertical fractures, which is gradually limited by polygonal karst, to the extent that there is drawdown of the water level. To the north of the Serra, these features are obscured by a greater degree of uvial incision, which develops in the form of canyons and alluvial plains. To the east, there is a predominance of karst plains with dolines in a thick soil covering, associated with residual hills. There are tufa deposits along the current uvial drainage system, and extensive older deposits occur in Quaternary terraces. Sandstone plains with innumerable dolines occur to the southeast of the Serra, reecting the presence of subjacent karst. Geomorphological mapping of this area will be able to contribute to the Serra da Bodoquena National Park management plan, or assist in the development of anthropic soil use/occupation plans.

Mapeamento e caracterização de feições cársticas de superfície na Faixa Itaiacoca nas regiões de Nova Campina e Bom Sucesso de Itararé, SP/PR

O trabalho apresenta uma caracterização de feições cársticas de superfície identificadas a partir de fotointerpretação de detalhe (1:25.000) nos terrenos carbonáticos da Faixa Itaiacoca nas regiões de Nova Campina e Bom Sucesso de Itararé, estados de São Paulo e Paraná. As maiores concentrações de sumidouros e depressões fechadas situam-se próximas às áreas urbanas de Nova Campina e de Bom Sucesso de Itararé e no extremo sudoeste da área estudada, já no Estado do Paraná. Nessas áreas identifica-se o desenvolvimento do padrão de carste poligonal, semelhante ao descrito na Bacia do Rio Betari, no Alto Vale do Ribeira. A análise morfométrica das depressões fechadas revelou que, em geral, apresentam área, perímetro, amplitude e declividade inferiores aos observados nas faixas Lajeado e André Lopes, no Vale do Ribeira; índices de circularidade, no entanto, são maiores. Considerando-se a área total de captação das depressões, foi possível estimar que a contribuição da recarga autóctone é expressivamente mais importante que a alóctone na Faixa Itaiacoca. A diversidade do uso e ocupação do solo na área demanda um planejamento adequado para proteção do carste. O mapeamento e caracterização de feições cársticas apresentados nesse estudo constituem a base para estudos futuros sobre a dinâmica hidrológica subterrânea dos sistemas cársticos da região.

Les karsts de Nouvelle-Zélande

Karsts of New-Zealand. New-Zealand presents numerous karts developped as well in ancient rocks (Paleozoic) as in recent ones (Oligocene). The stretching in latitude of the land, the high vegetal biodiversity and the strong rainfalls explain the importance of the karstification and the variety of the morphologies. Endokarsts are well developped , but many are still to explore. The polygonal karst of the King Country (North Island) in one hand, and the karsts of the Marble Mountains (Souh Island) in another one, are the most interesting. The possibilities of crossing of numerous datations (dendrochronology, speleothems, volcanism, etc.) and the location of these karsts in the south hemispher provide to these last exceptional paleo environmental recordering systems.

A polygonal karst in Alte Murge (Puglia, Southern Italy)

A polygonal karst in Alte Murge (Puglia, Southern Italy)

Spatial dispersion of polygonal karst sinks

Spatial dispersion of polygonal karst sinks

Point-recharge of limestone aquifers — A model from New Zealand karst

Closed depressions of moderate dimensions (solution dolines, sinkholes, cockpits) are a widely described feature of limestone terrains but very little attention has been paid to their contemporary hydrological function. In many areas the depressions act as funnels concentrating near surface waters and forming important point-sources of recharge to limestone aquifers. In this paper the mechanisms by which flow is concentrated and then transmitted to the underlying aquifer are examined and a model of depression hydrology is proposed. The model is shown to be useful in explaining the recharge mechanisms of conduit flow dominated aquifers which drain polygonal karst terrain in the Waitomo district, New Zealand.

Morphometric Analysis of Polygonal Karst in New Guinea

An attempt is made to analyse the planimetric morphometry of humid tropical karst in eight districts in east New Guinea. The geology, process environments, and morphology of sample localities provide a background for judging the morphometric results. The morphometry section includes information on procedure, spatial dispersion and association analysis, and terrain differentiation; it concludes with a growth model for polygonal karst. Closed depressions completely pit the landscapes and, when delimited on the basis of their topographic divides, form a cellular network termed polygonal karst. These cells tend more toward pentagons than hexagons. The stream-sinks associated with the depressions have dispersion patterns that tend toward uniformity. This probably comes about through competition. Each polygonal cell is a solution depression that drains centripetally to an internal stream-sink, and some striking morphometric similarities to “normal” drainage basins are observed. Correlation and regression techniques demonstrate that various morphologic parameters have a well-defined and generally similar form of association in each of the sample districts. There is no sign of the landscape chaos often ascribed to karst. Yet despite organizational similarities, multiple range tests indicate significant differences in terrain statistic values. The range tests permit the identification of three polygonal karsts: pinnacle, conic, and linear styles or subsets. The disjoint pinnacle and conic subsets are intersected by linear subsets, which thus possess intermediate landscape types. The conic and linear styles correspond roughly to “cone karst” and “directed karst,” respectively. A growth model for polygonal karst is proposed that envisages scattered small depressions on an uplifted surface expanding and capturing smaller neighbors until the entire surface is occupied by adjoining polygonal depressions. In the majority of cases, depression growth leads to no significant change in external shape, although it is often accompanied by increasing internal asymmetry about the stream-sink. Parallel retreat of slopes is suspected in one locality only. The boundaries of the depressions are largely stabilized by competition, and growth of the depression is also limited by the permeability of karstified rock, with large depressions breaking into smaller units if a certain size is exceeded. Once a cellular polygonal karst is established, its geometry undergoes only minor modification through time, unless altered by an important environmental factor.