4,664 research outputs found

    The Cyrilka Cave-the longest crevice-type cave in Czechia: structural controls, genesis, and age

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    The Cyrilka Cave is the second longest pseudokarst cave and the longest crevice-type cave in Czechia. Developed within the headscarp area of a deep-seated landslide, the cave became a focus of scientific research in recent years when new passages were discovered. Structural analysis provided a general tectonic plan of the cave, as well as more detailed data on geometry and kinematics of the relaxed rock massif. The primary structure of NNE- to ENE-striking bedding is broken by a system of NNE-striking fissures interconnected by two continuous ENE-striking dextral fracture zones. Abundant signs of recent sinistral strike-slips within the rock massif represent a bold structural feature of the cave. Along with DEM imaging and a detailed survey of the cave, 2-D and 3-D ERT measurements completed an image of the main predispositions and revealed the internal structure of the slope deformation. These measures also detected unknown crevices above the existing headscarp, which indicate the retrograde evolution of the landslide. Methodologically, we used the 3-D electrical resistivity tomography in the incoherent sedimentary flysch rocks for the first time. Based on radiocarbon dating of the stalactite core, the minimum age of the cave is up to 19,900 +/- 280 cal BP, which is the oldest age detected in the area of the Outer Flysch Carpathians so far; we thoroughly discuss further indirect evidence indicating a probable Late Pleistocene age of the cave.Web of Science47339237

    Evaporite karst geohazards in the Delaware Basin, Texas: review of traditional karst studies coupled with geophysical and remote sensing characterization

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    Evaporite karst throughout the Gypsum Plain of west Texas is complex and extensive, including manifestations ranging from intrastratal brecciation and hypogene caves to epigene features and suffosion caves. Recent advances in hydrocarbon exploration and extraction has resulted in increased infrastructure development and utilization in the area; as a result, delineation and characterization of potential karst geohazards throughout the region have become a greater concern. While traditional karst surveys are essential for delineating the subsurface extent and morphology of individual caves for speleogenetic interpretation, these methods tend to underestimate the total extent of karst development and require surficial manifestation of karst phenomena. Therefore, this study utilizes a composite suite of remote sensing and traditional field studies for improved karst delineation and detection of potential karst geohazards within gypsum karst. Color InfraRed (CIR) imagery were utilized for delineation of lineaments associated with fractures, while Normalized Density Vegetation Index (NDVI) analyses were used to delineate regions of increased moisture flux and probable zones of shallow karst development. Digital Elevation Models (DEM) constructed from high-resolution LiDAR (Light Detection and Ranging) data were used to spatially interpret sinkholes, while analyses of LiDAR intensity data were used in a novel way to categorize local variations in surface geology. Resistivity data, including both direct current (DC) and capacitively coupled (CC) resistivity analyses, were acquired and interpreted throughout the study area to delineate potential shallow karst geohazards specifically associated with roadways of geohazard concern; however, detailed knowledge of the surrounding geology and local karst development proved essential for proper interpretation of resistivity inversions. The composite suite of traditional field investigations and remotely sensed karst delineations used in this study illustrate how complex gypsum karst terrains can be characterized with greater detail through the utilization of rapidly advancing technologies, especially in arid environments with low vegetation densities

    Mapping of Potential Show Caves in the Racha Limestone Massif (Country of Georgia)

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    Abstract: The Racha limestone massif is located in the eastern part of the karst zone of western Georgia. The massif is a typical example of Georgian mountain karst regions, where diverse surface and subsurface karst landforms are found. The main aim of this research is to present mapping of two potential show caves, and document speleological information from the Racha limestone massif. The morphological parameters and tectonic directions of the Muradi and Usholta Caves were mapped using the compass-clinometer and laser distance meter, to compile 3D models of the caves. To our knowledge these are the first 3D models of karst caves in Georgia

    The ribbed drapery of the Puerto Princesa Underground River (Palawan, Philippines): morphology and genesis

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    During the 2011 speleological expedition to the Puerto Princesa Underground River (Palawan, Philippines) a drapery characterized by several close-to-horizontal ribs has been noticed. Even without sampling and analyzing its internal growth layers, a detailed morphological study allowed to present a possible genetic model. The presented model helps to explain its evolution, which is mainly controlled by variation in water flow as a consequence of the Palawan climate. When validated by further analyses, the same genetic mechanism could define also the evolution of the very common but still unexplained complex flowstones, which exhibit several close-to-horizontal steps, widenings and narrowings along their growth axis

    The influence of light attenuation on the biogeomorphology of a marine karst cave: a case study of Puerto Princesa Underground River, Palawan, the Philippines

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    Karst caves are unique biogeomorphological systems. Cave walls offer habitat for microorganisms which in-turn have a geomorphological role via their involvement in rock weathering, erosion and mineralisation. The attenuation of light with distance into caves is known to affect ecology, but the implications of this for biogeomorphological processes and forms have seldom been examined. Here we describe a semi-quantitative microscopy study comparing the extent, structure, and thickness of biocover and depth of endolithic penetration for samples of rock from the Puerto Princesa Underground River system in Palawan, the Philippines, which is a natural UNESCO World Heritage Site. Organic growth at the entrance of the cave was abundant (100% occurrence) and complex, dominated by phototrophic organisms (green microalgae, diatoms, cyanobacteria, mosses and lichens). Thickness of this layer was 0.28 ± 0.18 mm with active endolith penetration into the limestone (mean depth = 0.13 ± 0.03 mm). In contrast, phototrophs were rare 50 m into the cave and biofilm cover was significantly thinner (0.01 ± 0.01 mm, p < 0.000) and spatially patchy (33% occurrence). Endolithic penetration here was also shallower (< 0.01 mm, p < 0.000) and non-uniform. Biofilm was found 250 m into the cave, but with a complete absence of phototrophs and no evidence of endolithic bioerosion. We attribute these findings to light-induced stress gradients, showing that the influence of light on phototroph abundance has knock-on consequences for the development of limestone morphological features. In marine caves this includes notches, which were most well-developed at the sheltered cave entrance of our study site, and for which variability in formation rates between locations is currently poorly understood

    Recent advances in karst research: from theory to fieldwork and applications

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    Karst landscapes and karst aquifers, which are composed of a variety of soluble rocks such as salt, gypsum, anhydrite, limestone, dolomite and quartzite, are fascinating areas of study. As karst rocks are abundant on the Earth's surface, the fast evolution of karst landscapes and the rapid flow of water through karst aquifers present challenges from a number of different perspectives. This collection of 25 papers deals with different aspects of these challenges, including karst geology, geomorphology and speleogenesis, karst hydrogeology, karst modelling, and karst hazards and management. Together these papers provide a state-of-the-art review of the current challenges and solutions in describing karst from a scientific perspective

    Aeromycology: studies of fungi in aeroplankton

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    Air is a natural environment for spores of many genera and species of fungi. Despite its small size and a significant dispersion they have a great impact on human health and different areas of our activities, such as agricultural production. The study on spores of fungi that belong to aeroplankton or bioaerosole is called aeromycology. The most frequent fungi present in the air are Cladosporium and Alternaria species. Their numbers are abundant regardless of latitude and height above the sea level and above the ground. They mostly originate from agricultural environment. Other frequently listed species of fungi, whose spores are present in the air include of Aspergillus, Penicillium, Fusarium, Sclerotinia and Ganoderma. The concentration of spores in the air strongly depends on the abundance of their formation during the studied period. This in turn relates to geobotanical region, vegetation, degree of urbanization, climatic conditions, season, current weather, wind force and direction, local microclimate, and many other factors. Changes in humidity affect the concentration of different types of fungal spores. In general they are divided to ‘dry’ (Alternaria, Cladosporium, Puccinia, Ustilago, Melampsora, Epicoccum, Drechslera) and ‘wet’ (Didymella, Fusarium, Ganoderma, Gliocladium, Leptosphaeria, Verticillium). Study of the composition of species and genera are being done using different types of spore samplers, mostly volumetric instruments. Visual identification is based on colony morphology of the fungus and the shape and size of spores. The identification at the species level is possible with molecular tools. Methods based on DNA/RNA amplification are very sensitive and accurate. They allow the identification below the species level, e.g. chemotypes, mating types or isolates with genes or alleles of interest. Aerobiological monitoring is widely used in the epidemiology of human diseases (inhalant allergies) and infections of arable crops (decision support systems for the protection of cultivated plants). Aeromycology is interconnected with such diverse areas as industrial aerobiology, bioterrorism, ecology, climatology or even speleology and cultural heritage.Powietrze jest naturalnym środowiskiem dla zarodników licznych rodzajów i gatunków grzybów. Pomimo niewielkich rozmiarów i znacznego rozproszenia mają one wielki wpływ na zdrowie ludzi i różne kierunki ich działalności, w tym w szczególności na produkcję rolniczą. Badania nad zarodnikami grzybów stanowiącymi część aeroplanktonu są przedmiotem aeromykologii. Niezależnie od szerokości geograficznej i wysokości nad poziomem morza w powietrzu szczególnie często występują grzyby z rodzajów Cladosporium i Alternaria, a ich źródłem jest najczęściej środowisko rolnicze. Innymi często notowanymi rodzajami grzybów, których zarodniki występują w powietrzu są m.in. Aspergillus, Penicillium, Fusarium, Sclerotinia i Ganoderma. Stężenie zarodników w powietrzu jest ściśle uzależnione od obfitości ich tworzenia w danym okresie, co jest pochodną regionu geobotanicznego, szaty roślinnej, stopnia zurbanizowania danej lokalizacji, warunków klimatycznych, pory roku, aktualnej pogody, siły i kierunku wiatru, lokalnego mikroklimatu i wielu innych czynników. Zmiany wilgotności powietrza wpływają na stężenie zarodników różnych rodzajów grzybów, określanych na tej podstawie jako „suche” (Alternaria, Cladosporium, Puccinia, Ustilago, Melampsora, Epicoccum, Drechslera) lub „mokre” (Didymella, Fusarium, Ganoderma, Gliocladium, Leptosphaeria, Verticillium). Badania składu rodzajowego i gatunkowego prowadzone są przy zastosowaniu różnego rodzaju chwytaczy zarodników, a identyfikacja wizualna na podstawie morfologii kolonii grzyba oraz kształtu i wymiarów zarodników uzupełniana jest obecnie przez wyjątkowo czułe metody detekcji molekularnej, specyficzne względem rodzajów, gatunków, chemotypów, a nawet składu genów i kompozycji poszczególnych alleli. Monitoring aerobiologiczny znajduje bezpośrednie wykorzystanie w epidemiologii chorób ludzi (alergologia) i roślin uprawnych (systemy wspierania decyzji w ochronie roślin uprawnych). Badania z zakresu aeromykologii znajdują zastosowanie w tak różnych kierunkach jak aerobiologia przemysłowa, bioterroryzm, ekologia, dziedzictwo kulturowe, klimatologia lub speleologia

    Cryomorphological topographies in the study of ice caves

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    Producción CientíficaThe current interest in ice caves requires that their varied manifestations be known as accurately as possible in view of their responses to a global change and also to their great potential as paleoenvironmental witnesses. This phenomenon has been known about for a long time but is still scarcely studied from the point of view of its cryological values and the evolution and distribution of many of their morphologies. For this, the development of cryomorphological topographies from traditional techniques to geodetic surveys with different tools, including terrestrial laser scanning, is one of the most current ways to characterize and quantify this type of cryospheric phenomena. It represents a new kind of periglacial cartography whose use is feasible in spite of the difficulties these environments present.Ministerio de Economía, Industria y Competitividad (project CGL2015-68144-R
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