Statistical metrics can be used to analyse the morphology of natural or simulated karst systems; they allow describing, comparing, and quantifying their geometry and topology. In this paper, we ...present and discuss a set of such metrics. We study their properties and their usefulness based on a set of more than 30 karstic networks mapped by speleologists. The data set includes some of the largest explored cave systems in the world and represents a broad range of geological and speleogenetic conditions allowing us to test the proposed metrics, their variability, and their usefulness for the discrimination of different morphologies.
All the proposed metrics require that the topographical survey of the caves are first converted to graphs consisting of vertices and edges. This data preprocessing includes several quality check operations and some corrections to ensure that the karst is represented as accurately as possible. The statistical parameters relating to the geometry of the system are then directly computed on the graphs, while the topological parameters are computed on a reduced version of the network focusing only on its structure.
Among the tested metrics, we include some that were previously proposed such as tortuosity or the Howard's coefficients. We also investigate the possibility to use new metrics derived from graph theory. In total, 21 metrics are introduced, discussed in detail, and compared on the basis of our data set. This work shows that orientation analysis and, in particular, the entropy of the orientation data can help to detect the existence of inception features. The statistics on branch length are useful to describe the extension of the conduits within the network. Rather surprisingly, the tortuosity does not vary very significantly. It could be heavily influenced by the survey methodology. The degree of interconnectivity of the network, related to the presence of maze patterns, can be measured using different metrics such as the Howard's parameters, global cyclic coefficient, or the average vertex degree. The average vertex degree of the reduced graph proved to be the most useful as it is simple to compute, it discriminates properly the interconnected systems (mazes) from the acyclic ones (tree-like structures), and it permits us to classify the acyclic systems as a function of the total number of branches. This topological information is completed by three parameters, allowing us to refine the description. The correlation of vertex degree is rather simple to obtain. It is systematically positive on all studied data sets indicating a predominance of assortative networks among karst systems. The average shortest path length is related to the transport efficiency. It is shown to be mainly correlated to the size of the network. Finally, central point dominance allows us to identify the presence of a centralized organization.
Terrestrial Laser Scanning (TLS) and 3D photogrammetry techniques were used in a relatively small (100-m-long) cave developed in Messinian gypsum in Emilia-Romagna (N. Italy). The surveys were ...carried out to compare the results obtained by both methods in mapping small-to medium-sized morphologies. These measurements allowed reconstructing the evolution stages of the paragenetic (anti-gravitative) morphologies (ceiling channels and pendants) that carved the roof of the cave, and their relationship with local geomorphology, infilling sediments, speleothems, and structural elements. Field measurements were integrated with morphometrical analyses of the digital models that then allowed a much greater number of observations to be made. The results are a clear example of how the combination of TLS and 3D-photogrammetric data can be used to study and measure mm- to dm-scale morphologies in geomorphological studies, including caves, helping to unravel the speleogenetic and, consequently, the hydrological evolution of these environments.
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•A small cave in Messinian gypsum of the N-Apennines has been studied.•Both Terrestrial Laser Scanning (TLS) and 3D photogrammetry have been used.•In-cave morphologies have been measured and described.•Part of the cave evolution has been reconstructed based on morphologies.•Both methods are powerful, and their combined use is recommended.
Abstract
The article tells about the collection of fossil mineralized wood kept in the Museum of Karst and Speleology of the Mining Institute of the Ural Branch of the Russian Academy of Sciences. It ...was formed from 2004 to 2020. The collection includes specimens of mineralized woods from eleven localities (five of them are located in the Perm Krai) belonging to four geological systems - Permian, Triassic, Jurassic and Paleogene. Despite the small volume (35 storage units), our collection is quite representative both geographically and chronologically.
This study is focused on speleogenesis of the Toca da Boa Vista (TBV) and Toca da Barriguda (TBR), the longest caves in South America occurring in the Neoproterozoic Salitre Formation in the São ...Francisco Craton, NE Brazil. We employ a multidisciplinary approach integrating detailed speleomorphogenetic, lithostratigraphic and geological structure studies in order to reveal the origin of the caves, their functional organization and geologic controls on their development. The caves developed in deep-seated confined conditions by rising flow. The overall fields of passages of TBV and TBR caves represent a speleogenetically exploited large NE–SW-trending fracture corridor associated with a major thrust. This corridor vertically extends across the Salitre Formation allowing the rise of deep fluids. In the overall ascending flow system, the formation of the cave pattern was controlled by a system of sub-parallel anticlines and troughs with NNE–SSW dominant orientation, and by vertical and lateral heterogeneities in fracture distribution. Three cave-stratigraphic stories reflect the actual hydrostratigraphy during the main phase of speleogenesis. Cavities at different stories are distinct in morphology and functioning. The gross tree-dimensional pattern of the system is effectively organized to conduct rising flow in deep-seated confined conditions. Cavities in the lower story developed as recharge components to the system. A laterally extensive conduit network in the middle story formed because the vertical flow from numerous recharge points has been redirected laterally along the highly conductive unit, occurring below the major seal — a scarcely fractured unit. Rift-like and shaft-like conduits in the upper story developed along fracture-controlled outflow paths, breaching the integrity of the major seal, and served as outlets for the cave system. The cave system represents a series of vertically organized, functionally largely independent clusters of cavities developed within individual ascending flow cells. Lateral integration of clusters occurred due to hydrodynamic interaction between the flow cells in course of speleogenetic evolution and change of boundary conditions. The main speleogenetic phase, during which the gross cave pattern has been established and the caves acquired most of their volume, was likely related to rise of deep fluids at about 520Ma or associated with rifting and the Pangea break-up in Triassic–Cretaceous. This study highlights the importance of speleogenetic studies for interpreting porosity and permeability features in carbonate reservoirs.
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Jaskinia Lodowa w Ciemniaku (Ice Cave in Ciemniak), in the Tatra Mountains (Tatry), is believed to host the largest subterranean ice mass in Poland. It has been known for over a century, however, the ...onset of its scientific investigations dates back to 1922, when Tadeusz and Stefan Zwoliński mapped it. Since then, it has become one of the best-known caves in Poland. It was described in over a hundred scientific and popular science papers. They include findings of international importance, e.g. works related to radioisotopes, ice-mass balance and age. However, some of the questions asked a century ago are still partly unanswered. One may wonder if they will be delivered before climate warming causes the largest ‘cave glacier’ in Poland to disappear.
Given the evidence of motor and exploring activities being related to spatial abilities on different scales, the present study considers the case of speleology, a peculiar underground exploratory ...activity. The relation of this practice with spatial abilities was examined. The study compares a group of expert speleologists (18), a group with a reduced amount of experience in speleology (19 novice speleologists), and a group with a similar amount of practice but in the outdoors (19 experts mountaineers). Group differences will be investigated in terms of (i) small-scale spatial task performance (rotation-based and spatial working memory); (ii) large-scale environment learning (reproduced using verbal descriptions) asking participants to learn a path through a cave or up a mountain (in a counterbalanced order) and then to test their recall with true/false spatial questions and graphical representation tasks; and (iii) self-reports of wayfinding attitudes. The results of linear models showed that, after controlling for age, gender, years of education, and vocabulary scores, expert speleologists had greater mental rotation and perspective-taking abilities and less spatial anxiety than expert mountaineers, and the former performed the true/false questions better than the latter. It should be noted that participants who reported having guiding/path-finding experiences had greater accuracy in graphical representation performance and higher scores in attitude towards orientation. Overall, expertise in speleology is related to spatial abilities on different scales and might have a distinctive role in comparison with other motor practices, pointing to the potential value of examining speleology in the spatial cognition framework.
This paper is intended to present a newly developed, comprehensive model to understand hydrochemical behaviors related to dissolutional growth of complex fractures underground. Under a fully implicit ...solution framework, the finite volume approach is employed to solve the reactive‐convective‐dispersive system. Based on the embedded discrete fracture model, a novel modeling approach is proposed to describe dissolutional fractures with various apertures in three dimensions (3‐D). This model is verified against preexisting numerical models. Then, a 3‐D field case study regarding hypogene speleogenesis in a deep‐seated, artesian setting is carried out, based on field data concerning karst terrain compiled from Western Ukraine. Finally, we perform a case study to elucidate the finger‐like dissolution process related to a synthetic 3‐D fracture network in gypsum and limestone with heterogeneous aperture fields. Simulation results suggest that (a) the combination of the kinetic trigger mechanism and the transverse speleogenesis concept favors the generation of hierarchical caves in homogeneous fractures; (b) the mechanism of reactive infiltration instabilities determines dissolutional propagation in gypsum with rough fractures; and (c) in limestone, nonlinear kinetics matters for both uniform‐ and variable‐aperture fractures.
Key Points
An innovative modeling approach is proposed to simulate karst aquifers' evolution
Embedded discrete fractures with variable apertures are used to simulate fingering growth in gypsum and limestone
Kinetic trigger mechanism and transverse speleogenesis concept are found to be important for generation of maze‐pattern caves in an artesian setting
Building on reinvigorated scholarly debates on the concept of value, this paper examines forms of valuation that coexist with and challenge those typically associated with capitalist natures. Based ...on archival, ethnographic, and interview data, we analyze a historical case of the Venezuelan Society of Speleology (SVE) that since 1967 has been exploring and mapping the country's caves. Its results are published in a national cave survey that the group manages. Not only is each cave entry the representation and materialization of the group's volunteer efforts. Each is also part of a relational regime of valuation by which all caves are worth mapping. The survey's classificatory logic not only transforms underground value, it also acts as boundary object bringing together diverse actors and promoting the SVE's collective ethos, at least in theory, of valuing all members. The survey is the fulcrum of distinct regimes of valuation, wherein value and values are two sides of the same coin. The spaces where these value/s are enacted matters, suggesting the critical contributions that geographers can make in understanding the spatial qualities that contribute to-or hinder-the materialization of certain regimes of valuation over others.
Caves formed by rising sulfuric waters have been described from all over the world in a wide variety of climate settings, from arid regions to mid-latitude and alpine areas. H2S is generally formed ...at depth by reduction of sulfates in the presence of hydrocarbons and is transported in solution through the deep aquifers. In tectonically disturbed areas major fractures eventually allow these H2S-bearing fluids to rise to the surface where oxidation processes can become active producing sulfuric acid. This extremely strong acid reacts with the carbonate bedrock creating caves, some of which are among the largest and most spectacular in the world. Production of sulfuric acid mostly occurs at or close to the water table but also in subaerial conditions in moisture films and droplets in the cave environment. These caves are generated at or immediately above the water table, where condensation–corrosion processes are dominant, creating a set of characteristic meso- and micromorphologies. Due to their close connection to the base level, these caves can also precisely record past hydrological and geomorphological settings. Certain authigenic cave minerals, produced during the sulfuric acid speleogenesis (SAS) phase, allow determination of the exact timing of speleogenesis. This paper deals with the morphological, geochemical and mineralogical description of four very typical sulfuric acid water table caves in Europe: the Grotte du Chat in the southern French Alps, the Acqua Fitusa Cave in Sicily (Italy), and the Bad Deutsch Altenburg and Kraushöhle caves in Austria.
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•Caves formed by rising sulfidic waters have typical morphologies•H2S oxidizes close to, at, or above the water table forming sulfuric acid•Sulfuric acid reacts with the host rock forming various sulfates•These caves are often precise recorders of past hydrological and geomorphological settings•Most cave volume is carved above the water table by condensation–corrosion
Urban infrastructures built over karst settings may be at risk of collapse due to hydro-chemical erosion of underlying rock structures. In such settings, mapping cave networks and monitoring ground ...stability is important to assure civil safety and guide future infrastructure development decisions. However, no technique can directly and comprehensively map these hydrogeological features and monitor their stability. The most reliable method to map a cave network is through speleological exploration, which is not always possible due to restrictions, narrow corridors/passages, or high water levels. Borehole drilling is expensive and is often only performed where the presence of karsts is suggested by other techniques. Numerous indirect and cost-effective methods exist to map a karst flow system, such as geophysics, geodesy, and tracer tests. This paper presents the outcomes from a challenging application in Quebec City, Canada, where a multidisciplinary approach was designed to better understand the groundwater dynamics and cave paths.
Two tracer tests in groundwater flowing through the cave system indicated that water flows along an approximately straight path from the sinking stream to the spring. It also suggests the presence of a parallel flow path close to the one already partially mapped. This observation was confirmed by combining Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) techniques, and ultimately by observing voids in several boreholes drilled close to the main cave path. Lowering the water levels at the suspected infiltration zone and inside the karst, the infiltration cracks were identified and the hydraulic link between them was confirmed. In fact, almost no infiltration occurs into the karst system when the water level at the sinking stream drops below a threshold level. Finally, SAR interferometry (InSAR) using RADARSAT-2 images detected movements on few buildings located over a backfilled sinkhole intercepted by the karst system and confirmed the stability of the rest of the karst area. The knowledge of the flow system described in this paper is used by policy makers to assure civil security of this densely populated area.
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