Speleogenesis, geometry, and topology of caves: A quantitative study of 3D karst conduits

Abstract : Karst systems are hierarchically spatially organized three-dimensional (3D) networks of conduits behaving as drains for groundwater flow. Recently, geostatistical approaches proposed to generate karst networks from data and parameters stemming from analogous observed karst features. Other studies have qualitatively highlighted relationships between speleogenetic processes and cave patterns. However, few studies have been performed to quantitatively define these relationships. This paper reports a quantitative study of cave geometries and topologies that takes the underlying speleogenetic processes into account. In order to study the spatial organization of caves, a 3D numerical database was built from 26 caves, corresponding to 621 km of cumulative cave passages representative of the variety of karst network patterns. The database includes 3D speleological surveys for which the speleogenetic context is known, allowing the polygenic karst networks to be divided into 48 monogenic cave samples and classified into four cave patterns: vadose branchwork (VB), water-table cave (WTC), looping cave (LC), and angular maze (AM). Eight morphometric cave descriptors were calculated, four geometrical parameters (width-height ratio, tortuosity, curvature, and vertical index) and four topological ones (degree of node connectivity, α and γ graph indices, and ramification index) respectively. The results were validated by statistical analyses (Kruskal-Wallis test and PCA). The VB patterns are clearly distinct from AM ones and from a third group including WTC and LC. A quantitative database of cave morphology characteristics is provided, depending on their speleogenetic processes. These characteristics can be used to constrain and/or validate 3D geostatistical simulations. This study shows how important it is to relate the geometry and connectivity of cave networks to recharge and flow processes. Conversely, the approach developed here provides proxies to estimate the evolution of the vadose zone to epiphreatic and phreatic zones in limestones from the quantitative analysis of existing cave patterns.
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https://hal.univ-lorraine.fr/hal-01615432
Contributeur : Pauline Collon <>
Soumis le : jeudi 12 octobre 2017 - 13:29:06
Dernière modification le : mardi 27 novembre 2018 - 08:22:02

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Johan Jouves, Sophie Viseur, Bruno Arfib, Cécile Baudement, Hubert Camus, et al.. Speleogenesis, geometry, and topology of caves: A quantitative study of 3D karst conduits. Geomorphology, Elsevier, 2017, 〈http://www.sciencedirect.com/science/article/pii/S0169555X17303975〉. 〈10.1016/j.geomorph.2017.09.019〉. 〈hal-01615432〉

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