Lookup NU author(s): Professor Paul Younger,
Dr John Lamont-Black,
Dr Catherine Gandy
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Subsidence hazards in karst terrains are a source of public concern in many parts of the world; they are also an enduring source of fascination (as well as employment) for many applied geoscientists. The world literature is replete with reports of subsidence in limestone karsts (e.g. Beck and Herring 2001; Green et al. 2002; Salvati and Sasowsky 2002). A lesser number of papers propose descriptive or interpretational frameworks for karst subsidence phenomena (e.g. Cooley 2002; Goodings and Abdulla 2002; Waltham and Fookes 2003); fewer still propose predictive and managerial guidelines for subsidence in limestone karst regions (e.g. Augarde et al. 2003). This Special Issue showcases a European research project which sought to do all of the above in relation to gypsum karst. ROSES (Risk of Subsidence due to Evaporite Solution) was a major R&D Project of the European Commission’s 4th Framework Programme of Research and Technological Development (project number ENV4-CT97-0603). Between 1998 and 2001, ROSES focused on the prediction and management of severe, localized land subsidence in areas underlain by karstified gypsum. As in all such European projects, the research was undertaken collaboratively by a consortium of five international partners, each of whom brought a specialist skill-set to the team: University of Newcastle, UK (Coordinator): applied hydrogeology, geotechnical engineering, subsidence engineering. National Academy of Sciences, Ukraine: Speleology, gypsum dissolution kinetics, karst hydrogeology. Eberhard-Karls Universität Tübingen, Germany: mathematical modelling of groundwater flow and dissolution in karst terrains. Universidad de Zaragoza, Spain: geomorphology. British Geological Survey, UK: Hazard mapping of gypsum karst terrains, applied geophysics. The ROSES team applied a systematic concept of speleogenesis in gypsum as the basis of all of its work. Central to our approach was recognition of the centrality of hydrogeological evolution in determining the present “hazard status” of a given locality: when we map different manifestations of gypsum karst in different places, we are really seeing “snap-shots” in geological time of the successive stages in karst evolution. Notwithstanding local peculiarities, from the global perspective we can begin to recognise that the major boundary conditions which drive karst development change between these successive stages in a more-or-less predictable manner. Consequently, the classification of specific karst terrains using a well-informed speleogenetic perspective provides a helpful framework for the identification of the factors that give rise to karst subsidence phenomena. The founding speleological perspective upon which ROSES successfully built was provided by Alexander Klimchouk (National Academy of Sciences, Ukraine). Truly the project “guru”, Alex was responsible for erecting the conceptual speleogenetic / hydrogeological framework (Klimchouk this volume) which provided the intellectual starting-point for all other activities in the project. One of the most fruitful avenues of research within ROSES was the development of the computer code ‘EVE’ (Birk et al., this volume) which for the first time allowed simulation of the processes of maze-cave development in realistic settings. Creative interactions between this novel modelling work and field characterisation of gypsum dissolution rates (Klimchouk and Aksem this volume) yielded mutually consistent results of high quality (see Birk et al. 2003). Fieldwork was a key activity for most of the ROSES partners. We focused on three contrasting study areas, which together represent most of the different settings in which gypsum karstification and associated subsidence problems are found in Europe: (i) In humid and temperate northern England, the belt of country between Ripon and Darlington is representative of areas overlain by glacial till mantles, in which differentiation of karstification and collapse processes appears to be fundamentally controlled by the degree of incision by rivers (Jones and Cooper this volume; Lamont-Black et al., this volume). (ii) In the arid valley of the Ebro River in northern Spain, the strong contrasts between ‘open’ and ‘mantled’ types of gypsum karst (see Klimchouk this volume) are strikingly displayed. In the open karst area, where gypsum is exposed at the surface without significant soil / vegetation cover, rainfall quickly reaches gypsum saturation, so that only surface karren develop, with no speloegenesis. The nearby mantled karst of La Puebla de Alfindén features active cave development beneath recent floodplain sediments of the Ebro, with concomitant surface collapse threatening buildings and roads (Gutiérrez-Santolalla et al., this volume). (iii) In the western Ukraine, the most extensive gypsum maze-caves yet discovered anywhere in the world provided the ideal testing ground for hypotheses relating to gypsum dissolution (Klimchouk and Aksem this volume) and processes of breakdown which lead to surface subsidence (Klimchouk and Andrejchuk this volume). Several partners in the ROSES consortium made significant advances in the science and art of hazard identification in gypsum karst, using both geomorphological mapping (Gutiérrez-Santolalla et al., this volume) and hydrogeological investigations (Lamont-Black et al., this volume). These advances in turn paved the way for the development of a decision-making framework for investigating subsidence problems potentially attributable to gypsum karstification (Lamont-Black et al. 2002), as well as the demonstration of full-scale engineering measures to safeguard roads in areas deemed to be at risk from gypsum karst (Jones and Cooper this volume). Based as it is upon a Europe-wide research project, we felt that this Special Issue ought to be brought to a close with a paper from another continent, providing a wider geographical perspective. In describing subsidence hazards associated with evaporite dissolution in the USA, Johnson (this volume) not only expanded our geographical horizons, but also included examples of karst in halite (a topic which the ROSES team decided to avoid very early in the life of the project!). All in all, we hope you find this Special Issue interesting; we especially hope that it may provide the basis for further research on this fascinating and important topic, far beyond the boundaries of ROSES’ European homeland. References (other than ‘this volume’ citations) Augarde, C.E., Lyamin, A.V., and Sloan, S.W. (2003) Prediction of undrained sinkhole collapse. Journal of Geotechnical and Geoenvironmental Engineering 129: 197 – 205. Beck, B.F., and Herring, J.G. (editors) (2001) Geotechnical and Environmental Applications of Karst Geology and Hydrology. (Proceedings of the 8th Multidisciplinary Conference on Sinkholes and Karst, Louisville, Kentucky, USA, 1-4 April 2001). Balkema, Rotterdam. 460pp.
Author(s): Younger PL, Lamont-Black J, Gandy CJ
Publication type: Editorial
Journal: Environmental Geology
ISSN (print): 0943-0105
ISSN (electronic): 1432-0495