Recherches nouvelles sur les karsts des gypses et des évaporites associées (Seconde partie : géomorphologie, hydrologie et impact anthropique)

Abstract

Surface features reflect not only the importance of cave collapse, but also the action of present and inherited zonal processes. The rates of geomorphological evolution are compared (main data in table 1). The particularities of hydrological circulation are studied, as well as the ivorkings of some karstic lakes, particularly the. Banyoles lake (Catalonia). The various processes generate numerous hazards enumerated in the paper and evident in urban and suburban areas and in the civil engineering works such as tunnels, dams, etc...

Gypsum karst of the world: a brief overview

“…In the Middle Atlas Mountains gypsum rocks are exposed in the Ain-Nokrah syncline, with some dolines and positive residual forms developed upon them (Nicod, 1993). In the High Atlas Mountains, at Ammougguez, gypsum with some dissolutional features presented difficult tunnelling conditions for a hydro-electric scheme (EI Ghorfi & Giafferi, 1991).…”

“…The main karstified gypsum sequences in France include gypsiferous Triassic strata in Provence and those in the Alps near Beaufortin and Mont Cenis, and Palaeogene (Lutetian and Ludien) gypsum in the Paris Basin (Nicod, 1976(Nicod, , 1992(Nicod, , 1993. Gypsum has long been exploited in mines (the Catacombs) and pits beneath Paris, giving rise to the English term "Plaster of Paris".…”

“…Much of the Alpine gypsum karst is actively evolving and related collapse is common Oulian and Nicod, 1990;Nicod, 1992Nicod, , 1993. Construction of the Mont Cenis Reservoir on gypsiferous strata in the Alps was made difficult by the effects of ongoing gypsum dissolution (Deletie et ai, 1990).…”

“…Since then knowledge of gypsum karst, in terms of its morphological and hydrogeological peculiarities, development mechanisms and geographical distrihution, has increased dramatically. Recently the glohal distrihution of gypsum karst has heen considered hy Nicod (1992Nicod ( , 1993.…”

Geomorphological aspects of gypsum karst areas with special emphasis on exposed karst

“…Most of them are open, but some are partially closed around "ponors". Examples include the polje of Bambini in Greece, the open palaeo-polje of Sant Maximin in France (Nicod, 1993), and some of the poljes in Sicily (such as il Pantano, to the west of Siculiana Mare). In the Alps a glaciokarstic polje has been described (polje of La Valoire; Nicod, 1976).…”