Les canyons karstiques "Nouvelles approches de problèmes géomorphologiques classiques" (spécialement dans les domaines méditerranéens et tropicaux) [The karstic canyons, geomorphological problems and new directions (particularly in mediterranean and tropical lands).]

In account of many studies (particularly geotechnical for dams build), these canyons are now defined in their relations with the karst hydrosystem : in their hydrological functions, and by the relations with neotectonics, change of base-level, and development of the endokarst. Exceptionally some anse from a collapse processes (breakdown in the karst passages). These news studies give data up the hydromecanical (evorsion) and hydrochemical processes and speed of the incision (maximum m proglacial canyons). The profiles of streams lead from chaotic to graded ; however in some mediterranean canyons travertines dams have blocked the incision. In most cases a turn or a sinuosity is in connection to fracturation and some incised meanders only in table like structures. The cutting of the Pont d'Arc (Ardèche) make a good model of karstic short cut. Many processes infere in the evolution of the cliffs and sides : unloading and gravity (mass-movements, collapses), cut off of the karst tubes and caves ("baumes-porches"), cryoclastism (inherited penglacial forms in North-mediterranean land, particularly frost-pockets and graded sides), weathering, calcrusts (case-hardening) and travertines deposits. On that account, the comparison between Sumidero of Grijalva (Chiapas, Mexico) and the mediterranean canyons is very useful.