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Abstract:
The dimension of the surface of Sainte Baume and its neighbourhood is close to 2,2. This value has been obtained the study of 5 contour lines (from 400 to 800 m) and 5 topographic profiles (3 N - S and 2 E - W). 3 methods were used for contour lines: box counting (DB); the information dimension (Di) and surface - perimeter relation (D(P)). Three methods have been used for topo_graphic profiles: the power spectrum (DSPEC); statistics R/S (DR/S) and vario_gramme (DVAR). Average results are: (DB) = 1.20; Di = 1.23; (D(P)) = 1.32; DSPEC = 1.17; DR/S = 1.24; DVAR = 1.23. Thus, the surface of Sainte Baume and its neighbourhood is fractal. It means, theoretically, that Sainte Baume can be characterised by an infi_nite surface in a bounded volume. This first approach focuses on karst surface approach, cave systems approach will be presented in a following paper (in this review). This result raises numerous geomorpho_logic questions. How to calculate a specific erosion? How to think forms in a theoretical frame, which could develo_ped out of the Euclidean geometry conventions? How to think an essential_ly irregular morphology? Elements of answer are brought on a theoretical plan. They constitute the first elements of a karst geometrical theory. Calculation of the specific erosion points out the problem of the size of the surface used. Due to fractal theories, this size is relative to the observation scale used. To be significant, specific erosion calcula_tion needs the use of an efficient scale, in regard of the erosion processes studied. Furthermore, specific erosion expresses only a balance of mass, not a morphoge_nesis. It corresponds to a chronological approach of the karst. Two dynamics can be distinguished in surface morphogenesis. In one hand, increase of the mean slopes is named spatial differentiation, in another hand, decrease of this value is classically called: aplanation or levelling. These 2 dynamics imply the wearing away of spatially various materials. It takes place essentially around thalwegs during the differentiation stage, around the crest during levelling. Thus morphology, space are important factors of the dynamics in the work. Space is not only a support, but an actor in morphogenesis.