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Morphologic dating of slowly evolving scarps using a diffusive analogue
Author(s) -
Niviére Bertrand,
Marquis Guy,
Maurin JeanChristophe
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/98gl01845
Subject(s) - fault scarp , geology , arid , temperate climate , mass wasting , vegetation (pathology) , physical geography , paleontology , fault (geology) , geography , sediment , medicine , botany , pathology , biology
Morphologic dating techniques that have been applied successfully in arid and semi‐arid areas are also suitable for slowly evolving scarps that are usually found in temperate climate environments. Two approaches, based on diffusion, to relate the present‐day shape of a scarp to its age are used here. The first assumes a model of scarp degradation based on a diffusive process (D method). The second evaluates the state of scarp degradation using the slope distribution along a topographic profile (SD method). Based on an anthropic scarp of known age, we have obtained a mass diffusivity close to 1.5 m²/ka, a reasonable value for areas characterized by a continuous vegetation cover and a temperate climate. We show that the SD method requires an age correction, since it does not take into account the earliest stage for which the mid‐height point is not yet affected by erosion. However only the SD method reveals that at several profiles a later scarp reactivation event has occurred. Such information can be important when trying to identity the recent geological or environmental events that have affected a region.