GIS and morphostructural mapping: a contribution to the morphotectonic study of the Baturité massif, Northeastern Brazil
Résumé
A method for regional-scale morphostructural mapping that is useful for morphotectonic studies in basement areas is presented for the Baturité massif, Northeastern Brazil. Belonging to an Early Cretaceous intracontinental rift shoulder and to the northern marginal scarp of the Brazilian “Nordeste”, this high plateau is suspected to be a residual relief preserved above a low regional planation surface (the Sertaneja pediplain) and the coastal piedmont, but tectonic controls on several of its outer border scarps cannot be excluded. In order to explain its outstanding position, we use a methodology consisting in integration of a wide set of digital data (SRTM DEM, geological maps, Landsat imagery, etc.) in a Geographic Information System that appears as a relevant technique to compare topographic features with geological structure. The results of the detailed morphostructural mapping reveal that differential erosion has played a predominant role in the geomorphic outlines of the Baturité massif. These observations confirm the incompatibility of important neotectonic movements in the relief differentiation. When replaced in its regional morphotectonic context, they rather suggest the partial preservation of the northwest shoulder of the Neocomian Potiguar rift, giving new constraints for a relevant modelling of the regional morphotectonic evolution.