Compartimentação geomorfológica e condicionamento estrutural da drenagem na bacia hidrográfica do rio Coreaú, Ceará, Brasil

Abstract

The watershed of the Coreaú River is located in the NW area of the State of Ceará, presenting an expressive topographic diversity and complex structural arrangement of ductile/rutile dune, which has conditioned the relief as well as the local drainage. The present analysis aims to elaborate a morphostructural study seeking out at the evidencing of the structural control exerted by the geological framework on the drainage of the Coreaú River. Here in, the main objective was to demonstrate the structural conditioning of drainage in the Coreaú River basin with the aid of geoprocessing techniques. In order to achieve the proposed goal, the work was divided into bibliographical surveys; geoprocessing techniques, with data acquisition and processing stages; and finally, fieldwork. Thru the analysis of the rosette diagrams it was possible to identify the NE-SW and E-W directions as the main ones for the ductile/brittle geological structures as well as the structural lineaments, and these directions are in agreement with the NE-SW and E-W regional trends of the septentrional sector of the Borborema Province. Throughout the analysis of the rosette diagrams, elaborated in order of drainage, it was possible to notice that, for the most part, the NE-SW and E-W directions are quite representative, however, a significant predominance of NW-SE direction was observed, this is warranted by the positive structural lineaments (crests), of predominant NE-SW direction, to form firstorder drains perpendicular to their axes. It was furthermore identified a possible change of direction of the fluvial channel of the Itacolomi River justified by neotectonic activities. Thereby, the structural lineaments and the ductile/rump structures, as well as the drainage network of the Coreaú River hydrographic basin present NE-SW and E-W directions, which confirm a concordance with the main directions of other expressive Septentrional Northeast watersheds.