Arcabouço geológico-geofísico da região nordeste do Estado do Pará

Abstract

The northeastern region of the State of Pará presents great potential for the occurrence of groundwater resources. Two hydrogeological systems are present in it: Pirabas and Barreiras. From a gravimetric survey conducted in this research, associated to secondary data collected in academic works and state projects (SIAGAS-CPRM), it was possible to advance the understanding of the regional geometric arrangement that determines the spatial distribution of the sedimentary packages. Map and geological-geophysical profiles of the bouguer anomaly behavior are presented, necessary to support the presented spatial ordering. The geophysical signature of the gravity anomalies in the Bouguer anomaly map analysis revealed positive and negative regions, which are limited by gravimetric lineaments, mainly NW-SE direction. Among the structures generated, in this arrangement, stands the Graben of Bragança - Viseu, partially contained in the work area. The indication of depth presented in the gravimetric profiles, and in the constructive profiles of wells, reveal to us outstanding aspects of the geometry of the sedimentary package. The geometric model of the morphostructural configuration of uneven tectonic blocks, responsible for the regional structuring of the area and the definition of places more favorable to the encounter of the largest thicknesses of sediments, in which the mentioned hydrogeological systems are closed, is confirmed in the obtained results. Thus, the methodologies and techniques used in this work proved to be robust to understand the geological compartmentalization of the work area, with respect to the guide with a higher success rate, the location of wells, in terms of expected productivity. as an important tool for planning and managing water resources.