Contribuição Da Gravimetria Na Prospecção De Água Subterrânea No Litoral Norte Do Ceará, Brasil

A gravity investigation is conducted in a coastal area in the northeastern Ceará State (Brazil). The objective of the survey is the detection of the regional geological structures which control the accumulation of underground water. This investigation consists of 1668 gravity stations, including previous surveys both in land and marine areas. The Bouguer gravity map is dominated by regional effect caused by the mantle uplift in the continental passive margin. To display more clearly the gravity anomalies caused by upper crustal heterogeneities, the local regional gravity field is removed by using a polynomial surface fitting. The resulting residual gravity anomaly map permits us to associate the gravity anomalies with known precambrian geologic units, granitic batholiths and surface structural features. The gravity lineaments are concordant with the NE-SW structural trends. In the northwestern of the studied area an elongated relative gravity low, visible in the residual map, indicates a NWSE secundary deformation trend, underlying of the sedimentary cover. These results will be prioritized and will be used to guide a more detailed geophysical survey.