2014-09-222014-09-221990-10-12CASTRO, David Lopes de. Interpretação quantitativa de anomalias gravimétricas ar-livre da margem continental norte brasileira, setor nordeste. 1990. 108 f. Dissertação (Mestrado) - Universidade Federal do Pará, Centro de Geociências, Belém, 1990. Curso de Pós-Graduação em Geofísica.https://repositorio.ufpa.br/handle/2011/5795Free-air gravity anomalies across continental margins of passive type present a general standard form. This form can be well explained by a distribution of simple horizontal two-dimensional discontinuities. An automatic process of random search was proposed for quantitative interpretation of the data. Using the method of flexible polyhedron (Simplex), the main parameters of the model were estimated, considering a convenient ration between number of points/number of parameters to be determined. The free-air gravity anomalies over the region of the continental slope can be explained by a single horizontal discontinuity (simple step) and, as the wavenumber domain has information about this anomaly, it was also proposed an iterative graphic procedure for the analysis of the amplitude spectral response for the anomalies. Applying the Fourier transform, it would possible to determine the depth and the off-set of this discontinuity, and, once these parameters are measured, the density is calculated. The basic aim for studying these procedures was to combine the two methods of interpretation in the space and wavenumber domains, in order to obtain a more constrained solution to the geological structure of the studied area. The two interpretative procedures discussed above were applied and their respective capacity of resolution were analysed, over the free-air gravity anomalies of profiles across the continental margin of northeast Brazil, covering the states of Maranhão to Rio Grande do Norte. The survey, called Project EQUANT I, LEG 1, was carried out during the period of August 27 to October 10, 1987, by the Oregon State University (OSU) using the oceanographic ship Prof. W. Besnard of the Oceanographic Institute of São Paulo University (USP). It was demostrated that the inversion done directly in the space domain is more favorable for the interpretation, even for typical anomalies, although the treatment in the spectral domain is relatively simpler.porAcesso AbertoGeofísica marinhaAnomalias gravimétricasMargens continentaisBrasil - PaísPerfis gravimétricos marinhosProjeto EQUANT INordeste do BrasilDissertaçãoCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOFISICA::GRAVIMETRIA