Abstract
Abstract Density differences among subsurface rocks cause variations in the gravitational field of Earth, which is known as gravity anomaly. Interpretation of these gravity anomalies allows assessment of the probable depth and shape of the causative body. For several decades, gravity data were acquired on the surface, but after the scientific and technological advances of the last decades, geopotential models were developed, including gravitational observations on a global scale through space satellite missions. This paper investigated the Moho structure in the region of Reconcavo-Tucano-Jatoba rift-basin system based on the information of the terrestrial gravity field from the EIGEN-6C4 geopotential model. The frequency domain inversion technique was applied, which is known as the Parker-Oldenburg iterative method. Bouguer anomaly data were used in the inversion procedure to determine the thickness and geometry of the crust in the region. Data inversion considered a two-layer model with constant density contrast, in which the entire signal was related to Moho topography. In addition, data inversion was carried out to determine the basement depths. The program proved to be efficient and able to manage large data sets. The results, both of the crust thickness and the sedimentary package, validated the geodynamic evolution understanding of the basin system.
Highlights
A classic problem of Geophysics is the subsurface determination of a density interface geometry associated with a gravitational anomaly, for instance, the mapping of Mohorovičić discontinuity
The gravity effect for each prism was calculated and the total gravitational field was determined by adding the effect of all prisms
This paper investigates the crustal structure in the region of Recôncavo-Tucano-Jatobá rift-basin system, determining the thickness and geometry of the crust in the region through data inversion by the Parker-Oldenburg iterative method, as presented by Gómez-Ortiz and Agarwal (2005)
Summary
A classic problem of Geophysics is the subsurface determination of a density interface geometry associated with a gravitational anomaly, for instance, the mapping of Mohorovičić (or Moho) discontinuity. In this case, the objective is to invert the gravity anomaly, which is usually filtered, to obtain the interface geometry. Several authors have presented different algorithms for calculating the density interface geometry related to a known gravity anomaly. Cordell and Henderson (1968), Dyrelius and Vogel (1972) used an approximation of the disturbing body through various rectangular prisms of constant density. The gravity effect for each prism was calculated and the total gravitational field was determined by adding the effect of all prisms. When the model is complicated or when a large number of observations are available, this process can be computationally time-consuming as the number of operations increases greatly with the product of the number of observations and points defining the model
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