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Detailed Reference Information |
De Sá, N.C., Ussami, N. and Cassola Molina, E. (1993). Gravity map of Brazil 1. Representation of free-air and Bouguer anomalies. Journal of Geophysical Research 98: doi: 10.1029/92JB00979. issn: 0148-0227. |
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Gravity data of Brazil were process to obtain continental scale free-air and Bouger anomaly maps for a large segment of the South American plate. Gravity measurements are referred to the International Gravity Standardization Net 1971 and the anomalies are calculated using Geodetic Reference System 1976 and 2.67 g cm-3 for Bouguer reduction. In the calculation of the gravity anomalies, information used included geopotential model, topography, geoidal heights, and astrogeodetic deviation of the vertical. Depending on the availability and distribution of land gravity data, various regions have been classified as complete, incomplete, or empty. In incomplete regions, the gravity field is represented by 0.5¿¿0.5¿ mean free-air and Bouguer anomalies which were computed from observed gravity data only. In complete regions, mean anomalies in empty 0.5¿¿0.5¿ blocks were computed from nearest known mean anomalies, by least squares collocation. Regions totally devoid of gravity data had the gravity field calculated by least squares collocation using all available geodetic data. The gravity map obtained using this approach allows one to identify the major gravity anomalies with dimensions greater than 100 km. Such anomalies are mainly caused by intracrustal density variations of geological and tectonic interest. ¿American Geophysical Union 1993 |
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Abstract |
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Keywords
Geodesy and Gravity, Regional and global gravity anomalies and Earth structure, Exploration Geophysics, Gravity methods, Information Related to Geographic Region, South America, Geodesy and Gravity, Local gravity anomalies and crustal structure |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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