Abstract

ARNAIZ-RODRIGUEZ, Mariano S.; RODRIGUEZ-MILLAN, Inírida  and  AUDEMARD, Franck. Gravimetric and flexural analysis of western Venezuela. Rev. mex. cienc. geol [online]. 2011, vol.28, n.3, pp.420-438. ISSN 2007-2902.

The main purpose of this research is to generate gravimetric/crustal models for Western Venezuela, based on the flexure of the lithosphere theory and using data extracted from the Red Gravimétrica Nacional, wells and seismicity. Statistical and geostatistical controls were applied to the gravimetric data, and Bouguer anomaly and free air anomaly maps were interpreted. The depth of the crustal interfaces was estimated using power spectra of the anomalies, and deep gravimetric sources were interpreted from upward field continuation with the purpose of modelling the crustal structures of the area. It is concluded that: a) flexure of Barinas-Apure basin is mainly generated by the Mérida Andes; b) flexure of Maracaibo block is not controlled by the Andean load, but by the load distribution along this tectonic feature; c) the estimated crustal thickness for the South American plate is 40 km, and for Maracaibo block is 36 km; the elastic thickness estimated for the South American plate is 24 km, and for Maracaibo block is 16 km; d) the upper crust-lower crust discontinuity is about 19 km deep; e) the contact between both plates resembles a type A subduction with NW strike, in which South America underlays the Maracaibo block, although the existence and polarity of this subduction remains uncertain.

Keywords : gravimetry; flexure model; Western Venezuela; Mérida Andes.