Formation of the Maturín Foreland Basin, eastern Venezuela: Thrust sheet loading or subduction dynamic topography

[1] The Maturin Basin in eastern Venezuela is considered a good example of a peripheral foreland basin. Earthquake and tomographic data indicate that eastern Venezuela is affected by the oblique subduction of the South American Plate underneath the Caribbean Plate. New forward flexural isostatic modeling of eastern Venezuela has been carried out in order to determine whether the Maturin Basin was generated purely by thrust sheet loading from the Serrania and Monagas Foreland Thrust Belts. A sequence of forward models from middle Miocene to Present was generated for 3 profiles across the Serrania del Interior Thrust Belt, the Monagas Foreland Thrust Belt, and the Maturin Foreland Basin. The predictions of these models are constrained using seismic reflection and well data. The flexural isostatic modeling shows that thrust sheet loading associated with the Serrania del Interior and Monagas Foreland thrust belts is insufficient to generate the observed subsidence within the Maturin Basin. Dynamic fluid flow modeling of subduction related dynamic topography of eastern Venezuela has been used to investigate the influence of South American Plate subduction on the generation of the accommodation space observed in the Maturin Basin. Fluid flow modeling of subduction related dynamic topography suggests that the subduction of the South American lithospheric mantle caused downward deflection of the South American crust affecting the Maturin Basin and the Serrania Thrust Belt. This modeling suggests that the Maturin Basin subsidence has two components: 55% related to thrust sheet loading and 45% driven by continental subduction.