TECTONIC INHERITANCE AND STRUCTURAL STYLES IN THE MERIDA ANDES (WESTERN VENEZUELA).

The Barinas-Apure basin extends from the Andean foothills in the northwest to the Guyana shield in the southeast, thus encompassing most of the drainage area of the Rio Apure, a tributary of the Orinoco River. Southwards, it connects directly with the Llanos basin in Colombia. The Barinas basin hardly compares with a flexural basin. It is largely dominated by either north- or south-verging basementinvolved structures. The tectonic inheritance is obvious, as Paleogene normal faults are locally inverted and early emplaced Paleogene Caribbean nappes are frequently reactivated or refolded by younger oblique Neogene Andean structures. Seismic profiles in this area also attest to the strong Neogene structural inversion of Upper Jurassic-Lower Cretaceous grabens. Seemingly, Paleozoic, Hercynian or more likely Caledonian structures were reactivated during both the Tethyan rifting and the Andean deformations, and account for local pre-existing crustal heterogeneities.