Abstract: Paleogeographic Evolution and Hydrocarbon Systems of Northern South America

James L. Pindell

Mesozoic-Cenozoic paleogeographic evolutionary maps at the formation level of detail are presented to outline the main elements and important tectonic and depositional processes of the regional evolution of northern South America. Main elements include: (1) Triassic-Jurassic, westwardly diachronous rifting and initial margin sedimentation, associated with the rotational separation of the Yucatan Block, which left several serrated marginal re-entrants and salients at which distinctive stratigraphies have developed (Venezuela and Trinidad); in Colombia, sinistrally transtensional backarc extension produced a series of basins which subsided thermally into the Cretaceous to create the broad epeiric sea platform (2) Jurassic-latest Cretaceous/E Tertiary passive margin development from Colo bia (arc extinct) to Trinidad, possibly interrupted by a Late Jurassic epeirogenic event in the east that preceded Barranquin Fm deposition; (3) latest Cretaceous to Middle Miocene eastwardly diachronous migration of: (a) a peripheral bulge ahead of the relatively migrating, Pacific derived Caribbean plate, (b) a foredeep wedge adjacent to the Caribbean Plate, (c) overthrusting by Caribbean allochthonous and South American paraallochthonous nappes/terranes, and (d) isostatic rebound of the footwall, and subsidence of the hanging wall, within the overthrust zone, associated with the propagation of transform faults within the plate interface which allowed Caribbean-South American relative migration to continue even though already-emplaced Caribbean terranes had come to rest; (4) Late Mioce e to Recent transtension in the previously oblique collision zone of E Venezuela and Trinidad, associated with a regionally documented change in Caribbean relative plate motions at about 10 Ma; and (5) Middle Miocene to Recent northward escape of the Maracaibo and other terranes in the northern Andes as a result of enormous E-W Andean convergence in Colombia. Within this framework, three principle hydrocarbon systems are outlined, one involving the latest Cretaceous-Miocene eastwardly-migrating foredeep/overthrust section, the second involving the Neogene Andean foredeep and intermontaine basinal accumulations, and the third involving deposition associated with the Late Miocene-Recent transtensive phase in the east. Implications are summarized.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994