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PINDELL, JAMES, Dartmouth College, Hanover, NH

ABSTRACT: Mesozoic-Cenozoic Paleogeographic Evolution of Northern South America

A model for northern South American tectonic and stratigraphic evolution is presented in 14 detailed, palinspastic, paleogeographic plates showing paleosedimentation and paleotectonic data. Main deformational, depositional, and basin forming events along with HC maturation/migration are outlined in relation to progressive tectonic evolution. A cause-and-effect relationship between Caribbean plate motions/associated basin development and hydrocarbon maturation and migration is clear.

Triassic-Jurassic rifting from Yucatan/North America produced a northern segmented passive margin, and the Cocuy backarc basin in Colombia. To the west, at end Jurassic, a marginal seaway developed west of Central Cordillera which led to passive margin conditions along the Cocuy Basin/Central Cordillera, southward to Ecuador. The margin remained passive until Campanian, when Amaime-Chaucha Terrane (leading edge of Caribbean crust) collided with east vergence (southwest-dipping subduction) with Central Cordillera, closing the marginal seaway. The Colon foredeep was thus established each of Central Cordillera; continued convergence occurred by east-dipping flat-slab subduction of Caribbean crust beneath Colombia. The northerly Caribbean crust continued eastward migration along north Sou h America. Maastrichtian?-Paleogene opening of Grenada Basin accommodated a southwest-direction of interplate thrusting of Lara Nappes, producing the north Maracaibo foredeep. Paleocene-Miocene sedimentation patterns record the eastward migration of (1) peripheral bulge uplift, (2) foredeep basin and oil kitchen, (3) allochthon emplacement, (4) erosion due to isostatic rebound caused by extension. Since Middle-Late Miocene, Maracaibo Block escaped northward from Eastern Cordillera convergence by >100 km, and the southeastern Caribbean region has become transtensional rather than transpressional.

AAPG Search and Discovery Article #90988©1993 AAPG/SVG International Congress and Exhibition, Caracas, Venezuela, March 14-17, 1993.