--> The Lower Cretaceous through Eocene Passive Margin Section in Northeastern Venezuela, by J. P. Erikson; #90986 (1994).

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Abstract: The Lower Cretaceous through Eocene Passive Margin Section in Northeastern Venezuela

Johan P. Erikson

Northeastern Venezuela's Serrania del Interior (SdI) exposes a Valanginian-middle Eocene passive margin sedimentary section that permits fine-scale assessment of the behavior of depositional systems on a Mesozoic passive margin. 22 paleogeographic maps span approximately 100 My of passive margin sedimentation and are based on abundant original field work and sedimentologic interpretation in conjunction with thorough review of existing published and unpublished material. The exposed Valanginian-Aptian strata are composed of dominantly siliciclastic, wave-dominated shelf facies. A major delta supplied coarse siliciclastic sediment from southwest of the SdI through at least Aptian time. A late Aptian-early Albian, shallow carbonate platform retrograded southward during a significant rela ive sea level rise, while continued siliciclastic influx from the south created a complex platform geography. Facies retrogradation was temporarily and locally halted in middle Albian time, but was reinstated by latest Albian time. Transgression and retrogradation led to deposition on a deep shelf/ramp of pelagic limestone and mudstone (source rock) accumulation over the entire region during latest Albian-Campanian time. North/south differences in Campanian-Maastrichtian pelagic/hemipelagic sediments reflect localized up-welling, while a Maastrichtian age lens of submarine fan deposits reflects the culmination of the Late Cretaceous regression. Widespread Paleocene hemipelagic shale deposition was succeeded by middle Eocene progradation from the southwest of submarine fan deposits. The e d of passive margin sedimentation is marked by the eastward migrating or mity/hiatus/sequence boundary of late middle Eocene to early Oligocene age.

Paleogeographic reconstructions reveal both the temporal and spatial variability of depositional systems. Early Cretaceous depositional systems were laterally continuous generally for no more than a few tens of kilometers. The resultant sequence stratigraphies are areally limited and geographies were short lived, particularly when depositional systems varied between siliciclastic and carbonate dominated.

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