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ABSTRACT: Paleogeographic Maps, Maturin Basin of East Venezuela and Trinidad

Gene M. Rohr

The northern margin of the Maturin basin of east Venezuela and Trinidad is part of the Caribbean-South American plate-boundary zone, and deformation within the zone reflects relative motions of these two plates. Stratigraphic sections within this zone do not record sedimentation at a fixed site but rather the different paleogeographic locations occupied by a piece of lithosphere as it migrated through space and time. This paper presents a method of restoring stratigraphic control to its site of deposition. The method assumes a constant rate of 2 cm/yr of relative eastward motion for the Caribbean plate in the vicinity of Trinidad and a uniform distribution of shear among numerous wrench faults within the boundary zone. A compressional component is independently derived by restoring a north-northeast-south-southeast cross section through Trinidad. Lithostratigraphic reference sections from Venezuela and Trinidad are reinterpreted as a paleoshelf edge which has undergone more than 90° of clockwise rotation since the middle Eocene. The buried thrust front found productive in Venezuela at El Furrial is traced eastward across Trinidad and into the offshore. Restored paleogeographic maps are presented for middle Pliocene (3 m.y.); middle Miocene (14 m.y.); the Oligocene-Miocene boundary (22 m.y.) and middle Eocene (45 m.y.).

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990