Subsurface faults were studied across an area of approximately 160 sq km of the Eastern Venezuelan

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basin, a foredeep of an earlier formed geosyncline. Among the significant characteristics of these faults are: (1) an arcuate shape in map view, the concave side being toward the craton (Guayana shield) on the south; (2) cratonward dips at unusually low angles, averaging approximately 34°; (3) general increase in throw with depth, the faults evidently extending into basement; and (4) upthrown (north side) sedimentary thicknesses showing "normal" cratonward thinning, whereas downthrown sections are anomalously thick.

Evidence indicates that these are growth faults whose movements extended during a period of time ranging from at least the Oligocene into the Pliocene. Such movements, at least in part, appear to have taken place concurrently with thrust faulting on the northern margin of the basin and with possible large-scale strike-slip displacements still farther north, near the edge of the Caribbean Sea.

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