Margen norte costa afuera de Venezuela : sísmica marina de alta resolución entre Golfo Triste y Cabo Codera

Subtitle:Northern offshore margin of Venezuela : high-resolution marine seismic survey between Golfo Triste and Cabo Coders

The continental shelf north of Central Venezuela is partially or completely structurally controlled by major right lateral strike slip active faults (e.g San Sebastian fault), comprising three physiographic provinces, from west to east: The Golfo Triste Playorm, the Choroni Basin and the La Guaira Platform. The two mentioned platforms are of erosional type while the Choroni basin is a deep depression, which is incised by submarine canyons. These canyons seem to be related to turbidity currents with greater flows during the Pleistocene wetter periods. "Wowing several authors, there submarine canyons are partially or completely structurally controlled by major structures present in the north-central coastal range of Venezuela. Five major regional uncon-formities and/or seismostratigraphic limits have been identified GVe propose to correlate the most recent to MIS 2 (Last Glacial Maximum similar to 20 ka) lowstand. The chronological significance of the deepest detected major uncomformity (strong erasion) is tentatively attributed to MIS 6 (similar to 130 ka) lowstand. Based on the present-day position of the later one, we propose an estimation of similar to 1.2 mm.y(-1) of the mean subsidence rate in the La Guaira Shelf; considering that the obtained value may locally represent a minor vertical component of the dominantly horizontal displacement along the San Sebastian Fault. The San Sebastian fault shows a linear deformation in the eastern profiles. In contrast to the west, we observe in some profiles an intense deformation zone.

Publication year:2021

Accessibility:Open