Abstract: Geophysical Modeling of the Shale Ridges in the Eastern Venezuelan Basin

Gelvis M. Diaz, Azavache Armenio

Gravimetric and magnetic modeling, along with seismic data, was used to characterize the geophysical expression of shale ridges with the Eastern Venezuelan Basin. Two aero-gravimetric and magnetic profiles, coincident with NW-SE seismic profiles, were utilized to match seismic, gravity and magnetic data.

This diapiric trend extends further east into the Gulf of Paria and Trinidad.

The principal findings described from the modeling are as follows:

1. In the West profile the diapiric ridges were divided in two levels with a density of 2.20 gr/cm³ from 0-4100 m and 2.33 g/cm³ from 4100-7000 m in depth, respectively.

2. In the East profile the density of the diapiric ridges were fixed at 2.20 gr/cm³, from 0-8600 m.

3. The modeling of the bodies in the study shows densities of 2.20 gr/cm³ in the Plio-Pleistocene sediments, 2.40 gr/cm³ in the Middle Miocene, and 2.68 in the Lower Miocene beneath the shale ridges.

Since the diapiric trend has no known magnetic signature in the area, the magnetic anomalies are attributed to the crystalline basement.

The diapiric ridges are interpreted to be relative to deep-seated thrusting which created a weak zone, permitting the development trend.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela