The Eastern Venezuelan basin is located south ofthe Serrania del Interior Oriental range, which represents the easternmost branch of the Andean uplift (Figure I). The northernmost boundary of the Serrania del Interior Oriental range, is controlled by right lateral strike-slip motion. It includes the El Pilar Fault system, a major dextral fault, considered to be the main contact between Caribbean and South American plates ; it's
dextral movement, seems to have started in the Upper Miocene; current slip rate is about I cm / year and total offset is around 70 km . An igneous - metamorphic and sedimentary Caribbean belt, lying to the north of the El Pilar fault, was progressively thrusted over, against the South American passive margin (from west to east), during the Eocene / Miocene times.Towards the east, the Serrania del Interior Oriental range, ends up against a series of plio / pleistocene grabens (i.e. San Juan) , related to a NE - SW tectonic extension. The mud diapir tract and its related structures occupies an WSW - ENE trending belt that stretches from Tonoro, to the west, to Pedernales in the Orinoco
delta. These features, two hundred kilometers long and ten wide, have also been reported offshore and onshore in Trinidad with various degrees of activity that range from mud emanations to mud volcanoes, which occasionally rise above sea level. Also associated to this diapir trend a number of oil and gas seeps as well as asphalt lakes
have been discovered. The age of diapirism seems to be restricted to a period from Pliocene to Recent. Seismic transects perpendicular to diapir development evidence both their geometry and growth .