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TECTONICS AND SEDIMENTATION OF THE GULF OF PARIA AND NORTHERN BASIN, TRINIDAD

By
Stephen Babb, Ph.D.
The University of Texas at Austin
1997

Trinidad lies within a complex, active plate boundary zone separating the South America continental plate from the Caribbean plate composed of arc and oceanic plateau rocks. Detailed analysis of seismic reflection profiles integrated with well data from the Gulf of Paria and Northern Basin of Trinidad has resulted in the definition of five stratigraphic sequences.

The oldest two stratigraphic sequences are Late JurassicEarly Cretaceous in age and were deposited in a passive margin setting following the separation of North and South America. During this passive margin phase flatlying thick carbonateevaporite facies were deposited in a Late Jurassicmiddle Valanginian carbonate megaplatform that covered most of the present day area of westcentral Trinidad. During the Barremian middle Aptian time this megaplatform disintegrated and more localized carbonate banks grew upward from the megaplatform. These banks were progressively drowned during the middlelate Aptian, probably as a result of long term eustatic sea level rise, as well as tectonic and other environmental factors.

The other three sequences range in age from late Miocene to Pleistocene. They consist of clastic rocks deposited along an active strikeslip margin between the eastward moving Caribbean plate and South America. Analysis of isochron maps, seismic facies and well logs constrains the effects of Cenozoic strikeslip faulting in Trinidad. Migration of clastic depocenters suggests that the locus of rightlateral strikeslip faulting shifted southward from the El Pilar fault zone to the Warm SpringsCentral Range fault zone between 12 and 8 million years ago. This shift in fault activity produced a zone of oblique extension and a northeastoriented pullapart basin in the Gulf of Paria (Goodrich subbasin). The eastward continuation of the Warm Springs strikeslip fault into the Central Range bends northeast and resulted in a restraining bend and late Neogene uplift of the Central Range. This uplift provided clastic sediments into the Northern Basin and Gulf of Paria.

Figure 1.1. Location and plate tectonic setting of Trinidad within the active zone of interaction between the Caribbean and South America plates.

Figure 1.3. Location of the Gulf of Paria and Northern Basin study area and seismic reflection and well data used in this study.