A re-examination of the rock types and depositional environments of Trinidadian sediments, combined with a consideration of the structural controls on sedimentation and subsequent translation, have enabled the division of Trinidad’s stratigraphy into three stratigraphic groups: the Upper Jurassic through Maastrichtian Northern Range Group metasediments, the Cretaceous and Tertiary Trinidad Group sediments and the Cretaceous igneous and sedimentary rocks of the Sans Souci Group.The Sans Souci Group rocks are stratigraphically and structurally distinct from Trinidad’s other rocks, and have probably been transported from the west with the Caribbean plate over many hundreds of kilometers. In contrast, the Trinidad and Northern Range Groups, which make up the majority of Trinidad, were deposited on the northern South American margin. Depositional environments interpreted from both groups suggest a rapid deepening around the Late Jurassic/Earliest Cretaceous time which may have been the result of the transition from a Middle/Late Jurassic phase of Proto-Caribbean rifting to Cretaceous passive margin development. The majority of the Late Jurassic through Late Eocene sedimentation history of both groups was on the outer shelf or middle to upper continental slope, and sedimentological variations appear to relate almost exclusively to long period eustatic variations in sea level and/or shifts in sediment pathways. Global oceanic anoxia, combined with upwelling and excessive fluvial run-off, at a time of high eustatic sea level, may explain the deposition of quality source rocks of the Gautier and Naparima Hill Formations from the Albian through to the Campanian time in Trinidad.Deep-water passive margin sedimentation is interpreted to have continued in Trinidad through to Late Eocene/Early Oligocene time. Rapid shallowing, indicated by Late Eocene biostratigraphic data leads to an upward transition from the pelagic marls of the Navet Formation into shallow-water limestones and localised conglomerates in the San Fernando Formation. Following this, Early and Middle Oligocene sedimentation was very slow or non-existent. A similar shallowing and slowing of sedimentation is known from eastern Venezuela in the late Middle Eocene time, slightly earlier than in Trinidad, and at progressively older times farther west along the northern South American margin. Progressive west to east uplift induced by the passage of the flexural forebulge in front of the eastwardly migrating Caribbean plate, or in plane stresses resulting from the convergence of North and South America, both explain this diachroneity in uplift.Trinidadian depocenters subsided rapidly in the Middle to Late Oligocene time, and up to 3 km of deltaic clastics and deep-water marls accumulated over 10 Ma (Late Oligocene to early Middle Miocene time). This is in sharp contrast to the thick passive margin sequence underlying these deposits that accumulated over an 80-Ma time period (Barremian to Eocene) and represents the onset of foreland basin sedimentation in Trinidad.With the progressive approach of the Caribbean plate in Early to Middle Miocene time, the foreland basin was deformed causing depositional environments to generally shallow through the Early to Middle Miocene time. Thrust, and/or strike-slip pop-up highs locally reached the photic zone in the Central Range, resulting in deposition of early Middle Miocene inner neritic platform limestones of the Tamana Formation.From the Late Miocene to Recent time, much of central and southern Trinidad subsided rapidly. In the last 5 Ma, up to 10 km of deltaic sediment accumulated in the Columbus basin to the south of Trinidad. The proximity of the Orinoco delta to the foreland basin is largely responsible for this rapid increase in sedimentation rate and may partially explain the subsidence. However, the subsidence observed in, and to the north and west of Trinidad may also be related to right-lateral strike-slip pull-apart basin development, possibly aided by a component of north-south extension as the Caribbean/South American plate boundary zone transforms into a zone of transtension.

We performed zircon fission-track dating on twenty low-grade metamorphic rocks from the Northern Range and eight unmetamorphosed sandstones from the Central Range of Trinidad. Reset and partially reset zircon populations from the Northern Range gave a consistent fission-track age of 11.7 ± 1.1 Ma. This dates the cooling of the Northern Range through 240 ± 25°C. Assuming a geothermal gradient of 25°C km 1 which is unproved, and a constant rate of uplift, the Northern Range uplifted at an average rate of 0.7 to 1.0 mm yr 1 from the Late Miocene to Recent. If the uplift was not at a constant rate, then the true uplift rates may have been greater than 1.0 mm yr-1. In areas of lower grade metamorphism, Northern Range zircon fission-track ages were not reset, and thus gave information on the provenance of the Cretaceous sediments. Permian and Late Jurassic fission-track ages determined for the Maastrichtian Galera Formation sandstones are interpreted to have been derived, respectively, from granitoids and rift-related volcanics along the northern South American margin. Albian and Early Silurian/Late Ordovician zircon fission-track ages from the Lower Cretaceous Toco Formation have no provenance local to Trinidad but may have been derived further west, possibly from the Caribbean island arc and northern Andes respectively. This difference between the two formations is entirely consistent with structural and stratigraphic work which show the Toco Formation to be part of the Sans Souci Group, an allochthonous terrane transported from the west with the Caribbean plate. The Galera Formation is part of the Northern Range Group, which makes up the majority of the Northern Range, and is inteipreted to have been deposited on the northern South American margin, probably within 400 km of its present location.Zircon fission-track ages from unmetamorphosed sandstones of central Trinidad’s Pointe-a-Pierre Formation constrain deposition of the formation to later than 34 Ma (Lower-Middle Oligocene or later). This is much younger than the faunally estimated Lower Eocene (55 Ma) depositional age, probably because the fauna, which are “arenaceous,” have been reworked. Similar zircon fission-track ages are found in central Trinidad’s Nariva Formation, which is faunally dated as Middle Oligocene to Middle Miocene age.