FORMATIONS OF TRINIDAD AND TOBAGO
Age: Upper Jurassic
Hollis conglomeratic limestone
(Saunders 1997) previously part of the Rio SecoFormation based on Kugler (1959)
Thickness: 500 m
Reference: Hutchinson, 1938; Kugler, 1959, Furrer, 1968; Saunders, 1997;
Type Locality: The outcrops of Maraval, the Verdant Vale area north of Arima, in the heights north of the Hollis Reservoir, in the headwaters of the Oropouche River, the Platanal area, the north-western headwaters of the Rio Seco, Turure Quarries off the Cumaca road and in a tributary of the Turure River.
Lithology and Depositional Environment: This formation represents the oldest rocks in the Northern Range with no basal exposure. The lower part of the formation comprises massive recrystallised limestones similar to former reefal mounds and platforms which are separated by recrystallised, phyllitic limestones. Higher in the formation, more thinly bedded phyllitic limestones prevail together with interbedded phyllites, often calcareous. Fossil recoveries are rare in the Maraval Formation but Jurassic Tithonian ammonites were recovered at the Hollis dam-site near the top of the formation (Hutchison, 1938); Echinoid and algal fossil material was found in that general area proposing Upper Jurassic, shallow marine deposition (Furrer, 1968). Based on mineralogy sericite is common based on thin section evidence even in in massive units as well as on bedding planes of the bedded limestones. A noticeable association of sparite and quartz in clusters of larger crystals and layers, suggests that the quartz was developed during metamorphism. Dolomitisation of the limestones in the is inferred based on field observations from samples collected at BrassoSeco, where one pyroclastic fragment was also found (Furrer, 1968).
Age: Upermost Jurassic-Lowermost Cretaceous
Thickness: 1,200 to 1,500 m
Reference: Suter H.H. 1951, Saunders, 1997
Type Locality: On the North Coast road, north of Green Hill. South flank of the range extending eastward nearly to the Oropouche River.
Lithology and Depositional Environment:
The lowest part of the formation encompasses more slates and sericitic phyllites than average, with some thin interbedded sericiticquartzites. Further up the formation, massive ortho-quartzites of limited lateral extent outcrops with individual beds reaching 100m in thickness. These units form high cliffs and deep gorges and they underlie the highest peaks in the western part of the Northern Range. Interbedded quartzites and phyllites make up a large part of the Maracas Formation. A number of sedimentary structures can still be noticed in laminated outcrops, such as rare graded bedding, slump folds, convolute bedding, and poorly defined ripple flow marks. Current indications seem to be southwards which is as against most palaeo-geographic reconstructions which infer deposition to be north to south in northern South-America. In the lower part of the Maracas Formation, a couple recrystallised thinly bedded limestones similar to the Maraval limestone exist, interbedded with phyllites and slates which appear to be insitu. In addition there are small isolated outcrops of more massive recrystallised limestones or marbles which look like Maraval limestone; some may be klippen and some may be exotic blocks of Maraval Fm. The Maracas Formation, lies conformably on the Maraval Formation. All these metavolcanics appear to have been tholeiitic volcanic ash deposits as suggested by Jackson, Smith and Duke (1991). The Grande RiviereFm is no longer recognised and is mapped as Maracas Formation to south and west and based on work by Algar and Pindell (1991), outcrops to the north and east have been remapped as GuayamaraFm, which represents a relatively fine grained equivalent of the Maracas Fm. Mapping of the Maracas Formation eastwards along the north coast leads reflects a change from quartzites to interbedded dark coloured phyllites.
Age: Upper Jurassic
Thickness: Approximate thickness of 800m.
Type Locality: There is doubt about the two most southeasterly outcrops of the range in the Matura Point area and the Fronton de Saline area, mapped by Kugler (1959) as Grande Rivere Fm and by Algar and Pindell as Rio Seco Fm. With some hesitation they are now mapped as Guayamara Fm based on detailed mapping in the Primera Pria River area. The formation consists predominantly of interbedded slates, siltstones and sandstones with occasional quaitzitic grits and areas of slates.
Reference: Kugler 1959, Barr 1963, Algar & Pindell 1991
Lithology and Depositional Environment: S.T. Algar introduced a new unit - the Guayamara Fm into the geology of the Toco area, based on very good exposures along the east coast. The lithology appears very like the Grande Riviere Fm . The Guayamara Fm also seems similar to the phyllitic facies of the Maracas Fm east of Chupara Bay and on the Yarra River. The revised map has extended the Guayamara outcrop from the east coast to Chupara Bay, as Algar (1991) did in one of his maps. In addition, the new map has extended the Guayamara Fm into the Platanal Graben, an area of poor exposure except for the folded and faulted structures in the surrounding Maraval limestone. An east-west trending limestone pericline in the upper reaches of the Salybia River and the Rio Seco is noteworthy.
The formation was formally established by Algar & Pindell (1991). It replaces the northern outcrop of the Grande Riviere Fm as shown by Kugler (1959) and stretches from Guayamara Bay on the East Coast, westward to Chupara Bay in the middle of the Range, where there appears to be facies change and the Guayamara is replaced to the west by the Maracas Fm. The Guayamara Fm is confined to the north flank of the range except in the headwaters of the Oropouche and Platanal rivers where it seems to extend southwards into part of the core of the range.
Age: Lower Cretaceous
Upper phyllitic beds
Upper limestone sequence
Lower limestone member lying apparently conformably on the Maracas Formation
Thickness: 500 meters average but varies
Type Locality: Lady Young Road or Dumas Bay at the southwest end of the island on Monos, the uppermost bedded limestones are interbedded with conglomerates.
Reference: Potter 1972, 1974 & 1976, Saunder, 1997. Kugler2001
Lithology and Depositional Environment: Although the Chancellor Fm (formerly Chancellor Beds) is confined to the western end of the Northern Range, extending 36 km eastwards, it does outcrop on the north coast as well as on the south coast of the peninsula and islands. The formation occurs overturned on Maravaca Island, Medine Point and Les Boquets Islands lying under the overturned Maracas Fm. It therefore provides important additional evidence on details of the main north-vergentent form.
There appear to be four members in the Chancellor Fm - a lower limestone member lying apparently conformably on the Maracas Fm, succeeded by a phyllite member which is followed in turn by an upper limestone sequence; then finally by upper phyllitic beds. The Morvant beds may lie unconformably on the Chancellor Fm, although evidence for the nature of the unconformity is not everywhere clear. The thickness of the Chancellor Fm. varies and seems to average about 400m.
The Chancellor limestones are usually dark grey, recrystallised and thinly bedded (1cm to 1 m) with interbedded dark grey slates, phyllites and occasional schistose quartzites. The lower limestone has a number of sedimentary structures in the interbedded phyllites. In this section the Chancellor limestones appear less pure than Maraval limestones, and are finer grained. Quartz is present in almost every Chancellor limestone and sericite is common in irregular bands. Pyrite is also common. Recrystallisation has not been carried as far as in the Maraval limestones, possibly because of the thinner bedding and the higher pelitic content.
Type Locality Lady Young Road or Dumas Bay at the southwest end of the island on Monos, the uppermost bedded limestones are interbedded with conglomerates.
RIO SECO FM
Age: Tithonian, Late Jurassic by Kugler, 1959 and later dated by Saunder 1972, as Early Cretaceous
Thickness: 2000 m
Type Locality: The Rio Seco Formation extends eastward from the Aripo River along the southern boundary of the Northern Range.
Reference: Kugler 1953, Saunders, 1997; Algar& Pindell (1991)
Lithology and Depositional Environment:
In the Kugler 1959 map, Rio Seco Fm is shown as entirely Jurassic with four members - Caure limestone, Hollis conglomeratic limestone, Maraval beds and Aripo limestone, in order of increasing age. These members would all fit into the Maraval Formation as shown on the new map. However, on the 1959 map the Rio Seco Fm also included Barr's 1963 original type locality in the Rio Seco and Sena Bay on the East Coast. Partly based on the misnamed
Balandra Anticline, Barr suggested a Jurassic age. J.B. Saunders (1972) suggested a Lower Cretaceous age for Rio Seco samples from the east coast and the Turure River.
Most of the formation consists of grey to dark grey shales and slates, often calcareous with bedded limestones and occasional quartzitic sandstones. The thick sandstones of the Balandra Grit mapped by Kugler and Barr as in the Grande Riviere Fm, but which Algar (1991) assigned to the Rio Seco Fm, have been returned, as it were, by now mapping them as part of the Guayamara Fm. The Formation is much folded especially in the western part of the outcrop and it is difficult to measure the thickness accurately. Algar & Pindell (1991) suggest an approximate thickness of 2000m but this may be excessive.
Type Locality: As now mapped, the Rio Seco Fm extends eastward from the Aripo River along the southern boundary of the Northern Range. At the western end of the outcrops it is faulted against Maracas Fm by the eastern extension of the Arima Fault, then from the Oropouche River to the Matura River it is thrust in a somewhat unclear manner against Maraval limestones, then successively outcrops against Maracas and Guayamara formations until it reaches the East Coast.
Age: Lower Cretaceous
Thickness: 500 feet
Type Locality: Laventille Hills, Five Islands,
Reference: Kugler, 1959, Potter, 1974, Algar& Pindell 1991, Wall &Sawkings 91860
Lithology and Depositional Environment:
The name Laventille is here restricted to the massive limestones with interbedded slates and shales that form the isolated hill in the eastern suburbs of Port of Spain, and then outcrop to the West in Five Islands, Carrera, Cronstadt and Point Gourde. They are considered to be equivalent to the conglomeratic limestones of Patos Island in Venezuela. The eastern boundary of the Laventille limestone in the Laventille Hills appears to be a stratigraphic feature - the edge of a platform limestone development which covers the whole of the Laventille hills area. However, in this area there are upper and lower limestone member separated by shales and slates of variable thickness. There appears to be an unconformity in the middle of the sequence during which the Lower Limestones are faulted, while neither the Middle slates nor the Upper Limestone are faulted. In the Lower Limestones there are also what appear to be pinnacle reefs over which the Middle slates are draped (Potter, 1974).
In addition, the limestones are underlain by phyllityic slates and overlain by similar rocks. These phyllites, slates and shales are now assigned to the Lopinot Fm which now extends eastwards to the Arima area. Formerly, as in Kugler's 1959 Geological map, the Laventille Fm included both the limestone and the shales and slates that continue in outcrop almost as far east as Arima. This practice was followed by Potter in 1974. These beds now fall within Algar & Pindell's Lopinot Fm (1991).
Type Locality: However, the shales and slates between the limestones in the Laventille Hills are mapped within the Laventille Fm. Minor ore deposits of fluorite and haematite occur in the Laventille Limestone on Gaspar Grande. Rare evaporites occur. Kugler observed lenses of gypsum at the foot of Gonzalez Quarry, and Gonzalez & Scott reported gypsum northeast of Fort Picton associated with graphitic shales. It is not clear what the tectonic position of these isolated evaporites.
Age: Barremian to Aptian
Reference: Kugler (1959), Potter (1974), Saunder, (1997), Algar& Pindell (1991)
Type Locality: Laventille Hills and running eastwards from along the southern margin of the Northern Range as far as Arima.
Lithology and Depositional Environment: This formation largely comprises slates, occasionally calcareous, with some interbedded siltstones and sandstones. Limestone beds are also present as at Champ Fleurs and west of St Joseph some bedded anhydrite and gypsum (couple meters thick) lay upright in contorted shales and slates.
These rocks were formerly mapped as part of the LaventilleFm by Kugler (1959) and maintained later by Potter (1974). However, palaeontological variations observed by Saunders led him to follow Algar& Pindell (1991) in using the Lopinot Formation as compared to the Tompire Member of the Toco Fm. used in 1972.
Age: Upper Cretaceous
Thickness: 220 m
Type Locality: These beds outcrop in the area between Laventille and San Juan in a number of small synclines.
Reference: Potter, 1974, Saunders, 1997
Lithology and Depositional Environment; The Morvant Formation comprise of coarse yellow to buff quartzitic sandstones, frequently in thick massive beds, and slates and shales that resemble similar rocks in the Galera Fm. It is likely that the Morvant Beds are the southwest equivalent of the Galera Formation and may also occur further west at the southern edge of the Lady Chancellor road where these beds appear to lie on the Chancellor Formation unconformable. Similar outcrops seem to be faulted against the Chancellor Formation and not in stratigraphic continuity as seen at Cocorite Bay.
Age: Upper Cretaceous
Type Locality: Galera, Toco
Reference: Barr 1963, Donovan and Jackson, 1994, Algar & pindell 1991
Lithology and Depositional Environment; The Galera Formation comprises non-calcareous, dark grey shales interbedded with occasional siltstones and quartzitic sandstones. Sandstones predominate in the lower part of the formation, the upper part of the section being shaley.
SANS SOUCI FORMATION
Age: Aptian to Santonian
Type Locality: San-Sousi, Gran Riviere
Reference: Liddle 1946, Wadge & Macdonald 1985, Donovan and Jackson, 1994
Lithology and Depositional Environment; The Sans Souci Formation represents the only outcrop of igneous rocks in Trinidad. The formation comprises massive basaltic volcaniclastics, basaltic lavas, intrusive gabbros and terrigenous sedimentary rocks, including limestones, shales, sandstones and conglomerates. The contact with the Toco Formation to the south is faulted.
Age: Berriasian–Early Aptian
Maridale Marl Member
La Carriere Shale Member
Thickness: 600-1500 m
Top: Overlain unconformably by the Gautier, Naparima Hill, Guayaguayare or Paleocene Lizard Springs Formation
Base: Post-syn rift Couva Evaporites.
Type Locality: Central Range, Cuche River
Reference: Hutchinson 1938b, Barr, 1952; Donovan and Jackson, 1994; Pindell et al. 2009,
Lithology and Depositional Environment: The Cuche Formation is comprises calcareous shales, marls, sandstones, nodular ironstones, anhydrite, massive limestone slip, masses, and calcareous mudstones. In the Central Range, the Cuche Formation comprise a sequence of dark shales with occasional intercalations of arkosic quartz arenites, and rare, exotic limestone blocks (Barr, 1952). The La Carriere Member comprises dull grey, calcareous, silty shales with occasional thin sandstones and nodular ironstone bands, carbonaceous partings and anhydrite. The upper part of the member is an increasingly calcareous mudstone, with intercalated arkosicquartzites. Rare, intraformational conglomerates comprise massive limestone blocks occurring as slip masses containing corals and caprinid and rudists. The Maridale Member includes belemnite bearing, foraminiferal marls and calcareous mudstones and outcrops in the core of the Central Range. Contacts are always faulted. The foraminifera indicate this member to be Upper Aptian to Lower Albian. The Cuche Formation is overlain unconformably by Upper Cretaceous shales and the Paleocene Chaudiere Formation (Donnovan and Jackson, 1994). May be correlative with the late Aptian to early Albian Garcia shale in Venezuela. The sediments of the Central Range Cuche could be derived from a southern sediment source if the shelf edge was at or near their site of deposition and subsequently back-stepped to the south. Pindell et al. 2009 interpret the coarse Cuche facies as south-derived flushes of material encased in shale.
Age: Upper Albian to Lower Cenomanian
Thickness: Up to 610 m
Top: Overlain unconformably by the Narapima Hill Formation
Base: Resting unconformably on the Cuche Formation
Reference: Bolli 1951a, Barr, 1952; Donovan and Jackson, 1994; Pindell et al. 2009
Lithology and Depositional Environment: The Gautier Formation is defined by bituminous and calcareous shales, sandy, conglomerates, and mudstones. This represents a deeper water facies and contains an abundant fauna of planktonic foraminifera of Upper Albian to Lower Cenomanian age. The Gautier Formation is separated from the overlying Naparima Hill Formation by a disconformity. The Gautier Formation consists of mudstones, sandstones and conglomerates and was deposited in a deep marine environment -most likely a slope setting (600 - 3,000 feet water depth). The Gautier like the Naparima Hill Formation was deposited during lowstands or periods of wetter climate in their sediment source areas.
NAPARIMA HILL FORMATION
Age: Turonian to Campanian
Thickness: 600 feet estimate
Top: Disconformably overlain Guayaguayare Formation or by Paleogene formations
Base: Resting uncomfortably on the Gautier Formation
Type Locality: San-Fernando Hill or Chert Hill Central Range (just for Campanian)
Reference: Kugler 1950, Donovan and Jackson, 1994; Pindell et al. 2009
Lithology and Depositional Environment: The Upper Cretaceous Naparima Hill Formation is a sequence of well-bedded, sometimes bituminous mudstones and shales, with some marls and bituminous lime. The upper part of this formation is made of silicified siltstone/claystone referred to colloquially as "argiline" or "argillite." Cherts are abundant in these upper layers. Biostratigraphic markers include both benthonic and planktonic foraminifera. The Turonian to Campanian Lower Naparima Hill Formations were deposited during lowstands or periods of wetter climate in their sediment source areas. Facies variations and the geometry of slump folds and slump faults, fold and fault vergence, ripples, and pebble orientation and imbrication in oriented cores all indicate southward derivation and that palaeobathymetry deepened to the north/northwest (Pindell et al., 2009). Fresh samples show darker grey streaks resulting from bioturbation. Locally it may be very cherty. It is considered to represent deep-water, quiet, uniform conditions of deposition during this period of the Upper Cretaceous. This Naprima Hill lithology is widespread, being found in wells in Trinidad and the Serraniadel Interior of Eastern Venezuela. It has also been seen from DSDP drill sites in the Southern Caribbean. Argillite is blue-grey when fresh, weathering to a buff colour. The lower part of the formation is made up of sandstones, siltstones, clays and shales, these coarse clastics are interpreted to have been deposited by turbidity currents.
Thickness: Estimated 120 m
Top: Overlain unconformably by the Lizards Springs
Base: Disconformably overlies the Naparima Hill Formation
Type Locality: Guayaguayare
Reference: Bolli 1952, Donnovan and Jackson, 1994
Lithology and Depositional Environment:
The Maastrichtian Guayaguayare Formation is a dark grey, calcareous shale, disconformable on the Naparima Hill Formation and unconformably overlain by the Lizard Springs Formation. Slip masses of Guayaguayare Formation occur in the Paleogene Chaudiere Formation. shale would have been widely deposited above the three previous Type I/II source rocks.
Age: Early Paleocene N16 - N 19 Zone
Thickness: Estimated 80 feet at Soldado Rock and 400 feet at Marac Quarry
Base: Unconformably on the Guayaguayare Formation
Type Localities: Soldado Rock, Marac Quarry Moruga
References: Kugler 1923a & 1938a, Maury 1925,
Lithology and Depositional Environment: Soldado Rock: Bed 1- Massive pale brown and whitish, impure glauconitic limestone, algal, with oyster shell fragments and echinoderm breccia. Upper beds highly glauconitic while lower bed not exposed at site. These features indicate inner shelf deposition within the influence of wave action.
Soldado Rock: Bed 2: Very glauconitic grey marl, irregular indurated with brownish pink mottled siltstone, sandy limestone and calcareous sandstone. Very fossiliferous unit with large foraminifer and molluscs observed.
Marc Quarry: Red, ferruginous, argillaceous limestone with plentiful ferruginous ooliths, molluscs, coguinoid, grading upward into light grey, argillaceous limestone with massive or poorly bedded, glauconitic with dispersed shell fragments and large nautaloids. Calcareous benthonic foraminifera with rare ostracods, rarer invertebrate and vertebrate remains are common. Basal unit is a highly glauconitic/ ferruginous carbonate deposited in inner-neritic environment above SWWB. Upper Marac mudstones to wackestones deposited in a deep setting within an inner-neretic shelf with progressively deepening suggested by decreasing carbonate units.
LIZARD SPRINGS FORMATION
Age: Early – Late Paleocene
Upper Lizard Springs
Lower Lizard Springs
Thickness: 370 m
Top: Overlain unconformably by Eocene to Oligocene Formation
Base: Unconformably overlying the Guayaguayare or older Cretaceous Formations
Type Locality: Lizard Springs Anticline Guayaguayare
References: Cushman & Renz 1946, Beckman, 1994; Donovan and Jackson, 1994
Lithology and Depositional Environment: Traditionally both members have been considered to represent deep water deposition of calcareous shales and marly facies of the aranaceous Chaudiere and Point-a-Pierre Formations. The lower Lizard Springs consists of weakly stratified greenish grey shales defined by a rich abundance of lower bathyal agglutinated foraminiferal assemblage which adds a greenish hue to the shale. The litho and biofacies grades vertically and laterally into medium grey shales and marls with mixed planktic – agglutinated poorly stratified calcareous bethic foraminiferal faunas. The more calcareous Lizard Springs facies comprises medium to dark grey, calcareous claystones/shales and light grey marls. Agglutinated foraminiferal faunas indicated Lower Lizard Springs deposited at a lower bathyal and possibly abyssal depths (>2,000 m). Similar evidence indicates Upper Lizards Springs deposited at middle to lower bathyal depths (500 – 2,000 m).
Age: Palaeocene – Early Eocene
Thickness: True thickness estimated 600 m from Mt. Harris 1 well
Members: St. Joseph Conglomerate
Top: Overlain by the Pointe-a-Pierre Formation
Base: Unconformably overlaying the Naparima Hill Formation
Reference: Kugler, 1956; Kugler 2001, Suter 1951
Type Locality: Mt. Harris, Chaudiere River
Lithology description: Dark grey to olive green, fine grained, well-bedded, non-calcareous slightly silty shales with alternating layers of fine-grained grit layers. (Kugler, 1956). The basal 10 m comprises the St Joseph Conglomerate Member which disconconformably overlies the Turonian to CampanianNaparima Hill Formation. The St Joseph Conglomerate comprises medium-grey, con-calcareous, silty, sub-rounded to angular dispersed clasts of Naparima Hill affinities as in grey- black chert and siliceous claystones. Sedimentology and agglutinated microfossils indicate mass-flow deposition as lower bathyal depth. This member is dated as being Early-Middle Palaeocene. Well-bedded quatzose sandstones less than 10 feet in thickness are present with graded bedding, weathering into rod like blocks with cubic fracturing. Some of the shale shave been discoloured to a tin-like colour which occur where hematiticclaystone layers show the original presence of iron sulphates. Generally a flysch deposit with dominant shale layers with thin, lower units of fine-grained, poorly bedded sandstones units and thicker coarse grained sandstone units to the top. These features as indicated with shales cut by irregular coarse grained sandstones, rip up shales, and fining upward units are indicative of turbidites.
Age: Early – Middle Eocene (Note some studies suggest latest Paleocene to Late Eocene)
Point- a- Pierre Sandstone
Thickness: 125 m estimated
Type Locality: Point-a-Pierre coast and Petrotrin’s Compound
References: Pindell and Keenan, 2009 and Illing, 1928.
Lithology and Depositional Environment: Charuma Silt Member: grey brown, non-calcareous, micromicaceousclaystone to silty claystone.
Point- a- Pierre Sandstone- Light to medium grey, non-calcareous, poorly to moderately sorted, medium to very coarse grained quartz sandstone and conglomerates, which usually are referred to as grits. These units are massive to thick bedded with angular to sub-angular quartziticclasts. Conglomerates with small, well-rounded, polished (grey-black to caramel brown) chert pebbles imbedded in the sandstone matrix is not uncommon. These coarse grained sandstones, conglomerates and fine grained interbedded units typically fine upwards as is common with Ta – Tb units of the Bouma Sequence. Likewise, well cemented, very hard, coarse grained sandstones have been observed in Nariva Formation which appear indistinguishable from the Point-a-Pierre but stable heavy mineral assemblage comprising ziron, tourmaline, and rulite as suggested by Pindel et al. (2009) ziron, tourmaline, rulite and ilmenite as suggested by Illing 1928 help to distinguish these from the Nariva. The Nariva comprises both stable and unstable heavy mineras as ziron, tourmaline, rulite and, garnet, chloritoid, staurolite, kyanite, glaucophane, apatite, epidote, corundum, monazite. Interbedded, non-calcareous blue – grey, micromicaceous claystones and silts are normal. These are usualy poorly fossiliferous or dominated by flysh type agglutinated foraminifers. This formation is characteristic of a bathyal, channelized turbidite deposition of Ta-Tb units of massive, poorly bedded coarse-grained sandstone and conglomerate units.
Age: Middle to Late Eocene
Hospital Hill Marls (P15 to basal P16)
Navet River Marl (P14)
Penitence Hill Marl (P13)
Fitt Trace Marl (P12)
Dunmore Hill Marl (P11)
Friendship Marl (P10)
Thickness: 300 m
Type Locality: Navet River
References: Kugler 2001, Saunders 1997
Lithology and Depositional Environment: Uniform, grey, hemipelagic chalks and marls rich in planktonic foraminifera, lesser agglutinants and even lesser calcareous benthonics with a few rich layers of radiolaria rich fauna. The Hospital Hill is greenish grey to light grey, nodular, indurated, marl or marlyclaystone which are poorly bedded. The Friendship Quarry marl is represented by chalk like beds and is practically indistinguishable from the Hospital Hill marls lithologically. Planktonic zonations are relied on to create the divisions. Penitence Hill Marl (P13) and the Fitt Trace Marl (P12) are defined by light grey to white, marly, chalky, blocky, well-bedded marls with chalky limestones as well as medium grey thin bedded marls interbedded at some intervals. One such level is defined by the abundance of glauconitic and phosphaticfaecal pellets. These were deposited in bathyal depths with shallow water sediment influxes being evident in the form of glauconite and Amphistegina sp.
SAN FERNANDO FORMATION
Age: Late Eocene
Members: Kugler 2001, Saunders 1997
Vistabella Limestone/ Marl
Mount Moriah sandstone
Thickness: 100 meters
Type Locality: Mount Moriah Hill, San-Fernando
Lithology and Depositional Environment: The Vistabella limestone and marls are dense, inner shelf limestones and highly fossiliferous, glauconitic marls, rich in algal nodules, abundant planktic and larger benthic foraminifers as well as macrofossils as echinoids.
Plaisance Conglomerate is defined by its polymict, pebble to boulders clasts embedded in a matrix of very poorly sorted granular to pebbly sandstone. Clasts are sub-rounded, and include, red clay ironstone which gives the rock its cherry cake appearance, also a fine-grained, non-calcareous, sandstone as well as a marly limestone, bioclastic limestone, shale and chert which are more than likely reworked Naparima Hill affinities. Reworked micro and marco faunas of Aptian, Cenomanian – Santonian, Maastrichtian, Paleocene, and Eocene ages have been recovered from clasts. Poorly sorted, polymictclasts as well as marine bioclasts recovered suggest that these facies were deposited as marine gravity flow. The rounded clasts indicate high energy wave abrasion while angular clasts may originate from proximal sub-marine fans or localised uplifts.
Mt. Moriah Sandstone is a light grey to green, fine to medium grained, hard, glauconitic orbitoid sandstone (95% glauconite) with some siltstone intervals. These are shallow marine deposits. These are exposed at Mt. Moriah San-Fernando, and at the southwest termination of the Central Range by the Mount Moriah boulder bed which is a conglomeratic facies comprised of argilline (siliceous mudstone) facies of the Naparima Hill Formation based on lithological similarities.
Age: Late Oligocene (P22) to Early Miocene (N3- N9)
Thickness: 1500 meters
Type Locality: Nariva Hill
Lithology and Depositional Environment: Dark grey to brown, non-calcareous, sometimes well-bedded, claystones with common sub-rounded quartz grains, thin to thick sandstone units and intermittent thin carbonaceous lignite beds up to 15 feet thick often associated with blanket sands. Foraminiferal evidence indicates middle to outer neretic deposition and sedimentological characteristics suggest gravity flow deposition of prodeltaic sediments. This formation is often associated with an unconformity at its base and may directly overlie rocks of Eocene through Cretaceous.
Age: Late Oligocene to Middle Miocene
Herrera Sandstone (N9 – N13)
Golconda Marl (N10 – N11)
Retrench Sandstone and Marl (N7 – N8)
Morne Diablo Limestone
Princess-Town Marl (N6-N7)
Mejias Limestone/ Kapur Limestone
Marabella Conglomerate/ Flat Rock Silty Marl
Top: Apparent normal contact with base of Lengua
Base: Overlying the Hospital Hill Marl of the Navet Formation and the San Fernando Formation
Thickness: 2,300 feet
Reference: Kugler 2001; Carr-Brown
Type Locality: exposed cliffs off the coast of San-Fernando and mouth of the Cipero River
Age and Planktic Zonations:
Upper Cipero: N8 – N12
Middle Cipero: N4 – N8
Lower Cipero: P17 – P22
Lithology and Depositional Environment: The Cipero formation predominantly comprises of light grey to grey green marls and very calcareous clays which contain non-calcareous, aranaceous, grey with brownish black grains, of well-bedded, fining upward sandstone or conglomeratic turbidite deposits as the Retrench and Herrera members. This represents deep-water calcareous ooze comprising a large composition of planktic and benthic calcareous foraminiferal tests. Orbitoidal faunas and reefal limestones are developed occasionally in the Cipero Formation. The basal unit occurs often as a dark brown silt and based on lithology resembles similar facies as Mt. Moriah Silt of the San-Fernando Frm.
The Golconda and Princess Town marls are mostly light grey to brown, blocky, bioturbated marls which are very rich in planktic foraminifera. Thin argillaceous beds of lithic arenites or lithic wackstones are exposed in the Golconda sections with burrows infiltrated by unconsolidated sands. Argillaceous limestone beds are also developed in these sections as very thin units.
The Retrench member exposed at Golconda along the Sir Solomon Hochoy Highway exists as greyish quartz arenites to lithic arenites and wackstone with some thin units of siltstones. The sandstone units have a salt and black pepper colour, are moderately sorted, with angular grains of quartz and chert and minor amounts of feldspars and micas. These are interpreted as Early Miocene intervals in some studies and Late Early Miocene to Early Middle Miocene units by others. The presence of Amphistegina sp. and shallow water foraminiferal affinities indicate shelfal derived sediments being transported as submarine turbidites into bathyal depths as deep as 1.5 km as suggested by bethonic foraminifera as Planulinawuellerstorfi.
The Herrera Sandstones are very fine grained to coarse grained, greyish black, moderately sorted, with angular grains of quartz and chert and minor amounts of feldspars and micas. These occur as arenites to lithic arenites and wackstones. Conglomeratic and shale pebble beds are sometimes found in this member. This is a proper representation of a deep water bathyal turbidite facies with proximal channelized Ta-Tb units of the Bouma sequence being observed in coarser sections and Tc Td and Te being observed in more distal units of the submarine fan complex.
These turbidite units are often associated with regression caused by eustatic or tectonic induced base level change or some incorporation of both. As such, some authors have even added their own turbidite members which occupy different intervals of the Cipero as in the ‘Oropouche Member’ which is dated as being just older than the Herrera but younger than the Retrench. Earlier work also suggested the Nariva Formation as the oldest member unit as it often interfingers with the Cipero in south of the southern flank of the Central Range. The Nariva is differentiated based on its agglutinated foraminiferal assemblage.
Age: Early to Middle Miocene (N5 – N12)
Navarro River Clay
Cumuto Road Limestone
Tunnel Hill Silty Clay
St Croix Limestone
Thickness: 1,150 m
Reference; Kugler 2001
Type Locality: Central Range
Lithology and Depositional environment: Poorly bedded, inky blue, silty calcareous shale with intercalations of calcareous shales with common macroscopic shell fragments as gastropods, thin-shelled bivalves, scaphopods, pteropods and small crabs as well as plant impressions. The Brasso is the shallow water equivalent of the Cipero Formation developed further north of it. It consists of medium to dark grey calcareous clays and silty clays with thin layers of conglomerates, sandstones, glauconitic sands and major reefal limestone. The limestone is interbedded with the Navarro River Clay and the Esmeralda Calacareous Clay Members. The St. Croix Limestone was described as light grey to brown calcareous clays with layers of clayey limestone, rich in molluscs or orbitoids. The calcareous clays contain rich, diverse benthic calcareous and agglutinated foraminifera. The Biche Limestone consists of masiive, nodular, light grey, bioclastic, argillaceous, thin-bedded, nodular limestone with orange coloured marls. Lager benthic foraminifera and macrofossils as albal balls, bivalves, gastropods, and oysters are abundant with small amounts of plant matter.
Age: Middle Miocene
Thickness: 2,000 feet
Type Locality: Lengua, Princess Town
Lithology and Depositional Environment: Greenish grey calcareous claystone and mar with rich planktonic foraminifera indicative of upper to middle bathyal deposition. This formation is unconformable with the underlying Brasso or Cipero Formations and grades laterally south-eastward into the Karamat Frm., which is dominated by agglutinated benthic foraminiferal faunas. Upper and Lower Lenguamembersinterfingers laterally with the Concord Frm., limestones, siltstones and marls. The upper Lengua calcareous claystones grade upward and interdigitate with the Late Miocene Lower Cruse Formation which is a deltaic marine facies.
Age: Late Miocene
Thickness: 1,200 m
Top: Overlain by Lengua Formation
Base: Overlying the CiperoForrmation
Reference: Donovan and Jackson, 1994
Lithology and Depositional Environment: The Karamat Formation is a non-calcareous, greenish grey clay. Silty sand lenses in the lower part of the formation are late Herrera Sand units. Included olistoliths are of Upper Cretaceous to Lower Miocene. The distinctive fauna comprises arenaceousforaminiferans. The formation has a maximum thickness of about 1,200 m. The lack of calcium carbonate is in contrast to the underlying Cipero and overlying Lengua Formations.
Age: Late Miocene (N16) to Early Pliocene (N18)
Top: Overlain by the Forest Formation
Base: Overlying the Lengua Formation
Thickness: 1,430 min Palo-Seco to 6,000 feet in Erin
Top: Underlying the Lower Forest Clay of the Forest Formation
Base: Overlying the Lengua Formation
Type Locality: Penal Rock Road
Reference: Macready 1921, Kugler 1956, Kugler 2001
Lithology and Depositional Environment: This formation comprises sandstones, siltstones and claystones parasequences encompassing a variety of deposits from basin-floor fan, to slope fans and muds, to shelfal siltstones and claystones. The upper Cruse is dominate by a dark grey, non-calcareous shale with irregular nodules of hard grey claystone. The Lower Cruse contains mainly grey to black, gypsiferous clays which weather brownish yellow to red with common silty clays and silts and sandstone units which coarsen upward into thick sandstone units of the Upper Cruse. Cruse represents a large scale shallowing up, basin fill sequence. It is dominated by incised shelfal deposits, slope fans and mid neritic submarine fans. The Lower Cruse Member encompasses mostly slope and basin floor claystones and siltstones with slope incised turbidites and basin floor submarine fans. The Lower Cruse Member is less sand dominated than the overlying section and the sands are more laterally constrained. The Middle and Upper Cruse Members are increasingly sand dominated, reflecting the overall shallowing upwards and progressive basin facies shifts and basin fill. The middle and lower part of the Upper Cruse comprises upper slope and mid - outer shelf silts and clays with shelf incised turbidites, shelfal turbidites and detached coastal zone derived olistoliths. The highest part of the Cruse comprises inner shelf and transition zone silts with well-developed parasequences stacked coastal sand sequences. The formation is difficult to define on petrophysical logs in relation to the lowermost Lengua Formation and the internal member units as significant basin/landward facies shifts are difficult to identify. The overlying Lower Forest Clay is highly transgressive with respect to the underlying Upper Cruse, representing a major landward facies shift and may also be associated with unconformity. The Moruga and Mayaro Formations inclusive of the GrosMorne Formation are considered lateral equivalents of the Upper and Middle - Lower Cruse Members.
GROS MORNE FORMATION
Age: Early Pliocene
Middle GrosMorne Silts
Lower GrosMorneTop: Overlain by the Lawaii Clay of the Mayaro Formation
Base: The Lower Cruse/Roseau Formation
Reference: Kugler 1956, Kugler 2001
Lithology and Depositional Environment: The GrosMorne Formation comprises medium to fine grained, coastal sandstones with inrregular interbedded submarine shelf and slope fan deposits. The Middle GrosMorne interbedded silts are of middle to outer shelfal/neritic origin. The sand dominated sequences of the Lower GrosMorne represent a shift in facies from the Lower Cruse claystones. The upper limit of the formation represents a transgression into the Lawaii Clay. Kugler (1959) mapped the GrosMorne as comprising the basal unit of the Moruga Formation which was later adjusted through greater access to well-logs and subsurface data. The Upper GrosMorne is considered to be the equivalent in age and stratigraphy of the Trinity Hill Sandstone, whilst the St. Hilaire Silt can be correlated with the Middle GrosMorne Silts based on structure and straigraphy.
Age: Early Pliocene N18
Casa Cruz Sandstone
Las Tablas Silt
Trinity Hill Sandstone
St. Hilaire Silt
Thickness: 3,000 feet
Top: Overlain by the transgressive Palmiste Clay member of the Palmiste Formation
Base: Overlies shaly Roseau Formation
Type Locality: Sandstone Quarry, 1 mile north of Moruga Village, South Coast.
Reference: Kugler 1956, Kugler 2001; Saunders 1997
Lithology and Depositional Environment: The Moruga Formation comprises interbedded sandstone and siltstone sequences which are aggradationally stacked. These units were formed in sand dominated, neritic settings where thick coastal sand complexes formed in response to concurrent accommodation space resulting from continued growth faulting. The oldest members of the formation, the GrosMorne Silt and GrosMorne sandstone were defined by Kugler (1959) and later defined by a facies change from the shale dominated sequences of the Roseau Formation in the subsurface. The St. Hilaire sandstone member comprises shelfal and slope siltstone and sandstones. The Casa Cruz Sandstone Member is separated from the St Hilaire Sandstone by the Las TablasSiltone which encompasses very fine grained sandstones and siltstones of middle to outer shelf origin and with at least two regional flooding surfaces. The Moruga Formation is interpreted to be equivalent to the Lower - Middle Cruse and entire Upper Cruse Formation to the west and the Mayaro Formation to the east based on growth faulting patterns and depositional stratigraphy. The Casa Cruz Sandstone is thought to be correlative of the Mayaro Sandstone; the Las Tablas Silt correlative of the Lawai Clay; the Trinity Hill Sandstone correlative of the Upper GrosMorne and the St Hilaire Silt correlative of the Middle GrosMorne Silt.
Age: Early - Late Pliocene (intra N18)
Lower Forest Clay
Base: Unconformably overlies the Cruse Formation
Type Locality: Forest Reserve Field/ Penal
Reference: Macready G. A. 1921, Bower 1968, Kugler 1956, Kugler 1959, Kugler 2001.
Lithology and Depositional Environment: Thick sequence of marine, shelfal to slope sandstones and claystones. The Lower Forest Clay represents a flooding event overlying the Cruse Formation. The Upper Forest claystones and Forest siltsones, are now recognised by most authors in the MorneL'Enfer Formation. Forest Formation exists in the Southern Basin, in areas west and north of the Rock Dome Anticline but lithostratigraphic continuity of the Forest facies has been made with the Palmiste Formation to the east.
Age: Late Miocene to intra Early Pliocene
Monserrat Glauconitic Sandstone
San Jose Calcareous Siltstone
Thickness: 5,000 feet
Type Locality: Manzanilla Coast, East Trinidad
Top: Unconformably overlain by the Springvale Formation
Base: Overlies the Brasso Formation with minor unconformity
Reference: Waring 1926, Kugler 1959, Kugler, 2001
Lithology and Depositional Environment: Clastic sedimentary, deltaic unit
The Manzanilla formation comprises calcareous silts and sands in the lower part, overlain by glauconitic sands and bluish black silty clays, locally highly fossiliferous. The basal San Jose Calcareous Siltstones comprises fossiliferous silts and sands, overlain by the glauconitic sandstone units of the Montserrat Glauconitic Sandstone which in turn is overlain by the interbedded silty claystones and sandstones of the Telemaque Sandstone which also contains lignite in its uppermost beds.
This formation represents a regressive, shallowing upward sequence. It transitions from open marine shelf siltstones/ mudstones to marginal marine deposits often associated with fluvial and coastal sandstone parasequences. Common bedforms include hummocky cross stratification and symmetrical ripples indicative of storm influenced open coast conditions. Interfingering coarse-grained lithic-rich deposits comprising of vein quartz and schistose fragments strongly suggests direct input from the Northern Range. These deposits take the form of coarse-grained debris flows or finer-grained turbidite beds. Lignite and mud drapes in the upper part of the formation indicate that there was significant river influence which introduced mud and organic matter to the delta. Coarsening upward parasequences are well developed throughout the formation especially noticeable in the lowermost interval. Facies change from pro-delta sediments at the base up into the Telemaque Member. The overlying Springvale Formation represents a marine transgressive sandstone/claystone unit. The Formation is known as a hydrocarbon reservoir within fields in Gulf of Paria and Northern Basin.
Age: Early to Late Pliocene, N18/N19 age for part of the Formation (Saunders & Muller-Merz 1979). Equivalent in age to the Palmiste Formation of the Southern Basin.
Savaneta Glauconitic Sandstone
Top: Unconformably overlain by Talparo Formation
Base: Unconformably overlying the Telemaque Sandstone of the Manzanilla Formation
Type Locality: Various, depending on Member (Kugler 2001)
Reference: Guppy 1910, Renz 1942, Kugler 1959, Kugler 2001
Lithology and Depositional Environment: The Springvale Formation is present in the Northern Basin of Trinidad with the Gransaul Clay interpreted to equate with the Forest Formation and the higher parts of the Springvale Fm with the MorneL'Enfer Fm. The shell bed of the Savaneta Glauconitic Sandstone Member is well developed in the west of the island where it unconformably overlies the Manzanilla Formation. The Gransaull Member has been mapped as representing the whole formation in the east of the Northern Basin. The formation comprises interbedded successions of glauconitic sandstones, lignites, claystones and shell beds. Facies within the Springvale reflect esturine environments with strong tidal influence.
MORNE L'ENFER FORMATION
Age: Late Pliocene - Early Pleistocene
Upper MorneL'Enfer Sandstone
Lot 7 Silt
Lower MorneL'Enfer Sandstone
Upper Forest Clay
Top: Overlain unconformably by the Erin Formation
Base: Transitional from the Forest Formation
Type Locality: MorneL'Enfer Hill. Co type localities, Erin and Cedros bays
Reference: Macready G. A. 1921, Bower 1968, Kugler 1959, Kugler 2001, Vincent et al., 20087, Vincent 2008, Si Chen 2014, Si Chen 2015; Dasgupta 2016.
Lithology and Depositional Environment: The MorneL'Enfer Formation can be considered one of the better described rock units in Trinidad with multiple publications ranging from the early 20th century to recent. It is one of the few stratigraphic units that are superbly exposed both along coasts and inland outcrops alongside hundreds of subsurface well penetrations. The various members of the MorneL'Enfer Formation comprise variably bioturbated sand, silt and claystone beds arranged within multiple coarsening and thickening-upward or aggradational deltaic successions that represent one of the later stages of basin infill (relative to the Cruse and Forest formations). Depositional environments range from prodelta, delta front and delta top environments. The delta top is evidenced by excellent exposures of distributary and estuarine channels, and lagoonal muds that are most prominent within the Upper MorneL'Enfer Member. The sequence stratigraphy of the formation is also well known, as key flooding events (e.g. Lot 7 Silt Member) and unconformities are well described. The formation is best known for the oil sand resources that are mined from two quarries in the Guapo area, both within the Lower MorneL'Enfer Member. The Upper MorneL'Enfer also hosts the famous La Brea pitch lake. Otherwise, the sands of the MorneL'Enfer Formation form hydrocarbon reservoirs in fields of the southern Gulf of Paria.
Age: Early Pliocene N18
Top: Unconformably underlying the Plamiste Clay member of the Palmiste Formation
Base: Overlying the GrosMorne Formation
Type Locality: Mayaro Bay
Reference: Kugler 1956, Kugler 1959, Carr- Brown 1995. Carr-Brown 1995, Wood, 2000; Kugler 2001; Sydow et al., 2004; Bowman, 2004, 2014; Dasgupta 2016
Lithology and Depositional Environment: Deltaic sandstones and mudstone successions comprising stacked shallowing up cycles. The Lawai Clay Member is the oldest unit within the Formation, comprising mid - outer shelf clays and silts. This Member is is correlative with the Las Tablas silt whilst the Mayaro Sandstone is equivalent to the Casa Cruz Sandstone.
The Mayaro Formation is best exposed along Mayaro Bay north of the Galeota Complex facility. The formation is interpreted as stacked prodelta to delta front successions deposited within a high-accommodation setting at or adjacent to the depositional shelf edge and associated with syntectonic growth faults. It has become renown as one of the global type exposures of shelf edge deltas. Lithofacies are predominantly amalgamated swaley and hummocky cross stratified sandstones, though wave ripples, ball and pillow structures, contorted beds and low density turbidites are also common.
Age: Early Pliocene - Late Pliocene
Member: Palmiste Clay
Thickness: 900 m
Top: Overlain by the Mayaro Formation
Base: Unconformably overlies Karamat Formation
Type Locality: Mayaro Bay
Reference: Carr-Brown & Young-On 1995, Kugler 1959, Payne, 1991.
Lithology and Depositional Environment:
Description: The Palmiste Formation comprises interbedded claystone, siltstone and sandstone units of open marine shelf and slope origin. This formation was formerly assigned to the Talparo Formation (Kugler 1959) but Carr-Brown, 1995, assigned Formation status to the Palmiste Clay Member. The basal formation contact is unconformable. The Formation is interpreted as the chronostratigraphic equivalent to the Forest Formation and may also be equivalent to the lower part of the as a MorneL'Enfer Formation (Upper Forest Clay and MorneL'Enfer Silt Members). The upper parasequences are not exposed onshore and thought to be associated with an unconformity with the equivalent units being deposited further east in the Poui/Teak gas fields. It represents a progradational phase of deposition
Age: Early Pleistocene equivalent to the Erin Formation of the Southern Basin
Thickness: 425 m
Chin Chin Clay
Sum Sum Sand
Thickness: 1200m thick
Top: Unconformity with the Pleistocene Terraces of the Cedros Formation overlying
Base: Rests unconformably on the Springvale Formation
Type Locality: Mahaica Area, Caroni Basin
Reference: Renz 1942, Kugler 1956, Kugler 1959, Kugler 2001, McClean ?2016, 2018;
Lithology and Depositional Environment: Parasequences of sandstones, siltstones and claystones which are often lignitic at many intervals. These deposits constitute a variety of shallow marine, lower delta plain - transition zone and continental deposits. The Sum Sum Sand Member comprises a sand dominated sequence of a fluvial, braided stream complex inter-fingering with transition zone facies and forms a widespread lithostratigraphic marker. The base represents an unconformity, with a subsequent shift in facies from the marine dominated Springvale Formation to the shallow marine, transition zone and continental deposits of the Talparo. The upper limit of the Formation is defined by unconformity with the Pleistocene Terraces of the Cedros Formation. The basal contact/unconformity is considered to represent a tectonically enhanced sequence boundary (1.65 M.Y.) coincident with the major sea level fall at the beginning of the Pleistocene. The Talparo Formation is best known for the multiple red sand quarries across the Northern Basin, from which almost all of the red sand used for construction, is acquired. The Formation is also an important aquifer in parts of the Northern Basin.
Age: Latest Pleistocene - Holocene
Top: Alluvium/ Sub-aerial exposure
Base: Unconformably overlying the Talparo Frm.
Type Locality: Cedros and extensively along the southern margins of the Northern Range, Siparia, or Forest Reserve
Reference: Liddle R. A. 1928, Kugler 1956, Kugler 1959, Kugler 2001
Lithology and Depositional Environment: Poorly bedded, red to brown, very poorly consolidated, ferrigenous sandstones of continental and marine origin. These are terrace deposits formed at varying heights above sea level but comprising predominantly comprise marine inner shelf and shore face deposits.
Age: Early to Late Pleistocene
Thickness: 3,470 feet
Top: Unconformably overlain by the Cedros Formation/ Alluvium
Base: overlying the Upper MorneL'Enfer Formation at Esperanza and Erin bays.
Type Locality: Cedros Point
Reference: Kugler 1956, Kugler 1959, Kugler 2001, McClean 2016, McClean 2018
The Erin Formation is the chronostratigraphic equivalent to the Talparo Formation of the Northern Basin. It comprises a clastic succession of sands, silts, clays and lignites predominantly of coastal and transition zone, to lower delta plain origin. The Erin/Upper MorneL'Enfer Member contact at Esperanza Bay occurs just south of Cedros Point porcellanites. The base of the Erin is described as the base of a sandstone overlying shallow marine/transition zone clay, which marks the top of the Upper MorneL'Enfer Sandstone. Kugler (2001) did not recognized a distinctive linear contact, though refers to changes in bedding styles that are characteristic of the Erin Formation. These include the occurrence of lenticular bedset geometries with common cross bedding and mud clasts, a facies association that is not common to the underlying MorneL’Enfer. A similar change in lithofacies and sedimentary structures can be observed at Erin Bay around Quoin Cliff porcellanite deposits, usually interpreted as the base of the Erin Formation. The Erin Formation comprise predominantly tide dominated fluvio-estuarine sediments, with rare marine incursions (McClean 2017). Regionally, the Erin differs from the underlying deltaic successions in bedding styles, sedimentology and palaeocurrentsand represents one of the final stages of basin infilling that occurred during the Plio-Pleistocene. It can be considered a topsethighstand deposit in sequence stratigraphic terms, though may also be representative of a basinallowstand given the predominant shallow water facies and shifts palaeocurrents.
TECTONOSTRATIGRAPHIC UNITS/ BASINS
Northern Basin/ GOP Pull Apart Basin/ Caroni Plains
Columbus Basin/ East Coast offshore stratigraphy
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