FORMATIONS OF TRINIDAD AND TOBAGO

MARAVAL FORMATION

Age: Upper Jurassic

Members:

Cauralimestone

Hollis conglomeratic limestone

Aripo limestone

Maraval beds

(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).

 

MARACAS FM

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.

 

GUAYAMAR FM

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.

 

CHANCELLOR FM

Age: Lower Cretaceous

Members:

Upper phyllitic beds

Upper limestone sequence

Phyllite member

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.

 

LAVENTILLE FM

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.

 

LOPINOT FM

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.

 

MORVANT BEDS

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.

 

GALERA FORMATION

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. 

 

CUCHE FORMATION

Age: Berriasian–Early Aptian

Members:

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.

 

GAUTIER FORMATION

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.

 

GUAYAGUAYARE FORMATION

Age: Maastrichtian

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.

 

SOLDADO FORMATION:

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

Members:

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).

 

CHAUDIERE FORMATION

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.

 

POINTE-A-PIERRE FORMATION

Age: Early – Middle Eocene (Note some studies suggest latest Paleocene to Late Eocene)

Members:

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.

 

NAVET FORMATION

Age: Middle to Late Eocene

Members: 

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

Plaisance conglomerate

Mount Moriah sandstone

Thickness: 100 meters

Type Locality: Mount Moriah Hill, San-Fernando

References:

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.

 

NARIVA FORMATION

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.

 

CIPERO FORMATION

Age: Late Oligocene to Middle Miocene

Members:

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

Paradise Marl

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.

 

BRASSO FORMATION

Age: Early to Middle Miocene (N5 – N12)

Members: 

Navarro River Clay

Cumuto Road Limestone

Corial Limestone

Biche Limestone

Tunnel Hill Silty Clay

St Croix Limestone

Guaracara

Tamana

Briggand Hill

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.

 

LENGUA FORMARTON

Age: Middle Miocene

Members:

Upper Lengua

Lower Lengua

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.

 

KARAMAT FORMATION

Age: Late Miocene

Thickness: 1,200 m

Top: Overlain by Lengua Formation

Base: Overlying the CiperoForrmation

Type Locality:

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.

 

 

CRUSE FORMATION

Age: Late Miocene (N16) to Early Pliocene (N18)

Members:

Upper Cruse

Middle Cruse

Lower Cruse

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

Member:

Upper GrosMorne

Middle GrosMorne Silts

Lower GrosMorneTop: Overlain by the Lawaii Clay of the Mayaro Formation

Base: The Lower Cruse/Roseau Formation

Type Locality:

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.

 

MORUGA FORMATION

Age: Early Pliocene N18

Member:

Casa Cruz Sandstone

Las Tablas Silt

Trinity Hill Sandstone

St. Hilaire Silt

GrosMorne Sandstone

GrosMorne 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.

 

FOREST FORMATION

Age: Early - Late Pliocene (intra N18)

Member:

Forest Sands

Lower Forest Clay

Top: MorneL’Enfer

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. 

 

MANZANILLA FORMATION

Age: Late Miocene to intra Early Pliocene

Members:

Telemaque Sandstone

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. 

 

SPRINGVALE FORMATION

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.

Members:

Chickland Clay

Savaneta Glauconitic Sandstone

Gransaull Clay

Thickness: 600m

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

Members:

Upper MorneL'Enfer Sandstone

Lot 7 Silt        

Lower MorneL'Enfer Sandstone

MorneL'Enfer Silt

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.

 

MAYARO FORMATION

Age: Early Pliocene N18

Member:

Mayaro Sandstone

Lawai Clay

Thickness:

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. 

 

PALMISTE FORMATION

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 

 

TALPARO FORMATION

Age: Early Pleistocene equivalent to the Erin Formation of the Southern Basin

Thickness: 425 m

Members:

Chin Chin Clay

Sum Sum Sand

Caparo Clay

Durham 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.

 

CEDROS FORMATION

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.

 

ERIN FORMATION

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 Coast

Northern Range

Northern Basin/ GOP Pull Apart Basin/ Caroni Plains

Central Range

Southern Basin

Columbus Basin/ East Coast offshore stratigraphy

References

Ager, D.V. 1981.The nature of the stratigraphic record (2nd edition).Macmillan, London, xiv+122 pp.

 Ahmad, R. 1988. Kinematic history of the Northern Range, Trinidad.Abstracts, Recent Advances in Caribbean Geology, Kingston, Jamaica, 18th-20th November, 1-2.

 Ahmad, R. 1991. Structural styles in Trinidad: in Gillezeau, K. A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-of- Spain, Trinidad, April 3-8, 1990, 244-265.

 Algar, S.T. & Pindell, J.L. 199la. Structural development of the Northern Range of Trinidad, and implications for the tectonic evolution of the southeastern Caribbean: in Gillezeau, K. A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-of-Spain, Trinidad, April 3-8, 1990, 6- 22.

 Algar, S.T. & Pindell, J.L. 1991b. Stratigraphy and sedimentology of the Toco region of the Northern Range, N.E. Trinidad: in Gillezeau, K. A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-of-Spain, Trinidad, April 3- 8, 1990, 56-69.

 Barker, M.H.S. & Roberts, K.H. 1968. Excursion 6A south Trinidad: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-ofSpain, Trinidad, 28th March-12th April, 1965, 438- 441.

 Barr, K.W. 1952. Limestone blocks in the Lower Cretaceous Cuche Formation of the Central Range, Trinidad, B.W.I. Geological Magazine, 89, 417-425.

Barr, K.W. 1966. A cross-section through the Northern 1-10.

Bartenstein, H., Bettenstaedt, F. & Belli, H.M. 1957. Die Foraminiferan der Unterkreide von Trinidad, B.W.I. ErsterTeil: Cuche- and Toco-Formation. EclogaeGeologicaeHelvetiae, 50, 5-67.

Bartenstein, H., Bettenstaedt, F. &Bolli, H.M. 1966. Die Foraminiferen der Unterkreide von Trinidad, W.I. ZweiterTeil: Maridale-Formation (Typlokalitat). EclogaeGeologicaeHelvetiae, 59, 129-178.

Batjes, D.A.J. 1968. Palaeoecology of foraminiferal assemblages in the late Miocene Cruse and Forest Formations of Trinidad, Antilles: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of-Spain, Trinidad, 28th March-12th April, 1965, 141-156.

 Bertrand, W.G. 1985. Geology of the Point Fortin Field: in Transactions of the Fourth Latin American Geological Conference, Port-of-Spain, Trinidad, 7th-15th July, 1979,2, 690-699.

 Bower, T.H. & Hunter, V.F. 1968. Geology of Texaco Forest Reserve Field, Trinidad, W.I.: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of-Spain, Trinidad, 28th Marchnth April, 1965,75-86.

 Bray, R. & Eva, A. 1989. Age, depsoitional environment, and tectonic significance of the Couva marine evaporite, offshore Trinidad: in Duque-Caro, H. (ed.), Transactions of the Tenth Caribbean Geological Conference, Cartagena de Indias, Columbia, 14th-22nd August, 1983, p. 372. INGEOMINAS, Bogota.

 Burke, K., Cooper, C., Dewey, J.F., Mann, P. & Pindell, J.L. 1984.Caribbean tectonics and relative plate motions. Geological Society of America Memoir, 162, 31-63.

 Carr-Brown, B. & Frampton, J. 1979.An outline of the stratigraphy of Trinidad. Field Guide, Fourth Latin American Geological Conference, Port-of-Spain, Trinidad, 7th-15th July, 12pp.

Carr-Brown, B. & Young-On, V. 1990. Age and stratigraphic status of the Palmiste Formation, Trinidad, West Indies: in Larue, D.K. & Draper, G. (eds), Transactions of the Twelth Caribbean Geological Conference, St. Croix, U.S. Virgin Islands, 7th-llth August, 1989, p. 534. Miami Geological Society, Florida.

 Case, I.E., Holcombe, T.L. & Martin, R.G. 1984. Map of geologic provinces in the Caribbean region. Geological Society of America Memoir, 162, 1-30.

 Chaitan, W.B. &Graterol, V.R. 1991. A gravity investigation of the pitch lake of Trinidad and Tobago: in Gillezeau, K. A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-of- Spain, Trinidad, April 3-8, 1990, 49.

Farfan, P. & Bally, K. 1991. An outline of the geology of the Samaan Field, Trinidad West Indies: in Gillezeau, K.A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-of- Spain, Trinidad, April 3-8, 1990, 139-156.

 Frey, M., Saunders, J. &Schwander, H. 1988.The mineralogy and metamorphic geology of low-grade metasediments, Northern Range, Trinidad. Journal of the Geological Society, London, 145, 563-575. 25Frost, C.D. &Snoke, A.W. 1989. Tobago, West Indies, a fragment of a Mesozoic oceanic island arc: petrochemical evidence. Journal of the Geological Society, London, 146, 953-964.

 Furrer, M.A. 1968. Paleontology of some limestones and calcphyllites of the Northern Range of Trinidad, West Indies: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of Spain, Trinidad, 28th March-12th April, 1965,21-24.

 Harland, W.B., Armstrong, R.L., Cox, A.V., Craig, L.E., Smith, A.G. & Smith, D.G. 1990. A geologic time scale 1989. Cambridge University Press, Cambridge, xvi+263 pp.

 Higgins, G.E. & Saunders, J.B. 1967. Report on the 1964 Chatham Mud Island, Erin Bay, Trinidad, West Indies. American Association of Petroleum Geologists Bulletin, 51, 55-64.

 Higgins, G.E. & Saunders, J.B. 1968. Excursion no. 4 western Central Range: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of-Spain, Trinidad, 28th March-12th April, 1965,435-437.

 Hosein, F. 1990. Exploitation of the Middle Miocene oil bearing intermediate Herrera Sandstone reservoirs in Trinidad, West Indies: in Larue, D.K. & Draper, G. (eds), Transactions of the Twelth Caribbean Geological Conference, St. Croix, U.S. Virgin Islands, 7th-llth August, 1989, 430-443. Miami Geological Society, Florida.

Imlay, R.W. 1954. Barremian ammonites from Trinidad, British West Indies.Journal of Paleontology, 28,662- 667.

 Jackson, T.A., Smith, T.E. & Duke, M.J.M. 1991. The geochemistry of ametavolcanic horizon in the Maracas Formation, Northern Range, Trinidad: evidence of ocean floor basalt activity: in Gillezeau, K.A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Portof-Spain, Trinidad, April 3-8, 1990, 42-41.

Jones, H.P. 1968. The geology of the Herrera Sands in the Moruga West Oilfield of south Trinidad: in Saunders, 226 Trinidad J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of-Spain, Trinidad, 28th Marcel2th April 1965, 91-100.

 Kerr, P.P., Drew, I.M. & Richardson, D.S. 1970.Mud volcano clay, Trinidad, West Indies.American Association of Petroleum Geologists Bulletin, 54, 2101- 2110.

 Kirmani, K.U. 1985. Geology of the Inniss, Catshill and BalataEast Oilfields in Trinidad, West Indies: in Transactions of the Fourth Latin American Geological Conference, Port-of-Spain, Trinidad, 7th-15th July, 1979, 2,700-713.

 Kuarsingh, H.B. 1990. The sedimentology and patrology [sic] of the Herrera Sandstones of Trinidad W.I.: in Lame, D.K. & Draper, G. (eds), Transactions of the Twelfth Caribbean Geological Conference, St. Croix, U.S. Virgin Islands, 7th-llth August, 1989, p. 551. Miami Geological Society, Florida.

 Kugler, H.G. 1953. Jurassic to Recent sedimentary environments of Trinidad.VereinigungSchweizerische Petroleum-Geologie und Ingenier Bulletin, 20 (59), 27-60.

 Kugler, H.G. 1956a. Trinidad—La Trinite with a map: in Beckmann et aL, LexiqueStratigraphique International, AmeriqueLatine, Fascicule 2b, Antilles, 41-116, 1 pl. CNRS, Paris.

 Kugler, H.G. 1956b. Trinidad. Geological Society of America Memoir, 65,351-365,1 pl. 40Kugler, H.G. 1961. Geological map of Trinidad, scale 1:100,000. Petroleum Association of Trinidad.

Kugler, H.G. 1968. Sedimentary volcanism: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of-Spain, Trinidad, 28th March-12th April, 1965,11-13.

 Liska, R.D. 1987. The Cipero and LenguaFormations and the middle late Miocene boundary: in DuqueCaro, H. (ed.), Transactions of the Tenth/Caribbean Geological Conference, Cartagena de Indias, Columbia, 14th-22ndAugust, 1983, 204-209. INGEOMINAS, Bogota.

 Liska, R.D. 1988. The Rio Claro Boulder Bed of central Trinidad, a sedimentary or tectonic event: in Barker, L. (ed.), Transactions of the Eleventh Caribbean Geological Conference, Dover Beach, Barbados, 20th-25th July, 1986,12.1-12.7.

Liska, R.D. 1991. The history, age and significance of the Globorotalia menardii Zone in Trinidad and Tobago, West Indies. Micropaleontology, 37, 173-182. 45Michelson, J.E. 1976.Miocene deltaic oil habitat, Trinidad. American Association of Petroleum Geologists Bulletin, 60, 1502-1519.

 Nath, M. 1985. Production geology of the Coora/Quany Field: in Transactions of the Fourth Latin American Geological Conference, Port-of-Spain, Trinidad, 7th15th July, 1979,2, 726-737.

 Persad, K.M. 1985. Outline of the geology of the Trinidad area: in Transactions of the Fourth Latin American Geological Conference, Port-of-Spain, Trinidad, 7th-15th July, 7979,2,738-758.

 Persad, K.M. 1988. Tectonosedimentary evolution of Trinidad and Tobago.Abstracts, Recent Advances in Caribbean Geology, Kingston, Jamaica, 18th-20th November, 20-21.

 Persad, K.M. 1989. 1990 Trinidad and Tobago petroleum consultants encyclopedia. Petroleum Consultants Trinidad Limited.

 Pindell, J.L. & Barrett, S.F. 1990. Geological evolution of the Caribbean region; a plate-tectonic perspective: in Dengo, G. & Case, J.E. (eds), The geology of North America, Volume H, The Caribbean region, 405-432. Geological Society of America, Boulder.

 Poole, W.G. 1968. Some sedimentary features of the Herrera Sands of the Clarke Road area, Barrackpore Oilfield; Trinidad, West Indies: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of- Spain, Trinidad, 227 Caribbean plate boundary. American Association of Petroleum Geologists Bulletin, 73, 490-509. 28th March-12th April, 1965,101-109.

 Potter, H.C. 1968. A preliminary account of the stratigraphy and structure of the eastern part of the Northern Range, Trinidad: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Portof-Spain, Trinidad, 28th March-12th April, 1965, 15- 20.

 Potter, H.C. 1973. The overturned anticline of the Northern Range of Trinidad near Port of Spain. Journal of the Geological Society, London, 129, 133-138.

 Potter, H.C. 1976. Type sections of the Maraval, Maracas and Chancellor Formations in the Caribbean Group of the Northern Range of Trinidad: in Cauusse, R. (ed.), Transactions of the Seventh Caribbean Geological Conference, Guadeloupe, 30th June-12th July, 1974, 505-527. B.R.G.M., Orleans.

 Potter, H.C. 1985. The geology of the central part of the Northern Range, Trinidad: in Transactions of the Fourth Latin American Geological Conference, Port-of-Spain, Trinidad, 7th-15th July, 1979, 1, 102-105.

 Radovsky, B. &Iqbal, J. 1985. Geology of the North Soldado Field: in Transactions of the Fourth Latin American Geological Conference, Port-of Spain, Trinidad, 7th-15thJuly, 7979,2, 759-769.

 Rambarran, H. 1985. Geology of the Parrylands Field: in Transactions of the Fourth Latin American Geological Conference, Port-of-Spain, Trinidad, 7th-15th July, 1979,2, 770-780.

 Robertson, P. & Burke, K. 1989.Evolution of southernRobertson, P., Burke, K. &Wadge, G. 1986. Structure of the Melajo Clay near Arima, Trinidad and strike-slip motion in the El Pilar Fault Zone: in Rodrigues,K.(ed.), Transactions of the First Geological Conference of the Geological Society of Trinidad and Tobago, Port-of-Spain, Trinidad, 10th-12th July, 1985, 21-33.

 Rodrigues, K. 1988. Petroleum source rock evaluation of the Tertiary of Trinidad: in Barker, L. (ed.), Transactions of the Eleventh Caribbean Geological Conference, Dover Beach, Barbados, 20th-26th July, 1986, 38.1-38.16. 61Rohr, G.M. 1991.Exploration potential of Trinidad and Tobago. Journal of Petroleum Geology, 14, 343-354.

 Rowley, K. &Ambeh, W. 1991. The case of the El Pilar Fault system in Trinidad and its implications for seismic hazard in the S.E. Caribbean: in Gillezeau, K.A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-of-Spain, Trinidad, April 3-8, 1990, 106.

 Saunders, J.B. 1968. Excursion no. 1 Manzamlla coast: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of-Spain, Trinidad, 28th March- 12th April, 1965, 427-429.

Saunders, J.B. 1972. Recent paleontological results from the Northern Range of Trinidad: in Petzall, C. (ed.), Transactions of the Sixth Caribbean Geological Conference, Maragarita, Venezuela, 6th-14th July, 1971, 455-460.

 Saunders, J.B. 1974. Trinidad: in Spencer, A.M. (ed.), Mesozoic-Cerrozoic orogenic belts: data for orogenic studies. Special Publication of the Geological Society, London, 4, 671-682. [Not seen.]

 Saunders, J.B. 1977. Slumping phenomena and olistostromes in the Tertiary geologic history of Trinidad. GUA Papers on Geology, series 1, no. 9, p. 171.

 Saunders, J.B. &Bolli, H.M. 1985. Trinidad's contribution to world biostratigraphy: in Transactions of the Fourth Latin American Geological Conference, Portof-Spain, Trinidad, 7th-15th July,1979, 2, 781-795.

 Saunders, J.B. & Kennedy, J.E. 1968. Sedimentology of a section in the Upper Morne 1'Enfer Formation, Guapo Bay, Trinidad: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of Spain, Trinidad, 28th March-12th April, 1965, 121- 140.

 Schubert,C. 1979. El Pilar Fault Zone, northeastern Venezuela: brief review. Tectonophysics, 52, 447-455. 70Spath, L.F. 1939.On some Tithonian ammonites from the Northern Range of Trinidad. Geological Magazine, 76, 187-189.

 Speed, RC. 1987. South American-Antfllean Arc collision and the El Pilar Fault: in Duque-Caro, H. (ed.), Transactions of the Tenth Caribbean Geological Conference, Cartagena de Indias, Columbia, 14th-22nd August, 1983, p. 170. INGEOMINAS, Bogota.

 Speed, R.C. & Poland, K.A. 1990.Miocene metamorphism and Neogene tectonics of Northern Range rocks. Abstracts, Second Geological Conference of the Geological Society of Trinidad and Tobago, Port of Spain, Trinidad, 2nd-8th April, 19??, 19-20.

 Stainforth, R.M. 1978. Was it the Orinoco? American Association ofPetroleum Geologists Bulletin, 62, 303- 306.74Suter, H.H. 1960.The general and economic geology of Trinidad, B. W.I., 2nd edition, with revisionary appendix by G.E. Higgins. HMSO, London, 145 pp.

 Telemaque, C.P. 1990. An evaluation of the geological history and hydrocarbon potential of the late Miocene?Plio/Pleistocene sediments of the Goudron Field - Trinidad: in Lame, D.K. & Draper, G. (eds), Transactions of the Twelth Caribbean Geological Conference, St. Croix, U.S. Virgin Islands, 7th-llth August, 1989, 415- 429. Miami Geological Society, Florida.

 Trechmann, C.T. 1935. Fossils from the Northern Range of Trinidad. Geological Magazine, 72, 166-175. 77Tyson, L. 1990. Structural features associated with the Los Bajos Fault and their interpretation in the light of current theories of strike-slip tectonics: in Larue, D.K. & Draper, G. (eds), Transactions of the Twelth Caribbean Geological Conference, St. Croix, U.S. Virgin Islands, 7th-11th August, 1989, 403-414. Miami Geological Society, Florida.

 Tyson, L. & Ali, W. 1991. Cretaceous to Middle Miocene sediments in Trinidad: in Gillezeau, K. A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-ofSpain, Trinidad, April 3-8, 1990, 266-277.

 Tyson, L., Babb, S. & Dyer, B. 1991. Middle Miocene tectonics and its effects on late Miocene sedimentation in the Trinidad: in Gillezeau, K.A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-of-Spain, Trinidad, April 3-8, 1990, 26-40.

 Vierbuchen, R. 1977. New data relevant to the tectonic history of the El Pilar Fault. GUA Papers on Geology, series 1, no. 9, 213-214.

Wadge, G. & Macdonald, R 1985. Cretaceous tholeiites of the northern continental margin of South America: the Sans Souci Formation of Trinidad. Journal of the Geological Society, London, 142, 297-308.

Wall, G.P. &Sawkins, J.G. 1860. Report on the geology of Trinidad. Memoir of the Geological Survey, 211 pp. 228 Trinidad [Not seen.]

Wharton, S., Dupigny, A. & Keens-Dumas, J. 1986. A preliminary investigation of the Brigand Hill Limestone, Brigand Hill Quarry, Plum Milan Road: in Ro drigues, K. (ed), Transactions of the First Geological Conference of the Geological Society of Trinidad and Tobago, Port-of-Spain, Trinidad, 10th-12th July, 1985, 102-113.

Wielchowsky, C.C., Rahmanian, V.D. &Hardenbol, J. 1991. A preliminary tectonostratigraphic framework for onshore Trinidad: in Gillezeau, K.A. (ed.), Transactions of the Second Geological Conference of the Geological Society of Trinidad and Tobago, Port-ofSpain, Trinidad, April 3-8,1990, 41.

Wilson, C.C. 1968. The Los Bajos Fault: in Saunders, J.B. (ed.), Transactions of the Fourth Caribbean Geological Conference, Port-of-Spain, Trinidad, 28th March-12th April, 1965, 87-89.