Distributions of ostracod (Crustacea) biofacies on the continental shelf off south-east Trinidad, western central Atlantic Ocean, suggest the location of an offshore river-induced front within the Orinoco Plume

Wilson, Brent

doi:10.1007/bf03055276

Cited by 11 publications

(3 citation statements)

References 43 publications

(18 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The complete disappearance of temperate species was placed at 15ºS, while the northern boundary of the Brazilian Province is still unclear due to lack of data from a large area which includes Guyana, Suriname and French Guyana, and the scarcity of data on marine ostracods off Venezuela and Colombia. However, Wilson (2007Wilson ( , 2008 observed that 12 out of the 37 shallow-water ostracod species registered in Trinidad and Tobago, also occur in the Brazilian Province, as follows: Bairdopillata dorsoangulata, Bythoceratina carmoi, Callistocythere fossulata, Caudites nipeensis, Costa variabilicostata recticostata, Cytherura sp. (= Cytherura duracina Coimbra, Carreño & Michelli, 1999), Gangamocytheridea dictyon, Kangarina ancyla, Paracytheridea tschoppi, Pellucistoma ex gr.…”

Section: Biogeographymentioning

confidence: 99%

Provinciality of Ostracoda (Crustacea) in the Northeastern and Eastern Brazilian shelves based on neontological and paleontological analyses

Machado¹,

Coimbra²,

Bergue³

2020

Rev. bras. paleontol.

View full text Add to dashboard Cite

This study analyzes the geographical distribution of 131 podocopid ostracod species recovered from the Brazilian continental shelf between Cabo de São Roque (lat. 05°30'S) and Cabo Frio (lat. 23 o S). This very large area corresponds to the northeastern and eastern Brazilian marine regions. The 104 samples studied were collected in water depths ranging from 12 to 110 m as part of the legs 4 and 7 of the REMAC Project. The cosmopolitan species, as well as those shared with the Caribbean and/or Gulf of Mexico region, represent a small part of the ostracods herein studied and it is assumed that their dispersion was prompted by processes linked to events of relative sea level changes during the Neogene and Quaternary. The fossil record of some species spans to the Neogene, mostly from the Atlantic coast of North and Central America, while one species has Tethyan origin. Three species known from the Neogene of the Caribbean have been recorded as relicts in the study area. From the 131 species herein identified, 36.5% are more widespread in temperate waters south of Cabo Frio town, 46.5% of warm waters north of Cabo Frio town, 4% are present only in the studied area, and 11.5% are rare and probably restricted to the E region. A new province-the Brazilian Province-is herein proposed based on the species occurrence.

show abstract

Section: Biogeographymentioning

confidence: 99%

Provinciality of Ostracoda (Crustacea) in the Northeastern and Eastern Brazilian shelves based on neontological and paleontological analyses

Machado¹,

Coimbra²,

Bergue³

2020

Rev. bras. paleontol.

View full text Add to dashboard Cite

show abstract

“…The Savonette area lies within their Zone VI, which they characterize as occupying a sandy zone little influenced by Orinoco outflow. Wilson (2007, 2008) found ostracod biofacies off SE Trinidad to be arrayed perpendicular to bathymetric contours and concluded that this reflects the interplay of Amazon- and Orinoco-derived water along an estuarine front within the Orinoco Plume. The Ibis and Savonette Fields lay on opposite sides of this front, the Savonette Field being beneath surface water derived from the River Amazon.…”

Section: Previous Workmentioning

confidence: 99%

The significance of iron-stained foraminifera off SE Trinidad, West Indies, western central Atlantic Ocean

Wilson

2010

Geol. Mag.

Self Cite

View full text Add to dashboard Cite

Eleven samples of seafloor sediment were taken from water depths of 78-90 m within the Savonette Field, off SE Trinidad, western Atlantic Ocean. This surface sediment is relict, having been deposited during an early Holocene transgression. The samples yielded much iron-stained quartz and a rich assemblage of dead foraminifera, of which 75 % of planktonic foraminifera were stained with iron, as was 66.5 % of the calcareous benthonic foraminiferal assemblage. The fauna, both iron-stained and unstained, was dominated by Cibicidoides ex. gr. pseudoungerianus, and is concluded, despite the proximity of the Orinoco Delta, to be equivalent to a relict Cibicidoides biofacies in carbonate-rich areas of the Gulf of Mexico. Staining was by limonite and hematite. Differing percentages of calcareous benthonic species had been stained with iron, ANOVA revealing three groups of species within which the mean percentage of iron-stained specimens per sample did not differ: (a) Globocassidulina subglobosa and Hanzawaia concentrica; (b) Amphistegina gibbosa, Cassidulina norcrossi australis Cibicioides ex. gr. pseudoungerianus, C. io, Elphidium translucens and Quinqueloculina lamarckiana; and (c) Eponides antillarum and E. repandus. It is concluded that species differ in their susceptibility to iron staining, and that planktonic foraminifera are more susceptible than most benthonic species. Although waters off northern South America are turbid and the photic zone only ∼ 25 m deep, the relict assemblage contained 8.4 % algal symbiont-bearing foraminifera (especially A. gibbosa and E. translucens) that would be limited to the photic zone. These are thought to have lived at a time early in the Holocene transgression when sequestration of sediment within the Orinoco delta rendered the water sufficiently clear for viable populations of symbiont-bearing foraminifera. Should iron-stained foraminifera prove to be restricted to transgressive systems tracts, this would make them a useful sequence stratigraphic tool.

show abstract

“…Planktonic and calcareous benthonic foraminifera are abundant, however, on the modern continental shelf and slope SE of the island (Drooger & Kaasschieter, 1958; Pocknall et al . 2001; Wilson, 2006, 2010) despite this area lying within the hyperpycnal Orinoco low-salinity plume (Agard & Gobin, 2000; Wilson, 2007, 2008 a ), so water clarity seems an unlikely mechanism to explain the agglutinated Miocene assemblage. Jones (1998) thought the exclusion of calcareous matter might either be (a) penecontemporaneous and due to elimination from surface water of marine phytoplankton, which serve as food for at least some planktonic and deep-water benthonic calcareous foraminifera, or (b) diagenetic and due to salinity stratification, which would reduce circulation and oxygenation of bottom waters, allowing dissolution of calcite by acids released from decaying organic matter.…”

Section: Introductionmentioning

confidence: 99%

Benthonic foraminifera in the Upper Miocene Cruse Formation at Quinam Bay, Trinidad, western tropical Atlantic Ocean, and their palaeoenvironmental significance

Wilson

Vincent

2013

Geol. Mag.

View full text Add to dashboard Cite

The Upper Miocene Cruse Formation of Trinidad yields predominantly agglutinated foraminifera. The limited assemblage has previously hampered palaeoenvironmental interpretations. Twenty-two samples taken from a basal Cruse section at 0.5 m intervals from Quinam Bay (10°05′07.7″N, 61°45′04.7″W) yielded 2938 foraminifera in 33 species, almost all agglutinated. The absence of calcite-cemented agglutinants suggests post-mortem dissolution of calcareous specimens. Dominant Spirosigmoilinella compressa indicates lower bathyal to abyssal palaeodepths, although the low values of the information function H are typical of shallower water. Subdominant Haplophragmoides carinatus and Haplophragmoides sp. 1 indicate low dissolved oxygen levels. Diversities measured using species richness S and H were especially low in the lowest 3.5 m of the section. The proportional abundance of the dominant species in each sample, max(pi), indicated three subsections, being low in the middle of the section but higher at the top and bottom. SHE analysis indicated six abundance biozones (ABs) containing one to seven samples each. Of the three ABs with more than three samples, two had Type 1 community structures and one had a Type 0 community structure. ABs with one or two samples indicate that environmental change at the top of the interval with low diversity is rapid. This is reflected in a change from abundant morphotype M3a (surficial epifauna flattened) at the base of the section to abundant M4a (shallow infauna planispiral) with M4b (deep infaunal) towards the top, which shows a downward shift in the position of the redox front part way through the section.

show abstract

Distributions of ostracod (Crustacea) biofacies on the continental shelf off south-east Trinidad, western central Atlantic Ocean, suggest the location of an offshore river-induced front within the Orinoco Plume

Cited by 11 publications

References 43 publications

Provinciality of Ostracoda (Crustacea) in the Northeastern and Eastern Brazilian shelves based on neontological and paleontological analyses

Provinciality of Ostracoda (Crustacea) in the Northeastern and Eastern Brazilian shelves based on neontological and paleontological analyses

The significance of iron-stained foraminifera off SE Trinidad, West Indies, western central Atlantic Ocean

Benthonic foraminifera in the Upper Miocene Cruse Formation at Quinam Bay, Trinidad, western tropical Atlantic Ocean, and their palaeoenvironmental significance

Contact Info

Product

Resources

About