Geochemistry and sequence stratigraphy of regional Upper Cretaceous limestone units, offshore eastern Canada

Wielens, Hans; MacRae, R. Andrew; Shimeld, John

doi:10.1016/s0146-6380(02)00103-1

Cited by 5 publications

(8 citation statements)

References 16 publications

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“…The palaeoenvironmental interpretation of these lithofacies is similar (Wielens et al, 2002). The absence of diagnostic shallow-water foraminifer and the high ratio of planktonic to benthic foraminifer imply that they were deposited in a deep-water setting (McIver, 1972).…”

Section: Lithofaciesmentioning

confidence: 70%

“…2) covering an area of 300,000 km 2 (Hansen et al, 2004) and extending for 500 km along the Scotian Margin (Wielens et al, 2002). The Wyandot Formation is a 400 m thick Upper Cretaceous (Santonian-Maastrichtian) succession of autochthonous chalk and interlayered marlstone.…”

Section: Regional Geologymentioning

confidence: 99%

“…(Ekdale and Bromley, 1983b). The Wyandot Formation was deposited below storm wave base in an offshore shelf to upper slope setting (Wade et al, 1995;Wielens et al, 2002). A water depth of 150-200 m is implied from the abundance of the coccolith species Lucianorhabdus cayeuxii (Doeven, 1983).…”

Section: Regional Geologymentioning

confidence: 99%

“…Hydrocarbons have been discovered in the Wyandot Formation and the Petrel Member of the underlying Dawson Canyon Formation ( Fig. 3) but are not currently considered commercially significant (Wielens et al, 2002).…”

Section: Regional Geologymentioning

confidence: 99%

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Ichnofabrics and biologically mediated changes in clay mineral assemblages from a deep-water, fine-grained, calcareous sedimentary succession: an example from the Upper Cretaceous Wyandot Formation, offshore Nova Scotia

Phillips

McIlroy

2010

Bulletin of Canadian Petroleum Geology

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The Upper Cretaceous Wyandot Formation is a 400 m thick succession of fine-grained calcareous mudstone deposited in an outer shelf to upper bathyal setting. The formation is divided into two lithofacies, a pure chalk and an interbedded kaolinite-bearing, argillaceous and calcareous claystone. Components of both lithofacies are derived from primary production in the photic zone, being rich in foraminifers and coccoliths. The Wyandot Formation is bioturbated, showing classic tiering and continual overprinting of trace fossils related to low pelagic sediment accumulation rates. Ichnological analysis reveals trends of environmental deterioration and amelioration. Changes in trace fossil assemblages are linked to fluctuations of organic matter input leading to rising of the redox front and low porewater/sediment oxygenation which excluded many endobenthic organisms. Mineralogical differences between burrow fill and host sediment demonstrate that bioturbation affects sediment texture by altering authigenic clay mineral assemblages. The clay mineral assemblage within burrows was found to be more diverse than in the surrounding sediment. This is probably the result of low temperature authigenesis in the digestive system of deposit feeding endobenthos, ingesting sedimentary particles and egesting material of a different mineralogical composition. RÉSUMÉLa Formation de Wyandot du Crétacé supérieur est une succession de 400 m d'épaisseur de mudstone calcareux à grains fins déposé dans un contexte variant de la plate-forme continentale externe à la zone bathyale supérieure. La formation se divise en deux lithofaciès, le premier en craie pure et le second en claystone argilo-calcareux interstratifié contenant de la kaolinite. La composition des deux lithofaciès dérive de production primaire dans la zone euphotique riche en foraminifères et coccolithes. Soumise à la bioturbation, la Formation de Wyandot se présente sous la forme d'étagement classique et de superposition d'ichnofossiles relatifs à un faible taux de sédimentation pélagique. L'analyse ichnologique révèle une évolution de détérioration et d'amélioration environnementales. Les changements dans les assemblages d'ichnofossiles sont liés aux fluctuations des matières organiques conduisant à une hausse d'activité du front d'oxydo-réduction et à une faible oxygénation de l'eau interstitielle et des sédiments, ce qui excluait de nombreux organismes endobenthiques. Les différences minéralogiques entre le sédiment hôte et le remblai des trous démontrent que la bioturbation affecte la texture sédimentologique en altérant l'assemblage des minéraux argileux authigènes. La diversité de l'assemblage des minéraux argileux dans les trous était plus diversifiée que dans les sédiments adjacents. Ce qui précède résulte probablement de la faible température authigenèse du système digestif des endobenthons limivores ingérant des particules sédimentaires et explulsant des matières composées de minéraux différents.Michel Ory 203

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Section: Lithofaciesmentioning

confidence: 70%

Section: Regional Geologymentioning

confidence: 99%

Section: Regional Geologymentioning

confidence: 99%

Section: Regional Geologymentioning

confidence: 99%

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Ichnofabrics and biologically mediated changes in clay mineral assemblages from a deep-water, fine-grained, calcareous sedimentary succession: an example from the Upper Cretaceous Wyandot Formation, offshore Nova Scotia

Phillips

McIlroy

2010

Bulletin of Canadian Petroleum Geology

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“…The overlying Upper Cretaceous Dawson Canyon Formation consists mainly of shales and a persistent limestone unit (the Turonian Petrel Member) which are, in turn, overlain by chalks, chalky limestones, marls, and shales of the Upper Coniacian-Maastrichtian Wyandot Formation (Wade and MacLean, 1990;Wielens et al, 2002). The Wyandot Formation is overlain by a succession of mudstones, sandstones, minor chalks and conglomerates (up to 1500 m thick) of the Maastrichtian-Pliocene Banquereau Formation (Wade and MacLean, 1990).…”

Section: Scotian Shelf Stratigraphymentioning

confidence: 99%

Diagenesis and porosity reduction in the Late Cretaceous Wyandot Formation, Offshore Nova Scotia: a comparison with Norwegian North Sea chalks

Ings

MacRae

Shimeld

et al. 2005

Bulletin of Canadian Petroleum Geology

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Porous chalk units have produced significant oil and gas discoveries around the world, including the world-class Tor Field of the Norwegian North Sea. On the Scotian Shelf of eastern Canada, the Upper Cretaceous Wyandot Formation is widespread, extending approximately 500 km along the length of the margin, and consists primarily of limestone with major chalk intervals. These chalks have porosities of up to 30% and are the reservoir for a gas and oil discovery at the Primrose N-50 well (1972) and a gas show at the Eagle D-21 well (1972). However, despite its potential as a hydrocarbon reservoir and/or seal, the Wyandot Formation is under-studied.In this paper, the Wyandot chalk is studied using conventional core samples, petrophysical logs, isotope geochemistry and SEM images to enhance the understanding of the depositional history, diagenesis and porosity-reducing mechanisms within the Wyandot Formation. Results indicate that the Wyandot chalks are in situ pelagic deposits, as opposed to the allochthonous North Sea chalks, and that mechanical compaction and dissolution/re-precipitation are the dominant mechanisms of porosity reduction. Given that significant volumes of Wyandot chalk have been eroded on parts of the Scotian Shelf, it is possible that North Sea type allochthonous reservoirs exist is distal locations on the Scotian Slope, and therefore an increased understanding of the sedimentology and porosity distribution of the in situ Wyandot Formation is important for further exploration in this frontier area. RÉSUMÉDes unités de craies poreuses ont produit d'importantes découvertes d'huile et de gaz à travers le monde, incluant le champ pétrolifère de Tor en Norvège, dans la mer du Nord, dont la renommée est mondiale. Sur le plateau de la Nouvelle Écosse, dans l'Est du Canada, la Formation de Wyandot du Crétacé supérieur est largement répandue, s'étend sur environ 500 km tout au long de la marge, et se compose en grande partie de calcaire avec des intervalles majeurs de craie. Ces craies présentent une porosité allant jusqu'à 30% et sont le réservoir où se trouve une découverte de gaz et d'huile du puits de Primrose N-50 (1972) et un indice de gaz du puits de Eagle D-21 (1972). Toutefois, en dépit de son potentiel de réservoir d'hydrocarbure et/ou d'obturation, la Formation de Wyandot demeure peu étudiée.Dans cet article, la craie de Wyandot est étudiée en utilisant des échantillons de carottes, des diagraphies pétrophysiques, la géochimie d'isotope, et des images MEB afin d'améliorer la compréhension de l'historique de déposition, la diagenèse, et les mécanismes de réduction de la porosité à l'intérieur de la Formation de Wyandot. Les résultats indiquent que les craies de Wyandot sont des dépôts pélagiques in situ, contrairement aux craies allochtones de la mer du Nord, et que le compactage mécanique et la dissolution/précipitation sont les mécanismes dominants de la réduction de la porosité. En considérant que les volumes importants de la craie de Wyandot ont été érodés sur des portions du plateau de la Nou...

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Upper Cretaceous Mass Transport Systems Above the Wyandot Formation Chalk, Offshore Nova Scotia

Smith

Deptuck

Kendell

2010

Submarine Mass Movements and Their Consequences

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Geochemistry and sequence stratigraphy of regional Upper Cretaceous limestone units, offshore eastern Canada

Cited by 5 publications

References 16 publications

Ichnofabrics and biologically mediated changes in clay mineral assemblages from a deep-water, fine-grained, calcareous sedimentary succession: an example from the Upper Cretaceous Wyandot Formation, offshore Nova Scotia

Ichnofabrics and biologically mediated changes in clay mineral assemblages from a deep-water, fine-grained, calcareous sedimentary succession: an example from the Upper Cretaceous Wyandot Formation, offshore Nova Scotia

Diagenesis and porosity reduction in the Late Cretaceous Wyandot Formation, Offshore Nova Scotia: a comparison with Norwegian North Sea chalks

Upper Cretaceous Mass Transport Systems Above the Wyandot Formation Chalk, Offshore Nova Scotia

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