Les formations d'âge Crétacé de l'Atlantique Nord et leur matière organique : paléogéographie et milieux de dépôt

Graciansky, P. C. de; Brosse, É.; Deroo, G.; Herbin, J. P.; Montadert, L.

doi:10.2516/ogst:1982016

Cited by 66 publications

(57 citation statements)

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“…Foraminiferal studies reveal a middle Albian through early Cenomanian hiatus. A similar hiatus is well known from other sites in the North Atlantic (de Graciansky et al, 1982). Although nannofossil evidence is equivocal, foraminiferal studies suggest that the upper Cenomanian section is missing.…”

Section: Site 549supporting

confidence: 80%

“…These layers, observed also at other sites in the North Atlantic (de Graciansky et al, 1982), correspond to an anoxic event which interrupted well-oxygenated conditions reflected in the remainder of the Upper Cretaceous sequence. This anomalous anoxic event was associated with a major marine transgression and a period of widespread volcanic activity (Müller, this vol.).…”

Section: Turonianmentioning

confidence: 52%

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Biostratigraphic, Paleoenvironmental, and Paleomagnetic Synthesis of the Goban Spur Region, Deep Sea Drilling Project Leg 80

Snyder¹,

Müller²,

Townsend³

et al. 1985

Initial Reports of the Deep Sea Drilling Project, 80

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A composite stratigraphic section based on the four DSDP-IPOD Leg 80 drill sites provides a nearly complete record of syn-rift and post-rift events in the vicinity of Goban Spur. Syn-rift sediments were deposited in marginal marine to outer shelf environments. Above the "breakup" unconformity (hiatus spanning most of the Aptian), post-rift Albian sediments indicate the development of a deep-water seaway in the Goban Spur region. The latest Campanian/Maestrichtian interval records the initiation of rather uniform, widely distributed marine sedimentation throughout the region. Climatic changes, rather than changes in water depth, became conspicuous during the Tertiary. Widespread, nearly synchronous periods of nondeposition or erosion occurred in the Paleocene, middle Eocene, middle Oligocene, and late Miocene. Differences in the sediment record among sites are due to their varying positions (1) along the margin of the developing Atlantic seaway and (2) within their respective half-graben depositional basins.

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Section: Site 549supporting

confidence: 80%

Section: Turonianmentioning

confidence: 52%

Biostratigraphic, Paleoenvironmental, and Paleomagnetic Synthesis of the Goban Spur Region, Deep Sea Drilling Project Leg 80

Snyder¹,

Müller²,

Townsend³

et al. 1985

Initial Reports of the Deep Sea Drilling Project, 80

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“…For example, although relatively high concentrations of organic carbon (up to 3%) occur in Lower Cretaceous sediments at DSDP Sites 105 and 398, this organic matter, which was already highly oxidized at the time of its entry into the water column, could not have significantly affected the oxygen content of the bottom waters (Tissot et al, 1979;de Graciansky et al, 1982).…”

Section: Richness Of Organic Mattermentioning

confidence: 99%

A Reappraisal of Anoxia and Richness of Organic Material, with Emphasis on the Cretaceous North Atlantic

Waples¹

1985

Initial Reports of the Deep Sea Drilling Project, 80

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Accumulation of anoxic sediments in the North Atlantic from Barremian through Turanian time (Early to middle Cretaceous) was apparently controlled mainly by local conditions, although global climatic and oceanographic factors may have played a supporting role. Evidence does not support the popular hypothesis developed over the past few years of global or ocean-wide anoxia. The data contradicting this hypothesis are based on a reevaluation of criteria for identifying sediments that accumulated in anoxic water, a critical reappraisal of reported world-wide occurrences of anoxic sediments of these ages, and an examination of the spatial and temporal distribution of anoxic sediments in the North Atlantic and elsewhere. A model is proposed in which the earliest anoxic sediments of Cretaceous age in the North Atlantic were deposited in deep restricted basins. By middle Cenomanian time (about 97 m.y. ago), however, sluggish circulation had led to a gradual expansion of the oxygen-minimum layer, permitting deposition of anoxic sediments in nonbasinal settings. The expansion of the oxygen-minimum layer caused the calcite compensation depth to rise, promoting oxidation of organic carbon and causing contraction of the oxygen-minimum layer. The development of anoxia was thus self-damping. Anoxia effectively disappeared by early Senonian time (88 m.y. ago) when improved circulation created oceans more like those of the present. Some evidence indicates that enhanced productivity and upwelling may have played a local role in fostering anoxia, but most data suggest that worldwide marine productivity was generally not high during Early and middle Cretaceous time.

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“…A total of 137 samples were examined (111 from the Barremian and 26 from the Albian). The soft material, after washing, was sieved at 63µm, and the microfossils recovered were used to make an ecostratigraphic inventory similar to recent studies at other DSDP sites (Sigal, 1979 andde Graciansky et al, 1982). In total, 180 samples were examined (150 from the Barremian and 30 from the Albian).…”

Section: Methodsmentioning

confidence: 99%

Barremian and Albian Foraminifera, Site 549, Leg 80

Magniez¹,

Sigal²

1985

Initial Reports of the Deep Sea Drilling Project, 80

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The Early Cretaceous series of Site 549 have been analyzed from both an ecological and a chronostratigraphical viewpoint. Lithology and microfaunal assemblages allow the division of these deposits into two parts. The lower part extends from the lower Barremian to the basal upper Barremian and possibly down into the upper Hauterivian. Three foraminiferal associations suggest an orderly evolution from a low-energy, littoral environment, in which continental influences dominated, to progressively more open marine conditions. A dolosparite bed (which has not yet been dated) separates these synrift deposits from lower to basal middle Albian postrift sediments that developed in a pelagic bathyal environment on the middle to nearby lower continental slope.

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Les formations d'âge Crétacé de l'Atlantique Nord et leur matière organique : paléogéographie et milieux de dépôt

Cited by 66 publications

References 0 publications

Biostratigraphic, Paleoenvironmental, and Paleomagnetic Synthesis of the Goban Spur Region, Deep Sea Drilling Project Leg 80

Biostratigraphic, Paleoenvironmental, and Paleomagnetic Synthesis of the Goban Spur Region, Deep Sea Drilling Project Leg 80

A Reappraisal of Anoxia and Richness of Organic Material, with Emphasis on the Cretaceous North Atlantic

Barremian and Albian Foraminifera, Site 549, Leg 80

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