Le probleme des relations de l'Atlantique Sud et de l'Atlantique Central au Cretace moyen; nouvelles donnees microfauniques d'apres les forages D.S.D.P

Moullade, Michel; Guérin, Serge

doi:10.2113/gssgfbull.s7-xxiv.3.511

Cited by 28 publications

(9 citation statements)

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“…Moullade & Guerin (1981) from microfossil and ammonite data and Lancelot (1980) have argued that shallow South Atlantic waters could have penetrated the North Atlantic at approximately this time. A rapid regression-transgression of eustatic origin (Vail et al 1979) occurred during this period.…”

Section: (D) Event E2mentioning

confidence: 98%

Organic-rich sediments and palaeoenvironmental reconstructions of the Cretaceous North Atlantic

Graciansky

Brosse

Deroo

et al. 1987

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A survey of DSDP black shales from the North Atlantic has been carried out in order to study the evolution of Cretaceous palaeoenvironments in the region. The study involved a reappraisal of the biostratigraphy of the Cretaceous formations and considered accumulation rate, mineralogical and organic geochemical data. Special attention was paid to distinguishing between redeposited and autochthonous sediments. Three main phases of deposition are recognized which are separated by two unconformities:The Blake-Bahama phase (Valanginian-early Aptian (Bedoulian)) corresponds to relatively uniform depositional conditions over the whole of the North Atlantic with periods of anoxia. The clay mineral assemblages reflect different sedimentary influxes from the continents into the eastern and western parts of the basin which were separated by the midocean ridge.The transition to the Hatteras phase (Event El) is marked by a drastic fall in sediment accumulation rate and by a rapid rise in the CCD but not by any appreciable change in clay mineral fluxes.The Hatteras phase (late Aptian-late Cenomanian) is characterized by distinctly diverse depositional conditions. In the southeastern part of the basin anoxic conditions were persistent, while in the northeast along the European margin there is no, or only very rare, evidence of anoxia. In the west, periods of oxia and anoxia alternated. Over the mid-ocean ridge conditions were oxic. A 'barrier' in the region of the present-day Bermuda Rise separated two areas of distinct clay mineral deposition.The transition to the Plantagenet phase (Event E2) corresponds to low sedimentation rates. It was immediately preceded by, or was coincident with, deposition of a black shale rich in marine organic matter.The Plantagenet phase (Turonian-Senonian) was a period of uniform sedimentation under oxic conditions.Possible causes of these changes in sedimentation are outlined.

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Section: (D) Event E2mentioning

confidence: 98%

Organic-rich sediments and palaeoenvironmental reconstructions of the Cretaceous North Atlantic

Graciansky

Brosse

Deroo

et al. 1987

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“…The Turonian to Santonian sediments from Hole 959D are partly characterized by high TOC, and contain some well-preserved benthic foraminifer assemblages, which are especially important for understanding the early paleoenvironments of the CIGTM and for retracing the paleoceanographic evolution of the Atlantic gateway during mid-Cretaceous times. The opening of this equatorial seaway between the North and South Atlantic was initiated in the Early Cretaceous, following the rifting between the African and South American continents (de Klasz, 1978;Moullade and Guérin, 1982;Moullade et al, 1993;Bonatti et al, 1996). During the early stages of continental breakup, the area was a key oceanic gateway, which first enabled the change from an equatorial oceanic circulation regime to the meridional circulation scenario characteristic of the present-day ocean.…”

Section: Introductionmentioning

confidence: 99%

TuronianSantonian benthic foraminifer assemblages from Site 959D (Côte d'Ivoire-Ghana Transform Margin, equatorial Atlantic): indication of a Late Cretaceous oxygen minimum zone

Holbourn¹,

Kuhnt²

1998

Proceedings of the Ocean Drilling Program, 159 Scientific Results

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Turonian-Santonian organic-rich fissile black claystones with laminated intervals from Hole 959D on the Côte d'IvoireGhana Transform Margin, drilled during Ocean Drilling Program Leg 159, contain benthic foraminifer assemblages dominated by buliminid associations. The lower Turonian assemblage from Core 159-959D-68R is strongly dominated by Bolivina anambra, Praebulimina sp. 1, Praebulimina sp. 2, Praebulimina sp. 3, and Gavelinella spp. The upper Turonian to lower Coniacian assemblage from Core 159-959D-67R displays low abundance and low diversity and consists mostly of organically cemented agglutinated taxa and/or some corroded tests of Lenticulina, Bolivina, Gyroidinoides ex gr. nitidus. The middle Coniacian to lower Santonian assemblage from Core 159-959D-66R and from the base of Core 159-959D-65R contains high numbers of Praebulimina robusta, Praebulimina fang, Neobulimina subregularis, and Buliminella cf. gabonica, but shows marked fluctuations in abundance and diversity, which appear to be related to changes in total organic carbon. The distinct composition of the two buliminid associations in Core 159-959D-68R and Core 159-959D-66R suggests that endemism was stronger during the early Turonian, when circulation was probably more restricted and connections between equatorial Atlantic basins were limited. We interpret the late Coniacian-early Santonian depositional environment to be an oxygen minimum zone in a more open marine outer shelf or upper slope setting. A sudden increase in the proportion of deep-water agglutinated foraminifers in Sample 159-959D-65R-5, 30−34 cm, points to rapid deepening during the early Santonian. The higher diversity and the abundance of cosmopolitan taxa in samples from Cores 159-959D-66R and 159-959D-65R indicate that deep circulation between the North and South Atlantic was well established by the middle Coniacian to early Santonian.

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“…Moullade and Guerin (1982) prove, using benthonic and planktonic foraminifera, that the South Atlantic was clearly open to the Central Atlantic from the Middle Albian (Fig. Several periods in the Albian -Turonian have been proposed for the opening of the communication between the North and South Atlantic oceans.…”

Section: Paleobiogeographymentioning

confidence: 93%

“…Points represent studied wells (AfterMoullade and Guerin 1982); arrow denotes direction of migration 50.…”

mentioning

confidence: 99%

Stratigraphy

1992

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Le probleme des relations de l'Atlantique Sud et de l'Atlantique Central au Cretace moyen; nouvelles donnees microfauniques d'apres les forages D.S.D.P

Cited by 28 publications

References 0 publications

Organic-rich sediments and palaeoenvironmental reconstructions of the Cretaceous North Atlantic

Organic-rich sediments and palaeoenvironmental reconstructions of the Cretaceous North Atlantic

TuronianSantonian benthic foraminifer assemblages from Site 959D (Côte d'Ivoire-Ghana Transform Margin, equatorial Atlantic): indication of a Late Cretaceous oxygen minimum zone

Stratigraphy

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Le probleme des relations de l'Atlantique Sud et de l'Atlantique Central au Cretace moyen; nouvelles donnees microfauniques d'apres les forages D.S.D.P

Cited by 28 publications

References 0 publications

Organic-rich sediments and palaeoenvironmental reconstructions of the Cretaceous North Atlantic

Organic-rich sediments and palaeoenvironmental reconstructions of the Cretaceous North Atlantic

TuronianSantonian benthic foraminifer assemblages from Site 959D (Côte d'Ivoire-Ghana Transform Margin, equatorial Atlantic): indication of a Late Cretaceous oxygen minimum zone

Stratigraphy

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TuronianSantonian benthic foraminifer assemblages from Site 959D (Côte d'Ivoire-Ghana Transform Margin, equatorial Atlantic): indication of a Late Cretaceous oxygen minimum zone