Paleoenvironmental changes across the Cenomanian/Turonian Boundary Event (Oceanic Anoxic Event 2) as indicated by benthic foraminifera from the Demerara Rise (ODP Leg 207)

Friedrich, Oliver; Erbacher, Jochen; Mutterlose, Jörg

doi:10.1016/j.revmic.2006.04.003

Cited by 94 publications

(68 citation statements)

References 61 publications

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“…The Cenomanian/Turonian boundary interval is barren of foraminifera in most of the studied sites from the North Atlantic and Europe (Kuhnt, 1992;Coccioni and Luciani, 2004;Scopelliti et al, 2004;Bak, 2006 among others), but in the Ganuza section, Spain and the deepest sites of Demerara Rise, ODP Leg 207, a benthic extinction is not evident, only low diversity and poor assemblages occur as result of low oxygen levels represented by this interval (Peryt, 2004;Friedrich et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Biostratigraphy of the Cenomanian-Turonian boundary in the Eastern Carpathians (Dâmboviţa Valley): preliminary observations

Cetean¹,

Bălc²,

Kaminski³

et al. 2008

Studia UBB, Geologia

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ABSTRACT. Planktonic and benthic foraminiferal assemblages from an Upper Albian to Lower Turonian interval in the East Carpathians were investigated in a well and in an outcrop from the Stoeneşti -Cetăţeni area (Dâmboviţa Valley), Romania. The benthic foraminiferal extinction that occurred at the Cenomanian/Turonian boundary and the first stage of the faunal recovery are documented here for the first time in the Romanian Carpathians. Bioevents and changes in the foraminiferal record from this area show that low oxygen conditions occured already in the Late Cenomanian, as suggested by the presence of radiolarian-rich shales. Impoverished assemblages of small, thin walled agglutinated foraminifera are present in the lowermost Turonian after the benthic-free interval corresponding to the "Bonarelli Level". Calcareous nannofossils are also documented from this level in the well from the Stoeneşti locality.

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Section: Discussionmentioning

confidence: 99%

Biostratigraphy of the Cenomanian-Turonian boundary in the Eastern Carpathians (Dâmboviţa Valley): preliminary observations

Cetean¹,

Bălc²,

Kaminski³

et al. 2008

Studia UBB, Geologia

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“…1A) recovered a 50-90-m-thick sequence of Cenomanian-early Santonian, fi nely laminated, organic-rich, calcareous claystones (herein black shales), separated from the overlying Campanian-Paleocene chalks by a condensed interval and/or hiatus, and from the underlying Aptian and older claystones by a structural and/or depositional unconformity. We focus on the Cenomanian record, exclusive of OAE2, at Sites 1260 and 1258; water paleodepths at these sites are estimated at ~600 and ~1500 m, respectively (Arthur and Natland, 1979;Friedrich et al, 2006). The MCE is characterized by a 1‰ positive δ 13 C shift in planktonic foraminifera at Site 1258 (Moriya et al, 2007) and a 4‰ positive δ 13 C org shift at Site 1260 (Friedrich et al, 2008).…”

Section: Methodsmentioning

confidence: 99%

Nutrient trap for Late Cretaceous organic-rich black shales in the tropical North Atlantic

Berrocoso

MacLeod

Martin

et al. 2010

Geology

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Neodymium isotopes of fi sh debris from two sites on Demerara Rise, spanning ~4.5 m.y. of deposition from the early Cenomanian to just before ocean anoxic event 2 (OAE2) (Cenomanian-Turonian transition), suggest a circulation-controlled nutrient trap in intermediate waters of the western tropical North Atlantic that could explain continuous deposition of organic-rich black shales for as many as ~15 m.y. (Cenomanian-early Santonian). Unusually low Nd isotopic data (ε Nd(t) ~−11 to ~−16) on Demerara Rise during the Cenomanian are confi rmed, but the shallower site generally exhibits higher and more variable values. A scenario in which southwest-fl owing Tethyan and/or North Atlantic waters overrode warm, saline Demerara bottom water explains the isotopic differences between sites and could create a dynamic nutrient trap controlled by circulation patterns in the absence of topographic barriers. Nutrient trapping, in turn, would explain the ~15 m.y. deposition of black shales through positive feedbacks between low oxygen and nutrient-rich bottom waters, effi cient phosphate recycling, transport of nutrients to the surface, high productivity, and organic carbon export to the seafl oor. This nutrient trap and the correlation seen previously between high Nd and organic carbon isotopic values during OAE2 on Demerara Rise suggest that physical oceanographic changes could be components of OAE2, one of the largest perturbations to the global carbon cycle in the past 150 m.y.

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“…This exactly spells out the difference between the two bathymetry dataset and highlights the importance of reconstructing the shelf-slope-wedge. This has special significance especially for the C-T time, as for decades the paleoclimate community has argued for extensive shallow epicontinental seas [36,[62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] for example, to explain oceanic anoxic events. The OES C-T Ocean compared to Modern Ocean, has 4.75% more area (ocean area) less than 1000 m deep (maximum extent of combined euphotic and disphotic zone depth).…”

Section: Discussionmentioning

confidence: 99%

“…The meriodional thermal gradient may have been at its lowest in the Cretaceous during the C-T transition. Unfortunately, Cretaceous paleoclimate modeling with GCMs has consistently underestimated the warm polar temperatures that are indicated by fossil and geochemical data (e.g., [74,80,81]). …”

Section: Discussionmentioning

confidence: 99%

Realistic Paleobathymetry of the Cenomanian–Turonian (94 Ma) Boundary Global Ocean

et al. 2018

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At present, global paleoclimate simulations are prepared with bathtub-like, flat, featureless and steep walled ocean bathymetry, which is neither realistic nor suitable. In this article, we present the first enhanced version of a reconstructed paleobathymetry for Cenomanian-Turonian (94 Ma) time in a 0.1 • × 0.1 • resolution, that is both realistic and suitable for use in paleo-climate studies. This reconstruction is an extrapolation of a parameterized modern ocean bathymetry that combines simple geophysical models (standard plate cooling model for the oceanic lithosphere) based on ocean crustal age, global modern oceanic sediment thicknesses, and generalized shelf-slope-rise structures calibrated from a published global relief model of the modern world (ETOPO1) at active and passive continental margins. The base version of this Cenomanian-Turonian paleobathymetry reconstruction is then updated with known submarine large igneous provinces, plateaus, and seamounts to minimize the difference between the reconstructed paleobathymetry and the real bathymetry that once existed.

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Paleoenvironmental changes across the Cenomanian/Turonian Boundary Event (Oceanic Anoxic Event 2) as indicated by benthic foraminifera from the Demerara Rise (ODP Leg 207)

Cited by 94 publications

References 61 publications

Biostratigraphy of the Cenomanian-Turonian boundary in the Eastern Carpathians (Dâmboviţa Valley): preliminary observations

Biostratigraphy of the Cenomanian-Turonian boundary in the Eastern Carpathians (Dâmboviţa Valley): preliminary observations

Nutrient trap for Late Cretaceous organic-rich black shales in the tropical North Atlantic

Realistic Paleobathymetry of the Cenomanian–Turonian (94 Ma) Boundary Global Ocean

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