The stratigraphic and palaeogeographic setting of the late Cenomanian ‘anoxic’ event

Hart, Malcolm B.; Leary, Paul

doi:10.1144/gsjgs.146.2.0305

Cited by 44 publications

(20 citation statements)

References 16 publications

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“…The lower is in the uppermost Cenomanian, a well-known and widespread source rock interval throughout the Atlantic (de Graciansky et al 1987;Hart & Leary 1989) and locally reported from Wells 6506/12-4 and 35/3-5. The upper is in the Campanian, reported from Wells 6507/2-1 and 6607/5-1.…”

Section: Late Cretaceousmentioning

confidence: 88%

The prospectivity of the Vøring and Møre basins on the Norwegian Sea continental margin

Brekke¹,

Dahlgren²,

Nyland³

et al. 1999

PGC

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The focus of exploration activity on the Norwegian Sea Continental Shelf has shifted westwards from the shallow water areas over the Trondelag Platform and Halten Terrace to the deep water areas over the Cretaceous Voring and More basins. The basins, especially the Voring Basin, have been involved in a complex tectonic development since the main extensional phase in the late Middle Jurassic to Early Cretaceous, including Cenomanian-Campanian and Maastrichtian-Eocene extension and thermal uplift and intermittent phases of compression/transpression. While the Jurassic is the prospective interval in the Trondelag Platform and Halten Terrace, the potential in the Voring and More basins is seen mainly in the Cretaceous and Paleocene -the Jurassic is too deeply buried. The two first deep water exploration wells in these basins, 6707/10-1 and 6305/5-1, have already proven two effective plays, with excellent reservoir sands in the Upper Cretaceous and lower Paleocene charged with thermogenic gas in structural traps in rotated fault blocks and compressional domes. Palaeogeographical reconstructions indicate that these reservoir rocks may be widespread within the basin areas. No good oil-prone source rock at a suitable depth of burial is so far proven, but the palaeogeographical reconstructions linked to surrounding well data and regional analyses indicate a chance for the existence of Upper Cretaceous oil source intervals. The thermal history of the basins is as complex as their tectonic history, and is further complicated by the possible effects of the Paleocene-Eocene magmatic activity, making any basin modelling results at the present stage unreliable.

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Section: Late Cretaceousmentioning

confidence: 88%

The prospectivity of the Vøring and Møre basins on the Norwegian Sea continental margin

Brekke¹,

Dahlgren²,

Nyland³

et al. 1999

PGC

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“…They dominate the planktonic assemblages from the R. cushmani and the H. helvetica TRZ, which are periods characterized by welloxygenated water with low nutrient levels allowing a specific diversification and the development of more sophisticated morphotypes (Grosheny and Malartre, 1997;Caron et al, 2006;Mort et al, 2007). The second group is composed of globular trochospiral and biserial forms with small and simple morphotypes (e.g., Whiteinella and Heterohelix), which mainly lived in the upper-water column with high nutrient levels (Hart and Leary, 1989;Petters, 1980;Jarvis et al, 1988;Grosheny and Malartre, 1997;Leckie et al, 1998;Keller and Pardo, 2004). They are interpreted as r-selected species (MacArthur and Wilson, 1967) and date from the W. archaeocretacea PRZ.…”

Section: Planktonic Foraminifera As Environmental Proxiesmentioning

confidence: 99%

Evidence for oxic conditions during oceanic anoxic event 2 in the northern Tethyan pelagic realm

Westermann

Caron

Fiet

et al. 2010

Cretaceous Research

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Upper Cenomanian pelagic sediments from the northern Alpine Helvetic fold-and-thrust belt (northern Tethyan margin) coeval with Oceanic Anoxic Event (OAE) 2 are characterized by the temporal persistence of micrite sedimentation and lack of organic carbon-rich layers. We studied an expanded section in the Chrummflueschlucht (east of Euthal, Switzerland), which encompasses the OAE 2 time interval. In order to identify the paleoceanographic and paleoenvironmental conditions during OAE 2 in this part of the northern Tethyan margin, and more specifically to trace eventual changes in nutrient levels and oxic conditions, we investigated the biostratigraphy (planktonic foraminifera), the bulk-rock mineralogy, and measured stable carbon-and oxygen-isotopes, total phosphorus (P) and redox-sensitive trace-element (RSTE) contents.We were able to determine e with some remaining uncertainties e the different planktonic foraminiferal biozones characteristic of the CenomanianeTuronian boundary interval (Rotalipora cushmani, Whiteinella archaeocretacea and Helvetoglobotruncana helvetica zones). In the lower part of the section (R.cushmani total range zone), the bulk-rock d 13 C record shows a long-term increase. Within sediments attributed to the W. archaeocretacea partial range zone, d13 C values reach a maximum of 3.3& (peak "a").In the following the values decrease and increase again to arrive at a plateau with high d13 C values of around 3.1&, which ends with a peak of 3.3& (peak "c"). At the top of the section, in sediments belonging to the H. helvetica total range zone, d13 C values decrease to post-OAE values of around 2.2&.The last occurrence of R. cushmani is observed just above the positive d 13 C shift characterizing OAE 2. P contents display small variations along the section with a long-term decreasing trend towards the top. Before the OAE 2 interval, P values show higher values and relatively good covariation with detrital input, indicating higher nutrient input before OAE 2. In sediments corresponding to the onset of the d 13 C positive excursion, P content is marked by a sharp peak probably linked to a slowdown in sedimentation rates and/or the presence of a small hiatus, as is shown by the presence of glauconite and phosphatic grains. In the interval corresponding to OAE 2, P values remain low and increase slightly at the end of the positive shift in the d 13 C record (in the H. helvetica total range zone). The average contents of RSTE (U, V, As, Co, Mo and Mn) remain low throughout the section and appreciable RSTE enrichments have not been observed for the sedimentary interval corresponding to OAE 2. No correlation is observed with stratigraphic trends in RSTE contents in organic-rich deeper-water sections. The presence of double-keeled planktonic foraminifera species during most of the Cenomanian/Turonian boundary event is another evidence of relatively well-oxygenated conditions in this part of the northern Tethyan outer shelf.Our results show that the Chrummflueschlucht section corresponds to one of the most...

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“…Distinct intervals of black shale deposition with unusually high concentrations of total organic carbon (TOC) termed oceanic anoxic events (OAE) were deposited on a global scale during the Aptian-Albian, Cenomanian-Turonian and Coniacian-Santonian (e.g., Hart and Leary, 1989;Crowley, 1991;Johnson et al, 1996;Wilson et al, l998;Jones and Jenkyns, 2001;Norris et al, 2002;Leckie et al, 2002). At these times, the sequestration of the organic carbon due to high burial rates favored the formation of petroleum source rocks and reduced atmospheric PCO 2 , which affected climate (e.g., Kuypers et al, 1999;Kolonic et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Oceanic events and biotic effects of the Cenomanian-Turonian anoxic event, Tarfaya Basin, Morocco

Keller

Adatte

Berner

et al. 2008

Cretaceous Research

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a b s t r a c tProfound biotic changes accompanied the late Cenomanian d 13 C excursion and OAE2 in planktic foraminifera in the Tarfaya Basin of Morocco. Planktic foraminifera experienced a severe turnover , though no mass extinction, beginning with the rapid d 13 C excursion and accelerating with the influx of oxic bottom waters during the first peak and trough of the excursion. Species extinctions equaled the number of evolving species, though only the disaster opportunists Guembelitria and Hedbergella thrived along with a low oxygen tolerant benthic assemblage. The succeeding d 13 C plateau and organic-rich black shale deposition marks the anoxic event and maximum biotic stress accompanied by a prolonged drop in diversity to just two species, the dominant (80-90%) low oxygen tolerant Heterohelix moremani and surface dweller Hedbergella planispira. After the anoxic event other species returned, but remained rare and sporadically present well into the lower Turonian, whereas Heterohelix moremani remained the single dominant species. The OAE2 biotic turnover suggests that the stress to calcareous plankton was related to changes in the watermass stratification, intensity of upwelling, nutrient flux and oxic levels in the water column driven by changes in climate and oceanic circulation. Results presented here demonstrate a 4-stage pattern of biotic response to the onset, duration, and recovery of OAE2 that is observed widely across the Tethys and its bordering epicontinental seas.

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The stratigraphic and palaeogeographic setting of the late Cenomanian ‘anoxic’ event

Cited by 44 publications

References 16 publications

The prospectivity of the Vøring and Møre basins on the Norwegian Sea continental margin

The prospectivity of the Vøring and Møre basins on the Norwegian Sea continental margin

Evidence for oxic conditions during oceanic anoxic event 2 in the northern Tethyan pelagic realm

Oceanic events and biotic effects of the Cenomanian-Turonian anoxic event, Tarfaya Basin, Morocco

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