The Mid-Cretaceous Organic-Rich Sediments from the Vocontian Zone of the French Southeast Basin

Bréhéret, Jean-G.

doi:10.1007/978-3-642-78849-9_21

Cited by 35 publications

(39 citation statements)

References 41 publications

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“…The early Barremian is thus characterized by relatively high values in the four studied sections as well as in the global curve of Fö llmi (1995). Following Bréhéret (1994) and Erba et al (1999), the early Barremian in the western tethyan realm is characterized by the deposition of black shales that appear contemporaneous with the positive peaks in PAR. Finally, in the late Barremian, PAR values are more or less constant (with a slight decrease), although the global curve of Fö llmi (1995) shows a slight increase (Fig.…”

Section: Comparison Of the Par Curves Between The Four Sectionsmentioning

confidence: 81%

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

Bodin

Godet

Föllmi

et al. 2006

Palaeogeography, Palaeoclimatology, Palaeoecology

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In the uppermost Hauterivian sediments of the western Tethys, a short-lived anoxic event (Faraoni event) is documented both in the form of an interval enriched in organic matter (pelagic realm) and in a condensed interval enriched in glauconite and phosphate (shelf realm). This latter interval represents the onset of a drowning episode on the Helvetic carbonate platform along the northern tethyan margin that lasted throughout the early Barremian. This drowning episode marks a turning point in the way the platform carbonate factory functioned: during the Hauterivian carbonate production was dominated by heterozoans, whereas during the late Barremian a photozoan assemblage developed that is preserved in the so-called Urgonian limestone. The late Hauterivian Faraoni oceanic anoxic event is of particular interest because it is not accompanied by a major positive shift in y 13 C unlike other oceanic anoxic events during the Cretaceous (Valanginian, early Aptian, Cenomanian-Turonian boundary).We have analyzed four (hemi-)pelagic sections with regards to their phosphorus content to better understand the palaeoceanographic conditions related to this anoxic event and the associated changes in the shallow-water carbonate factory. The sections are located in Angles (SE France), Fiume-Bosso and Gorgo a Cerbara (central Italy), and Veveyse de Châtel-St. Denis (west Switzerland). We calculated phosphorus mass accumulation rates by using a cyclostratigraphic approach in order to obtain an adequate age model. We observe a comparable and correlatable long-term trend for the four sections, which suggests that the phosphorus mass accumulation rates and temporal changes therein are representative for the western tethyan pelagic realm. The Faraoni event is marked by a minimum in phosphorus accumulation and a positive shift in the C org /P tot ratios, which is interpreted as a reflection of the decreased capacity of storing and preserving phosphorus in oxygen-depleted sediments. Moreover, the onset in the decrease in phosphorus accumulation coincides with a sea level rise, while the Faraoni level itself corresponds to a maximum flooding interval. This phase of sea-level rise may have been important in the establishment of marine connections between the boreal and tethyan realms and, as such, in the exchange of nutrient-enriched waters. The model for the origin of the Faraoni oceanic anoxic event proposed here incorporates these aspects together with a positive feedback loop generated by phosphorus regeneration and a negative feedback loop related to changes in the ocean oxygen cycle.The subsequent long-term changes in phosphorus burial rates during the Barremian suggest that the Faraoni event marks the onset of a long period of environmental instability with regards to platform growth, leading to periodic phases of eutrophication * Corresponding author. Tel.: +41 32 718 26 05; fax: +41 32 718 26 01.E-mail address: stephane.bodin@unine.ch (S. Bodin).and drowning of the northern tethyan carbonate platform. This environmental cr...

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Section: Comparison Of the Par Curves Between The Four Sectionsmentioning

confidence: 81%

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

Bodin

Godet

Föllmi

et al. 2006

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…Equivalent horizons in other areas of Italy have also been termed 'Livello Selli' or 'Livello Selli equivalent' (Coccioni et al 1987;Bersezio, 1992Bersezio, , 1993Bersezio, , 1994. Several coeval black organic-rich horizons have been recorded in other Tethyan areas both in the marine shelf and continental-margin successions of Europe (Bréhéret, 1994;Aguado et al 1999;Erba et al 1999;. The record of this event is also known from the Atlantic and Pacific oceans as well as California (e.g.…”

Section: A the Selli Level: Previous Datamentioning

confidence: 94%

Biotic and geochemical response to anoxic events: the Aptian pelagic succession of the Gargano Promontory (southern Italy)

2001

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Microfossil distribution patterns and high-resolution δ 13 C and δ 18 O curves, calibrated against planktonic foraminiferal and calcareous nannofossil data, are provided for the Aptian pelagic Coppitella section of the Gargano Promontory (southern Italy). The succession consists of cyclically arranged couplets of bioturbated grey marlstones and off-white marly limestones, referable to the Marne a Fucoidi. In the lower portion of the section, two thin black shales were recognized. The highresolution δ 13 C curve presented here correlates with those of other Alpine-Tethyan sections, albeit with lower absolute values. The onset of deposition of organic-rich sediments falls at the top of the interval of unchanging carbon-isotope values, whereas the upper black shale is documented from the interval of the main Aptian positive δ 13 C excursion. According to our biostratigraphic data, the deposition of organic matter in the Gargano Promontory persisted through Early/Late Aptian boundary time. Using a chemostratigraphic definition, only the lower black shale is referred to the Selli Level. As far as the biotic response is concerned, the onset of the 'nannoconid crisis' is recorded considerably below the lower black shale, whereas the 'Globigerinelloides eclipse' is recorded below and within the upper black shale. The distribution of meso-eutrophic indices (Zygodiscus spp., radiolaria) vs. moderate-fertility indices (Rhagodiscus asper and Lithraphidites carniolensis) testifies to a modest increase of surfacewater fertility only throughout the stratigraphically higher black shale. The occurrence of a benthic foraminiferal fauna, albeit impoverished, in both the basal and upper black horizons clearly documents dysaerobic rather than completely anoxic conditions on the sea floor. Relative sea-level rise at the time of the Selli Event in the Gargano Promontory is documented by drowning and foundering of the Apulia platform margin, situated adjacent to the basin in which the Marne a Fucoidi accumulated. ‡Author for correspondence: Hugh.Jenkyns@earth.ox.ac.uk

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“…Additional intervals of black shale accumulation include the late Aptian (∼116 Ma), latest Aptian–early Albian (OAE1b; ∼113–109 Ma), late Albian (OAE1c and OAE1d; ∼102 and ∼99.2 Ma, respectively), and mid‐Cenomanian (∼96 Ma [ Arthur et al , 1990; Bralower et al , 1993, 1999; Bréhéret , 1994; Erbacher et al , 1996, 2001; Wilson and Norris , 2001]). A black shale event in the late Aptian, between OAE1a and OAE1b in the Globigerinelloides algerianus biozone [ Bralower et al , 1999; Sliter , 1999], may prove to be an OAE.…”

Section: Oceanic Anoxic Eventsmentioning

confidence: 99%

“…OAE1d ( Rotalipora appenninica biozone), on the other hand, is widely preserved as a black shale across Tethys (“Breistroffer”) with sporadic occurrences in the South Atlantic, southern Indian, and eastern Pacific Ocean basins; it is associated with marine organic matter [ Bréhéret and Delamette , 1989; Bréhéret , 1994; Erbacher et al , 1996; Wilson and Norris , 2001]. Cyclic black shales in the uppermost Albian of Ocean Drilling Program (ODP) Site 1052 on Blake Nose are correlative to OAE1d and correspond to an interval marked by collapse of upper water column stratification caused by intensified winter mixing and reduced summer stratification [ Wilson and Norris , 2001].…”

Section: Oceanic Anoxic Eventsmentioning

confidence: 99%

“…This is an interval that contains several prominent black shales spanning the time of the Aptian/Albian boundary [ Arthur and Premoli Silva , 1982; Bréhéret et al , 1986; Bréhéret and Delamette , 1989; Premoli Silva et al , 1989; Tornaghi et al , 1989; Bréhéret , 1991, 1994; Erbacher et al , 1996, 1998, 1999; Erbacher and Thurow , 1997]. A sea level fall near the Aptian/Albian boundary [ Weissert and Lini , 1991; Bréhéret , 1994; Weissert et al , 1998] separates uppermost Aptian black shales (“Jacob” in the Vocontian Basin, and “113” in central Italy) from lower Albian black shales (“Paquier” and “Leenhardt” events in the Vocontian Basin, and the “Monte Nerone” and “Urbino” events in the Apennines of central Italy; Figure 1). Erbacher et al [1998] interpreted the uppermost Aptian Jacob event of the Vocontian Basin as a DOAE (formed by detrital input; “fed black shale”) and the lower Albian Paquier and Leenhardt events as POAEs (driven by productivity and rising sea level; “condensed black shale”).…”

Section: Oceanic Anoxic Eventsmentioning

confidence: 99%

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Oceanic anoxic events and plankton evolution: Biotic response to tectonic forcing during the mid‐Cretaceous

2002

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[1] Mid-Cretaceous (Barremian-Turonian) plankton preserved in deep-sea marl, organic-rich shale, and pelagic carbonate hold an important record of how the marine biosphere responded to short-and long-term changes in the ocean-climate system. Oceanic anoxic events (OAEs) were short-lived episodes of organic carbon burial that are distinguished by their widespread distribution as discrete beds of black shale and/or pronounced carbon isotopic excursions. OAE1a in the early Aptian ($120.5 Ma) and OAE2 at the Cenomanian/Turonian boundary ($93.5 Ma) were global in their distribution and associated with heightened marine productivity. OAE1b spans the Aptian/Albian boundary ($113-109 Ma) and represents a protracted interval of dysoxia with multiple discrete black shales across parts of Tethys (including Mexico), while OAE1d developed across eastern and western Tethys and in other locales during the latest Albian ($99.5 Ma). Mineralized plankton experienced accelerated rates of speciation and extinction at or near the major Cretaceous OAEs, and strontium isotopic evidence suggests a possible link to times of rapid oceanic plateau formation and/or increased rates of ridge crest volcanism. Elevated levels of trace metals in OAE1a and OAE2 strata suggest that marine productivity may have been facilitated by increased availability of dissolved iron. The association of plankton turnover and carbon isotopic excursions with each of the major OAEs, despite the variable geographic distribution of black shale accumulation, points to widespread changes in the ocean-climate system. Ocean crust production and hydrothermal activity increased in the late Aptian. Faster spreading rates [and/or increased ridge length] drove a long-term (Albian-early Turonian) rise in sea level and CO 2 -induced global warming. Changes in ocean circulation, water column stratification, and nutrient partitioning lead to a reorganization of plankton community structure and widespread carbonate (chalk) deposition during the Late Cretaceous. We conclude that there were important linkages between submarine volcanism, plankton evolution, and the cycling of carbon through the marine biosphere.

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The Mid-Cretaceous Organic-Rich Sediments from the Vocontian Zone of the French Southeast Basin

Cited by 35 publications

References 41 publications

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

Biotic and geochemical response to anoxic events: the Aptian pelagic succession of the Gargano Promontory (southern Italy)

Oceanic anoxic events and plankton evolution: Biotic response to tectonic forcing during the mid‐Cretaceous

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