Geochemistry of oceanic anoxic events

  title={Geochemistry of oceanic anoxic events},
  author={Hugh C. Jenkyns},
  • H. Jenkyns
  • Published 1 March 2010
  • Environmental Science, Geography
  • Geochemistry
Oceanic anoxic events (OAEs) record profound changes in the climatic and paleoceanographic state of the planet and represent major disturbances in the global carbon cycle. OAEs that manifestly caused major chemical change in the Mesozoic Ocean include those of the early Toarcian (Posidonienschiefer event, T‐OAE, ∼183 Ma), early Aptian (Selli event, OAE 1a, ∼120 Ma), early Albian (Paquier event, OAE 1b, ∼111 Ma), and Cenomanian–Turonian (Bonarelli event, C/T OAE, OAE 2, ∼93 Ma). Currently… 

Cretaceous oceanic anoxic events prolonged by phosphorus cycle feedbacks

Abstract. Oceanic anoxic events (OAEs) document major perturbations of the global carbon cycle with repercussions for the Earth's climate and ocean circulation that are relevant to understanding

Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event

The Early Jurassic Toarcian oceanic anoxic event (~183 Ma) was marked by marine anoxia–euxinia and globally significant organic-matter burial, accompanied by a major global carbon-cycle perturbation

Mexican archives for the major Cretaceous Oceanic Anoxic Events

Oceanic Anoxic Events (OAEs) are interpreted as brief episodes of oxygen-depleted conditions in the global ocean that resulted from profound perturbations in the carbon cycle. These events favored

Effect of a Jurassic oceanic anoxic event on belemnite ecology and evolution

It is inferred that belemnites adapted to environmental change by shifting their habitat from cold bottom waters to warm surface waters in response to expanded seafloor anoxia, enabling a strong evolutionary diversification after the Toarcian oceanic anoxic event.

Transient cooling episodes during Cretaceous Oceanic Anoxic Events with special reference to OAE 1a (Early Aptian)

  • H. Jenkyns
  • Environmental Science, Geography
    Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2018
High-resolution studies of OAE 1a show at least three cooling episodes of probable global distribution, one of which is documented at high enough resolution to show correlation with an increase in carbon-isotope values that was probably due to a rise in the quantities of organic matter being buried globally, with consequent potential drawdown of atmospheric CO2 and/or reduction in volcanic input of this greenhouse gas.

Changing inputs of continental and submarine weathering sources of Sr to the oceans during OAE 2

Abstract Ocean anoxic events (OAE) are characterized by increased organic content of marine sediment on a global scale with accompanying positive excursions in sedimentary organic and inorganic δ13C

Uranium isotope evidence for two episodes of deoxygenation during Oceanic Anoxic Event 2

Significance Past “Oceanic Anoxic Events” (OAEs) represent important carbon cycle perturbations that offer the opportunity to study Earth’s response to extreme climate warming. A fundamental



Molybdenum isotope evidence for global ocean anoxia coupled with perturbations to the carbon cycle during the Early Jurassic

Relatively brief periods of severe paleoenvironmental change during the Jurassic and Cretaceous were associated with the widespread accumulation of organic-rich marine deposits, termed oceanic anoxic

Calcareous nannofossils and Mesozoic oceanic anoxic events

  • E. Erba
  • Environmental Science, Geography
  • 2004

A volcanic CO2 pulse triggered the Cretaceous Oceanic Anoxic Event 1a and a biocalcification crisis

The Aptian Oceanic Anoxic Event 1a (OAE1a, ca.120 Ma ago) is one of the most prominent of a series of geologically brief intervals in the Cretaceous characterized by the deposition of organic

Global enhancement of ocean anoxia during Oceanic Anoxic Event 2: A quantitative approach using U isotopes

During the Mesozoic greenhouse world, the oceans underwent several oceanic anoxic events (OAEs) characterized by intervals during which organic-rich black shales were deposited, indicating strong

Cretaceous oceanic anoxic event 2 triggered by a massive magmatic episode

Se seawater osmium isotope ratios in organic-rich sediments from two distant sites are indicative of a widespread magmatic pulse at the onset of OAE2, which may have triggered the subsequent deposition of large amounts of organic matter.

Increased thermohaline stratification as a possible cause for an ocean anoxic event in the Cretaceous period

Stable isotope data from a mid-Cretaceous ocean anoxic event that occurred 112 Myr ago are presented and that point to increased thermohaline stratification as the probable cause, suggesting that processes leading to such ocean an toxic events in the North Atlantic and western Tethys were able to act over a much larger region, and sequester far more carbon, than any of the Quaternary sapropels.

Valanginian Weissert oceanic anoxic event

Biotic changes in nannofossils and radiolarians associated with the Valanginian δ 1 3 C anomaly are documented at Ocean Drilling Program Hole 1149B in the Pacific Ocean: they are coeval and similar

Calcareous nannoplankton changes across the early Toarcian oceanic anoxic event in the western Tethys

[1] Calcareous nannoplankton were profoundly affected by environmental perturbations coincident with the early Toarcian oceanic anoxic event (T-OAE). We quantify the abundance of nannofossils across

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

[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

Cretaceous oceanic anoxic events: causes and consequences

Organic carbon-rich sediments are globally developed in pelagic sedimentary sequences of Aptian-Albian and Cenomanian-Turonian age. They formed in a variety of paleo-bathymetric settings including