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Records of past mid-depth ventilation: Cretaceous ocean anoxic event 2 vs. recent oxygen minimum zones

Present day oceans are well ventilated, with the exception of mid-depth oxygen minimum zones (OMZs) under high surface water productivity, regions of sluggish circulation, and restricted marginal basins. In the Mesozoic, however, entire oceanic basins transiently became dysoxic or anoxic. The Cretaceous ocean anoxic events (OAEs) were characterised by laminated organic-carbon rich shales and low-oxygen indicating trace fossils preserved in the sedimentary record. Yet assessments of the intensity and extent of Cretaceous near-bottom water oxygenation have been hampered by deep or long-term diagenesis and the evolution of marine biota serving as oxygen indicators in today's ocean. Sedimentary features similar to those found in Cretaceous strata were observed in deposits underlying Recent OMZs, where bottom-water oxygen levels, the flux of organic matter, and benthic life have been studied thoroughly. Their implications for constraining past bottom-water oxygenation are addressed in this review. We compared OMZ sediments from the Peruvian upwelling with deposits of the late Cenomanian OAE 2 from the north-west African shelf. Holocene laminated sediments are encountered at bottom-water oxygen levels of < 7 µmol/kg under the Peruvian upwelling and 10 µmol/kg showed an inverse exponential relationship of bottom-water oxygen levels and organic carbon accumulation depicting enhanced bioirrigation and decomposition of organic matter with increased oxygen supply. In the absence of seasonal laminations and under conditions of low burial diagenesis, this relationship may facilitate quantitative estimates of palaeo-oxygenation. Similarities and differences between Cretaceous OAEs and late Quaternary OMZs have to be further explored to improve our understanding of sedimentary systems under hypoxic conditions.

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Cite this as

Schönfeld, Joachim, Kuhnt, Wolfgang, Erdem, Zeynep, Flögel, Sascha, Glock, Nicolaas, Aquit, Mohamed, Frank, Martin, Holbourn, Ann E (2015). Dataset: Records of past mid-depth ventilation: Cretaceous ocean anoxic event 2 vs. recent oxygen minimum zones. https://doi.org/10.1594/PANGAEA.844808

DOI retrieved: 2015

Additional Info

Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.844808
Author Schönfeld, Joachim
Given Name Joachim
Family Name Schönfeld
More Authors
Kuhnt, Wolfgang
Erdem, Zeynep
Flögel, Sascha
Glock, Nicolaas
Aquit, Mohamed
Frank, Martin
Holbourn, Ann E
Source Creation 2015
Publication Year 2015
Resource Type application/zip - filename: schoenfeld_2015
Subject Areas
Name: Ecology

Name: Lithosphere

Related Identifiers
Title: Records of past mid-depth ventilation: Cretaceous ocean anoxic event 2 vs. Recent oxygen minimum zones
Identifier: https://doi.org/10.5194/bg-12-1169-2015
Type: DOI
Relation: IsSupplementTo
Year: 2015
Source: Biogeosciences
Authors: Schönfeld Joachim , Kuhnt Wolfgang , Erdem Zeynep , Flögel Sascha , Glock Nicolaas , Aquit Mohamed , Frank Martin , Holbourn Ann E .

Title: Physical oceanography during METEOR cruise M77/1
Identifier: https://doi.org/10.1594/PANGAEA.777978
Type: DOI
Relation: References
Year: 2012
Source: IFM-GEOMAR Leibniz-Institute of Marine Sciences, Kiel University
Authors: Krahmann Gerd , Krahmann Gerd , Krahmann Gerd .

Title: Physical oceanography during METEOR cruise M77/2
Identifier: https://doi.org/10.1594/PANGAEA.778021
Type: DOI
Relation: References
Year: 2012
Source: IFM-GEOMAR Leibniz-Institute of Marine Sciences, Kiel University
Authors: Krahmann Gerd , Krahmann Gerd , Krahmann Gerd .

Title: Physical oceanography during METEOR cruise M77/3
Identifier: https://doi.org/10.1594/PANGAEA.777255
Type: DOI
Relation: References
Year: 2012
Source: IFM-GEOMAR Leibniz-Institute of Marine Sciences, Kiel University
Authors: Krahmann Gerd , Krahmann Gerd , Krahmann Gerd .