Oceanic Anoxia and the End Permian Mass Extinction

Wignall, Paul B.; Twitchett, Richard J.

doi:10.1126/science.272.5265.1155

Cited by 1,042 publications

(493 citation statements)

References 18 publications

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“…Likewise, warmer conditions would have favoured the inorganic production of carbonate mud diluting any biogenic silica that may have been produced. The sluggish circulation would also have favoured pervasive oceanic strati¢cation and life-stressing sea-£oor anoxia (Wignall and Hallam, 1992;Wignall and Twitchett, 1996;Wignall et al, 1998).…”

Section: End-permian Global Warmingmentioning

confidence: 99%

Growth and demise of Permian biogenic chert along northwest Pangea: evidence for end-Permian collapse of thermohaline circulation

Beauchamp

Baud

2002

Palaeogeography, Palaeoclimatology, Palaeoecology

272

132

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The Permian Chert Event (PCE) was a 30 Ma long episode of unusual chert accumulation along the northwest margin of Pangea, and possibly worldwide. The onset of the PCE occurred at about the Sakmarian^Artinskian boundary in the Sverdrup Basin, Canadian Arctic, where it coincides with a maximum flooding event, the ending of high-frequency/high-amplitude shelf cyclicity, the onset of massive biogenic chert deposition in deep-water distal areas, and a long-term shift from warm-to cool-water carbonate sedimentation in shallow-water proximal areas. A similar and coeval shift is observed from the Barents Sea to the northwestern USA. A landward and southward expansion of silica factories occurred during the Middle and Late Permian at which time warm-water carbonate producers disappeared completely from the northwest margin of Pangea. Biotically impoverished and increasingly narrow cold-water carbonate factories (characterised by non-cemented bioclasts of sponges, bryozoans, echinoderms and brachiopods) were then progressively replaced by silica factories. By Late Permian time, little carbonate sediments accumulated in the Barents Sea and in the Sverdrup Basin, where the deep-to shallow-water sedimentary spectrum was occupied by siliceous sponge spicules. By that time, biogenic silica sedimentation was common throughout the world. Silica factories collapsed in the Late Permian, abruptly bringing the PCE to an end. In northwest Pangea, the end-Permian collapse of the PCE was associated with a major transgression and with a return to much warmer oceanic and continental climatic conditions. Chert deposition resumed in the distal oceanic areas during the early Middle Triassic (Anisian) after a 8^10 Ma interruption (Early Triassic Chert Gap). The conditions necessary for the onset, expansion and zenith of the PCE were provided by the thermohaline circulation of nutrient-rich cold waters along the northwestern and western margin of Pangea, and possibly throughout the world oceans. These conditions provided an efficient transportation mechanism that constantly replenished the supply of silica in the area, created a nutrient-and oxygen-rich environment favouring siliceous biogenic productivity, established cold sea-floor conditions, hindering silica dissolution, while increasing calcium carbonate solubility, and provided conditions adverse to organic and inorganic carbonate production. The northwest margin of Pangea was, for nearly 30 Ma, bathed by cold waters presumably derived from the seasonal melting of northern sea ice, the assumed engine for thermohaline circulation.This process started near the Sakmarian^Artinskian boundary, intensified throughout Middle and Late Permian time and ceased suddenly in latest Permian time. It led to oceanic conditions much colder than normally expected from the palaeolatitudes, and the influence of cold northerly-derived water was felt as far south southern Nevada. The demise of silica factories was caused by the rapid breakdown of these conditions and the establishment of a much warm...

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Section: End-permian Global Warmingmentioning

confidence: 99%

Growth and demise of Permian biogenic chert along northwest Pangea: evidence for end-Permian collapse of thermohaline circulation

Beauchamp

Baud

2002

Palaeogeography, Palaeoclimatology, Palaeoecology

272

132

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“…Levels of oxygen in the water column, expressed as the redox conditions, influence the oxidation state of some elements and selectively control their solubility in seawater and consequently their degree of enrichment in marine sediments (e.g., Myers and Wignall, 1987;Wignall and Twitchett, 1996;Arnaboldi and Meyers, 2007;Wignall et al, 2007). Uranium is among the elements which are sensitive to redox conditions in seawater.…”

Section: Redox Conditionsmentioning

confidence: 99%

“…The termination of glaciation left behind 12 C-depleted surface waters to recover productivity, which is reflected by the negative ␦ 13 C shifts exhibited in the cap carbonates immediately above the glaciogenic diamictites (e.g., Halverson et al, 2005Halverson et al, , 2007. On the other hand, the redox conditions influence the oxidation state and solubility of some rare earth elements (REEs) in ocean water such as Ce, and U, relative to other elements that stay unaffected such as Th (e.g., Wignall and Twitchett, 1996;Shields et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…Preserved marine carbonates are known to retain their primary chemical, elemental and isotopic, signatures that reflect the effect of prevailing oceanographic conditions and patterns (e.g., Wignall and Twitchett, 1996;Shields et al, 1997;Azmy et al, 1998;Veizer et al, 1999;Arnaboldi and Meyers, 2007;Wignall et al, 2007). Anoxic conditions have a dramatic impact on the organic productivity in oceans and, in most cases, may result in global mass extinction events (e.g., Wignall and Twitchett, 1996).…”

Section: Introductionmentioning

confidence: 99%

“…Anoxic conditions have a dramatic impact on the organic productivity in oceans and, in most cases, may result in global mass extinction events (e.g., Wignall and Twitchett, 1996). Although anoxic events in the Phanerozoic oceans developed mainly in stratified oceans, the Neoproterozoic anoxia is believed to have been caused by extensive global glaciation that reached as far as the equatorial latitudes (Snowball Earth hypothesis) and the ice cover separated the ocean from atmosphere, thus resulting in severe drop in oxygen levels in sea surface waters (Hoffman et al, 1998;Hoffman and Schrag, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Oceanic redox conditions in the Late Mesoproterozoic recorded in the upper Vazante Group carbonates of São Francisco Basin, Brazil: Evidence from stable isotopes and REEs

Azmy

Sylvester

Oliveira³

2009

Precambrian Research

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a b s t r a c tThe Vazante Group consists of a late Mesoproterozoic (∼1.0-1.1 Ga) carbonate-dominated marine platform sequence in east-central Brazil. The upper part of the sequence consists of a glaciomarine diamictite unit overlain by a cap carbonate. The ␦ 13 C profile of the upper Vazante shows significant negative plunges, one preglacial (drop of ∼5.5‰ VPDB) and two postglacial (drops of ∼9 and 5‰VPDB, respectively). The C-isotope plunge in the preglacial carbonates is correlated with low Th/U ratios (0.1-1.4) and a negative Ce/Ce* shift (∼0.4), suggesting deposition under relative reducing conditions. In contrast, the C-isotope plunges in the postglacial carbonates are associated with high Th/U ratios (>2) and positive Ce/Ce* shifts (up to ∼1.5), thus reflecting oxidizing conditions. Variations in the redox conditions of the late Mesoproterozoic ocean, reflected by changes in the Th/U and Ce/Ce* ratios, are likely attributable to a combination of both global and local climatic and oceanographic changes, similar to what has been inferred for the Neoproterozoic oceans.

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Decadal to centennial fluctuations in the intensity of the eastern tropical North Pacific oxygen minimum zone during the last 1200 years

et al. 2016

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Oxygen minimum zones (OMZs), located below highly productive marine regions, are sites of microbially mediated denitrification and biogeochemical cycling that have global significance. The intensity of OMZs fluctuates naturally; however, the degree of these fluctuations and a comprehensive understanding of the factors that drive these fluctuations on decadal to centennial time scales is lacking. Our high-resolution (near-annual) record of δ 15 N sed from laminated sediments at the Pescadero Slope in the Gulf of California (eastern tropical North Pacific) fluctuates between maximum values of 10.5‰ and minimum values of 8.0‰ over the past 1200 years. An analysis of the relationship between δ 15 NO 3 À and [O 2 ] in the water column suggests that the observed range of δ 15 N sed values is equivalent to an approximately 8 μM fluctuation in O 2 content and that these changes can occur in less than 25 years. Our findings show that the OMZ typically intensifies quickly and contracts gradually; the average rate of OMZ intensification (À0.24 μM O 2 /yr) is twice as fast as the rate of OMZ reoxygenation. Spectral analyses of the δ 15 N sed record and Br/Cl counts, with the latter are used as a proxy for organic carbon preservation, suggest that the Pacific Decadal Oscillation and the Suess (deVries) solar cycle (solar irradiance) may influence the intensity of the OMZ and carbon production/export during the late Holocene. Coherence between δ 15 N sed and weight percent organic carbon also suggests that similar mechanisms influence both OMZ fluctuations and variation in organic carbon production/export.

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Oceanic Anoxia and the End Permian Mass Extinction

Cited by 1,042 publications

References 18 publications

Growth and demise of Permian biogenic chert along northwest Pangea: evidence for end-Permian collapse of thermohaline circulation

Growth and demise of Permian biogenic chert along northwest Pangea: evidence for end-Permian collapse of thermohaline circulation

Oceanic redox conditions in the Late Mesoproterozoic recorded in the upper Vazante Group carbonates of São Francisco Basin, Brazil: Evidence from stable isotopes and REEs

Decadal to centennial fluctuations in the intensity of the eastern tropical North Pacific oxygen minimum zone during the last 1200 years

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