What controls the duration and intensity of ocean anoxic events in the Paleozoic and the Mesozoic?

Reershemius, Tom; Planavsky, Noah J.

doi:10.1016/j.earscirev.2021.103787

Cited by 30 publications

(8 citation statements)

References 321 publications

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“…Chemical weathering intensity was addressed calculating the Chemical index of alteration (CIA; defined as [Al2O3/(Al2O3+CaO*+Na2O+K2O)]x100 in molar concentrations; Nesbitt and Young, 1982), and Th/U and Rb/Sr element ratios to assess paleoclimate conditions during sediment deposition (Cole et al, 2009;Gao an Wedepohl, 1995;González-Álvarez and Kerrich, 2012;Mazumder, 2017;McLennan et al 1993;Rieu et al, 2007;Yan et al, 2010). Redox conditions can also give important information of the rock environment and the most representative redox proxies selected in this study has been Ce/Ce*, FeOt/Al2O3, (Bolhar et al, 2004;Phillips and Xu, 2021;Raiswell et al, 2018;Reershemius and Planavsky, 2021;Rudnick and Gao, 2003). The Ce anomaly is calculated according to the following equation 1 (Murray et al, 1990): Ceanomaly = Ce/Ce* = CeN / (0.5 LaN + 0.5 PrN) (eq.…”

Section: Discussionmentioning

confidence: 99%

Gondwana platform paleoenvironment reconstruction: Insights from Ordovician black-grey shales in NW Iberia

Lozano,

González-Menéndez,

González-Álvarez

et al. 2024

Preprint

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Gondwana developed marine platforms at its northern edge with Paleozoic deposits reflecting varied paleoclimatic conditions. In the northwestern (NW) Iberian Peninsula (NW Gondwana), Ordovician black-grey shales and sandstones were deposited in these platforms at southern polar latitudes. The current research contributes to a better understanding of the recycling, climate, and redox conditions during the deposition of black-grey shales in the low/mid-Ordovician period. During the Lower-Middle Ordovician period, the black-grey shales recorded an increase in recycling (Th/Sc, Zr/Sc, Zr/Ti, La/Th), low level of chemical alteration (CIA, Th/U) and relatively low oxygen conditions (Ce/Ce*, Y/Ho). These data indicate arid-cold conditions with a seasonal glacial-periglacial environment, consistent with the location of the NW Iberian Peninsula at low latitudes close to the South Pole. Towards the Middle Ordovician, the black-grey shales recorded a more temperate climate with higher levels of chemical alteration, less recycling, and a relatively more oxygenated environment, what suggests a transition to a moderate climate with no glacial events developed. This climate evolution could have been promoted by the progressive Gondwana drift away from the south pole aided by CO2 input to the atmosphere from alkaline mafic intraplate volcanism linked with a previous felsic LIP event in this area. The rapid decline of this volcanism and the partial alteration of its products (fixing CO2) could have contributed to the development of the Hirnantian glacial conditions during the Upper Ordovician, which brings a new view of the secular climatic evolution of the Earth during the Ordovician.

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Section: Discussionmentioning

confidence: 99%

Gondwana platform paleoenvironment reconstruction: Insights from Ordovician black-grey shales in NW Iberia

Lozano,

González-Menéndez,

González-Álvarez

et al. 2024

Preprint

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“…At the same time, a fully oxidized ocean provided a wider living environment for complex eukaryotic life, thus extending the P cycling from the Precambrian coastal environments into deep ocean (Nelson et al, 2010;Ruttenberg, 2014). In addition, we note that considering the much shorter residence time of P in organisms, especially in ocean biota (Ruttenberg, 2014;Karl, 2014), long-term geological activities are difficult to directly affect the fast biotic P cycling in ecosystems although during the mass extinctions when previous ecosystems broke, the long-term regulation of tectonic and marine redox on Earth's P cycle could be re-highlighted (Schobben et al, 2020;Reershemius and Planavsky, 2021;Ma et al, 2022b).…”

Section: Stage Iv: High-efficiency Biotic P Cycling (~ 380 Ma To Near...mentioning

confidence: 95%

A Five‐stage Evolution of Earth's Phosphorus Cycle

JIAO,

DODD,

ALGEO

et al. 2023

Acta Geologica Sinica (Eng)

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Phosphorus (P) is a key biological nutrient and probably the ultimate limiter of marine productivity during Earth history. In recent years, a wealth of new knowledge has revolutionized our understanding of the global P cycle, yet its long‐term evolution remains incompletely documented. In this paper, we review the effects of three major controlling factors on the long‐term evolution of the global P cycle, i.e., tectonics, marine redox conditions, and bio‐evolution, on the basis of which a five‐stage model is proposed: Stage I (>∼2.4 Ga), tectonic‐lithogenic‐controlled P cycling; Stage II (∼2.4 Ga to 635 Ma), low‐efficiency biotic P cycling; Stage III (∼635 Ma to 380 Ma), transitional biotic P cycling; Stage IV (∼380 Ma to near‐modern), high‐efficiency biotic P cycling; and Stage V (Anthropocene), human‐influenced P cycling. This model implies that the earlier‐proposed Ediacaran reorganization of the marine P cycle may represent only the start of a ∼250–Myr–long transition of the Earth's P cycle (Stage III) between the low‐efficiency biotic mode of the Proterozoic (Stage II) and the high‐efficiency biotic mode of the Phanerozoic (Stage IV). The development of biologically‐driven, high‐efficiency P cycling may have been a key factor for the increasing frequency and volume of phosphorite deposits since the late Neoproterozoic.

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“…Dramatic middle and late Mesozoic climate events are often associated with significant spread of reducing conditions and linked to increases in extinction rates 1 , 2 . These discrete episodes are characterised by intense perturbations in the global carbon cycle that typically record low O 2 conditions and widespread changes in ocean chemistry, called Oceanic Anoxic Events (OAEs) 2 – 5 . The OAEs are conventionally described as being characterized by black and dark shales with fine laminations and absence of bioturbation, increased sedimentary organic matter and presence of pyrite crystals that attest to low-oxygen conditions 2 .…”

Section: Introductionmentioning

confidence: 99%

“…The OAEs are conventionally described as being characterized by black and dark shales with fine laminations and absence of bioturbation, increased sedimentary organic matter and presence of pyrite crystals that attest to low-oxygen conditions 2 . However, the black shale record is sometimes limited in some OAEs or even absent, as occurred for the Paleocene-Eocene Thermal Maximum (PETM) 5 , 6 . In addition to these sedimentological markers, concentrations and isotopes of several chemical species (e.g., Mo, V, U) are largely applied as redox indicators to identify the OAEs 1 , 5 .…”

Section: Introductionmentioning

confidence: 99%

“…However, the black shale record is sometimes limited in some OAEs or even absent, as occurred for the Paleocene-Eocene Thermal Maximum (PETM) 5 , 6 . In addition to these sedimentological markers, concentrations and isotopes of several chemical species (e.g., Mo, V, U) are largely applied as redox indicators to identify the OAEs 1 , 5 . Most OAEs also are characterized by an initial negative δ 13 C excursion (CIE) due to input of light carbon ( 12 C) into the ocean–atmosphere system, followed by a positive CIE due to burial of excess 12 C in organic-rich sediments 1 , 5 , 7 .…”

Section: Introductionmentioning

confidence: 99%

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Unveiling a new oceanic anoxic event at the Norian/Rhaetian boundary (Late Triassic)

Rigo,

Jin,

Godfrey

et al. 2024

Sci Rep

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The latest Triassic was characterised by protracted biotic extinctions concluding in the End-Triassic Extinction (~ 200 Ma) and a global carbon cycle perturbation. The onset of declining diversity is closely related to reducing conditions that spread globally from upper Sevatian (uppermost Norian) to across the Norian-Rhaetian boundary, likely triggered by unusually high volcanic activity. We correlate significant organic carbon cycle perturbations to an increase of CO2 in the ocean–atmosphere system, likely outgassed by the Angayucham igneous province, the onset of which is indicated by the initiation of a rapid decline in 87Sr/86Sr and 188Os/187Os seawater values. A possible causal mechanism involves elevated CO2 levels causing global warming and accelerating chemical weathering, which increased nutrient discharge to the oceans and greatly increased biological productivity. Higher export production and oxidation of organic matter led to a global O2 decrease in marine water across the Norian/Rhaetian boundary (NRB). Biotic consequences of dysoxia/anoxia include worldwide extinctions in some fossil groups, such as bivalves, ammonoids, conodonts, radiolarians.

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What controls the duration and intensity of ocean anoxic events in the Paleozoic and the Mesozoic?

Cited by 30 publications

References 321 publications

Gondwana platform paleoenvironment reconstruction: Insights from Ordovician black-grey shales in NW Iberia

Gondwana platform paleoenvironment reconstruction: Insights from Ordovician black-grey shales in NW Iberia

A Five‐stage Evolution of Earth's Phosphorus Cycle

Unveiling a new oceanic anoxic event at the Norian/Rhaetian boundary (Late Triassic)

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