What question did this study set out to answer?

To determine the geochemical mechanisms driving three negative seawater strontium-isotope (87Sr/86Sr) excursions during the Jurassic and Cretaceous periods and evaluate their connection to Oceanic Anoxic Events.

February 1, 2001American Journal of Science

Seawater strontium isotopes, oceanic anoxic events, and seafloor hydrothermal activity in the Jurassic and Cretaceous

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To determine the geochemical mechanisms driving three negative seawater strontium-isotope (87Sr/86Sr) excursions during the Jurassic and Cretaceous periods and evaluate their connection to Oceanic Anoxic Events.
Calculated seawater strontium budget mass balances to test required adjustments in riverine fluxes, riverine 87Sr/86Sr ratios, and hydrothermal inputs.
Evaluated external geologic influences including continental weathering variations, sea-level fluctuations, and flood basalt volcanism.
Simulating the 5- to 13-million-year isotope excursions required either a 6% to 15% reduction in riverine strontium flux, a 0.00019 to 0.00046 drop in fluvial 87Sr/86Sr ratios, or a 7% to 104% increase in seafloor hydrothermal fluxes.
Riverine input variations were ruled out as the primary cause, identifying increased hydrothermal activity from ocean-crust creation at mid-ocean ridges as the most probable driver.
Elevated hydrothermal crust production chronologically aligns with Oceanic Anoxic Events via carbon dioxide outgassing and warming, with sea-level transgression acting as the terminal trigger.

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Implication

Geochemical modeling links Mesozoic seawater strontium isotope drops to enhanced seafloor hydrothermal activity, indicating crustal spreading preconditioned oceanic anoxic events.

Cite This Study

Charlie Jones (2001) studied this question.

synapsesocial.com/papers/6ab72a9229bf103ad7e6868b https://doi.org/10.2475/ajs.301.2.112

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Implication

Geochemical modeling links Mesozoic seawater strontium isotope drops to enhanced seafloor hydrothermal activity, indicating crustal spreading preconditioned oceanic anoxic events.

Seawater strontium isotopes, oceanic anoxic events, and seafloor hydrothermal activity in the Jurassic and Cretaceous

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Discussion

Implication

Cite This Study

Seawater strontium isotopes, oceanic anoxic events, and seafloor hydrothermal activity in the Jurassic and Cretaceous

Key Points

Discussion

Implication

Cite This Study

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