Volcanic ash as a driver of enhanced organic carbon burial in the Cretaceous

On greater than million year timescales, carbon in the ocean-atmosphere-biosphere system is controlled by geologic inputs of CO 2 through volcanic and metamorphic degassing. High atmospheric CO 2 and warm climates in the Cretaceous have been attributed to enhanced volcanic emissions of CO 2 through...

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Bibliographic Details
Published in:Scientific reports 2018-03, Vol.8 (1), p.4197-9, Article 4197
Main Authors: Lee, Cin-Ty A., Jiang, Hehe, Ronay, Elli, Minisini, Daniel, Stiles, Jackson, Neal, Matthew
Format: Article
Language:English
Subjects:
704/106/47/4112
704/2151/598
Biosphere
Carbon
Carbon - chemistry
Carbon cycle
Carbon dioxide
Carbon Dioxide - chemistry
Climate
Cretaceous
Degassing
Geologic Sediments - chemistry
Humanities and Social Sciences
Isotopes
Magma
multidisciplinary
Nutrients
Organic carbon
Preservation
Rivers
Science
Science (multidisciplinary)
Seawater
Seawater - chemistry
Volcanic ash
Volcanic Eruptions
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Summary:On greater than million year timescales, carbon in the ocean-atmosphere-biosphere system is controlled by geologic inputs of CO 2 through volcanic and metamorphic degassing. High atmospheric CO 2 and warm climates in the Cretaceous have been attributed to enhanced volcanic emissions of CO 2 through more rapid spreading at mid-ocean ridges and, in particular, to a global flare-up in continental arc volcanism. Here, we show that global flare-ups in continental arc magmatism also enhance the global flux of nutrients into the ocean through production of windblown ash. We show that up to 75% of Si, Fe and P is leached from windblown ash during and shortly after deposition, with soluble Si, Fe and P inputs from ash alone in the Cretaceous being higher than the combined input of dust and rivers today. Ash-derived nutrient inputs may have increased the efficiency of biological productivity and organic carbon preservation in the Cretaceous, possibly explaining why the carbon isotopic signature of Cretaceous seawater was high. Variations in volcanic activity, particularly continental arcs, have the potential of profoundly altering carbon cycling at the Earth’s surface by increasing inputs of CO 2 and ash-borne nutrients, which together enhance biological productivity and burial of organic carbon, generating an abundance of hydrocarbon source rocks.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-018-22576-3