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© 2025. This work is published under http://creativecommons.org/licenses/by/4.0/ (the "License"). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Feedback processes that drove Earth's second major increase in ocean–atmosphere oxygen levels during the Neoproterozoic are poorly constrained. Variability in seawater redox over geological timescales is commonly linked to changes in the biogeochemical cycling of P and thus the rate of primary production and generation of photosynthetic oxygen. In the modern surface ocean, an important source of bioessential P and micronutrients (Fe, Cu, Co, Zn, Mo, Cr and Ni) is aeolian dust derived from deserts and arid, post‐glacial landscapes. It is interpreted herein that glacial retreat following the Sturtian (ca 717 to 660 Ma) and Marinoan (ca 650 to 635 Ma) snowball glaciations provided copious dust to the global ocean. Correlation of interglacial siltstone successions in palaeogeographical context suggests that such dust accumulation was diachronous and concentrated in the palaeo‐horse latitudes (30° N and 30° S). Delivery of this dust from continents is likely reflected in the steep increase in global radiogenic Sr isotope values (87Sr/86Sr) in post‐Sturtian carbonates, and changes in the δ18O signatures of Cryogenian zircons derived from subducted marine sediments. Accumulation of sedimentary organic matter also peaked during interglacial periods, suggesting a causal link between glaciation, aeolian dust and primary production. This relationship implies windblown dust was an important source of P and micronutrients for an evolving biological pump that stimulated primary production, enhanced burial of organic carbon and increased ocean–atmosphere oxygen concentrations. Thus, delivery of aeolian dust to the global ocean was likely critical for sustaining Earth's second major increase in oxygen. Sequestration of atmospheric CO2 in organic‐rich siltstones and shales is also interpreted to have been an important negative feedback process, which together with silicate weathering, prevented runaway greenhouse conditions during interglacial periods. The oxygen produced by this aeolian marine biological pump may have helped pave the way for the evolution of multicellular animals in the Ediacaran.

Details

Title
Interglacial dust, ocean fertilisation and Neoproterozoic earth oxygenation
Author
DaSilva, Leandro G. 1   VIAFID ORCID Logo  ; Pufahl, Peir K. 1   VIAFID ORCID Logo  ; James, Noel P. 1 

 Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario, Canada 
Pages
654-674
Section
ORIGINAL ARTICLE
Publication year
2025
Publication date
Apr 1, 2025
Publisher
John Wiley & Sons, Inc.
e-ISSN
20554877
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3191214966
Copyright
© 2025. This work is published under http://creativecommons.org/licenses/by/4.0/ (the "License"). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.