A Sulfate Aerosol Trigger for the Sturtian Neoproterozoic Snowball Event
Abstract
Despite the dominance of the carbon cycle in determining the evolution of Earth's climate in general, certain events defy easy explanation via atmospheric CO2 changes alone. Here we discuss the particular role that transient planetary albedo changes via sulfate aerosol formation can play in major climate transitions. Specifically, we propose that SO2 outgassing associated with the eruption of the Franklin Large Igneous Province (LIP) led to the first Neoproterozoic Snowball event, the Sturtian, 716 Ma. We summarize U/Pb zircon and baddeleyite dating indicating the synchronicity of the Franklin eruptions and the onset of the Sturtian, and paleomagnetic data indicating that the Franklin erupted close to the equator. We then discuss in detail the modeling we have performed of eruption rate, the plume height achieved during basaltic fissure volcanism, the chemistry and microphysics of sulfate aerosol formation, and the dependence of aerosol longwave and shortwave radiative effects on atmospheric loading, particle size and surface albedo. We discuss the critical importance of the latitude of eruption, the tropopause height, and ocean dynamics in determining the strength and sign of aerosol radiative forcing. We finish by comparing the Franklin event with other LIP emplacement events in Earth history and make suggestions for future modeling.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMPP13E..07W
- Keywords:
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- 1032 Mid-oceanic ridge processes;
- GEOCHEMISTRY;
- 1699 General or miscellaneous;
- GLOBAL CHANGE;
- 4912 Biogeochemical cycles;
- processes;
- and modeling;
- PALEOCEANOGRAPHY;
- 8178 Tectonics and magmatism;
- TECTONOPHYSICS