Initiation of Snowball Earth with volcanic sulfur aerosol emissions

Abstract

We propose that the first Neoproterozoic Snowball Earth event, the Sturtian glaciation, was initiated by the injection of sulfate aerosols into the stratosphere. Geochronological data indicate that the Natkusiak magmatic assemblage of the Franklin large igneous province coincided with onset of the Sturtian glaciation. The Natkusiak was emplaced into an evaporite basin and entrained significant quantities of sulfur, which would have led to extensive SO2 and H2S outgassing in hot convective plumes. The largest of these plumes could have penetrated the tropopause, leading to stratospheric sulfate aerosol formation and an albedo increase sufficient to force a Snowball. Radiative forcing was maximized by the equatorial location of the Franklin and the cool Neoproterozoic background climate, which would have lowered the tropopause height, increasing the rate of stratospheric aerosol injection. Our results have implications for understanding Phanerozoic mass extinction events, exoplanet habitability, and aerosol perturbations to the present‐day climate.

Venusian Habitable Climate Scenarios: Modeling Venus through time and applications to slowly rotating Venus-Like Exoplanets

“…However, as noted in Macdonald and Wordsworth (2017) when the surface temperature is warmer (T>300K, see their Figure 2) more water vapor is injected into the stratosphere, which stabilizes the lapse rate. Such warm climates (as seen in the Venus models herein) would prevent the largest plumes from injecting SO 2 into the stratosphere, allowing CO 2 warming without offsetting cooling by H 2 SO 4 aerosols.…”

Did the transition to plate tectonics cause Neoproterozoic Snowball Earth?

“…Cooling as a result of increased explosive volcanism (2.9) may have caused NSE (Stern, Avigad, Miller, & Beyth, 2008). A similar effect was recently ascribed to LIP volcanism (2.10; Macdonald & Wordsworth, 2017). A transition to plate tectonics is very likely to have greatly increased explosive arc volcanism.…”

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Asteroid impact effects on Snowball Earth

“…). Today the discussion of mechanisms of the onset and cessation of the Snowball period includes many different possibilities, such as volcanic processes (MacDonald and Wordsworth ), volcano‐magmatic consequences of a single plate to modern plate tectonics transition (Stern and Miller ), changes in the cloud formation efficiency (Abbot et al. ; Abbot ; Feulner et al.…”