Neoproterozoic Snowball Earth Initiation From Silicate Weathering of a Large Igneous Province

The causes of Snowball Earth events, rare global glaciations important for the evolution of life, are unknown. Recent geochronology of the Sturtian Snowball and Franklin Large Igneous Province (LIP) suggest that the Franklin caused the Sturtian via ${\text{CO}}_2$ drawdown by silicate weathering. By modeling the climate response to LIP weathering, we show that this initiation mechanism is feasible given a cold background climate, rapid chemical weathering and erosion over a large area, and a weak sensitivity of the silicate weathering feedback strength. Our model indicates that similar Phanerozoic LIPs may have failed to trigger Snowballs due to hot background climates and lower erosion rates caused by lower topography or vegetation, while high ${\text{CO}}_2$ suppressed LIP perturbations earlier in Earth history. We therefore argue that Snowball initiation by weathering of the Franklin is plausible and consistent with the lack of Snowballs in the Phanerozoic and mid-Proterozoic, given specific conditions that motivate future geologic observations.