A team of geochemists published a fresh take on the Neoproterozoic Sturtian glaciation in the Proceedings of the National Academy of Sciences. Their coupled box model replaces the classic “Snowball” and “Slushball” pictures with alternating glacial and warm intervals lasting roughly four million years each. The approach directly addresses mismatches between predicted carbon‑oxygen cycles and the geological record.

The key trigger, they argue, was the weathering of the Franklin Large Igneous Province (LIP) around 717 Ma. Fresh basalt drew down atmospheric CO₂, plunging the planet into ice. Once glaciation halted, weathering stopped, volcanic outgassing rebuilt CO₂ until a threshold revived ice cover. This significant feedback produced repeated limit cycles that could span the observed 56‑million‑year Sturtian episode.

Oxygen levels, which would otherwise collapse during a continuous Snowball, remained sufficient for microbial life under this oscillating regime, matching isotopic evidence. Though the model abstracts many biogeochemical processes, it offers a coherent explanation for long‑standing paradoxes and provides a template for assessing similar freeze‑thaw cycles on rocky exoplanets. It also guides future climate models.