Climate Modelling of the late Neoproterozoic Era.

The late Neoproterozoic Era saw deep glaciation and possible rises in atmospheric and marine oxygen levels. It has been suggested that these environmental changes could be the consequence of supercontinent breakup and amplified continental weathering rates, which could have drawn down CO₂ and liberated nutrients. But this idea has not been tested using recent paleogeographic reconstructions and paleoclimate modelling. Here we present a suite of HadCM3L climate model simulations covering the late Neoproterozoic Era, specifically the descent into the Sturtian glaciation (800 – 715 Ma), based upon a new full-plate model and palaeogeographic framework. We outline the modelling strategy which includes representation of continental-scale icesheets and investigate the sensitivity of the climate to changing palaeogeography. To assess the implications for the carbon cycle, the resulting suite of climatologies are incorporated into the SCION climate-chemical model to produce a self-consistent reconstruction of biogeochemistry (including chemical weathering and atmospheric O₂ and CO₂) and climate.