GCM response to late Precambrian (~590 Ma) ice-covered continents

Abstract

Recent coupled energy balance/ice sheet modeling studies indicate that ice-covered continents can be simulated for the Late Precambrian with 6% solar constant reduction. We examine the ocean mixed layer response to such an ice sheet with the GENESIS 2 general circulation model and CO2 levels varying from 0.5-2.5 times present. The ocean ices over completely at 0.5-1.0X present levels, with the final phase of sea ice growth occurring within a single model year. A qualitatively different 2.5X CO2 solution is close to equilibrium and yields open water between ~25 °N and ~25 °S paleolatitude. The prevailing wind patterns suggest that an equatorial Pacific-type circulation may have developed in part of the Neoproterozoic ocean.