Foraminifera used to trace an early phase of glaciation. Glaciomarine sedimentation, resulting in the sequential development of four contrasting foraminiferal populations (assemblage zones). Gradual climatic deterioration culminated in major ice build-up by the late early Miocene. Intensification of glaciation within the Ross Sea area may be responsible for the increase in production of Antarctic Bottom Water and associated development of widespread early Neogene deep-sea hiatuses reported from lower latitude regions.--Modified journal abstract.