60 million years of glaciation in the Transantarctic Mountains

The Antarctic continent reached its current polar location similar to 83 Ma and became shrouded by ice sheets similar to 34 Ma, coincident with dramatic global cooling at the Eocene-Oligocene boundary. However, it is not known whether the first Antarctic glaciers formed immediately prior to this or were present significantly earlier. Here we show that mountain glaciers were likely present in the Transantarctic Mountains during the Late Palaeocene (similar to 60-56 Ma) and middle Eocene (similar to 48-40 Ma). Temperate (warm-based) glaciers were prevalent during the Late Eocene (similar to 40-34 Ma) and, in reduced numbers, during the Oligocene (similar to 34-23 Ma), before larger, likely cold-based, ice masses (including ice sheets) dominated. Some temperate mountain glaciers were present during the Miocene Climatic Optimum (similar to 15 Ma), before a widespread switch to cold-based glaciation. Our findings highlight the longevity of glaciation in Antarctica and suggest that glaciers were present even during the Early-Cenozoic greenhouse world.