Drake Passage opens
The gap between South America and Antarctica widens, and the last barrier to a circumpolar current gives way.
- When
- —
- Duration
- 7 million years
- Known to
- ± 4 million years
- Era
- Eocene, Cenozoic
South America and the Antarctic Peninsula pull apart through the Eocene, with a shallow gateway probably forming in the middle of the epoch and genuine deep-water connection developing between about 34 and 30 million years ago as seafloor spreading starts at the West Scotia Ridge. The timing is contested — estimates for the initial opening range from the Paleocene to the Oligocene — and so is its importance relative to falling carbon dioxide in freezing Antarctica. Both probably mattered; the argument is about proportions.