Earth 35 Million Years Ago: The World Starts to Cool

Events of the time

• Popigai impact

  35.7 million years ago · Siberia, Russia

  A 100 km crater whose shocked rocks contain diamonds. Chesapeake Bay was struck within about a million years of it.

• Antarctica freezes over

  34 million years ago · Antarctica

  At the Eocene–Oligocene boundary the first lasting ice sheet formed on Antarctica, as CO2 fell and ocean gateways opened around it.

  ▶ Watch it happen on the globe

Which land was under the sea 35 million years ago?

On the map nearest this age (35 million years ago, Late Eocene), about 7% of today’s land was under the sea at some point, some 10.2 million km². That makes it number 73 of the 80 maps from 535 to 5 million years ago, which run from 2% to 50%. Each map shows the greatest flooding of its stage, so no single moment had quite this much sea.

• Tethys Ocean

  Permian to Miocene · Southern Europe, North Africa, the Middle East, Iran, the Himalaya and South-East Asia

  The ocean between the northern and southern continents. As Africa, Arabia and India moved north it closed, raising the Alps and the Himalaya; the Mediterranean is what is left of it.

• Turgai Strait

  Jurassic to Oligocene, on and off · Western Siberia and Kazakhstan, east of the Urals

  A sea east of the Ural Mountains that linked the Arctic to the Tethys and kept Europe apart from Asia for animals that could not swim. The map under-draws it.

• Mississippi Embayment

  Late Cretaceous to Eocene · The lower Mississippi valley, from the Gulf of Mexico north to southern Illinois

  A long bay of the Gulf of Mexico that reached up the Mississippi valley. It left the sands and clays under Mississippi, Arkansas and Tennessee.

Was it under the sea? 3 of 42 cities

2,044 marine fossil sites in the Paleobiology Database are dated closely enough to this map. Of those on today’s land, 85% fall in its shaded sea.

Seas: Ancient seas: PaleoCoastlines v7 (Kocsis & Scotese 2021), CC BY 4.0 · Fossils: Paleobiology Database.