Until Now
BiologyEnvironmentGeology

The first neotropical rainforest

A Colombian coal mine preserves the oldest rainforest of the modern kind — hotter than any today.

When
Duration
2 million years
Known to
± 1 million years
Era
Paleocene, Cenozoic

The Cerrejon Formation in northern Colombia, exposed by one of the world's largest open-pit coal mines, preserves a tropical forest from around 58 million years ago whose plant families — legumes, palms, aroids, moonseeds — are those of the modern Amazon. It is the oldest known neotropical rainforest, and it grew at mean temperatures some 3 to 5 degrees above present tropical values. That matters for a live argument: it shows lowland rainforest can persist, and indeed flourish, at temperatures once thought to exceed its limit.

Just before

Just after