03/22/2026
You won’t believe what climbers found near the top of Mount Everest: seashells older than 400 million years.
The summit of Mount Everest is made of Ordovician limestone that is roughly 450 million years old and contains fossils of ancient marine creatures including crinoids, trilobites, and brachiopods. These fossils were first documented by geologist Noel Odell during the 1924 British expedition and have been confirmed by researchers many times since.
The explanation is plate tectonics. Hundreds of millions of years ago the rocks that now form the Himalayas were part of the Tethys Sea floor. When the Indian tectonic plate collided with the Eurasian plate around 50 million years ago, the seabed was slowly pushed upward over tens of millions of years, eventually forming the tallest mountain range on Earth.
The fact that the highest point on the planet was once at the bottom of an ocean is one of the most mind-bending things geology has ever proven.
