Why do Climbers Find Ocean Fossils on Mount Everest?
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If you scaled Mount Everest, you'd probably be surprised to find fossilised marine creatures on Earth’s highest peak, around 8,000m (26,000ft) above sea level. But there are lots up there.
At the summit, there is the sedimentary rock limestone known as the Qomolangma Limestone, and within it are a number of fossilized marine creatures from the Ordovician Period 488 million to 443 million years ago. Such fossils are found across the Himalayas, and finds include trilobites, brachiopods, ostracods and crinoids. Almost all sedimentary rocks are formed by water erosion, grinding up rocks over thousands or millions of years, before they are compacted and turned under pressure into sedimentary rock. The sedimentary rock and the presence of ancient marine creatures tell us that the rock at the summit of Mount Everest was once underwater. It also tells us that something happened to bring that rock over 8,000 meters (26,000 feet) above sea level.
The answer, of course, is plate tectonics. Everest and the Himalayas were formed in a collision between the Eurasian and Indian continental plates, which began around 40-50 million years ago, slowly pushing Mount Everest into the sky.
When the supercontinent Pangea broke apart 200 million years ago, the Indian plate began moving northwards towards Asia. Eventually, it collided with the Eurasian plate, forcing the land - including part of the seabed of the ancient Tethys Ocean - upwards. This enormous collision of two tectonic plates created the Himalayas and the Tibetan Plateau, lifting ocean fossils over 8,000m (26,000ft) above sea level.
"The Eurasian plate was partly crumpled and buckled up above the Indian plate but due to their low density/high buoyancy, neither continental plate could be subducted," The Geological Society explains. "This caused the continental crust to thicken due to folding and faulting by compressional forces pushing up the Himalayas and the Tibetan Plateau."
