Fish Fossils Become Buried Treasure

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Rare metals crucial to green industries turn out to have a surprising origin.

Rare metals crucial to green industries turn out to have a surprising origin. Ancient global climate change and certain kinds of undersea geology drove fish populations to specific locations. As remains of the fish fossilized, they accumulated valuable elements and these fossil beds became concentrated deposits of such metals. This discovery could aid future prospects for deposits of so-called rare-earth elements in other undersea locations.

Did you know that key components for things like wind turbines, LEDs and rechargeable batteries rely heavily on a group of metals known as rare-earth elements and yttrium (REY)? At present, the world’s supply of these metals mainly comes from mines in China; however, a large deposit near the Japanese island of Minamitorishima could soon help satisfy the ever-increasing demand. But how did the REY deposit get there and why that location?

“That story begins back in time in the Eocene epoch 34.5 million years ago, about halfway between now and the time of the dinosaurs,” said Assistant Professor Junichiro Ohta. “At that time, several things happened that led to the REY deposit. Firstly, vast amounts of nutrients accumulated in the deep ocean. Secondly, the planet underwent cooling which altered sea currents, stirring up these nutrient deposits. The seamounts then caused upwellings of nutrients delivering them to the fish, which thrived as a result.”

Read more at University Of Tokyo

Image: Purified osmium. Osmium concentration is typically very low, just parts per trillion. Accurate measurement of the element was a huge challenge for the team. Image: CC BY-NC-ND 3.0 Wikimedia Commons/Alchemist-hp