Scientists reveal how 34.5 million-year-old fish fossils help build up rare earth mineral deposits used to make LED TVs, wind turbines, and rechargeable batteries
- Researchers in Japan studied rare-earth mineral deposits off the coast of Japan
- They found ancient fossilized fish played a key role in forming the deposits
- The mineral deposits are commonly mined today for components used in a range of contemporary technology, including wind turbines and LED TVs
Scientists in Japan have documented the surprising link between fossilized fish from tens of millions of years ago to modern technological machinery, including wind turbines, rechargeable batteries, and LEDs used in flatscreen TVs and other digital displays.
A team from the University of Tokyo, led by Junichiro Ohta, set out to study a group of minerals collectively known as REY, or rare-earth minerals and yttrium, a specific metallic element with a long use-history in electronics.
REY deposits are commonly found in coastal regions of China and extracted for use in a range of technologies, but because they’re most often located undersea it can be challenging and expensive to find new deposit locations.
Researchers from the University of Tokyo studied undersea rare-earth mineral deposits and found they were partially formed by the presence of fossilizing fish in the seafloor
To try and develop a more efficient way of predicting where REY deposits might be found, the team studied a newly discovered deposit off the coast of Minamitorishima, a remote Japanese island in the North Pacific.
They compared the composition of ancient fish fossils found on the site to the chemical makeup of the REY deposits and found the fossils played a direct role in building up the REY deposits and could be used as an indicator of future deposit locations.
According to Ohta, the REY deposits began forming around 34.5 million years earlier.
“At that time, several things happened that led to the REY deposit,’ Ohta told Eurekalert. ‘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.’
As ancient fish dating back as far as 34.5 million years began to fossilize, minerals from the sea floor mixed with other nutrients and minerals the fish had absorbed while alive, creating the basis for new rare-earth mineral deposits
When generations of these ancient fish began to fossilize, their bodies attracted new minerals that mixed with the nutrients and other compounds they’d absorbed while alive, creating the basis for what would slowly transform into the future REY deposit.
‘I’m really pleased we made this discovery by looking at fragments of bones and teeth,’ Ohta said.
‘It was a difficult but satisfying task dating the deposits by comparing fossils we uncovered against a database of fossils with known ages.’
Today, these deposits are used to create components for a range of contemporary technology, including LED TVs, wind turbines, and rechargeable batteries
‘Equally so was another way we dated the deposits, by measuring the ratio of osmium isotopes in seawater trapped in REY-rich mud and comparing those to established records.’
While REY deposits are still plentiful around the world, the team hopes their research will make it easier to identify new sources for extraction.
‘Based on this new theory for the genesis of REY deposits in the ocean, we can improve the way we find future deposits,’ said Ohta.
‘We can target the feet of large seamounts on the seabed, many of which are distributed from the western North Pacific Ocean to the Central Pacific Ocean, so are in theory accessible to Japan.’