Posted: Nov 15, 2021 05:15 GMT
Scientists theorized for years about the existence of this mineral, but until now no specimen has been found, since it decomposes into other minerals as it rises towards the Earth’s surface and the pressure decreases.
An international team of scientists published this November 11 in the journal Science a study in which they revealed that they had discovered inside a diamond a mineral never seen before.
Called davemaoita, this mineral is the first example of a perovskite stone, formed by calcium silicate under the high pressure and high temperatures of the Earth’s mantle. Researchers they had hypothesized for years on the existence of davemaoite, which would be an abundant and geochemically important mineral in the depths of our planet. However, until now no specimen had ever been foundas davemaoite breaks down into other minerals as it rises to the surface and the pressure decreases.
The study authors analyzed a diamond mined in Botswana that formed in the mantle, about 660 kilometers below the earth’s crust, and found a sample of intact davemaoite trapped inside it, which has led the International Mineralogical Association to confirm davemaoite as a new mineral.
“The davemaoite discovery was a surprise,” Oliver Tschauner, lead author of the study and a mineralogist at the University of Nevada, told Live Science.
Tschauner explained that to find the davemaoite sample, he and his colleagues used a technique known as synchrotron X-ray diffraction, which focuses a high-energy X-ray beam at certain points within the diamond with microscopic precision. By measuring the angle and intensity of the returning light, it is possible to decipher what is inside. The davemaoite sample measured about few micrometers (millionths of a meter), so according to Tschauner, other less powerful sampling techniques would not have detected it.
The scientific community theorizes that davemaoite may contain trace elements such as uranium and thorium, which release heat through radioactive decay. Tschauner pointed out that, due to this property, the mineral could contribute to generating a substantial amount of heat in the Earth’s mantle.
“Tschauner’s work inspires hope in the discovery of other difficult high-pressure phases in nature,” said Yingwei Fe, a geophysicist at the Carnegie Institute of Sciences in Washington DC, who concludes that “such direct sampling of the inaccessible lower mantle would fill our knowledge gap on the chemical composition of the entire mantle of our planet “.