Scientists have discovered for the first time a new mineral, more than 600 km deep within Earth’s lower mantle, a diamond that they say must have collapsed before reaching the surface.
Earth’s lower mantle is the area between the planet’s core and crust.
This was a highly improbable discovery because minerals typically break apart before they reach Earth’s surface, unable to maintain their structure outside of the high-pressure environment, say the researchers, which include Las Vegas (UNLV). ), including people from the University of Nevada in the US. ,
The team’s study says that the newly discovered mineral – named devamaoite – may have survived such tremendous changes in pressure as it was inside the diamond. Published on Thursday in the Journal Science,
“I think we were very surprised. We didn’t expect it,” said UNLV mineralogist and study co-author Oliver Tschauner, said in a statement.
“For jewelers and buyers, the size, color, and clarity of a diamond are all that matter, and inclusions—those dark spots that haunt jewelers—to us, they are a gift,” said Dr.
Davamoite, the scientists say, is a calcium silicate compound, CaSiO₃-perovskite that appeared as tiny dark spots in diamonds discovered in the 1980s.
It came to the surface decades ago via the Orapa mine in Botswana – the world’s largest diamond mine by area.
A gem dealer later sold the diamond to a mineralogist at the California Institute of Technology in Pasadena in 1987.
Dr. Tschuner and his team then got their hands on the diamond, and analyzed its internal structure using a new suite of scientific instruments.
They named the new mineral “davemaoite”, after Ho-Kwang “Dave” Mao, a geophysicist who developed many of the techniques that Dr. Tschuner and his team use today.
In the deep mantle, the researchers say, devamaoite plays a role similar to that of garnet in the upper mantle with a chemistry that allows the minerals to host many elements that are incompatible in upper-mantle minerals.
They found that devamaoite’s composition enables it to host key heat-producing elements, including uranium and thorium, that influence heat production in Earth’s lower mantle.
Scientists say the mineral may have formed between 660 and 900 km from Earth’s surface, adding that the discovery of more such minerals would allow geologists to model the evolution of Earth’s mantle in more detail.
They say the discovery also marks one of two ways in which highly pressurized minerals are found in nature – either in Earth’s interior or from inside meteorites.
Credit: www.independent.co.uk /