[Rockhounds] Superdeep diamonds confirm ancient reservoir deep under Earth's surface

[Kreigh Tomaszewski]

Analyses show that gases found in microscopic inclusions in diamonds come
from a stable subterranean reservoir at least as old as the Moon, hidden
more than 410 km below sea level in the Earth's mantle.

Scientists have long suspected that an area of the Earth's mantle,
somewhere between the crust and the core, contains a vast reservoir of
rock, comparatively undisturbed since the planet's formation. Until now,
there has been no firm proof if or where it exists. Now an international
group of scientists has measured helium isotopes
<https://phys.org/tags/helium+isotopes/> contained in superdeep diamonds
<https://phys.org/tags/diamonds/> brought to the surface by violent
volcanic eruptions, to detect the footprints of this ancient reservoir.
This work will be presented to scientists for the first time on Friday 23rd
August at the Goldschmidt conference in Barcelona, after publication today
(15 August) in the journal *Science*.

https://phys.org/news/2019-08-superdeep-diamonds-ancient-reservoir-deep.html