A team of geoscientists from Australia, Canada and the UK has detected primordial chemical signatures preserved within young kimberlites, small-volume volcanic rocks that are the source of most diamonds. Kimberlite from a mine in the United States. Image credit: Woudloper / CC BY-SA 1.0. “Knowing the chemical signature of Earth’s original building blocks is the holy grail of geochemistry,” said Professor Graham Pearson, a researcher in the Department...
![Backscattered electron images of experimental charges. Locations of images (A) to (D) from sediment-peridotite reaction experiments are schematically shown in capsule on the left. (A, C, and D) - reaction experiments at 5 GPa/1000 degrees Celsius with superimposed energy-dispersive x-ray maps of chlorine [green in (C) and (D)]. The sediment half of two-layer experiments recrystallized to garnet and clinopyroxene (Cpx), whereas orthopyroxene (Opx), magnesite (Mgs), and Na-K chlorides formed at the leading edge of the reaction zone against the peridotite. (B) - peridotite layer in the reaction experiment at 3 GPa/900 degrees Celsius contained phlogopite (Phl) behind the magnesite plus orthopyroxene zone, and Na-K chlorides were absent. (E and F) - sediment melting experiment (no peridotite included) at 4 GPa/1000 degrees Celsius showing silicate melt (E) in equilibrium with garnet (Gt), coesite (Coe), and Mg calcite (Mg-Cc) shown in (F). Scale bars - 100 μm (A and B) and 20 μm (C to F). Image credit: Förster et al, doi: 10.1126/sciadv.aau2620.](https://cdn.sci.news/images/2019/05/image_7241-Diamond-Salts-195x110.jpg)
