Here’s how miners could one day be prospecting for minerals before they’re even formed
The search for precious diamonds could get easier with Aussie researchers making a new discovery about how they come closer to the Earth’s surface.
Researchers from the University of Wollongong (UOW) have made significant progress in understanding how minerals, specifically diamonds, move within the Earth’s mantle.
And their findings could have broader implications in exploration of other minerals and moves to green energy.
The research by Associate Professor Nicholas Flament and Associate Research Fellow Dr Ömer Bodur of the School of Earth, Atmospheric and Life Sciences at UOW was funded by the world’s largest diamond mining company De Beers Group and the Australian Research Council.
Dr Bodur told Stockhead there is data on locations around the world of kimberlite eruptions (which carry diamonds), mostly where diamonds can be found and are mined.
He said what the researchers were trying to explain were those kimberlite eruptions in terms of space and time. Essentially, why diamonds were surfacing at some locations at specific times in history?
“We wanted to know why we see these diamonds in certain places,” he said.
He said kimberlite eruptions tend to happen on stronger continents such as Africa, Canada and North America.
“When a continent is strong the more rigid part of the uppermost earth is thicker and geologically less disturbed,” he said.
The research question then became what drives these kimberlite eruptions, which are essentially small volcanos?
“We tried to understand what is the source of heat that drives these kimberlite eruptions,” he said.
The researchers tracked the movement of heat within the Earth’s mantle to predict kimberlite eruptions that carry diamonds from deep underground closer to the surface.
First, a quick lesson on the Earth’s mantle. The Earth’s mantle is a layer of solid rock between the crust and the core, playing a crucial role in shaping the planet’s geological activity and dynamics.
The mantle experiences high temperatures and pressure, causing the rock to flow slowly over long periods through a process called mantle convection.
This flow drives volcanic eruptions, earthquakes, and the movement of tectonic plates.
Although challenging to study due to its inaccessibility, understanding the mantle is essential for unraveling the Earth’s geological processes and gaining insights into phenomena such as mineral distribution and plate tectonics.
The global mantle flow models developed by Bodur and Flament reveal that Earth’s deepest mantle and the surface are connected by broad mantle upwellings.
These are pillars of heat that carry material and heat from the base of the mantle to the surface.
The heat carried by the upwellings can trigger kimberlite eruptions.
Their models – developed with supercomputers at The National Computational Infrastructure (NCI) in Canberra – show that the dynamics in the deepest mantle impact the surface and where kimberlites will erupt over time.
The models also show that at the centres of these pillars of heat, Earth’s mantle flows upward much faster so that it can carry dense basal mantle material, creating different chemical compositions between the kimberlite samples.
Bodur said the research is particularly relevant in the pursuit of minerals that will support the global transition to green energy, where accurate knowledge of the Earth’s interior is crucial.
“The Earth’s mantle can drive the geological activity which helps the emplacement of minerals on the Earth’s surface,” he said.
“Understanding the dynamics of how heat is transported across the mantle can have broad implications in terms of how other minerals beyond diamonds can emplace on the surface.”