Macquarie scientists uncover critical metals' secret sites

Scientists from Macquarie University in Australia have identified locations where deposits of metals critical to economic development are likely to be found. These metals play a very important role in modernising energy and developing renewable energy sources.

When we talk about critical metals, in this case, we are referring to resources such as copper, rare earth elements, and cobalt. Conducting the energy revolution will require larger resources of these metals than are currently available.

The Australian scientists published the results of their research in Nature. The research was led by Dr Chunfei Chen. In their postdoctoral studies, the scientists pointed out probable locations and explained the mechanisms of accumulation of critical metals on the margins of ancient continental cratons.

- These cores are the thickest, bowl-shaped, parts of tectonic plates. Melts that form below their centres will flow upwards and outwards towards the edges, so that volcanic activity is common around their edges – says Chen.

Previous experiments by the research group showed that the initial melts at a depth of approximately 200 kilometres (124 miles) are rich in carbonate but contain much less silica than most molten rocks. New studies show that the melts will lose silica and become nearly pure carbonate as they flow upward.

- The initial melts can carry lots of critical metals and sulfur, but our new results show that these are dropped by the melt as it loses silica. This causes concentrations of critical metals and sulfur in linear arrangements around the edges of thick continental cores – says Prof. Stephen Foley.

The research shows that mantle samples brought to the surface in volcanoes in these areas contain more sulphur and copper than elsewhere. This means that critical metals accumulate around the edges of the cratons, putting these areas in the spotlight for deposit exploitation.