Scientists at the University of Geneva have discovered significant knowledge about the origins of the formation of copper deposits and the discovery of new copper deposits.
Copper is one of the most widely used metals on the planet due to its impressive electrical and thermal properties. The largest natural resources of copper are known as “porphyry” deposits, which originate from magma deep in the Earth.
In a new study, researchers from University of Geneva (UNIGE) reveal that these porphyry deposits are created mainly by mechanisms comparable to those that cause large volcanic eruptions.
This research is carried out in an imperative period, as this metal plays an important role in the transition to green energy, and current copper resources are declining. Therefore, this breakthrough opens important paths for the progress of new tools for finding new deposits.
The results of the research of the UNIGE team are published in Communications Earth and environment diary.
The need for new deposits of honey
Copper is an incredibly versatile resource; it is an exceptional conductor and is very resistant to corrosion, which means that it is used for the production of a wide range of wires and electrical connectors. It is also used in the production of alloys such as bronze and brass.
In addition, copper is highly valued as a vital metal for the transition to green energy. In particular, it is widely used in the production of electric vehicles (EVs) and with the growing demand for EVs, demand for copper is expected to exceed current supply over the next three decades. This means that finding new deposits of honey and learning more about the formation of deposits is vital in the future.
This study, led by Massimo Chiaradia, a senior lecturer in the Department of Earth and Environmental Sciences at the UNIGE Faculty of Natural Sciences, led to a significant breakthrough. He emphasizes that porphyry deposits are the result of mechanisms comparable to those that cause large volcanic eruptions.
“We have found that large reserves of copper are born out of failed eruptions,” the researchers explained.
Understanding the formation of deposits
Copper is formed from hot liquids – largely composed of water – which is released when magma is cooled. These magmas, which are at the root of the eruptions, originate from the layer of the Earth between the core and the crust called the mantle. The magmas then rise to the surface of the Earth, where they develop into what is known as a “magma chamber.”
This camera is usually located at a depth of between 5 km and 15 km. “If the volume and rate of magma injection in this reservoir is very large, large amounts of liquid can be catastrophically released into the atmosphere with magma during a volcanic eruption,” Kiaradia said. However, these liquids can also appear below the earth’s surface and lead to a copper-porphyry deposit at a depth of between 1 km and 6 km.
It is also important to note that this phenomenon is much less frequent, which to some extent sheds light on the rarity of copper deposits. “It takes tens to hundreds of thousands of years for a copper deposit to form, while volcanic eruptions are more common. The failure of the eruption depends on a combination of several parameters: the rate of magma injection, the rate at which it cools, and the hardness of the earth’s crust that surrounds the magma chamber. The latter must be flexible to absorb the pressure exerted by the new magma arriving, so that the eruption does not occur, “added Luca Carici, second author and associate professor in the Department of Earth and Environmental Sciences.
To study a deposit
“Discovering the similarities between large eruptions and deposits will make it possible to use a large amount of knowledge acquired by volcanologists to improve our understanding of the formation of porphyry deposits,” said Kiaradia.
To achieve its results, the UNIGE team uses data and figures provided by mining companies, as well as data collected in the field and laboratory by various researchers. This was then combined with petrological and geochemical models.
The exciting discoveries of the team open new opportunities for the development of geological, mineralogical and geochemical instruments for future successful exploration of the largest copper-porphyry deposits on Earth. “The next step will be to work on a model that will help us quantify the total copper content and therefore the quality of a potentially exploitable field as accurately as possible,” Kiaradia concluded.