Lava in lab study suggests potential for new iron-ore deposits

16 April 2018 (Last Updated April 16th, 2018 12:41)

A new lab-based study conducted on iron-ore deposits by researchers from various institutions has determined that some magmas split into two separate liquids, including one that is rich in iron.

Lava in lab study suggests potential for new iron-ore deposits
The samples were placed in small golden capsules and subjected to temperatures of 1,000°C-1,040°C and one thousand times the atmospheric pressure of Earth. Credit: Lennart A Fischer.

A new lab-based study conducted on iron-ore deposits by researchers from various institutions has determined that some magmas split into two separate liquids, including one that is rich in iron.

The discovery could pave the way for the identification of new iron-ore deposits.

The institutions that participated in the project include KU Leuven, Leibniz University Hannover and University of Liège (ULiège).

A majority of iron ore deposits worldwide are currently found within sedimentary rocks.

However, certain accumulations known as Kiruna-type deposits, which contribute approximately 10% of the global production of iron, are mined in volcanic complexes such as El Laco in Chile and Kiruna, Sweden.

The researchers noted that there is no information in the public domain regarding how Kiruna-type deposits are formed.

KU Leuven Department of Earth and Environmental Sciences last author Olivier Namur said: “Previous studies have always focused on the texture or the composition of natural rocks.

"We wanted to reproduce the conditions found in magma chambers, where molten rock accumulates when it cannot rise to the surface of the earth."

“We were the first to actually reproduce magmas in the lab such as the ones found in El Laco, Chile.

“We wanted to reproduce the conditions found in magma chambers, where molten rock accumulates when it cannot rise to the surface of the earth.”

The team produced a mixture of iron-rich ore samples and lavas that are typically obtained in the vicinity of Kiruna-type deposits.

A bulk magma composition of this kind is believed to exist in the deep magma chambers beneath volcanoes.

The researchers placed the mixture in a furnace and raised the temperature to 1,000°C-1,040°C in order to replicate the conditions of a magma chamber.

The pressure inside the furnace was also raised to roughly 1,000 times the atmospheric pressure of Earth.

Namur noted that under these conditions, the magma split into two separate liquids.

He further added: “This process is known as immiscibility. Just think of what happens when oil spills into the ocean: the water becomes streaked with oil because oil and water cannot mix.”

One of the liquids was found to contain high levels of silica, while the other possessed abundant amounts of iron and phosphorus.

The cooling of the iron-rich liquid subsequently results in the formation of iron-phosphorous Kiruna-type ore deposits, as per the findings of the study.

The ​geologists concluded that immiscibility is a significant factor in the formation of iron ore deposits such as the ones mined in El Laco.

In addition, the researchers noted that conducting the latest study was a crucial step in the ongoing effort to address the growing global demand for iron.