Antarctic ice shows traces of Martian mineral

Jarosite. (Image by Rob Lavinsky, Wikimedia Commons).

Researchers trying to understand ice age cycles by examining deep ice cores in Antarctica found jarosite, a mineral that is abundant on the Martian surface.

In a study published in the journal Nature Communications, the scientists explain that this finding is important because it may help confirm previous theories that suggest there has been liquid water on Mars. This is because on Earth, jarosite is rare and when it forms, it does so as the result of low-temperature acidic-oxidative weathering of iron-bearing minerals in water-limited settings. It may also appear as a byproduct of zinc refining.

The yellow-brown mineral was detected with X-ray absorption testing and electron microscopy in samples found below 1000 metres depth

In detail, the researchers believe their discovery backs a theory that suggested that Mars may have been covered by an ice blanket billions of years ago and that this coverage had dust blowing into it, thus, leading to the formation of jarosite in ice pockets. 

In Antarctica, the team led by Giovanni Baccolo from the University of Milano-Bicocca detected the yellow-brown mineral with X-ray absorption testing and electron microscopy in samples found below 1000 metres depth. 

Jarosite was adhering to residual silica-rich particles, which have been identified in the Talos Dome ice core and interpreted as products of weathering involving aeolian dust and acidic atmospheric aerosols. 

“The progressive increase of ice metamorphism and re-crystallization with depth, favours the relocation and concentration of dust and the formation of acidic brines in isolated environments, allowing chemical reactions and mineral neo-formation to occur,” their paper reads. “This is the first described englacial diagenetic mechanism occurring in deep Antarctic ice and supports the ice-weathering model for jarosite formation on Mars.”

Even though their findings back the model they still have to find a solid explanation as to why Antarctica contains small amounts of jarosite while in the red planet the mineral is found in large slabs.

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