Jarosite is very rarely found on Earth, but is common on Mars.
An international team of researchers has found evidence of the mineral jarosite in ice cores mined from Antarctica, and they believe it could reinforce theories about the presence of the same mineral on the surface of Mars.
Jarosite was found on Mars by the Opportunity rover in 2004 and has been found to be abundant. Finding jarosite on Mars created a lot of excitement at NASA and around the world, because previous research had shown that water must be present for the formation of jarosite .
The discovery of jarosite on Mars led researchers to develop theories to explain how it might have originated. Some suggested that it might have been left behind when the salty water evaporated. Others suggested that Mars could have been covered by a huge ice sheet billions of years ago .
They further suggested that the jarosite could have formed in bags of ice. That would have been possible if the ice blanket had grown slowly and dust blew on it . At the time the theory was formulated it was difficult to prove because it had never been found to form that way anywhere else, including Earth.
But this new finding of jarosite on Earth would support this theory. Now that jarosite has been found deep in the Antarctic ice, this latest theory is likely to become the most prominent.
Still , the theory still has a problem : Ice in Antarctica contains very small amounts of jarosite, but on Mars, the mineral is found in large plates. The researchers suggest that the difference could be explained by the huge amounts of dust on the Martian surface, but we don’t know for sure.
Jarosite is a mineral, sulfate of potassium and iron with hydroxyl. It was described in 1852 by August Breithaupt , from specimens obtained in the Observation, Esperanza, Carmen and Estrella mines, in the Jaroso ravine, in the Sierra Almagrera, municipality of Cuevas del Almanzora, (Almería) Spain.