The journal Nature Communications of January 19, 2021 reports the research work on climate change by Baccolo and his colleagues. By digging up to 1,620 meters deep in the Antarctic ice cap, they detected the presence of jarosite . This is concentrated in the lower layers of ice whose age is estimated at 153,000 years BC. JC. Pale yellow in color, sometimes yellowish brown or yellow ocher, jarosite occurs as tabular crystals or in powdery clusters.
Abundant on Mars, it is rare on Earth and is only found in small quantities in mining waste and sometimes in volcanic vents. The hypothesis widely shared by researchers is that just like Mars, the earth was covered with a lump of dust. This, trapped in the layers of ice that have accumulated over the millennia, has partly formed into jarosite.
It is the German Rammelsberg who, in 1838, described for the first time this matter which would form only under certain conditions which the environment of the Antarctic met.
How is jarosite formed?
Jarosite is made up of hydrated sulfate, iron and potassium with trace amounts of sodium, silver and lead. This rare mineral is found in liquids with low pH and high concentrations of iron and sulphate, such as process water at mining sites. It is only formed when mixed with water containing certain acidity properties.
Natural formation thus occurs through the oxidation of iron sulphides, but jarosite is often found as a by-product of zinc purification. Researchers see its abundance on Mars as proof that water once existed on this planet.
Theories relating to jarosite
Some researchers believe that it was the dust trapped in the ice sheet since the Ice Age that gave rise to jarosite. It formed in the form of pockets trapped in the ice. This theory is supported by the observation of particles using the electron microscope. This is far from being the case on Mars where jarosite does not appear in particles scattered here and there, but in thick layers.
Mine waste containing jarosite can be mixed with iron slag and various other materials such as lead, chromium and copper to be smelted. The resulting fusion results in a material which, when hardened, allows various uses such as bricks and tiles.