Jarosite is a yellow-brown mineral that accommodates potassium, iron, and sulphate — and researchers have discovered it may function a natural geological clock on Mars.
Recently, a crew of researchers from round India sampled six jarosite veins from Kachchh in Gujarat, whose arid, salty terrain is much like that of Mars.
In the lab, the crew analysed how a lot mild the mineral emitted as a result of vitality it had saved from natural radiation, a phenomenon referred to as luminescence. First, they washed the grains in weak acid to roughly double their brightness, then zapped them with radiation, heated them, cooled them, and repeated the cycle many instances.
This approach, they revealed 4 clear emissions at about 100° C, 150° C, 300° C, and 350° C, even after baking the grains to 450 °C. This meant jarosite may survive being heated by a rover’s drill with out dropping its skill to luminesce.
When the crew measured how the glow grew with further radiation, they discovered the grains turned saturated between 590 and a couple of,600 grey (the SI unit of absorbed radiation dose). On Mars, natural radiation is roughly 65 milligray/12 months, so jarosite can file occasions that occurred inside the final 25,000 years.
Because jarosite is frequent on Mars, powerful, and simple to learn with small heaters and LEDs, the researchers have steered future rovers may use it so far mud storms, historic flood deposits, and volcanic ash.
Published – May 20, 2025 01:43 pm IST
