Iron-rich rocks could could hold signs of life

A robotic mission's search for life on Mars may seem worlds away from human scientists wandering around hot springs in Yellowstone National Park. But a study of the Yellowstone hot springs has revealed new clues about how organic materials might get preserved in similar environments on the Red Planet, bettering our chances of finding possible signs of life.

Most studies have focused on the preservation of organic material in silica-rich rocks—the primary source of tiny fossils on Earth that can only be seen with a microscope. But some researchers have begun looking at how iron-rich rocks can also contain possible signs of life. Their Yellowstone hot springs study found that iron could either preserve or react with organic material in a way that helps form a fossil record. Such findings counter previous assumptions that iron-rich rocks would destroy organic material through the chemical reaction known as oxidation.