The metals» solubility depends strongly on the amount of oxygen present, so the amount and type of those metals in ancient sedimentary rocks reflect how much oxygen was in the water long ago, when the sediments formed. (scientificamerican.com)
«You've got your work cut out if you're looking at ancient sedimentary rock for microfossils here on Earth — and even more so on Mars,» said Craig Marshall, the paper's lead author and an associate professor of geology at the University of Kansas. (sciencedaily.com)
The scientists turned to one of the world's oldest outcroppings of ancient sedimentary rock, located in Australia. (scientificamerican.com)