image: Spherical iron concretions on Earth and Mars. This material relates to a paper that appeared in the Dec. 5th, 2018, issue of Science Advances, published by AAAS. The paper, by H. Yoshida at Nagoya University in Nagoya, Japan, and colleagues was titled, "Fe-oxide concretions formed by interacting carbonate and acidic waters on Earth and Mar." view more
Credit: [Credit: NASA/JPL-Caltech/cornell/University, rests are all Nagoya Univeristy Museum (NUM)]