In southern Germany just north of the Danube, there lies a large circular depression between the hilly surroundings: the Nördlinger Ries. Almost 15 million years ago, an asteroid struck this spot. Today, the impact crater is one of the most useful analogs for asteroid craters on early Mars.
This article has been reviewed according to Science X's editorial process and policies . Editors have highlighted the following attributes while ensuring the content's credibility: Drill core from borehole taken in 1981 from the Nördlinger Ries. There are distinctive layers of light-colored dolomite between fine-layered dark sediments of the former crater lake. Credit: Gernot Arp, Göttingen University Studying the deposits of the former lake that formed in the crater is particularly informative. These deposits have been of great interest ever since NASA began exploring Martian craters for signs of water and life on Mars. However, the chemical development of the former crater lake and its habitable areas is only partially understood. An international research team led by the University of Göttingen has now uncovered clues about the past: they analyzed dolomite rocks in a drill core and found an extremely high proportion of the carbon isotope C-13. Further investigations traced this back to a phase of strong methane formation by microorganisms known as archaea in water with a low sulfate content. In contrast, the sediments of the previous, first phase of the crater lake showed clear traces of high sulfate content and bacterial sulfate decomposition. This…