Geochemical research could help identify microbial activity in Earth’s rock record and perhaps in Martian sediments
Because oxygen-bearing sulfate minerals trap and preserve signals from Earth’s atmosphere, scientists closely study how they form. Sulfates are stable over billions of years, so their oxygen isotopes are seen as a time capsule, reflecting atmospheric conditions while they were evolving on early Earth—and possibly on its planetary neighbor Mars. ⌘ Read more