The Milos Island Fe-Mn Deposit: Implications for anoxic environments on Earth and Mars

Banded iron formations (BIFs) are Precambrian marine sedimentary rocks used for the reconstruction of the early biogeochemical processes that enabled the development of a habitable Earth. However, because of great age, severe metamorphic processes have compromised Precambrian BIFs. Moreover, the lack of modern analogues hinders attempts at constraining the accuracy of BIFs as early evolving planet ocean-atmosphere biogeochemical proxies. This presentation reports on the first finding of a modern BIF analogue since its disappearance from the sedimentary rock record, ~600 million years ago. The data provide vital information on the biogeochemical processes that formed the BIF-type rocks, with important implications for deciphering the biogeochemical origin of Precambrian BIFs, dating back to 3800 million years ago. The results add to a body of growing work critical for the identification of Earth-like habitable conditions elsewhere in the universe and for designing biosignatures for the potential detection of extraterrestial life.