Lecure: What Midwestern Lakes Tell Us About Early Earth and Mars

They Contain Depths: What Midwestern Lakes Tell Us About Early Earth and Mars

Elizabeth Swanner

NASA’s Curiosity and Perseverance rovers are exploring dried lake beds on Mars, remnants of a wetter climate about three billion years ago. Clues about the environments within these ancient lakes lie in the lake sediments left behind. The ancient martian atmosphere contained little to no oxygen, as it does now, and the lake waters were enriched in iron. These conditions are very similar to Earth and its oceans three billion years ago. To be able to interpret the chemical and mineralogical information left in Mars’ Lake sediments and Earth’s Ocean sediments, scientists need to investigate mineral formation in water bodies that have little oxygen and are enriched in iron.

Betsy Swanner’s research investigates Midwestern lakes that share common features to ancient martian lakes and Earth’s oceans. She uses a special type of lake that does not undergo seasonal mixing, and always has oxygen-free deep waters. Because there is no oxygen, microbes are the dominant life form. Microbial metabolisms can influence the composition of the minerals that form. Swanner will discuss how some minerals form, and how their presence in ancient Earth sediments or old martian lakebeds can tell us about past microbial life on Earth, or possibly Mars.