Brain Food: "Rock Varnish" On Mars?

Apr 27, 2017

By studying the relationship between minerals and microbes on Earth, scientists hope to learn more about the environment on Mars. The recent discovery of high concentrations of manganese on the Red Planet may suggest the signature of life. Now, a group of scientists is studying similar manganese-rich rock samples near Flagstaff to try to make a biological connection.

"Rock Varnish" found near Flagstaff
Credit Bonnie Stevens


Woody Fischer is a biologist at Cal Tech and part of the research team. He says, "Usually, when we find manganese we find evidence of life. But we want to know whether or not that might also be the case for other planets. We’re trying to recognize what are the minerals present, how are they being formed, are they being formed in environments that have cells present in them?"

Studying manganese-rich "rock varnish" found near Flagstaff
Credit Bonnie Stevens

The rocks Fischer is studying were taken from the Black Point Lava Flow on Babbitt Ranches. The samples are covered in a thin, manganese coating called “Rock Varnish”. DNA will be extracted from the varnish to find out what kinds of fungi and bacteria are living on it.

Nina Lanza is a planetary geologist at Los Alamos National Laboratory, also participating in the study. "We're trying to understand the role of this rock varnish", she says,  "and I’m going to try to understand, using just instruments on Mars: what are the chemical and mineralogical signatures that we could find? If these rocks were on Mars, could I tell if there was life or not, just using those data alone?"

Project researchers say the DNA testing will focus on “genes and pathways” that could allow microorganisms to flourish in the face of extreme environments, like the arid deserts of Earth, or the freezing temperatures of Mars.