Scientists, last month, reported that the Mars atmosphere was probably rich in oxygen about 4 billion years ago.
Scientists studied the compositions of Martian meteorites present on Earth and the data from NASA’s rovers. They found that surface rocks have five times more nickel than the meteorites.
“What we have shown is that both meteorites and surface volcanic rocks are consistent with similar origins in the deep interior of Mars but that the surface rocks come from a more oxygen-rich environment, probably caused by recycling of oxygen-rich materials into the interior,” explained study senior author Prof Bernard Wood.
“This result is surprising because while the meteorites are geologically young, around 180 million to 1.4 billion years old, the Spirit rover was analyzing a very old part of Mars, more than 3.7 billion years old.”
Scientists suggested that Martian surface was oxidized about 4 billion years ago and through the process of subduction, this oxygen-rich material was taken down into the shallow interior and recycled back to the surface. While the meteorites are much younger than the surface as they are less influenced by the process.
“The implication is that Mars had an oxygen-rich atmosphere at a time, about 4 billion years ago, well before the rise of atmospheric oxygen on earth around 2.5 billion years ago. As oxidation is what gives Mars its distinctive color it is likely that the red planet was wet, warm and rusty billions of years before Earth’s atmosphere became oxygen rich,” Prof Wood said.
J. Tuff,J. Wade & B. J. Wood (2013). Volcanism on Mars controlled by early oxidation of the upper mantle Nature DOI: 10.1038/nature12225