A NASA rover has made a significant discovery on Mars, uncovering a plentiful mineral that was invisible to orbiters studying the Red Planet from space. The discovery of siderite, an iron carbonate mineral, is crucial evidence supporting the theory that Mars once had a thick carbon dioxide-rich atmosphere, allowing for a warm enough environment to support oceans, lakes, and streams.
The Curiosity rover, which has been exploring Mount Sharp in Gale Crater, analyzed four rock samples drilled at different elevations. Three of the samples showed considerable amounts of siderite, while one sample with no significant traces of siderite contained other iron-rich minerals that can form as siderite breaks down.
Siderite forms on Earth under specific chemical conditions involving water, iron, and carbon dioxide. The study suggests more carbon is stored in the Martian crust than previously thought. If similar carbonates exist in other sulfate-rich regions, they could represent a hidden trove of Mars’ ancient atmosphere.
The discovery contributes to mounting evidence that ancient Mars had the right chemical and environmental conditions not only to have liquid water but also to trap and cycle carbon in the air – factors that may speak to the planet’s past habitability. The presence of siderite in the rock samples suggests a gradual drying of ancient Martian lakes, leaving behind other minerals.
The findings provide a crucial piece of evidence for scientists studying Mars’ geologic and atmospheric evolution. “Drilling through the layered Martian surface is like going through a history book,” said Thomas Bristow, a NASA research scientist. The discovery could hold large amounts of carbon – perhaps equal to or even more than the carbon dioxide in Mars’ air today.
Source: https://mashable.com/article/nasa-mars-rover-atmosphere-discovery