Carbonates found on Mars, increases chance of past life

William Atkins
Friday, 19 December 2008 22:06

Science - Space

The NASA Mars Reconnaissance Orbiter has found carbonate minerals on the planet Mars. Its discovery by U.S. and French scientists is now prompting planetary astronomers to rethink their theories that Mars once had a primarily global acidic environment (which is not very conducive to life).


The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) flying within the NASA Mars Reconnaissance Orbiter (MRO) imaged the carbonates on the planet Mars.

The NASA article “Scientists find ‘missing’ mineral and clues to Mars mysteries,” states that “Researchers using a powerful instrument aboard NASA's Mars Reconnaissance Orbiter have found a long sought-after mineral on the Martian surface and, with it, unexpected clues to the Red Planet's watery past.”

The scientists used CRISM to analyze bedrock layers on Mars. Specifically, they looked at bedrock layers surrounding the Isidis impact basin.

The 925-mile (1,489-kilometer) diameter basin was formed over 3.6 billion years ago. The instrument aboard the spacecraft found a region called the Nili Fossae, a 414-mile (666-kilometer) long trough system. Analysis of the data found that the area contains magnesium carbonate, which is associated with olivine, a mineral that reacts with water to form carbonate.

Such a discovery of the presence of carbonates indicates that the planet contained neutral-to-alkaline water when these minerals first formed over 3.6 billion years ago. Scientists had previously thought that the planet was exclusively acidic in nature.

Carbonates consist of various types of salts or esters of carbonic acid. They quickly dissolve with exposed to acid.

On Earth, carbonates include such minerals as chalk and limestone (specifically calcium carbonate [CaCO₃]).

Page two continues with this discovery, which is helping to re-shape our viewpoints of the Martian past.