Categories: AstrobiologyMars

New Analysis of Clay Deposits in Ancient Martian Lakes

[/caption]

Mars was once a much wetter world than it is now, with hot springs, rivers, lakes and perhaps even oceans. Just how wet exactly, and for how long, is still a subject of considerable debate. One vital clue comes from clay mineral deposits and sediments left over after the water disappeared, but still visible now. They provide a valuable insight into what Mars used to be like, and why it is the cold, dry place we see today.

A team of scientists from Brown University has just completed a new study of ancient lake beds on Mars, specifically looking at the clay deposits within them, to try to determine how many of these lakes still contain such deposits and their composition. So what do they tell us about conditions on early Mars? How does this affect the search for evidence of life?

As it turns out, about a third of the lake beds examined still show evidence for clay deposits. A total of 79 lake beds out of 226 studied to be exact, indicating that they are less common on Mars than on Earth. The reason for this may be that the chemistry of the water was not ideal for preserving clays or that the lakes were relatively short-lived.

The paper was just published in Icarus on March 2, 2012.

From the abstract:

“These results indicate that hydrated and evaporite minerals are not as commonly associated with lacustrine deposits on Mars as they are on Earth. This suggests in situ alteration and mineral precipitation, a common source of such minerals in terrestrial lakes, was not a major process occurring in these paleolacustrine systems, and that the observed minerals are likely to be present as transported material within the lacustrine deposits. The lack of widespread in situ alteration also suggests that either the water chemistry in these paleolake systems was not conducive to aqueous alteration and mineral precipitation, or that the open-basin lake systems were relatively short-lived.”

Images for the study came from the Mars Reconnaissance Orbiter, Mars Odyssey and Mars Express spacecraft.

Clay deposits have become a primary focus of study by orbiters and rovers, as they could preserve fossil traces of early life, just as they do on Earth. Even if they are less common on Mars, the fact that they do exist there is exciting, and there is now much interest in exploring them further. Apart from underground, they are the best places to look for such evidence of life. It is also possible that additional deposits have been buried underground, waiting to be discovered.

The Opportunity rover is currently very close to a treasure trove of clays in Endeavour crater, and it is expected to head straight for them after its winter “hibernation” is over in the next few months. The Curiosity rover, en route to Mars right now, will land in Gale crater next July, where there are also clay deposits near the base of a mountainous peak within the crater. Gale crater is thought to be another site of a former Martian lake.

The abstract is available here (with full paper available for purchase).

Paul Scott Anderson

Paul Scott Anderson is a freelance space writer with a life-long passion for space exploration and astronomy and has been a long-time member of The Planetary Society. He currently writes for Universe Today and Examiner.com. His own blog The Meridiani Journal is a chronicle of planetary exploration.

Recent Posts

The Historic Discussion of Ptolemy’s Star Catalog

From the time of its writing in the 2nd century CE, Claudius Ptolemy’s Almagest stood…

2 hours ago

The First Stars May Have Weighed More Than 100,000 Suns

The universe was simply different when it was younger. Recently astronomers have discovered that complex…

3 hours ago

Drag Sail Success! This Satellite Won't Turn Into Space Junk

The European Space Agency successfully tested a solar-sail-type device to speed up the deorbit time…

3 hours ago

Good News! Webb is Fully Operational Again

The James Webb Space Telescope is back to full science operations. One of the telescope’s…

6 hours ago

Soon Every Spacecraft can Navigate the Solar System Autonomously Using Pulsars

If you want to know where you are in space, you’d better bring along a…

16 hours ago

Astronomers Come Closer to Understanding How Mercury Formed

Simulations of the formation of the solar system have been largely successful. They are able…

16 hours ago