Featured Research

from universities, journals, and other organizations

Patterns In Mars Crater Floors Give Picture Of Drying Lakes

Date:
September 16, 2009
Source:
Europlanet Media Centre
Summary:
Networks of giant polygonal troughs etched across crater basins on Mars have been identified as desiccation cracks caused by evaporating lakes, providing further evidence of a warmer, wetter martian past.

Detailed image of large-scale crater floor polygons, caused by desiccation process, with smaller polygons caused by thermal contraction inside. The central polygon is 160 metres in diameter, smaller ones range 10 to 15 metres in width and the cracks are 5-10 metres across.
Credit: NASA/JPL

Networks of giant polygonal troughs etched across crater basins on Mars have been identified as desiccation cracks caused by evaporating lakes, providing further evidence of a warmer, wetter martian past.

The findings were presented at the European Planetary Science Congress by PhD student Mr M Ramy El Maarry of the Max Planck Institute for Solar System Research.

The polygons are formed when long cracks in the surface of the martian soil intersect. El Marry investigated networks of cracks inside 266 impact basins across the surface of Mars and observed polygons reaching up to 250 metres in diameter. Polygonal troughs have been imaged by several recent missions but, until now, they have been attributed to thermal contractions in the martian permafrost. El Maarry created an analytical model to determine the depth and spacing of cracks caused by stresses building up through cooling in the martian soil. He found that polygons caused by thermal contraction could have a maximum diameter of only about 65 metres, much smaller than the troughs he was seeing in the craters.

“I got excited when I saw that the crater floor polygons seemed to be too large to be caused by thermal processes. I also saw that they resembled the desiccation cracks that we see on Earth in dried up lakes. These are the same type of patterns you see when mud dries out in your back yard, but the stresses that build up when liquids evaporate can cause deep cracks and polygons on the scale I was seeing in the craters,” said El Maarry.

El Maarry identified the crater floor polygons using images taken by the MOC camera on Mars Global Surveyor and the HiRISE and Context cameras on Mars Reconnaissance Orbiter. The polygons in El Maarry’s survey had an average diameter of between 70 and 140 metres, with the width of the actual cracks ranging between 1 and 10 metres.

Evidence suggests that between 4.6 and 3.8 billion years ago, Mars was covered in significant amounts of water. Rain and river water would have collected inside impact crater basins, creating lakes that may have existed for several thousand years before drying out. However, El Maarry believes that, in the northern hemisphere, some of the crater floor polygons could have been formed much more recently.

“When a meteorite impacts with the martian surface, the heat can melt ice trapped beneath the martian crust and create what we call a hydrothermal system. Liquid water can fill the crater to form a lake, covered in a thick layer of ice. Even under current climatic conditions, this may take many thousands of years to disappear, finally resulting in the desiccation patterns,” said El Maarry.


Story Source:

The above story is based on materials provided by Europlanet Media Centre. Note: Materials may be edited for content and length.


Cite This Page:

Europlanet Media Centre. "Patterns In Mars Crater Floors Give Picture Of Drying Lakes." ScienceDaily. ScienceDaily, 16 September 2009. <www.sciencedaily.com/releases/2009/09/090916092653.htm>.
Europlanet Media Centre. (2009, September 16). Patterns In Mars Crater Floors Give Picture Of Drying Lakes. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2009/09/090916092653.htm
Europlanet Media Centre. "Patterns In Mars Crater Floors Give Picture Of Drying Lakes." ScienceDaily. www.sciencedaily.com/releases/2009/09/090916092653.htm (accessed August 29, 2014).

Share This




More Space & Time News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
Powered by NewsLook.com
Space to Ground: Hello Georges

Space to Ground: Hello Georges

NASA (Aug. 18, 2014) Europe's ATV-5 delivers new science and the crew tests smart SPHERES. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins