Featured Research

from universities, journals, and other organizations

Pebbly rocks testify to old streambed on Mars

Date:
May 30, 2013
Source:
NASA/Jet Propulsion Laboratory
Summary:
Detailed analysis and review have borne out researchers' initial interpretation of pebble-containing slabs that NASA's Mars rover Curiosity investigated last year: They are part of an ancient streambed. The rocks are the first ever found on Mars that contain streambed gravels. The sizes and shapes of the gravels embedded in these conglomerate rocks -- from the size of sand particles to the size of golf balls -- enabled researchers to calculate the depth and speed of the water that once flowed at this location.

NASA's Curiosity rover found evidence for an ancient, flowing stream on Mars at a few sites, including the rock outcrop pictured here, which the science team has named "Hottah" after Hottah Lake in Canada's Northwest Territories. It may look like a broken sidewalk, but this geological feature on Mars is actually exposed bedrock made up of smaller fragments cemented together, or what geologists call a sedimentary conglomerate. Scientists theorize that the bedrock was disrupted in the past, giving it the titled angle, most likely via impacts from meteorites.
Credit: NASA/JPL-Caltech/MSSS

Detailed analysis and review have borne out researchers' initial interpretation of pebble-containing slabs that NASA's Mars rover Curiosity investigated last year: They are part of an ancient streambed.

Related Articles


The rocks are the first ever found on Mars that contain streambed gravels. The sizes and shapes of the gravels embedded in these conglomerate rocks -- from the size of sand particles to the size of golf balls -- enabled researchers to calculate the depth and speed of the water that once flowed at this location.

"We completed more rigorous quantification of the outcrops to characterize the size distribution and roundness of the pebbles and sand that make up these conglomerates," said Rebecca Williams of the Planetary Science Institute, Tucson, Ariz., lead author of a report about them in the journal Science this week. "We ended up with a calculation in the same range as our initial estimate last fall. At a minimum, the stream was flowing at a speed equivalent to a walking pace -- a meter, or three feet, per second -- and it was ankle-deep to hip-deep."

Three pavement-like rocks examined with the telephoto capability of Curiosity's Mast Camera (Mastcam) during the rover's first 40 days on Mars are the basis for the new report. One, "Goulburn," is immediately adjacent to the rover's "Bradbury Landing" touchdown site. The other two, "Link" and "Hottah," are about 165 and 330 feet (50 and 100 meters) to the southeast. Researchers also used the rover's laser-shooting Chemistry and Camera (ChemCam) instrument to investigate the Link rock.

"These conglomerates look amazingly like streambed deposits on Earth," Williams said. "Most people are familiar with rounded river pebbles. Maybe you've picked up a smoothed, round rock to skip across the water. Seeing something so familiar on another world is exciting and also gratifying."

The larger pebbles are not distributed evenly in the conglomerate rocks. In Hottah, researchers detected alternating pebble-rich layers and sand layers. This is common in streambed deposits on Earth and provides additional evidence for stream flow on Mars. In addition, many of the pebbles are touching each other, a sign that they rolled along the bed of a stream.

"Our analysis of the amount of rounding of the pebbles provided further information," said Sanjeev Gupta of Imperial College, London, a co-author of the new report. "The rounding indicates sustained flow. It occurs as pebbles hit each other multiple times. This wasn't a one-off flow. It was sustained, certainly more than weeks or months, though we can't say exactly how long."

The stream carried the gravels at least a few miles, or kilometers, the researchers estimated.

The atmosphere of modern Mars is too thin to make a sustained stream flow of water possible, though the planet holds large quantities of water ice. Several types of evidence have indicated that ancient Mars had diverse environments with liquid water. However, none but these rocks found by Curiosity could provide the type of stream flow information published this week. Curiosity's images of conglomerate rocks indicate that atmospheric conditions at Gale Crater once enabled the flow of liquid water on the Martian surface.

During a two-year prime mission, researchers are using Curiosity's 10 science instruments to assess the environmental history in Gale Crater on Mars, where the rover has found evidence of ancient environmental conditions favorable for microbial life.

More information about Curiosity is online at: http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ .

You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at http://www.twitter.com/marscuriosity .


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. R. M. E. Williams, J. P. Grotzinger, W. E. Dietrich, S. Gupta, D. Y. Sumner, R. C. Wiens, N. Mangold, M. C. Malin, K. S. Edgett, S. Maurice, O. Forni, O. Gasnault, A. Ollila, H. E. Newsom, G. Dromart, M. C. Palucis, R. A. Yingst, R. B. Anderson, K. E. Herkenhoff, S. Le Mouιlic, W. Goetz, M. B. Madsen, A. Koefoed, J. K. Jensen, J. C. Bridges, S. P. Schwenzer, K. W. Lewis, K. M. Stack, D. Rubin, L. C. Kah, J. F. Bell III, J. D. Farmer, R. Sullivan, T. Van Beek, D. L. Blaney, O. Pariser, R. G. Deen, and MSL Science Team. Martian Fluvial Conglomerates at Gale Crater. Science, 2013; 340 (6136): 1068-1072 DOI: 10.1126/science.1237317

Cite This Page:

NASA/Jet Propulsion Laboratory. "Pebbly rocks testify to old streambed on Mars." ScienceDaily. ScienceDaily, 30 May 2013. <www.sciencedaily.com/releases/2013/05/130530150547.htm>.
NASA/Jet Propulsion Laboratory. (2013, May 30). Pebbly rocks testify to old streambed on Mars. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2013/05/130530150547.htm
NASA/Jet Propulsion Laboratory. "Pebbly rocks testify to old streambed on Mars." ScienceDaily. www.sciencedaily.com/releases/2013/05/130530150547.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Space & Time News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) — NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. Video provided by Newsy
Powered by NewsLook.com
Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Reuters - US Online Video (Dec. 16, 2014) — NASA's Mars Curiosity rover finds methane in the Martian atmosphere and organic chemicals in the planet's soil, the latest hint that Mars was once suitable for microbial life. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Geminids Meteor Shower Lights Up Skies in China

Geminids Meteor Shower Lights Up Skies in China

AFP (Dec. 16, 2014) — The Geminids meteor shower lights up the skies over the Changbai Mountains in northeast China. Duration: 01:03 Video provided by AFP
Powered by NewsLook.com
Raw: Defense Satellite Launches from California

Raw: Defense Satellite Launches from California

AP (Dec. 13, 2014) — A U.S. defense satellite launched from California's central coast on Friday after weather delays caused by a major storm that drenched the state. (Dec. 13) Video provided by AP
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:

More Coverage


Rounded Stones on Mars Evidence of Flowing Water

May 30, 2013 — Observations by NASA's Mars rover Curiosity have revealed areas with gravel and pebbles that are characteristic of a former riverbed. Researchers have analyzed their shapes and sizes and the ... read more

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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