Morphological Evidence for Water on Mars

Overview

• Pictorial comparison of features on Earth and MarsGullies Alluvial fansSedimentary layers CrossbeddingVugsLake Missoula

Gullies

USGS image of Meteor Crater, AZMars Global Surveyor image of Mars

Gullies on Earth are formed by flowing water cutting through the soil. On Mars, frozen water near the surface is thought to melt and run to form gullies before refreezing or evaporating.

Alluvial Fans

USGS image of alluvial fan in Mojave Desert

Mars Global Surveyor image of alluvial fan

While alluvial fans on Earth are the result of sedimentary build up at the mouths of rivers, alluvial fans on Mars are found almost exclusively on crater rims.

Sedimentary Layers

Sedimentary layers like this are usually deposited wherelakes and other bodies of water occurred on Earth.

Mars Global Surveyor image of Candor Chasma

Crossbedding

Mars Opportunity rover image of crossbedding

Image of crossbedding on Earth

Common on Earth, this particular type of crossbedding (festoon)is the result of deposits made by flowing water.

Vugs

Mars Opportunity rover image of vugs

Vugs in rock sample from Earth

Vugs form when mineral deposits in rocks are eroded awayby flowing water, leaving irregularly shaped holes behind.

Ripples

Lake Missoula ripples

Mars Opportunity rover image of ripples

Boulder Fields

Scablands

Coulees

Grand Coulee, Montana

Coulees constitute the largest channels and are among the most spectacular erosional features in the scablands.

Echus Chasma - Mars

River System

Scablands - Eastern Washington

Mars

Summary

• Certain features on Mars are similar to features commonly found on Earth.

• The features on Earth are known to have been caused by the existence of water in those locations.

• Most scientists now believe that these features on Mars are evidence that water has existed on Mars in the past and may, in fact, still exist below the surface today.

Bibliography• Anderson, P. (2006, January 08). Festoon cross-bedding. Retrieved Jun 10, 2008 from The Meridian

Journal web site: http://themeridianijournal.blogspot.com/2006/01/festoon-cross-bedding.html

• Bortman, H. (2004, March 03). Evidence of water found on Mars. In Astrobiology Magazine. Retrieved June 10, 2008 from NASA web site: http://astrobio.net/news/article859.html

• Nemiroff, R and Bonnell, J. (2003, February 05). Unusual Gullies and Channels on Mars. In Astronomy Picture of the Day. Retrieved June 10, 2008 from NASA website: http://antwrp.gsfc.nasa.gov/apod/ap030205.html

• O’Brien, M. (2000, June 22). Visual evidence suggests water springs on Mars. Retrieved June 10, 2008 from CNN website: http://archives.cnn.com/2000/TECH/space/06/22/mars.water.03/

• Webster, G. and Savage, D. (2004, March 02). Opportunity rover finds strong evidence Meridiani Planum was wet. Retrieved June 10, 2008 from NASA website: http://marsrover.nasa.gov/newsroom/pressreleases/20040302a.html

• Craters may control alluvial fan formation on Mars. (2005, October 31). In the Jounral of Young Investigators. Retrieved June 10, 2008 from The Journal of Young Investigators web site: http://www.jyi.org/news/nb.php?id=600