This is an image showing a Martian outflow channel.
Click on image for full size
Image from: NASA

Martian Outflow Channels

The Martian surface exhibits a large number of large, tear-drop shaped outflow channels such as the one shown in this image. Most of these are found on the slopes of the Martian volcanoes. They seem to start from a hole in the ground, and quickly develop their mature form, as if whatever came out of the ground came out full steam. An examination of their structure helps scientists estimate the rate at which the fluid came out, or the channels "capacity". The channels are typically 10 m to 100 m deep (about the depth of a football field), 40 km across, and filled with rubble. Mars Pathfinder landed on a channel such as this called Ares Vallis.

The most plausible explanation for these is that they are eruptions of ground water. There is no water left in these channels today.

Shop Windows to the Universe Science Store!

Our online store includes books on science education, classroom activities in The Earth Scientist, mineral and fossil specimens, and educational games!

Windows to the Universe Community



You might also be interested in:

Olympus Mons

The largest volcano in the solar system is Olympus Mons, shown in the image to the left. Olympus Mons is a Martian shield volcano. The altitude of Olympus Mons is three times the altitude of the largest...more

Ares Vallis

Mars Pathfinder touched down in what appeared to be the remnants of a catastrophic flood. Thus, scientists had the opportunity to study the remains of what is thought to be a surface created by flowing...more

Martian Floods

Separate from the Martian outflow channels, or the river valley networks, are large Martian lakes (600 km, or ~1000 miles across) which exhibit evidence of a periodic and catastrophic release of water...more

Martian Volcanoes

On this map of Mars, the lightly cratered Tharsis Ridge is shown, as well as the heavily cratered Martian highlands (near the bottom of the picture), and Valles Marineris to the right. The volcanoes are...more

The Transfer of Water in Martian History

The unusual global geography of Mars helps to explain the fact that water has been drawn from the southern hemisphere to the northern hemisphere of the planet through all of Martian history (that is, from...more

The Martian Cryosphere

The Martian geography is one of high altitudes at high southern latitudes and low altitudes at low latitudes. The ground is less frozen at low latitudes because it is warmer and water can evaporate. Thus,...more

Martian Fog

This is an image of fog in a Martian canyon. The presence of fog provides evidence of water, and a water cycle on Mars. More fog has been seen in images returned by Mars Global Surveyor of the south polar...more

Martian Orbital Eccentricity

The Martian climate is more influenced by the shape of the Martian orbit than the climate of the Earth is influenced by the shape of the Earth's orbit. The orbit of Mars is more elliptical than that of...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF