Status Report

NASA Mars Odyssey THEMIS Image: Water Flow Evidence in Kasei Vallis

By SpaceRef Editor
April 29, 2005
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Medium image for 20050429a

Image Context:

Context image for 20050429a
Context image credit: NASA/Mars Orbiter Laser Altimeter (MOLA) Team
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ParameterValue ParameterValue
Latitude20.7 &nbsp InstrumentVIS
Longitude287.4E (72.6W) &nbsp Resolution (m)19
Image Size (pixels)3058×1403 &nbsp Image Size (km)58.1×26.7

Full data on this image has now been released via the THEMIS Data Releases website.

Kasei Vallis is our topic for the weeks of April 18 and 25.

Originating on the margin of Lunae Planum, the Kasei Vallis

complex contains two main channels that run east-west

across Tempe Terra and empty into Chryse Planitia. During

the week of April 18th we will concentrate on the northern

branch of Kasei Vallis. The week of April 25 will be

devoted to the southern branch.

The formation of Kasei Vallis is still being studied and several

theories exist. It is thought that volcanic subsurfaceing

heating in the Tharsis/Lunae Planum region resulted in a release

of water, which carved the channels and produced the landforms

seen within the channels. One theory is that this was a one-time

catastropic event, another theory speculates that several flooding

events occurred over a long time period. Others have proposed

that some of the landforms (especially scour marks and teardrop

shaped “islands”) are the result of glacial flow rather than

liquid flow. Teardrop shaped islands are common in terrestrial

rivers, where the water is eroding material in the channel.

A glacial feature called a drumlin has the exact same

shape, but is formed by deposition beneath continental glaciers.

This VIS image shows evidence of water flow long after

the main channel was formed. The steep walls of the main channel

have shed material covering the channel floor. Enough time passed

for many craters to form prior to the incision of the final

central channel. Note the small craters being erased along the

rough margins above and below the small channel. Within the

small channel the layers of deposit filling the main channel are


[Source: ASU THEMIS Science Team]

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA’s Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA’s Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image Credit: NASA/JPL/Arizona State University

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SpaceRef staff editor.