Status Report

Mars Odyssey THEMIS Image: Medusae Fossae

By SpaceRef Editor

July 31, 2002

Filed under Daily Themis Pictures, Mars Odyssey THEMIS, US

Image Context:

Context image credit: NASA/Mars Orbiter Laser Altimeter (MOLA) Team

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This image crosses the equator at about 155 W longitude and shows a sample of
the middle member of the Medusae Fossae formation. The layers exposed in the
southeast-facing scarp suggest that there is a fairly competent unit
underlying the mesa in the center of the image. Dust-avalanches are apparent
in the crater depression near the middle of the image. The mesa of Medusae
Fossae material has the geomorphic signatures that are typical of the
formation elsewhere on Mars, but the surface is probably heavily mantled with
fine dust, masking the small-scale character of the unit. The close proximity
of the Medusae Fossae unit to the Tharsis region may suggest that it is an
ignimbrite or volcanic airfall deposit, but it’s eroded character hasn’t
preserved the primary depositional features that would give away the secrets
of formation. One of the most interesting feature in the image is the
high-standing knob at the base of the scarp in the lower portion of the
image. This knob or butte is high standing because it is composed of material
that is not as easily eroded as the rest of the unit. There are a number of
possible explanations for this feature, including volcano, inverted crater, or
some localized process that caused once friable material to become
cemented. Another interesting set of features are the long troughs on the
slope in the lower portion of the image. The fact that the features keep the
same width for the entire length suggests that these are not simple
landslides.

[Questions? Email images@themis.asu.edu]

[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