The regularly-spaced lineations in the troughs in the lower third of the image are drifts of windblown material. Sun illumination is from the left. North is up. The regularly-spaced ridges hidden in the shadow on the caldera floor are drifts of windblown material. Illumination is from the left.
North is up.
You may need to adjust the images for the gamma of your monitor to insure proper viewing. This MOC image is made available in order to share with the public the excitement of new discoveries being made via the Mars Global Surveyor spacecraft. Release of this image does not constitute a release of scientific data. The image and its caption should not be referenced in the scientific literature. Full data releases to the scientific community are scheduled by the Mars Global Surveyor Project and NASA Planetary Data System.