This image shows the northern portion of east Candor Chasma, part of the Valles Marineris canyon system. In the center of the image is a light-toned mound that has dozens of layers exposed along its edge. As the upper layers weather and break apart into smaller grains, these grains subsequently fall down the edge, burying layers beneath and producing triangular-shaped debris aprons.

The color image of the mound doesn’t show any significant color variations between the different layers. However, another instrument on MRO called CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) has observed compositional differences between the layers and these results have been helpful in deciphering the origin of these layers.

This deposit is one of several examples exhibiting sulfate-rich layers with alternating hydration states. Cliff-forming kieserite-rich layers alternate with slope-forming polyhydrated sulfate layers. (Kieserite is a mineral containing magnesium). The apparent lack of slumping, channels, cross-bedding or bed truncation supports quiescent water or deposition from the air as the most likely origin for the layers.



Written by: Cathy  (27 February 2008)


This is a stereo pair with PSP_007179_1735.