The wild Martian terrain
This week’s image release from the high resolution camera on Mars Reconnaissance Orbiter illustrate well the wild and mysterious geology of the Martian surface. I include cropped sections from two images here, just to give you a taste. Go to the link to do your own exploring.
The image to the right is a cropped and scaled down version of the original image, so the details are not easily seen. Make sure you look at the original. The strange yardang ridges, all aligned alike, rise up out of a relatively smooth plain.
Yardangs are formed when a surface that is composed of materials of differing strengths (i.e., of both harder and softer materials) is shaped by the abrasive action of sand and dust carried by the wind. In this case, and given the proximity of the Apollonaris Patera volcanic center, we think that these wind-carved deposits are comprised of volcanic ash and pyroclastics that erupted from Apollonaris when it was last active in the not-too-distant geologic past. Over time, the softer materials (likely volcanic ash) were eroded away, leaving behind the harder materials in the form of elongated ridges that are parallel to the direction of the prevailing wind. The end result is a stunning, out-of-this-world display of yardangs, sculpted with the artistic chisel of the Martian wind.
That’s the theory, anyway. The actual geological process that formed these ridges is probably a lot more complicated.
The image below the fold illustrates the on-going surface activity on Mars.
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