Spiders in the South Polar Layered Terrain

Previously I talked about the South Polar Layered Deposits  (SPLD) that you’ve probably seen in some of the images you’re reviewing  on Planet Four: Terrains. Last week on Talk, I learned something new. Volunteer Ray noticed this image:

I thought it was pretty neat to see spiders directly carved into into some of the bands  of the SPLD. According to the rest of the science team, this can be a frequent experience, and they’ve seen it before. This was my first time encountering that, so I thought I’d share.Thanks Ray for spotting this.

Spider formation is caused by carbon dioxide gas trapped underneath a sublimated ice sheet during the Spring and Summer on the south pole of Mars. Eventually the gas breaks escapes through the ice sheet creating geysers but in the process it also exploits weaknesses in the surface regolith creating spiders. For some reason it appears those sections of the SPLD are weaker.

You can find more finds like this by classifying CTX (Context Camera) images of Mars’ south pole at http://terrains.planetfour.org