Knob in the South Polar Layered Deposits of Mars

The South Polar Layered Deposits of Mars are a thick stack of layers of ice and dust, deposited over millions of years. The rate of deposition changes over time, and in some times and places the stack is eroded.

Here, a low mesa or ring of hills occurs near the edge of the layered deposits. It is likely that this feature was once an impact crater. The floor of the crater became resistant, and was left behind as the rest of the surface eroded.

Images like this one can show us where the layered deposits are being eroded, and how much ice and dust has been lost. This, in turn, helps us understand the history recorded in the layers .

Written by: Colin Dundas   (10 July 2013)

This is a stereo pair with ESP_023066_0955 .

More info and image formats at

Image: NASA/JPL/University of Arizona