Today's Image of Mars is of layered deposits in the northern polar region of Mars. The layered deposits of dusty ice can stack up to 3 km. Differences in each layer's composition can tell a lot about the climate of the planet at the time of deposit.
These layered deposits are visible from orbit when troughs and scarps cut through the deposits. This is similar to a canyon on Earth, or a cliff, where the erosion has cut through the deposits and the layers can be seen by looking down the canyon. What is unusual about these deposits in Chasma Boreale is that not only are there layered ice deposits, but there are layered sand deposits as well.
This photo was taken by Mar Reconnaissance Orbiter's HiRISE camera in 2008. Clicking on this image will take you to the original captioned image by HiRISE where you can find more information on layered deposits.