Ice Caps MOC image 46103 subframe centered on outcrop of layered deposits in the north polar region of Mars. The picture was taken in July1998, during early Northern Spring.
Illumination is from the right.
Where rocks were initially formed as layers of sediment, the historic record of Earth is deciphered by knowing that older layers are found beneath the younger layers. Scientists investigating changes in Earth's climate over the past few million years also use this principle to examine cores of ice from Greenland and Antarctica. Layered rock and layered polar deposits on Mars may also preserve a comparable record of that planet's geologic and environmental history. The picture shows a slope along the edge of the permanent north polar cap of Mars that has dozens of layers exposed in it. Some of the layers form steeper slopes than others, suggesting that they are more resistant to erosion.