An ice age recorded in the polar deposits of Mars

Layered ice deposits at the poles of Mars record a detailed history of accumulation and erosion related to climate processes. Radar investigations measure these layers and provide evidence for climate changes such as ice advance and retreat. We present a detailed analysis of observational data showing that similar to 87,000 cubic kilometers of ice have accumulated at the poles since the end of the last ice age similar to 370,000 years ago; this volume is equivalent to a global layer of similar to 60 centimeters. The majority of the material accumulated at the north pole. These results provide both a means to understand the accumulation history of the polar deposits as related to orbital Milankovitch cycles and constraints for better determination of Mars' past and future climates.