Using radar reflectivity to unlock the climate record contained in the Martian North Polar Layered Deposits

The North Polar Layered Deposits of Mars are a formation of water ice ~1000 km across and ~2 km thick. For years, scientists have looked to these layers of ice and dust as a possible source of information regarding how the planet’s climate has changed over the past ~4 million years. However, connecting these layers to specific climate conditions remains a challenge. Previous research has attempted to tie both radar stratigraphy and outcrop stratigraphy to the orbital cycles of Mars, but the proposed relationships are often contradictory, and struggle identify how specific layer properties might be tied to ancient climate.

To help resolve these issues, I synthesized a combination of SHARAD radar data, HiRISE imagery, topography, and electromagnetic modeling in an effort to quantify layer properties such as thickness and composition, and connect those properties to past climate conditions. I was able to quantitatively show that a set of layers known as marker beds is likely responsible for causing radar reflectors, and was able to show how radar reflectors could be used to infer the composition and relative thickness of these layers throughout the polar cap. With this information in hand, scientists can, for the first time, begin to realize the full potential of the North Polar Layered Deposits as a global climate record of Mars.