Orbital changes drive deposition of south polar layered deposits

grl59231-fig-0001-m[Editor’s note: From a paper by Patricio Becerra and seven co-authors recently published in Geophysical Research Letters.]

Timescales of the Climate Record in the South Polar Ice Cap of Mars

• Patterns in the stratigraphy of Mars’ south polar ice sheet are consistent with orbital climate forcing
• Mars’ south polar ice sheet accumulated nonuniformly at rates of 0.11–0.39 mm/year
• Similar orbital oscillations forced the accumulation of the northern and southern ice sheets

The single location on Mars with the most water ice is in the southern polar ice cap, in the so‐called South Polar Layered Deposits (SPLD). Changes in Martian climate through time affect the locations on Mars where ice is stable, and it is believed that these changes drove the accumulation of layers upon layers of ice and dust in the SPLD.

The High‐Resolution Imaging Science Experiment and the Colour and Stereo Surface Imaging System are satellite cameras that have photographed troughs and scarps within the SPLD to produce 3‐D views of this layered internal structure. We analyzed this structure and found patterns in the layering related to variations of Mars’ orbit and spin axis.

These variations drive climate change on Mars, so our analysis confirms the connection between the SPLD and Mars’ astronomical parameters. From this relationship, we inferred that the ice and dust of the SPLD took at least 10–30 Myr to accumulate. [More at link]

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