Planetary science: Two-score ice ages for Mars

The forty major ice ages experienced by Mars over the past five million years can explain the present distribution of subsurface ice.

More so than the Earth, Mars experiences dramatic changes in incident sunlight that can redistribute ice on a global scale. By numerically simulating the retreat and growth of ground ice, Norbert Schorghofer has shown how the subsurface ice sheets would have evolved over the many ice ages that occurred on Mars over the past five million years, to end up in the state we see them today. These processes have given rise to a three-layer sequence of ice at high latitudes, and ice in the pores of rocks at mid-latitudes. Combined, these provide enough ice to be compatible with that predicted from spacecraft observations of Mars.

The dynamic nature of martian ice sheets makes them an ideal system in which to test our knowledge of astronomical climate forcing. Furthermore, a great deal might be learned about terrestrial ice ages from the study of martian ice layering — a longer, cleaner and simpler record than Earth’s.

CONTACT

Norbert Schorghofer (University of Hawaii, Honolulu, HI, USA)

Tel: +1 808 956 9086; E-mail: norbert@hawaii.edu