IA/U.Lisboa Seminar - The morphology and dynamic of large aeolian ripples in Gale Crater (Mars) - 24 janeiro 2019

Aeolian processes and sedimentary structures visible from orbital imagery can provide a unique insight into the wind conditions in other planetary surfaces. To achieve this purpose, a better comprehension of the dynamic and morphology of the bed forms is needed. I will focus on Martian dunes, which are sculpted by meter-scale bed forms, which have been interpreted as wind ripples based on orbital data. Because (terrestrial) aeolian ripples tend to orient and migrate transversely to the last sand-moving wind, they have been widely used as wind vanes on Earth and Mars. I will present new evidences that demonstrate that Martian large ripples are more complex and dynamically different from Earth's ripples. Consequently, the assumption of the transverse nature of the large Martian ripples must be used with caution when using these features to derive wind trends from orbital data.

Ongoing analogue studies of terrestrial ripple activity monitoring will also be discussed.