Martian winds lift sand grains into the air and drive them across the surface, where they erode soft sedimentary layers and gradually carve elongated grooves and ridges near the planet's equator. The remaining ridges, mounds, or columns, known as yardangs, stand above the surrounding terrain and often extend for tens of kilometres in the direction of the prevailing winds.
In northern Eumen Berlin, Germany (SPX) Jan 08, 2026
Martian winds lift sand grains into the air and drive them across the surface, where they erode soft sedimentary layers and gradually carve elongated grooves and ridges near the planet's equator. The remaining ridges, mounds, or columns, known as yardangs, stand above the surrounding terrain and often extend for tens of kilometres in the direction of the prevailing winds.
In northern Eumenides Dorsum, the yardangs share a common orientation that reflects a dominant wind direction sweeping in from the south-east and curving across a region roughly comparable in size to Belgium. These landforms occupy the northern end of the Eumenides Dorsum mountains, which lie just east of the Tharsis volcanic rise and form part of the dust-rich Medusae Fossae Formation identified in earlier Mars Express observations.
The area also contains a relatively fresh impact crater whose raised rim and extensive, wavy-edged ejecta blanket stand out against the wind-sculpted terrain. Material thrown out during the impact settled around the crater, forming a broad apron that interacts with nearby yardangs and helps scientists reconstruct the sequence of erosional and impact events in this sector of Mars.
A third key feature is a zone of so-called platy flow, located below and beside the main group of yardangs. This terrain resembles broken ice floes on terrestrial seas: as lava once advanced across the area, its surface crust solidified while molten rock continued to move beneath, breaking the crust into discrete plates that were carried along like rafts.
The yardangs border this platy flow terrain and also appear to sit on top of it, indicating that wind erosion operating on sedimentary deposits postdates the emplacement and cooling of the lava. This superposition relationship provides a relative timeline, with volcanism shaping the surface first and aeolian processes subsequently reworking it over long periods.
Mars Express acquired these data with its High Resolution Stereo Camera (HRSC), one of eight instruments carried by the orbiter. Since entering Mars orbit in 2003, Mars Express has returned colour, stereo, and high-resolution coverage of many martian landscapes, enabling detailed geological reconstructions of regions such as Eumenides Dorsum and the Medusae Fossae Formation.
The HRSC instrument was developed and is operated by the German Aerospace Center (DLR), which also carries out systematic data processing at its Institute of Space Research in Berlin-Adlershof. Researchers in the Planetary Science and Remote Sensing group at Freie Universitat Berlin used these processed data to generate derived products, including bird's-eye views and topographic maps of the northern Eumenides Dorsum region.
Related Links
European Space Agency Mars Express mission
Mars News and Information at MarsDaily.com
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