NASAのインスタグラム(nasa) - 10月3日 08時57分

Where does the sand on Mars come from? ?

The ultimate origin of the sediment that forms Martian dunes has long been debated. While sand dunes on Earth are primarily sourced by quartz-bearing components of granitic continental crust, it’s often suggested that sand on Mars derives from eroded volcanic flows or sedimentary deposits.

This image reveals a unique situation where this small dune field occurs along the summit of a large 1-mile-tall mound. The layered mound slopes are far too steep for dunes to climb, and bedform sand is unlikely to come from purely airborne material. Instead, the mound’s summit displays several dark-toned, mantled deposits that are adjacent to the dunes and appear to be eroding into fans of sandy material.

Since launching in 2005, our Mars Reconnaissance Orbiter spacecraft beams high-resolution imagery to help us better understand the Red Planet and in this case, reveal how landscape evolution occurs.
Credit: NASA/JPL/University of Arizona

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