Tag Archives: dunes

Grainfall

A Piece of Mars: The dunes climbing over a rocky surface in this 0.96x0.54 km (0.6x0.34 mi) scene are mostly yellow because they're covered (and therefore kept immobile) by dust. The crest of one dune, though, shows recent activity: dark ...

Dunes and rock hurdles in Gale crater (3D)

A Piece of Mars: Wind from the upper left is blowing dark dunes toward the lower right in this 1.92x1.08 km (1.19x0.67 mi) anaglyph (if you don't have your red/blue 3D glasses handy, you can also check out the black ...

Light and dark

A Piece of Mars: This 0.96x0.54 km (0.6x0.34 mi) late winter scene is a study in contrast. The dark top half is uniformly rippled. This is the shady surface of the main windward side of one of Mars' biggest dunes, ...

Eroded dune

A Piece of Mars: Barchan dunes on Mars have a characteristic crescent shape, with a steep slope ("slip face") on the inside of the sharpest curve (see examples like this, this, these, or this). This image (873x491 m, or 0.54x0.31 ...

Fossil dunes

A Piece of Mars: This 1.92x1.08 km (1.19x 0.67 mi) scene shows eroded ridges that are, in fact, lithified dunes. They are so old that you might not recognize them as dunes without more context. This doesn't happen much on ...

Dunes not in the global dune database

A Piece of Mars: Ten years ago I participated in a global survey of martian dunes. But we missed a few dune fields, like these beauties. They're small, low, and in rugged terrain, which made them difficult to spot in ...

Itty bitty changes: places where the wind barely moves sand

A Piece of Mars: Not all dunes on Mars are moving at a measurable pace. This 0.96x0.45 km (0.6x0.28 mi) scene looks a lot like one I posted 3 years ago called Martian Sports. This image shows the same dunes ...

Wind shadow

A Piece of Mars: There's a dune field migrating past a 230 m (755 ft) diameter crater, creating a 1.6 km (1 mi) long "shadow" that's empty of dunes. Why? The rim of the crater pokes up just enough to ...

Three types of windblown piles of stuff

A Piece of Mars: The wind blows different sorts of sediment in different ways. Ultimately they pile up because some oddity in nature makes one spot accumulate more sediment than other spots, allowing that windblown pile of stuff to grow. ...

Dune shadows

A Piece of Mars: Normally I post in color, but sometimes you need to back out to the grayscale images to see the big awesome things. This scene is 4.6x2.6 km (2.8x1.6 mi); the conical hill is 1.4 km (0.89 ...