Tag Archives: dunes

Is it an old fossil barchan dune?

A Piece of Mars: There are many barchans on Mars, those lovely isolated crescent-shaped dunes. In a few places there are what looks like ancient preserved barchans, now lithified. The mound in the center of this 0.96x0.54 km (0.6x0.33 mi) ...

Two directions

A Piece of Mars: Sometimes I just want to show the interior of a dune field, because it's full of waves: ripples and dune crests, slip faces, all of which signs of movement. The dunes in this 0.67x0.47 km (0.41x0.29 ...

Where on Mars is this dune?

A Piece of Mars: This 0.48x0.27 km (0.3x0.17 mi) scene shows a rotund barchan dune. Can you tell from looking at it where on Mars it might be? To me the most obvious feature are the bumpy piles at the ...

A big rock in a big air stream

A Piece of Mars: Sand pours in from the top of this 1.95x1.95 km (1.21x1.21 mi) scene. The sand piles up and up (here ~115 m or 377 ft high), but ahead (at the bottom) is a mountain poking up. ...

More Earth-like views of Mars

A Piece of Mars: In a recent post (Dunes in a Colorful Hole), I showed some dunes crawling over layered terrain, with a view that looked a lot like some desert regions of Earth. Here's another spot on Mars (0.95x1.1 ...

Hills made by wind and ice

A Piece of Mars: A fluid is something that fills a container it's put into, and it includes both gas and liquids. This 0.7x0.5 km (0.43x0.31 mi) scene shows hills of sediment left behind by two different fluids (wind and ...

Dunes in a colorful hole

A Piece of Mars: Gray dunes have migrated over reddish rock, moving toward a narrowing cleft surrounded by tall tan cliffs. Bright lines on the dunes are exposed internal layers (bones of the dunes, really) that show you where the ...

Who wins in the fight of wind vs. ice?

A Piece of Mars: This is the crest of one of the largest dunes on Mars (0.5x0.5 km or 0.31x0.31 mi). The wind mostly blows from the right, slowly pushing sand up the windward slope. But frost accumulates on (and ...

The two-faced dunes of Mars

A Piece of Mars: The focus of this 0.96x0.96 km (0.6x0.6 mi) scene is one of many two-faced dunes on Mars. The bright sunlit slope is one face, formed recently by wind blowing from the upper right. The dark shaded ...

Dunes carving up rock (3D)

A Piece of Mars: Get out your 3D blue/red glasses (or look here for a 2D version if you can't find them). This is a 3.2x1.8 km (2x1.13 mi) scene showing dark dunes carving lanes 50-70 m (165-230 ft) deep ...