Tag Archives: ripples

Ancient ripples?

A Piece of Mars: Potential signs of wind activity are everywhere on Mars. Take this 0.96x0.54 km (0.6x0.34 mi) scene, which is on bedrock dated to be several billion years old. There's a fabric of ridges trending from the upper ...

Where we have been

A Piece of Mars: This 0.98x0.54 km (0.61x0.34 mi) scene shows ancient windblown bedforms (maybe dunes) that have been partially eroded by the wind. The wind has left behind ghostly stripes: these are remnants of where these things once were, ...

Landslides unlike any on Earth

A Piece of Mars: Click on this 0.96x0.54 km (0.6x0.33 mi) scene to see it in detail. Many thin, narrow landslides have formed on these dust-coated hills. As far as I'm aware, there's nothing like this on Earth. Inside the ...

How to hide geology on Mars

A Piece of Mars: Three things are trying to hide in this 0.96x0.48 km (0.6x0.3 mi) scene. 1) Craters are slowly being both scoured and buried by migrating sand, 2) the sand itself is hiding in the lee of crater ...

Giant “combs” on Mars

A Piece of Mars: This 480x270 m (0.3x0.17 mi) scene shows a herd of 100-300 m fine-toothed combs grazing on the surface of Mars. Wait, what? No, it's not really combs. This is actually a landscape covered by two sets ...

Old ripples

A Piece of Mars: In this 480x270 m scene (0.3x0.17 mi), there are a bunch of "ripples" spaced by 5-20 m (the quotes are because we don't know yet if these are ripples, dunes, or some other new kind of ...

Stripes by wind and gravity

A Piece of Mars: This scene (800x450 m or 0.5x0.28 mi) is a steep slope, with high rocky outcrops on the upper right and both gullies and ripples heading downslope to the lower left. The wider, brighter stripes are gullies ...

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. ...

How far does the wind blow stuff?

A Piece of Mars: Hargrave crater has an amazing array of colorful surfaces, each of which reflects a different type of rock (this scene is 480x270 m or 0.3x0.17 mi). I like the ripples sitting on top of it all; ...

Remnants of erosion

A Piece of Mars: The gray area in the center of the 480x270 m (0.3x0.17 mi) area is an erosional remnant: once, more of this area was covered by the gray stuff, but some of it has eroded away (most ...