Tag Archives: layers

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 ...

Is it windblown or not?

A Piece of Mars: This scene is 0.96x0.54 km (0.60x0.34 mi) across. There's an old river valley running across it. The walls of the valley have been eroded and there's a washboard pattern with a wavelength of ~6m (20 ft). ...

Layered winds

A piece of Mars: On the left is high ground, covered with dunes (or maybe they're ripples) running from upper left to lower right. On the right is low ground, covered in deeply eroded dunes (ripples?) running almost from left ...

Ribbons on Mars

A piece of Mars: Bet you didn't know there were ribbons on Mars. Long, sweeping, velvety lines, delicately frayed at the ends. These are actually ancient ripples, formed by a wind blowing from right to left. Stripes on the ripples ...

Swoosh

A piece of Mars: What is this big swoosh? It's a big dark dune. The dark/light striping across it is found in all of the dunes in this area, but what is it? We're probably seeing the inside of the ...

How sand forms on Mars

A piece of Mars: All that sand on Mars -- where does it come from? It's often hard to figure that out. Here is a rare case where we can see material shedding from a stack of bright layered rocks, ...

What the wind brings, the wind takes away

A piece of Mars: These C and S-shaped things were once dunes that marched across the scene (from upper left to lower right), formed from sand deposited by the wind. Then that sand somehow became cemented, locking the dunes in ...

Topography

A piece of Mars: Topography makes for great landscapes. It also funnels winds, forcing dunes and ripples along particular pathways. Here a cliff (high ground is yellow) has forced low-lying, dark ripples to migrate up a slope at the end ...

Blue ribbon

A piece of Mars: In ancient, wind-carved hills, a bluish ribbon of actively moving sand still winds its way. It is a remnant of a long-lived period of wind scour that shaped this landscape. (And it's been stretched to look ...

Dune cannibals

A piece of Mars: Dunes often cannibalize each other, with new dunes forming from the sand in older dunes. Here the tan dunes have formed from the sand that made up the grayish blue dunes. Notice the banding on the ...