Tag Archives: erosion

Erosional remnants

A Piece of Mars: The erosionally-streamlined bright areas are on high ground. They are remnants of a vast dusty mantle that once covered this whole area - the rest of it has been blown away. The surrounding regions (check out ...

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 ...

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 ...

When the martian surface is eroded, pretty things emerge

A Piece of Mars: Just like at Earth's Grand Canyon, erosion on Mars has created some really beautiful landscapes. This 480x270 m (0.3x0.17 mi) scene shows rugged terrain that was once buried in sediment. Does the texture here represent the ...

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, ...

Dune cannibals II

A Piece of Mars: This 0.96x0.54 km (0.60x0.34 mi) scene shows two sets of bedforms (dunes), each aligned in different directions. The more closely-spaced set has sharper crests, and it's superposed on top of (and it is therefore younger than) ...

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 ...

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 ...

Windy windows

A Piece of Mars: Here's a tiny bit (0.69x0.39 km or 0.43x0.24 mi) of Jezero crater, one of the candidate landing sites for the Mars 2020 rover. On the bottom and left is high-standing volcanic terrain, former lava that flowed ...

The wind paints

A Piece of Mars: For the last few billion years, the wind has (by far) moved more sediment around on Mars than any other geological process. Not tectonics, volcanism, fluvial activity, or impact cratering (although a case has been made ...