scour

March 29, 2021

Once covered, now revealed

March 29, 2021 Mars is such a fun place. We’re finding out that it’s got oodles of geologic history. It’s got layers deposited by wind and water and lava, altered in place (sometimes many times), then eroded again by wind […]
February 1, 2021

Both wind-carved *and* ancient

1 February, 2021 Are we tired of the pandemic yet? My kids haven’t gone to an actual school since last March. Fortunately we’re all healthy. I’m able to do most of my work, but it’s not easy. So let’s go […]
August 13, 2018

Where dunes once trod

Mars has been dusty, and that’s affecting the quality of HiRISE images (just look at the recent images in the catalog and you’ll see they’re not that great). That’s made it hard for me to choose a good one for […]
March 26, 2018

Wind-exposed layers

On Earth, layers comprising the geological record of an area are most often exposed by fluvial erosion, as a river cuts through rock (a typical example is the Grand Canyon). On Mars, fluvial channels are not so common (especially in […]
November 15, 2017

Overhang

A Piece of Mars: There’s a fabric of erosion in this 1×1 km (0.62×0.62 mi) scene, with the main wind blowing from lower right to upper left (and if you look carefully you’ll see there’s a second, subtler fabric a […]
October 23, 2017

Just do it

A Piece of Mars: It’s all about wind scour here in this 0.75×0.75 km (0.47×0.47 mi) view. The big “swoop” is an erosional channel dug into the surface by winds (blowing from the lower left) trying to erode the hills […]
July 25, 2017

Cross-strata or not?

A Piece of Mars: Sand dunes are one of the few sedimentary phenomena that leave behind layers that aren’t horizontal. They tend to have a characteristic lean to them (and we call them cross-strata). So when I see something that […]
January 16, 2017

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 3.2×1.8 km (2×1.13 mi) scene showing dark dunes carving lanes 50-70 m (165-230 ft) deep […]
October 31, 2016

On Mars the wind carves stream channels

A Piece of Mars: This 1.6×2 km (1×1.24 mi) scene mostly shows what wind will do to fine-grained, weakly-consolidated surfaces. It has created topography that further strengthens wind scour in the hollows, which even leave kilometers-long grooves reminiscent of water-carved […]