Mi(ni)Geo

A Forest of Channels on the South Polar Layered Deposits (by Lunar and Planetary Institute)

The sublimation of seasonal carbon dioxide in the Martian polar regions seems to erode connected channels on the underlying surface, as escaping carbon dioxide gas scours the surface beneath the carbon dioxide ice. Such features are fairly common to the south polar region. However, the channel clusters here are unusually even in their spacing. The carbon dioxide gas-driven erosion will exploit pre-existing weakness in the underlying surface, so it’s possible that these features are following joints or fractures that exist in the layered deposits. The regularity of these features may suggest something about the thickness of ground ice deep below the surface. ASU-IPF-3256

Structural Colors (by zeesstof)

The slightly odd angle of the pale aeolian rocks here is the result of the interaction between two big faults. The inclined block between them is, in this case, a Relay Ramp. Partly because of the faults and partly due to erosion of the altered rock, the sediments show a multitude of reds, greens and other colors here.

Gullies in Bloom (by Lunar and Planetary Institute)

This observation shows mid-latitude-type gullies and dark and light materials. There are dunes in this crater as well (east of the gully aprons). One of the more stunning features is the gully formation right outside the center swath of the full image. ASU-IPF-3254

Argentina, 2010. Soil, wind erosion. (via Geology on Postage Stamps)

caveos:

Landmannalaugar, Iceland by Cor Laffra on Flickr.

(Source: caveo)

Argentina, 2010. Soil, water erosion. (via Geology on Postage Stamps)

ihalfshut:

New Zealand

planetsci:

I’m going to try something new on the Planetary Science Tumblelog today:

3D Thursday!

Space Missions take lots of pictures and they often take them close together. By overlapping two close images, we can make an anaglyph. Since Space is full of 3D stuff, we have lots to cover. Today PlanetSci will bring you two anaglyphs from Mars with NASA’s HiRISE Imager. So get out your red-cyan glasses!

This beautiful image shows Yardangs, which are created on Earth as wind carves sandstone into tall mounds. Even if you don’t have 3D specs, you should still check this picture out in 2D!

(Image Credit: NASA/JPL/University of Arizona)

Rocky Mountain National Park in Colorado contains many U-shaped glacial valleys, each of which ends at bowl-shaped region called a cirque. Cirques are the locations where glaciers accumulate most of their snow and ice, and so are the starting points for most glacial ice. Glacial erosion tends to create steep headwalls that frame in the cirque. The photo above shows the upper reaches of Glacier Gorge, which contains two cirques that merge downwards into one. The small peak (Spearhead) near the center of the photo forms a feature called an arete, as it separates the smaller cirques. (…) In the lower left corner, a hiker is perched on an outcrop of Proterozoic granite, directly in front of Longs Peak. Photo taken July 16, 2011. Credit: Marli Bryant Miller. (via EPOD)

While on a recent trip to the Canadian Rockies, we could not pass up a trip on the snowcoach, the bus that takes tourists out onto a safe bit of Athabasca Glacier, part of the larger Columbia Icefields. I was hugely impressed with the extent of the glacier’s retreat since my first visit in 1962. When we arrived at the safe spot (…) I found this lovely bit of otherwise undistinguished lateral moraine. The light couldn’t have been more dramatic as it highlighted the erosion on the loosely packed till. The surface of the glacier itself is seen at the bottom of the photo. Photo taken September 24, 2009. Credit: Stu Witmer. (via EPOD)

inlovewithgeosciences:

Karst landscape geology

“Cutaway artwork showing the features of a karst limestone landscape formed by erosion. The limestone rock has been shaped by natural chemical erosion. Carbon dioxide in the air dissolves in rainwater to form carbonic acid. This acid erodes the limestone rock as the water flows over it. At far right, a river flows down into the ground to form an underground river (across bottom), emerging at lower left. Two layers of caves are shown, with water seeping down from above to form stalactites, stalagmites, which can join to form large pillars. At left, the rock has been exposed, forming a limestone pavement.”

(via it-sfullofstars)

Gabbro Dreikanter (by Hypocentre)

Dreikanter is German for “three sides”. This gabbro ventifact is a classic dreikanter, sculpted by wind blown sand to produce a three-sided pyramid shape. I brought this sample which is about 25cm across back from the Atacama Desert of Chile.

A trio of weathering rinds (via Mountain Beltway)

A small amount of impact melt pooled and froze on the floor of this Copernican impact crater, and is 90 x 70 m in size. LROC NAC M111972680LE, image width is 750 m. Credit: NASA/GSFC/Arizona State University. (via LROC)

Bosques de rocas y algo de geoturismo. (via Geoextrema)