Mi(ni)Geo

Earth from Space: Algerian sands (by europeanspaceagency)

This image shows the sandy and rocky terrain of the Sahara desert in western Algeria. With the Mediterranean Sea almost 500 km away, the closest town to the area pictured here is Taghit in the Algerian province of Béchar. The commercial Ikonos-2 satellite acquired this image on 23 April 2008 at a spatial resolution of 4 m. Credit: EUSI.

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

Dune Migration 2 (by afmik)

SUNY Genseo Dept. of Geological Science

Earth from Space: Proba image of the Gobi Desert in China (by europeanspaceagency)

This Proba image shows numerous small lakes in the otherwise arid environment of the Gobi Desert in the Chinese Autonomous Region of Inner Mongolia, surrounded by some of the highest and largest sand dunes in the world. This image was acquired on 29 September 2005 by the Compact High Resolution Imaging Spectrometer (CHRIS). Credit: ESA.

Springtime at Marsʼ South Pole (by Lunar and Planetary Institute)

About two-thirds of the image is covered by part of the southern polar ice cap and other scattered ice deposits, near a feature known as Ulyxis Rupes. Ulyxis Rupes is a large cliff with a length of 390 km and a height of up to 1 km. The left side of the image is dominated by the polar capʼs ice shield, which is covered by dark dusty material that hides the bright ices beneath. (…) Just northward of the ice shield, about halfway across the image, there are large ice deposits that are heavily covered by overlying material blown into long dunes by the prevailing winds in this region. The orientation of the dunes suggests the wind must come predominantly from the northwest. With increasing distance from the south pole, ice becomes confined to larger impact craters, such as the one in the top right of the image. (…) Puzzling parallel structures in the martian dust can be seen in the bottom right quarter of the image. Although their origin is uncertain, it is possible that they are the result of underlying ice deposits, permanently frozen because they are protected by overlying dust and rocks. Image taken in January 2011.

A contrast of wet and dry near the Atlantic Ocean. This image is 2km (1.2mi) wide - Dunes of the Lencois Maranhenses National Park in Brazil. Credit: Google, DigitalGlobe. (via BingoPics)

This HiRISE image gives some clues to how the minerals are expressed on the surface [of Mars]. The banded bedrock is visible beneath a partial cover of much younger dunes. Bright, relatively white bands can be seen to alternate with slightly redder layers. These bright bands could be concentrations of opal. The darker bands might correspond to concentrations of brown jarosite. The minerals may have segregated because of gradients in the temperature or acidity of the fluid. These Martian deposits are not likely to be made up of pure opal of gemstone quality. However, opals and cherts on Earth are well known to preserve fossils and other biological evidence. Even a small sample of one of the bright bands in this scene would be priceless. Credit: Paul Geissler. (via HiRISE)

Death Valley National Park (via National Geographic)

Changes on Dunes in Russell Crater (by Lunar and Planetary Institute)