Rio Grande de Buba, Guinea-Bissau (via A.S.I.)
This image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite, shows wetlands in the Kitikmeot region of Nunavut Territory, in Canada, a region called “Barrend Grounds” or “Barren Lands”.
In this false-colour image of Mississippi River Delta, land vegetation appears pink, while the sediment in the surrounding waters are bright blue and green (via ESA)
Ouarkziz Impact Crater in Algeria. This crater (3.5 km wide) was formed by a meteor impact less than 70 million of years ago.
Natural-color image of the Caprivi Strip northeastern Namibia. On the bottom of the image there is the Okavango River.
Caprivi Strip is a stretch of land that “receives more than 600 millimeters (24 inches) of mean annual rainfall and experiences periodic floods”
The stripes visible in the images are linear dunes:
“[…] some are more than 100 kilometers (60 miles) long. Their presence suggests much drier conditions in the past.
Dunes generally form from wind-blown sand over many years. One characteristic of linear dunes is that they tend to remain intact long after the dry conditions cease. And because they don’t migrate like marching dunes, linear dunes preserve dirt and rocks that geologists can later use to understand past conditions.
A study published in 2000 sampled dunes throughout the Caprivi region and found that they likely formed under arid conditions between roughly 60,000 and 20,000 years ago. A study in 2003 concluded that dune construction may have been especially pronounced between 36,000 and 28,000 years ago. After the dunes formed, conditions in the Caprivi Strip moistened enough for the dunes to support vegetation—woodlands on the dune ridges, and grasses and shrubs in the valleys between.” (via EO)