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Crater Lakes

Credits
NASA Earth Observatory, Link: http://earthobservatory.nasa.gov/

Approximately 290 billion years ago, two big asteroids collided with the Earth. The craters are still visible - to astronauts in the orbit, the lakes inside the craters are popular subjects for photographs. The crater lakes' diameter is 26 resp. 36 kilometres.

 

The Large Salt Desert

Credits
USGS/EROS; Link: http://earthexplorer.usgs.gov/

The salt desert Dasht-e Kavir is located in Iran in the east of the Zagros Mountains. Being the largest Iranian desert, it is a gigantic salt pan whose crusts of salt protect the ground against total dehydration. On the left-hand side of the picture, you can see one of the few streets crossing the largely uninhabited wasteland.

 

Location: Iran
Picture taken on May 10, 2003
Sensor: Landsat 7 ETM+

Ouachita Mountains

Credits
NASA/GSFC (Jesse Allen, Robert Simmon); Link: http://earthobservatory.nasa.gov

The Ouachita Mountains in west central USA are more than 300 million years old. Today, they are weather-beaten and noticeably  eroded. The remains that you can see in this image were once a part of a much more extensive mountain range that is believed to have spanned from Texas to Southeast Canada. The image combined information from the wavelength ranges of infrared, red and green. The complex shape of the mountains is characterised by a pattern of longish, folded formations. Between the mountain slopes, you can see water, vegetation, cities and streets.

 

Zagros Mountains, Iran

Credits
USGS/EROS ; Link: http://visibleearth.nasa.gov

This image shows a part of the Zagros Mountains stretching across 1500 km from West to Southwest Iran where the Eurasian Plate and the Arabian Plate meet. This mountain range developed during the Alpine orogeny, the most recent and youngest mountain formation in the history of the earth. To this day, the Zagros Mountains have been growing continually.

 

Location: Iran
Picture taken on February 2, 2000
Sensor: Landsat 5, Landsat 7 ETM+
Band combination: G/SWIR/IR

Grand Staircase-Escalante National Monument, Utah

Credits
NASA (Jesse Allen, Robert Simmon); Link: http://earthobservatory.nasa.gov

The geological history of the Grand Staircase-Escalante National Monument in Utah, USA, goes back more than 275 million years. This image shows a central part of the basin. The dendritic relief reveals a myriad of canyons. The erosions was caused by rivers millions of years ago. In the past, precipitation in this region was considerably heavier than it is today. Due to tectonic uplift, the area has dried out more and more.

 

Location: Utah, USA

Picture taken on May 15, 2005

Sensor: EO-1 - ALI

 

 

Sand Dunes, Idaho

Credits
NASA (Jesse Allen, Robert Simmon); Link: http://earthobservatory.nasa.gov

Along highway 20 from Idaho Falls heading toward Yellowstone National Park, green and golden fields dominate the fertile plain of the Snake River. The circular areas indicate extensively irrigated farmland. The white dunes developed towards the end of the last ice age approximately 10 000 years ago when the global climate started to become warmer and drier. Lakes and rivers dried up leaving fine sand behind. Continuous winds from the south west blew the sand in northeasterly direction, passing lava fields which are quite dark in the picture.

 

Richat Structure, Mauretania

Credits
USGS; Link: http://www.usgs.gov

Since the first space missions, the circular “Richat Structure” in the northwest of Africa has ranked among the most striking points of orientation for astronauts. The “Eye of the Sahara” is 45 km in diameter and was initially interpreted as the result of a meteorite impact. Meanwhile, it is assumed to be a circular uplift of several layers of earth. Rocks of different solidness had been eroding to a greater or lesser extent over time, which led to the distinct looks of the “Richat Structure” as we know it today.

Flooding of Zambezi River

Credits
NASA/Earth Observatory (Jesse Allen, Robert Simmon); Link: http://earthobservatory.nasa.gov/

The Zambezi is the fourth-longest river in Africa. Along its way, it turns into the 110m deep waterfall Victoria Falls, flows through canyons and spreads out across wide wetlands. In this picture, you can see Zambezi River (at the top) and Chobe River (at the bottom) during the annually recurring floods. The green part of the picture indicates tidewater while the brown and yellow part signals relative aridity. These two landscape areas deviate from each other due to the Mambova fault: The dry area is located higher than the flooded area in the valley.