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Posts tagged Sahara

Mzab Limestone Plateau in Central Algeria

29.0N 2.0E

April 30th, 2010 Category: Rivers

Algeria - February 20th, 2010

Algeria - February 20th, 2010

This orthorectified image shows the M’zab (or Mzab), a region of the northern Sahara, in the Ghardaïa wilaya (“province”) of Algeria, around 500 km south of Algiers.

The Mzab is a limestone plateau, centred around the river valley Wad Mzab (Oued Mzab). The river appears as a light grey line, whereas the surrounding valley is dark grey. The limestone plateau is visible at the valley’s edges.

Tassili N’Ajjer National Park in Southeastern Algeria

25.5N 9.0E

February 9th, 2010 Category: Mountains

Algeria - January 3rd, 2010

Algeria - January 3rd, 2010

The Tassili N’Ajjer National Park, in the Tassili N’Ajjer Mountains, is a World Heritage Site in Algeria. It is located on a plateau of outstanding scenic and geological interest (dark brown areas), covered by eroded sandstone forests of rock.

The area is a floristic and faunal island of Sahelian life in the middle of the desert, and harbors a relict Mediterranean cypress, one of the rarest trees in the world. It also has one of the largest and best preserved groupings of prehistoric cave art in the world, an immense gallery of neolithic art of international importance.

The park has a surface area of 8,000,000ha (Biosphere Reserve 7,200,000ha). It is located in the central Sahara in far southeastern Algeria. The northern boundary runs east 440 kilometers (km) from Amguid on the Tamanrasset road via Illizi to the Libyan border. The east and south sides adjoin the Libyan and Nigerien borders for 600km. The southern boundary runs northwest 700km from the Nigerien border to Amguid, bulging in to exclude the sands of Erg d’Admer.

Emi Koussi Volcano, Chad

January 29th, 2009 Category: Volcanoes

Emi Koussi volcano, Chad - January 27th, 2009

Emi Koussi volcano, Chad - January 27th, 2009

Emi Koussi is an extinct high shield volcano that lies at the south end of the Tibesti Mountains in the central Sahara of northern Chad.

It is the highest mountain in Chad, and also the highest in the Sahara. The volcano is one of several in the Tibesti massif, and reaches 3445 m (11302 ft) in altitude, rising 2.3 km (1.43 mi) above the surrounding sandstone plains. The volcano is 60 by 80 km (37 to 50mi) wide.

Upon more detailed examination, the rim of the volcano appears to consist of two rings. This is because two nested calderas cap the volcano, the outer one being about 12 by 15 km in size. Within it on the southeast side is a smaller caldera, about 2-3 km wide and 350 m deep.

Numerous lava domes, cinder cones, maars, and lava flows are found both within the calderas and along the outer flanks of the shield.

source Wikipedia

Tibesti Mountain Volcanoes, Chad – October 31st, 2008

October 31st, 2008 Category: Image of the day, Volcanoes

Emi Koussi volcano, Chad

Emi Koussi volcano, Chad

Close-up of craters 1

Close-up of craters 1

Here we have a sharp image of the Tibesti Mountains, a group of dormant volcanoes forming a mountain range in the central Sahara desert in the Bourkou-Ennedi-Tibesti Region of northern Chad.

The mountains are the largest and highest range in the Sahara.

The highest peak is Emi Koussi, 3,415 m, visible in the third close-up.

Other summits include Kegueur Terbi (3,376 m), Tarso Taro (3,325 m), in the first close-up, and Soborom (3,100 m).

Close-up of craters 2

Close-up of craters 2

The active volcano Pic Toussidé (3,265 m), with tentacle-like lava flows running down its sides, is best observed in the second close-up.

While the high peaks themselves are all constituted of volcanic material, the mountains stand on broad uplifted area possibly caused by a mantle plume.

The range has a substantially wetter climate than the arid surrounding desert; annual rainfall is estimated at five inches (12 cm) in some of the highest areas of the mountains.

Close-up of craters 3

Close-up of craters 3

source Wikipedia

Dust Storm in Northern Chad – October 22nd, 2008

October 22nd, 2008 Category: Image of the day

Dust Storm in Northern Chad / Southern Libya - October 20th, 2008

Dust Storm in Northern Chad / Southern Libya - October 20th, 2008

Close-up of white sands

Close-up of white sands

Here we have a sharp image of a dust storm blowing over the northern third of Chad and parts of southern Libya, around the Emi Koussa volcano in the Tibesti Mountains.

Variations in local rainfall have created three major geographical zones in Chad: the North is a desert zone, the center is an arid Sahelian belt, and the South is a more fertile savannah zone.

The Sahara lies in the country’s northern third, the part of the country visible in the image. Yearly precipitation there is under 50 mm (2 in). In fact, Borkou, Chad (in the image, east of the mountains) is the most arid area of the Sahara. Vegetation in this region is scarce; only the occasional spontaneous palm grove survives, the only ones to do so south of the Tropic of Cancer.

Close-up of yellow sands

Close-up of yellow sands

In the image, we can see an interesting contrast in sand color. In the upper part, the sands streaming across the Libyan border into Chad are more yellow-red in color. In the area around Borkou, the colors mix, before giving way to the very white sand South of the mountains.

source Wikipedia

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