Contemporary evolution of the natural environment of the region between Antiatlas and Sahara (Morocco)
Skiba S., Krzemień K. (red.), 2008, Contemporary evolution of the natural environment of the region between Antiatlas and Sahara (Morocco), Prace Geograficzne, z. 118.
Język publikacji: angielski
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Morphostructural and geomorphological outline of Morocco
Recent erosion measurements in Morocco
Physical geography of the Coude du Dra region
Soils of the southern part of Morocco
Properties of the desert soils of the Mhamid area
Reasons for development of the dune fields in the Coude du Dra region
Extorted forms of aeolian accumulation in the Coude du Dra region
Summary: Two types of the extorted aeolian accumulation forms i.e. nebkhas and Tamarix cones, occur in the Coude du Dra region. The first ones are small sandy forms, usually of the height of several tens of centimetres and a significant elongation accordant to the wind direction. The second ones are forms several metres high, without observable elongation and with distinct layered structure. In the years 2000-2006 the studies comprised two kinds of the nebkhas. One kind was formed by accumulation around the halophyte arfej (Rhantherium suaveolens) growing in the area of the dried Lake Iriqui. Another kind formed around the grassy plant drinn (Aristida pungens) growing in numerous pits being the oxbow lakes of the braided bed of Oued (Wadi) Dra. The studied forms show great diversity, although both formed in similar climatic conditions. After a five-hour storm when the wind velocity exceeded 14 m per second, the change of morphology of the nebkhas accumulated behind the grass drinn was obserwed. From a uniform morphologically shape new forms developed with a depression caused by deflation directly behind the plant obstacle. Formation of the Tamarix cones is connected with accumulation of sediment around the Tamarix shrubs during low sandy-dusty storms, especially in their final parts, when the finest grains fall. This accumulation is frequently accompanied by rainfall. In the years 2005-2005 both nebkhas and Tamarix cones were significantly degraded. Some of the studied nebkha fields disappeared due to complete degradation of plants, which forced originally the material accumulation. The Tamarix cones were degraded in part as well. This is connected with lowering of the ground water table down to 3-4 m and more below the ground surface (outside the main bed of Oued Dra) and in the region of the Tamarix cones occurrence even deeper than 10 m. Degradation of the extorted forms of the aeolian accumulation caused expansion of the dune fields.
Słowa kluczowe (w języku angielskim): nebkhas, tamarix cones, textural features, formative process, Coude du Dra region, southern Morocco.
Prace Geograficzne, 2008, z. 118, s. 65-78.
Instytut Geografii i Gospodarki Przestrzennej UJ
The source of the Aeolian sediments in the Coude du Dra region
Surface features of sand grains from the Coude du Dra region (Morocco)
The geomorphological role of episodic rivers based on the example of the Oueds el Mut and el Feija (AntiAtlas Mountains, Morocco)
Natural and anthropogenic factors of the development of Erg Chebbi
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Ostatnia aktualizacja: 2017-12-08