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
Summary: The development of the dune fields in the region of Coude du Dra, occurring to the south of the Antiatlas, along the Moroccan border with Algeria, is described in this paper. The determination of the reasons for expansion of the dune fields was the aim of the studies presented here. The evaluation of the rate of expansion was made on the basis of the analysis of the topographical maps, satellite images and field investigations. Since 1932, the surface of the dune field has increased ca. 30 times. To estimate the causes of such a dynamic development of the dune fields, the source areas of the dune material were determined on the basis of the analyses of the sediment textural features, mainly the mineral and lithologic composition. It was found that local alluvial sediments in the Oued (Wadi) Dra valley and lacustrine beds (mainly of the Iriqui Lake) are the sources of the majority of the dune sediments in the Coude du Dra region. This is evidenced by great mineralogical conformity of the dune and basement sediments, namely the significant contents of the ferruginous-clayey particles forming in local, periodical water reservoirs. Large content of this component in dune sediments, combined with its very low resistance to mechanical abrasion, indicates that the dune material underwent short aeolian process and passed a limited distance from its source. After recognition of the source areas, the features of the natural environment of these areas were evaluated, taking into account especially those which are of special importance for the deflation process. It was found that the water table lowering is the most important change of the natural environment, which influenced during last several tens of years the distinct increase of the deflation process. Other features of the natural environment like the surface relief, climatic conditions or vegetation did not influence essentially the dynamic development of the dune fields in this region. Only today the distinct morphometric borders, especially in the north and in the south, may limit further expansion of the dune field in these directions. The construction of the dam system on the Oued Dra supplying water to the described region is the main reason for the ground water table lowering, thus resulting in drying of the surface sediments and making them ready to deflate. Change of the causes of the dune fields development from the factors determined by gradual climate changes to the factors connected with the local human activity influenced essentially the increase of the rate of the dune fields development in the region of Coude du Dra.
Słowa kluczowe (w języku angielskim): dune field development, dune sediment source, textural features of sediments, Coude du Dra region, southern Morocco.
Prace Geograficzne, 2008, z. 118, s. 51-64.
Instytut Geografii i Gospodarki Przestrzennej UJ
Extorted forms of aeolian accumulation in the Coude du Dra region
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