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
The source of the Aeolian sediments in the Coude du Dra region
Summary: Determination of the source of material building the dunes of the Coude du Dra region was the aim of the performed studies. To estimate the source areas, the selected textural features, especially the mineralogical and lithologic composition of the dune sand basement sediments were studied. This composition was determined by means of the microscope analysis of the granular preparations. On the basis of the obtained results one found that the dunes of the Coude du Dra region have high content of the components of low resistance to the deteriorating factors of transport and weathering processes. Only in the north-eastern part of the area and in the apical parts of the highest dune forms there occur the sediments with high content of the resistant minerals, mainly quartz. The results indicated also the insignificant difference in the mineral and lithologic composition of the sediments of the basement and those of the dunes. This allowed the conclusion that the source of the dune sediments occur in the close neighbourhood of the dunes. This yielded from the presence of numerous components of relatively coarse fraction and low resistance, transported mainly by saltation, which is the mode favouring intensive mechanic abrasion. They are mainly clayey-ferruginous clasts, moreover feldspars and carbonate rock grains. Moreover, the feldspars are well preserved and frequently of automorphic habit and certain feldspars occur as perfect crystals with sharp edges, which could not be preserved during a long transport. The close source of the dune material and short period of the dune formation were confirmed by the analysis of the composition of the heavy mineral fraction. On the basis of the obtained results one found that first of all the local sediments accumulated in stagnating water were the source of the dune material, mainly the sediments of the Iriqui Lake and numerous pits without water outflow, occurring in the area of the broad there valley of Oued (Wadi) Dra. This is indicated by a very high content of clayey-ferruginous clasts, which formed during the periodic water flow transporting to local, ephemeral basins fine detritic material coloured in red by dispersed iron compounds, forming commonly under strongly oxidizing desert conditions.
Słowa kluczowe (w języku angielskim): dune fields, source of dune material, mineral and lithologic sediment composition, Coude du Dra region, southern Morocco.
Prace Geograficzne, 2008, z. 118, s. 79-92.
Instytut Geografii i Gospodarki Przestrzennej UJ
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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