پديد آورندگان :
يماني، مجتبي دانشگاه تهران - دانشكده جغرافيا , لك، راضيه پژوهشكده علوم زمين، تهران , گورابي، ابوالقاسم دانشگاه تهران - دانشكده جغرافيا , شهبازي، رضا سازمان زمين‌شناسي و اكتشاف معادن كشور، تهران , شعباني عراقي، عارفه دانشگاه تهران - دانشكده جغرافيا
كليدواژه :
اريفر , پلاياي جازموريان , فرسايش بادي , گرد و غبار , رسوبات
چكيده لاتين :
Introduction
In this century, wind erosion as one of the most important processes in arid and semi-arid regions has
affected about one-sixth of the world's land area. Wind erosion is usually attributed to the process of
soil particles being removed and displaced by the wind. Wind is one of the dominant processes in
arid, semi-arid, and sub-arid regions and is the result of wind dynamics, transport of soil or sediment
particles, and the development and evolution of desert roughness based on erosion and sedimentation
intensity.The risk of wind erosion and dust is also more severe in areas where the soil is loose, dry,
and bare, with high winds and high repetition. This study was conducted in Jazmourian basin and its
playa. Jazmurian Playa has been studied as the most important area affected by wind erosion and the
source of dust hazard in the south-east of the country; because these two hazards are often found in
closed basins of old lakes or playa that contain loose sediments, and they are disconnected, they are
happening.
2- Methodology
Data used are library data, meteorological statistics, maps, field, and laboratory data. At first, using the
(Eriffer) model, nine effective factors in determining the wind erosion potential in the geomorphological
facies of the basin were investigated, and their sedimentation rate was determined. The annual windroses
were plotted with hourly data from the synoptic stations over the period (2009-2019) for six stations, and
the wind situation of the area was analyzed. Then, 20 surface sediment samples were taken from the area
to determine the effect of particle size on the performance of wind processes, and Granulometry was
performed. and the position of the sand-dune as the end point of wind erosion and the areas affected by
the dust were also identified.
3- Results
According to the results of the implementation of the Eriffer model for determining the wind erosion
potential in the Jazmourian basin of high and diverse sandstone facies - very high erosion class and
seasonal litter lithofacies, seasonal muddy salt marsh, terraces lakes and alluvial plain. There is a lot of
erosion in the classroom. Also, alluvial facies are in middle erosion grade and uneven mountain slopes in
low erosion grade. In fact, in the Jazmourian basin, there are scattered sandy masses, but the highest
distribution is in the southeast of Playa, with 44.49% of sedimentation of the whole basin. The wind Baft
situation in the area indicates that the maximum velocity at the station is 2.10 to 3.60 m / s. The highest
wind speed at this station is in the range of 5.70 to 8.80, which accounts for about 2 percent of all winds.
The Bam Station Wind in different directions at speeds below 4.5 m / s. Khash Station is about 2 percent
of the winds in the speed range of 8.80-70.70, and about 80 percent is between 0.50 to 3.60 m / s. Jiroft
Station is about 1 percent of the winds in the speed range of 8.80-70. Nikshahr Station At this station,
about 2% of the winds blow at a speed of 5.70 to 3.70 / 60 and the Other at lower speeds. Iranshahr
Station about 80% of the winds in this station are northeast to southeast and are classified at speeds of 0.50
to 3.60 m / s. Annual windrose show at stations in the area Local winds can create local dust. The results
of the analysis of the samples show that 74.75% of the eastern Playa sediments, 76.25% of the southern
Playa sediments, 67.50% of the northern sediments, and 95% of the Playa center sediments are below 63
microns in size. Surface sediments are the environment for the production of dust.
4- Discussion & Conclusions
The results show that the low and flat topography, the presence of fine particles in the sediments, and the
dominant winds during the dry season, with the dominant northwest and west direction, caused the
sediment to move suspended, then jump and creep. and the dust hazard has Extensive performance on
the playa and its margins, and more importantly, the Jazmourian playa is one of the main sources of dust
in the south-east of the country. Also, the areas covered by dust hazards are greater in the central, southern
and, western margins of the hole than in other areas.
