Grain Size and Shape of Sand Grains in Ergs of Iran

Document Type: Research Paper

Author

Assistant Prof., International Desert Research Center, University of Tehran, Tehran, Iran

Abstract

Large areas of Iran are under the influence of wind erosion thus it is important that we recognize three zones of
removal, transportation and deposition. The deposition zone is very important due to more damages and tangible
effects. In this study we try to obtain a comprehensive idea to Persian desert with use of laboratory facilities, remote
sensing, GIS and field surveying. We survey 28 ergs in this study that they have 6410600 ha area. Area of sand dune
is 4172500 ha and we analysis 66 samples from them. the range of grain size is 4000 micron to less than 62 μ. 11%
from samples have max grain size of 4000 μ, 3% 1700 μ, 5% 1180 μ13% 600 μ, 58% 300 μ, 9% 150μ, 2% 62μ. 28%
samples had min grain size of 75μ, 13% 62μ, and 59% less than 62μ. 3% samples had mod of 600μ, 3% 300μ, 59%
150μ, 30%75μ and 3% 62μ. The samples were transport 1 to 5 km, 2% were transport 5 to 20 km, 72% were
transport 20 to 50 km and 23% were transport 50 to 200 km. skewness coefficient of normal charts are -0.2 to 2.95
and most coefficients is in range of 2 that shown fine grain.

Keywords