Comparison the characteristics of grain size and morphoscopy in new and old wind deposits for sand sources determination in Damghan Erg

Grain size is one of the most obvious characteristics in many studies of Aeolian erosion, Ergs, moving of sand dune, etc. Comparison of Grain size and morphoscopy between new and old sand dunes in an Erg, help us to identify the sources sand and control reactivity sand dunes. This study, as first step, by aerial photography and satellite imagery attempting to identify areas were sedimented. Then Sediment samples took place from the new and old sand dunes and Sediment grain size parameters were evaluated and compared. By the statistical analysis determined that, there were no significant differences in the mean of diameter and median in new and old sand dunes. But the mean of skewness and kurtosis was shown to have difference. The mean of diameter in new sand dune is 176 µ and old one is 160.4 µ. In the old sand dunes Skewness were positive and in new one is negative. The mean of moving distance in new sand dune is less than old one. Because old sand dunes have Haloxylon plants we observe Particles less than 64 microns and greater than 500 microns. Morphoscopy compared showed that the new sand dunes have a halo form with a little roundness that indicating sediment transport by wind and old one have bright form and angular that indicating sediment transport by water.