Studying the Morphologic Maturation of Aeolian Sand Grains During Transportation Process of Wind Erosion (Case study: Khartouran Erg)

Wind, in the duration of its erosional process, affects considerable changes in a grain's morphologyfrom its removal (detachment) step to sedimentation. In other word, a grain undergoes its gradualevolution during the transit process. In this project, the maturation of Aeolian sand grains had beenstudied upon as based on texture maturity indicator which includes: sorting, mean size grain, roundness aswell as abrasion coefficient parameters. The study area is the transport region of Khartouran Ergsediments, which founded on the basis of ground index of wind erosion. According to these indicators,the direction of prevailing or strong winds is notably mentioned. In a later step, four transects are selectedin different area in alignment with wind direction. Samples of sediment grains are taken at varieddistances in any one of the transects. The samples were taken from the windward slope of Rebdoulandform. The samples were evaluated to using granulometry and morphoscopy techniques. Grain sizeanalysis of was done using dry sieve analysis while morphoscopy of grains carried out by studying thequartz grains of 150 to 300 μm diameter by using binocular microscope. Results indicate a gradualmaturity (evolution) in sediment texture in all transects starting from the upper parts (near sand source)toward the lower parts (in transportation area).Also, results indicate that from among the four indicatorsof grain maturity namely: sorting, grain size, roundness and abrasion coefficient the respective factors ofeither " abrasion coefficient index" or" roundness index " in the first value and then" sorting" and finally"grain’s mean size index" are the ones accounted for validation for determination of maturity.