Analysis of sand dunes to determine wind direction and detect sand source sites (case study: Khartooran Erg, Iran)

Wind regime and sand grain size are two of the factors that determine the morphology and dynamics of sand dunes in desert areas. Regarding the importance of wind effects on sand dunes especially in Iran, in this study, Khartooran Erg was analyzed to determine wind direction and to detect sand source sites. Khartooran Erg is located on eastern north of Iran and lies in Khorasan Razavi and Semnan provinces. The area of Erg was determined based on geological and topographical maps and satellite images. Then, sand dunes of erg were classified, based on aerial photograph and satellite image interpretation. Sand dune forms in the Khartooran Erg are often barchans and combination of barchanic ridges, but there are also complex types of linear sand dunes. Based on field survey findings, the stabilized in the southern part of the Erg were separated, because of these sand dunes having been deformed. According to the presented models relationship between morphology and wind direction, the sand dunes were analyzed. The studies have shown that wind prevailing direction is eastern-north to western-south, the strong wind being in north-south direction. It can also be said that sand dunes which are located in the adjacent of Erg and are simple and separate can be used as the most suitable criteria to determine predominant wind. Also, regarding the Erg location with respect to upper plains and determined wind direction, it can be noted that sand sources mostly come from silt-clay flats of ending parts of Sabzevar Kal River rather than Jajarm Kal River.