Analysis of sedimentary texture and effects of vegetation in the Nebkha dunes of Shahdad, eastern Kerman: Application in the formation mechanism

Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this study in order to achieve the formation of nebkha in the Shahdad plain, sedimentological parameters and the effect of vegetation on nebkha geomorphology have been investigated. Due to the expansion of the study area and the different geomorphology of the nebkha, 30 nebkha were sampled along with sediments between them. the analysis of these sediments shows that nebkha sediments are often fine sand sizes that are well-sorted and rounded. However, sediments between nebkha often have a range between gravel (pebble) and fine silt which are subdivided into either surface and sub-surface sediments (depth greater than 2 centimeters). Surface sediments are often coarse grains (granule to coarse sand) and have relatively well roundness and sorting. Field investigations and analyses have shown that genus and plant species are important in the geomorphology of nebkhas in the Shahdad plain but the effect of vegetation on the sedimentary parameters is insignificant. This is due to the fact that the three types of vegetation identified (Tamarix stricta, Seditzia rosmarinus, Prosopis farcta), the highest levels of nebkha is for Tamarix stricta but the sedimentary parameters with different vegetation are not significantly different.