The Contribution of Different Geomorphologic Facies in Sand Dunes Sediments Supply Using Sediments Tracing (Case Study: Ashkzar Sand Dunes)

Application of provenance method by tracers or fingerprinting has been demonstrated as a successful and effective way to determine the sediment sources. According to this method, physical, geochemical and biogenic features of sediment are used to determine the sediment sources and their importance. The main aim of this research is determining the contribution of different facies using the hybrid model in sediment supply for sand dunes of Ashkzar erg. For this aim, 65 surface samples from the sources region facies and 8 samples from the sand dunes were collected and the particles less than 62.5 micron, as the target, were tested. In order to measure the geochemical elements including rare earth elements (REE) and trace element, the ICP-AES was used. Then, ICP-MS was used to measure Strontium (87Sr & 86Sr) and Neodymium (143Nd & 144Nd) isotopes. The indices of rare earth elements were calculated and the elements, REE indices and isotopes were used as tracer. Then, initial choice and optimal combination of tracers were done by the statistical methods including one-way ANOVA, Kruskal-Wallis and discrimination analysis. Finally, contribution of the various facies on sediments supply was determined using hybrid models. The results showed that Rubidium (Rb), Cerium (Ce) and Strontium (Sr) were determined as the optimal combination. Moreover, the results of hybrid models showed that the distribution facies of fine sandy plains & dry river bed, fans & dry river bed, Kelot, farmlands, Neogene marl hills and Sebkha were 27, 22.7, 24.4, 13.26, 6.4 and 6.24 % respectively. Performance of the model was 0.999 indicating it's accurate and appropriate results.