Determining an appropriate combination of geochemical elements to investigate the relative importance of lithological units in sediment production of Khor-Sefidarak Basin

Due to difficulties in the application of traditional methods for identifying sediment sources، fingerprinting techniques، based on physical، chemical and organic properties of sediment and source materials، are increasingly being used as a valuable and effective alternative approach to obtain such information. The first step in this method is using an appropriate combination of diagnostic properties that is able to differentiate sediment sources. In this study a combination of properties was used in different subbasins of Khur-Sefidarak Basin، located in Savojbolagh Township، Alborz Province and the share of each lithological unit on production of suspened load was estimated. By preparing lithological map، lithological units are considered as sediment sources and sediment behind the small dams are considered as deposittional areas. Aboat 43 samples were taken from lithological units and trap sediments of small dams in outlet of different sub basins. Then particle sizes finer than 62. 5 µ were seprated and concentration of nine geochemical elements in the samples were obtained. After being certain about absence of outliers data and after using analysis of variance and Kolmogorov-Smirnov Tests، discriminant analysis is used for finding the final proper combination. Among different elements، Ca is the most important element for differentiating geological units in different subbasins of Khor-Sefidarak Basin. Finally، relative importance of each geological unit in producing suspended load was calculated. Results have shown that Zagun and Shemshak Formations have the highest share in sediment production of the area.