On the Geochemistry of Major and Trace Elements Distribution in Sediments and Soils of Zarafshon River Valley, Western Tajikistan

To assess the geochemical features of sedimentary material of Zarafshon river, (Western Tajikistan) catchment basin, the mass fractions of 38 major and trace elements were determined by Instrumental Neutron Activation Analysis (INAA) in 2 x 116 paired samples of sediments and soils collected along the Zarafshon River and its main tributaries from the sources to Tajik-Uzbek border. At each collecting location, the distance between sediments and soils' sampling was no greater than 10 m allowing the studying of the interrelation between sediments and soils. This evidenced a significant similarity between paired soils and sediments' samples, including the potentially contaminating elements As, Sb and Hg, whose mass fractions in some places were significantly higher than for the Upper Continental Crust (UCC) and North American Shale Composite (NASC), suggesting a common provenience. At the same time, the distribution of major, as well as of incompatible trace elements, Sc, Zr, REE, Th, and U, in spite of geological diversity of the Zarafshon river catchment basin, suggest a possible felsic origin of investigated material.