Content of Rare Earth Elements in Soils of the South-Eastern Part of the Sughd Region

The article presents the results of the study, obtained original data on the content and distribution of rare earth elements in the soils of the south-eastern part of Sughd region. The concentrations of rare earth elements were determined by using a highly sensitive inductively coupled plasma mass spectrometry method. A total of 30 samples were collected and analyzed. Peculiarities of accumulation of rare earth elements depending on regional characteristics have been revealed. The average concentrations of the studied rare earth elements are within the clarke index and below. The use of variational-statistical methods for processing the obtained results made it possible at least to some extent, streamline the results of analytical studies of soils within the south-eastern part of the Sughd region. Concentrations of rare earth elements in the soils of the southeastern part of the Soghd region vary within narrow intervals. At the same time, the distribution of REE bears a regular character in the areas (2.44−9.72%) under study. Quantitative criteria degree of accumulation and enrichment of soils have been calculated: here refer factors of enrichment, concentration coefficient, concentration clarke and dispersion clarke. On the base of the obtained values of these indicators it is shown that the soils of the studied points are characterized by a moderate level of accumulation and enrichment. Based on the data obtained, a series was compiled for the average content of rare earth elements: > > > > > > > > > > , while the contents of La, Eu and Gd are very close to the clarkes of the earth’s crust, lower – Ce, Pr, Nd, Sm, Dy, Ho, Er, Tm. The highest concentrations are cerium, lanthanum and neodymium, the lowest concentrations are praseodymium, gadolinium, samarium, dysprosium, erbium, europium, terbium and holmium. The distribution of all studied rare earth elements is close in terms of asymmetry and kurtosis, and is observed for some elements. We have established a significant correlation between the content of Ce and La (r = 0,98), Pr and La (r = 0,97), Pr and Ce (r = 0,95), Nd and La (r = 0,94), Nd and Ce (r = 0,91), Nd and Pr (r = 0,99), Sm and Pr (r = 0,86), Sm and Nd (r = 0,86), Sm and Nd (r = 0,91), Gd and Pr (r = 0,81), Tb and Gd (r = 0,84), Er and Dy (r = 0,84), Er and Ho (r = 0,90), Tm and Er (r = 0,94),which indicates to their lithogenic origin.