Distribution of Some Trace Elements in Modern Bottom Sediments of the Caspian Sea
The results of study of character of some trace elements distribution in modern bottom sediments of the Caspian Sea have been examined on the base of samples collected in 35th, 39th and 41st cruises of the R/V “Rift” and in the cruise of R/V “Nikifor Shurekov” in 2013. It is established that contents of Zr, Hf, Th, V, Cr, Co, Ni, Cu, Sr and Ba in bottom sediments of different areas of the Caspian Sea are transformed in comparison with riverine particulate matter discharge of Volga River and rivers flowing from the Caucasus. Comparison of geochemical peculiarities of modern bottom sediments of Volga delta and different sedimentary subsystems of the Caspian Sea with composition of Archean granites, Palaeozoic and Meso-Cenozoic basalts, which could be regarded as “geochemical image” of rocks of East-European Platform base, Urals and Caucasus (sources of clastics), demonstrated that none of these regions is the dominant source area for all subsystems of the Caspian Sea. While the similarity of Northern, Middle and Southern Caspian Sea and Volga delta bottom sediments with PAAS (including rare earth elements spectra) assumes substantial contribution of Volga River sedimentary discharge to their geochemical appearance formation. The role of clastics (including fine clastics) coming in to the Caspian Sea from Caucasus and Elburs mountains is very small even not far from the coasts, that largely is determined both by influence of marginal filter and large-scale circulation currents.