16 - Correlations between geochemical features of recent bottom and stream sediments in the Baikal geoecological polygon

Abstract

This chapter presents correlations of data on major elements (Si, Ti, A1, Fe, Mn, Mg, Ca, Na, K, P, and S) and trace elements (B, V, Cr, Co, Ni, Zn, Sr, Ba, Zr, Mo, Pb, and U) in recent stream and bottom sediment obtained from regional geochemical mapping and other projects in the Baikal geoecological polygon. The natural ecosystems of the region are very sensitive to anthropogenic influences and the polygon is also characterized by broad diversity of anthropogenic transformation of landscapes" from pure practically non-polluted areas to places under highly industrial pressure. The data demonstrates that the geochemical trend of sedimentation in Lake Baikal, in particular the increase in Fe, Mn, P, Cr, V, Ni, and Co, has a certain similarity to the sedimentation in deep seas and oceans. The composition of stream and bottom sediments in general reveals the more basic, as opposed to the upper continental crust, composition of upper crust of region. Although there is a correlation between the total composition of stream and bottom sediment, as compared with the upper continental crust, Baikal sediments do not fully reflect the average composition of the area drained. The main differences constitute the enrichment in Fe, Mn, P, Cr, V, Ni, Co, Si, U, B, and Mo, and lower levels of Ca, Mg and St. However, the Baikal bottom sediment area is perfectly outlined by Mn-P-Fe associations on the geochemical association map of the major elements. Trace element associations are mainly common to stream and bottom sediments and related adjacent drainage areas. The strong geochemical asymmetry of the westem and eastem sides of the Baikal region is evident on both the major and trace element maps of geochemical associations.