Features of the Mineral Composition of the Quaternary Sediments of the Development Areas of the Erosion Processes on the Territory of the Tunkinsk’s Depression

The article considers the some features of the Quaternary sediments mineral composition of the development areas of the erosion processes on the territory of the Tunkinsk’s depression.Main objectives of our research are to determine the entering forms of Na,Mg,Al,Si,P,S,K,Ca,Ti,Cr,Mn,Fe,Zn,Cu,Zr,and Ba in the composition of the investigated sediments.The mineral composition was studied by the method of an electron probe X-ray spectral microanalysis(XRM)using wave spectrometers,and the method of X-ray diffraction analysis.The localization centers of Cr,Cu,Zn,Zr,and Ba were established in the mineral composition of the studied sediments.Maximum content of BaO(14.42 wt%)was detected in alkali K-feldspar in the clay sediments of modern alluvial complex(aQ4).Crystallochemical formulas of different minerals were obtained.

Geochemical Features of the Quaternary Deposits of the Irkutsk’s Reservoir Zone under Technogenic Conditions

The article considers the some geochemical characteristic of the loesslike and bottom sediments of the area Novo-Razvodnoy of the Irkutsk’s reservoir.Main objectives of this research are to determine contents of trace elements(V,Cr,Co,Ni,Cu,Zn,Ga,Pb,As,Rb,Sr,Y,Zr,Nb,Ba,La,Ce,Nd)and major elements(CaO,TiO2,MnO,Fe2O3(total))in the investigated samples by X-ray fluorescence analysis method(XRF),to establish the trace elements distribution dynamics on the lateral profile of the area Novo-Razvodnoy,to reveal the pollution degree of the studied sediments and to calculate the specific geochemical coefficients Rb/Sr and Ca/Sr in the studied sediments.As a result of the studies,it is established that the dried part of the coastal shallows experiences the higher technogenic load in comparison with other considered zones of the lateral profile.This fact was confirmed by the maximum content of As(12 mg kg^-1)exceeding by 6 times the established value of the maximum permissible concentrations in soils(MPC)and the maximum calculated values of pollution load index(PLI)and geoaccumulation index(Igeo)for arsenic.