| Abstract [eng] |
Geochemical analysis of sediments helps identify their provenance and assess the extent of contamination with potentially harmful chemical elements (e.g., Cu, Zn, Pb, As). The thesis evaluates the elemental composition change of beach sediments along the Lithuanian sea coast in 2011, 2014 and 2018. The results showed that sediments rich in Mn, Ca, Mg, Ba, and Sr dominated the mainland coast, as the deposits of the moraine cliffs are the primary source. Meanwhile, the sediments of the Curonian Spit coast were rich in As, Cr, Fe, K, P, U, Ga, and V, implying the source – deposits from Sambia Peninsula. Additionally, the influence of coastal processes on the change of elements on the beaches was assessed, revealing that elemental content increases in the erosive stretches of the coast on the mainland coast. And on the Curonian Spit – in the accumulative stretches and in the section between Juodkrantė and Pervalka, where relict coarse sand predominate. The results also revealed that human activities such as beach nourishments or seacoast reconstruction might change beach sediments' geochemistry. Besides, the results confirmed the longitudinal sediment transport on the southeastern Baltic Sea coast facing northward. The work also revealed that the magnetic susceptibility method could be used in geochemical surveys on beaches, efficiently identify the accumulation of heavy minerals, and assess the dynamic processes prevailing on the shore. |
