| Abstract [eng] |
SUMMARY The main goal of thesis was to evaluate the peciuliarities of trace elements of Akmenynai – 149, Gėluva – 99 and Stoniškiai – 1 beroholes. The main tasks were: describe stratigraphy, litology of the boreholes mentioned; describe trace elements composition of the major rock types, as well as to establish the associations and trace elements variations during early and late Silurian. The studies of trace elements (associations mainly) enable to evaluate how thesedimentary paleoenvironment was changing from early to late Silurian. The trace elemental composition of the Silutian varies in a Wide range as indicated by variation coefficients. It is very clear for B, Ba, Mn, Ti and Zr. The highest median and maximal values of the trace elements were determined in clay and mudstone, while the lowest ( both median and minimal ) in dolostone and limestone. The accumulation of the most trace elements in early Silurian took part in Stoniškiai – 1 borehole section, while in late Silurian in Akmenynai – 149 borehole section none of the trace elements accumulated. The sedimentary environment during late Silurian was almost similar in all the boreholes sections studies. That is suggested by 2 trace elements associations established. According concentracion coefficient of the trace elements in mudstone in late Silurian Co, Ga and Mn started to concentrate, while Ba, Cr, Mo, Pb, Sn, Y, Yb were dispersed at that time. |
