| Abstract [eng] |
Contemporary the Pagėgiai regional stage of upper Silurian serias spreading her stratigraphic volume and corelation in sediment basin raise of much doubt. Preliminary conodonts investigatios show, that mention problems demand the stratigraphic and biostratigraphic prospecting essence. This regional stage is binomial, which in upper part of the Western Lithuanian section consist by Geniai and Aukštupiai members of Pagėgiai formation. Eastward after P.Lapinskas (2004) their gradually change over by upper members of Lapgiriai formation., Lateraly the Lapgiriai formation pass into Mituva and Ventspilis formations. In the Eastern Lithuania the analyzig straton belong to the Sudervė members of Pabradė formation. Such lithological correlation of uppermost part of Pagėgiai regional stage not be matched with existing biostratigraphic data. Fundamental work purpose is that ground conodonts prospecting expose the Pagėgių regional stage in upper part the biostratigraphy, and determine her spreading limit and make this ages rocks section correlation in all Lithuania scale and expose possibility lead stage boundary. The investigation of conodont fauna show that zone of Ozarkodina crispa correspond to uppermost part of Pagėgiai regional stage Eastern and Middle Lithuania sections. In the Western Lithuania the deposits of above mentioned conodonts zone step by step become younger in regard with local stratigraphic units. Such spreading tendency of this conodonts zone in Lithuanian sections across Ludlow and Pridolian stages boundary required a revision of lithological correlation. |
