| Abstract [eng] |
The dissertation examines carbonate class minerals (calcite and dolomite) genesis and distribution in the Lithuanian Quaternary sediments – Pleistocene tills, as well as carbonate content changes in the interglacial and Holocene sediments. Carbonates were investigated using polarizing and scanning microscopes, also by calcimeter, using analytical methodology modified by PhD author. It was found that the carbonate class minerals, common for the Pleistocene tills, are exclusively allochthonous. Studies have shown that relationship between these minerals is various for the different Pleistocene tills and depends on glacier flow direction and lithological composition of sub-glacial rocks. Thus, the dolomite and calcite ratio could be a quite reliable criterion for stratigraphic correlation of Pleistocene tills. The original stratigraphic correlation technique of Pleistocene tills based on mathematical statistics (Van der Vaerden criterion) application was developed. It was found that the amount of carbonates in the interglacial and Holocene sediments depends on the former paleoclimatic and, partly, on the palaeohydrodynamic conditions in the particular sedimentary basin. Changes in the amount of carbonates correlates well with palaeobotanical studies, so analysis of carbonates could be an important method which supplements the complex of currently applied methods (palaeobotanical, lithologcal, geochronologial, etc.) for interglacial and Holocene sediment’s survey. |
