Paleoenvironmental interpretation of elemental geochemical proxies of the borehole Jp 585: Lower Miocene lacustrine offshore clays of Cypris Formation, Sokolov Basin

This thesis presents geochemical study of the Lower Miocene lacustrine offshore clays of the Cypris Formation in the Sokolov Basin of the Eger Graben aimed at paleoenvironmental reconstruction. The applicability of elemental geochemistry proxies in the interpretation of 94 m thick lithologically monotonous, offshore lacustrine clay succession of the well core Jp 585 is tested. Geochemical proxy data seems to be a good indicator of changes in source areas ,erosion rates and climate. XRF analysis shows for example decrease of detrital input and the increase in amount of authigenic silica and carbonates upwards in the section. The results of CEC analysis point to a rapid variations of expandable clay minerals content. Marked increase of CEC is at 40 m depth. Combination of XRF and CEC enabled suggesting of four chemostratigraphical units. Their boundaries are often sharp, pointing to rapid changes in lake metabolism. These changes are preliminary interpreted as climate changes