Plio-Pleistocene floras of the Vildštejn Formation in the Cheb Basin, Czech Republic - a review and a new paleoenvironmental evaluation
Abstrakt
Plant fossil assemblages (foliage, fruits and seeds, pollen, wood) from the Pliocene and early Pleistocene deposits in W Bohemia (the Vildštejn Formation of the Cheb Basin, Tachov /Cheb-Domažlice/ Graben) are newly analysed using several palaeoenvironmental methods with the aim to reconstruct palaeovegetation and palaeoclimatic changes. Floras of four subsequent stratigraphic levels show a decrease of exotic elements in the Pliocene and a massive immigration of boreal elements in the early Pleistocene.
Vegetation changes start with broad-leaved deciduous and mixed mesophytic forests and continue towards light forests of the mentioned types in areas of zonal to extrazonal habitats. This vegetational change is characterised by an immigration of dry herbaceous and sclerophyllous elements.
Wetland communities from higher positions in the profiles stepwise loose exotic components and point to cool-temperate conditions similar to the present conditions. Palaeoclimatic signals show warmer and more humid conditions for the Pliocene levels (about 15°C of mean annual temperature, 5°C of mean temperature of the coldest month and 25°C of mean temperature of the warmest month, more than 900 mm of mean annual precipitation).
Early Pleistocene proxy data indicate the beginning of a cooler phase at the Plio-Pleistocene boundary (about 7°C of mean annual temperature and decreasing trend of precipitation), but conditions not colder than those of the present day in the NW part of the Bohemian Massif.