Zjawisko cementacji kalcytowej osadów fluwioglacjalnych w Starym Puszczykowie k. Poznania

Abstract

CALCITE CEMENTATION OF FLUVIOGLACIAL DEPOSITS AT STARE PUSZCZYKOWO NEAR POZNAŃ Summary Fluvioglacial sands and gravels at Stare Puszczykowo near Poznań, situated in a morainic plateau slope, are partially cemented by calcite. As a result, columns of sandstones and conglomerates (up to 0,5 m in diameter and 1 m in length) occur within loose sediments. There is a morainic till layer of Vistulian age (about 19000 years BP - 7) over the fluvioglacial deposits, which contains 12-14% CaCO3. The microscopic examination showed that cement was formed in a meteoric phreatic environment, while the cementation structures are located above the groundwater table now. Infiltration hypothesis explaining process of the cementation is accepted. The cementation is connected with the slope of the Warta - river valley. Fissures in the till used by migrating solutions rich in dissolved calcium carbonate were probably produced as a result of sliding the till on the morainic plateau slope. Possibility of origin the cementation structures in the late Vistulian and Holocene are discussed