Diamicton in Besiekierz (Central Poland) : how to avoid misinterpretation of superposition in Quaternary geology

Diamicton in Biesiekierz (central Poland), whose age and origin has long provoked debate, is located above unquestionable Eemian biogenic deposits documented by palynological and Cladocera analyses. Petrographically, this diamicton shows some similarities to Warthanian till. Lithologically, it shows considerable weathering of the deposit, a possible selection of the component minerals and addition of dispersed biogenic matter. The results obtained so far as well as the palaeomorphological situation indicate that the diamicton is reworked till material, as are sand intercalations within it. Given the organic content of this diamicton, we infer that a long-term agricultural exploitation of its immediate surroundings was the main factor behind colluvial reworking and displacement occurring above the Eemian biogenic deposits in the fossil depression.