The loess-paleosol sequence of Basaharc (Hungary) revisited: Mollusc-based paleoecological results for the Middle and Upper Pleistocene

The present study discusses the findings of detailed stratigraphical, sedimentological, geochemical and paleoecological investigations implemented as part of a 1990 campaign to Pécsi’s studied profile at Hungary’s important Danubian loess profile at Basaharc. In older studies, there were major discrepancies between the old lithostratigraphic classifications and the numerical ages. According to the findings of this study, the Basaharc Double Paleosol Complex, described formerly from the lower brickyard as a stratotype of Middle Würmian, is an isochronous heterotype of the Mende Upper Paleosol Complex from Profile #1 due to reworking. However, the lower member of the Mende Upper Paleosol Complex must have formed not at the boundary of the Upper and Middle Würmian as originally presumed, but during the Riss-Würmian interglacial. Conversely, the upper member of this same complex developed during an interglacial between the Upper and Middle Würmian, implying the presence of a huge erosional hiatus between the two members of the paleosol complex. The genetics of the individual paleosol layers needs a re-evaluation as well. The majority of the soils formerly conceived to be of steppe and forest steppe origin developed among closed woodland conditions.