The thickest and the most complete loess sequence in the Carpathian Basin: the section of the borehole Udvari–2A and its significance in the Quaternary stratigraphy

Abstract

The key borehole Udvari–2A is located in Hungary at the Tolna-Hegyhát (hills), in the central part of the Carpathian
Basin. Its detailed description yielded valuable information on the stratigraphy and the post-Pannonian continental
sedimentation regime of this territory. Stratigraphic data provided by the borehole facilitated the drawing up of a more
precise picture on the post-Pannonian palaeoenvironment and evolution history of the area. The borehole cut a thick
series of the post-Pannonian Tengelic Formation and the overlying, presumably complete sequence of the continental
loess sediments. The magnetostratigraphic correlation indicates that the 97 m thick loess–palaeosol series (borehole
Udvari–2A) is the thickest and most complete sequence that has been recorded in Hungary so far and the deposition of
loess started approximately at 1.1 Ma. In this sequence each of the four sedimentary periods of the loess are represented
by distinct sediments. Based on data from SE Transdanubia a theoretical stratigraphic column of the Paks Loess
Formation is given, defining and characterising its litological units. Since the formation is widely known, it was possible
to correlate the most complete sequence in SE Transdanubia with the Marine Isotope Stages (MIS), and this offers
opportunities even for global correlation.