Correlation of drilling cores and the Paks brickyard key section at the area of Paks, Hungary

摘要

The stratotype section of Paks brickyard provides the most detailed accessible loess-paleosol sequence from almost the entire Pleistocene in the middle part of the Carpathian Basin. The best and thickest loess archives of Hungary (Paks, Udvari-2A borehole) are preserved in this part of the basin and now two more drilling cores were deepened in this area on plateau position on loessic ridges: PA-I (similar to 85 m) and PA-II (similar to 50 m).In absence of numerical dating method available for the entire records an attempt was made to compare the cores and correlate them to Marine Isotope Stages (MIS) mainly based on the variations of their MS curves and soil characteristics. Characteristic patterns of MS seem to help the identification of Marine Isotope Stages and therefore the correlation among the sections. Macroscopic investigation of the paleosols can support the correlation, although the coeval paleosols can have different appearances due to their different environmental conditions and topographic positions. Thirteen samples were dated using luminescence from the upper part of the cores, covering the age range of 20-200 ka to check and revise the supposed correlation. The MS based correlation supported by soil characteristics was only partly confirmed by luminescence data. Therefore, we emphasize that any correlation solely based on MS data or soil morphology, without any numerical age control, has to be taken with great caution. The different thickness and the present altitude of the coeval loess and paleosols imply differences and changes in paleogeomorphological positions of the investigated profiles during the Pleistocene. Significant subsidence and/or tectonic movements are the main causes of the deficient appearance of MIS 6-3 sediments in the Paks brickyard outcrop compared to the more complete sequences of the cores.