Correlation of Pleistocene sediments from boreholes in the Ludwigshafen area, western Heidelberg Basin

Michael Weidenfeller,Maria Knipping

doi:10.3285/eg.57.3-4.1

Abstract

Abstract. Cores from several boreholes in the Ludwigshafen area were analysed to investigate their sedimentology, palynology, palaeomagnetics, rock magnetics and heavy mineral composition. The preliminary results are presented from the new Ludwigshafen-Parkinsel borehole P35, which was drilled 500 m WSW of borehole P34, to a total depth of 300 m. Correlation between the two boreholes reveals similarities and dissimilarities in stratigraphy, structure and the thickness of the sediments. As a result of core documentation and the preliminary evaluation of the investigation results, a good correlation is established between the coarse and fi ne-grained sequences in both boreholes down to a depth of 122 m. However, the Plio-Pleistocene boundary in borehole P35 is much deeper than in P34. A fault throw of 42 m is assumed, attributable to young tectonics. The poor correlation between the thicknesses of the sediments in the lower sections of the two boreholes suggests that tectonism was particularly active in the Pliocene and Lower Pleistocene. The different occurrence of interglacial sequences in the two Ludwigshafen boreholes can be attributed to fl uvial dynamics and neotectonic events. Further palynological analysis is required to determine whether the alternation of at least fi ve interglacial periods determined in the Ludwigshafen-Parkinsel P34 borehole, can also be confi rmed in the P35 borehole. The information gained so far from the correlation of the already analysed Middle Pleistocene interglacials in the Ludwigshafen/Mannheim area, as well as the links with the primarily Lower Pleistocene sections in Schifferstadt, already suggest that this would allow a much better understanding of the changes in vegetation and climate during the Pleistocene.

Highlights

To investigate hydrogeological aspects, numerous boreholes were cored in the Ludwigshafen/ Mannheim area in recent years
P34 contains pollen spectra (26.5 – 29.05 m) which are correlatable with a high degree of probability with the Middle Pleistocene Mannheim Interglacial (KNIPPING 2008)
The presence of a gastropod fauna in the same borehole at a depth of 23 – 28 m, which WEDEL (2008) interprets as indicating the Cromerian Complex, could indicate a possible classification as Cromerian. Another consequence of a correlation between Maudach with the older part of the Mannheim Interglacial would be to make the correlation between the Mannheim Interglacial with the earlier “Eemian” at Meikirch (PREUSSER et al 2004) very unlikely, because Carpinus pollen is very rare in the two lower interglacials of Meikirch “Holstein 1” and “Holstein 2” (WELTEN 1982, 1988), but accounts for nearly 40 % in Maudach

Summary

Introduction

Numerous boreholes were cored in the Ludwigshafen/ Mannheim area in recent years. These cores were analysed using a wide range of methods (Fig. 1, Table 1). Of particular value were the palynological analyses (KNIPPING 2008), heavy mineral analyses (HAGEDORN & BOENIGK 2008) and the palaeomagnetic and rock-magnetic analyses (ROLF et al 2008). This made it possible for the first time to reliably detect the Plio-Pleistocene boundary in the northern Upper Rhine Graben in a core, confirmed by various independent methods. The results are presented in this paper, including a preliminary correlation between the two boreholes

Results

Discussion

Conclusion