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Magnetostratigraphy of Pliocene and Pleistocene sediments of the Heidelberg Basin

Stephanie Scheidt1, Christian Rolf1, Ulrich Hambach2
1 S5, Leibniz Institut für Angewandte Geophysik, Hannover
2 LS Geomorphologie, Universität Bayreuth

P 1.8 in Fortschritte der Quartärstratigraphie

Since the late Pliocene / Early Pleistocene the Heidelberg Basin has acted as a trap for sediments from local to superregional delivery areas.  These sediments are transported by the rivers Rhine and Neckar. The on-going subsidence has led to one of the thickest, most complete successions of Quaternary sediments in Mid-Europe (Gabriel et al. 2008). These sedimentary deposits (gravel, sand, silt and clay) are expected to be slightly disturbed by unconformities. However, there are only a few high-resolution, long-term sedimentary records available. Since fluvial sedimentary processes are sensitive to tectonics and climatic changes, the Heidelberg Basin contains information about the whole drainage area of the Rhine, including the Alps. This provides a unique opportunity to study climate variations in Mid-Europe. Furthermore, the sedimentary record has the potential to deliver crucial insights into the relationship between the Alpine and the North Sea glacial evolution in Quaternary time.

The project 'Environmental Magnetism' and Magnetostratigraphy on Pliocene and Pleistocene sedimentary sequences of the Heidelberg Basin is one of three individual grants of the initiative Scientific Drilling Heidelberg Basin which are funded by the DFG. Within this frame drill cores taken from Viernheim, Ludwigshafen and Heidelberg are being studied. Based on pollen data (Knipping 2008), lithostratigraphic correlation (Ellwanger et al. 2008) and heavy mineral analysis (Hagedorn & Boenigk 2008) a preliminary relative stratigraphy has been established. The magnetostratigraphy sets out to support these data and to improve the chronostratigraphic framework. Fluviatile terrestrial sediments are a special challenge for palaeomagnetic investigations. Low susceptibility values, various synsedimentary and post depositional processes, as well as partially occurring deformations caused by the drilling process itself result in scattered data sets and areas with mixed (normal and inverse) remanent magnetisations. An important task is to disentangle primary and secondary magnetisations.  Components of natural remanent magnetisation (NRM) are separated by AF demagnetisation and analysed by principle component analysis (PCA). The resulting data of the characteristic remanent magnetisation (ChRM) still show a diffuse distribution in certain areas of the cores. On the whole the results support the findings of previous work (Rolf et al. 2005, Rolf et al.2008, Hambach et al. 2008, Gabriel et al. 2010). Further magneto-mineralogical analyses are on their way in order to solve remaining ambiguities and to establish a palaeoenvironmental reference profile based on rock magnetic proxies.

References

Ellwanger, D., G. Gabriel, T. Simon, U. Wielandt-Schuster, R. O. Greiling, E.-M. Hagedorn, J. Hahne, and J. Heinz (2008), Long sequence of Quaternary Rocks in the Heidelberg Basin Depocentre, E & G (Quaternary Science Journal), 57(3/4), 316-337.

Gabriel, G., D. Ellwanger, C. Hoselmann, and M. Weidenfeller (2008), Preface: The Heidelberg Basin Drilling Project, E & G (Quaternary Science Journal), 57(3/4), 253-260.

Gabriel, G., D. Ellwanger, C. Hoselmann, and M. Weidenfeller (2010), The Heidelberg Basin Drilling  Project – Characteristics of an outstanding archive of Quaternary sediments, paper presented at EGU General Assembly, Vienna.

Hagedorn, E.-M., and W. Boenigk (2008), The Pliocene and Quaternary sedimentary and fluvial history in the Upper Rhine Graben based on heavy mineral analyses, Netherlands Journal of Geosciences, 87(1), 19-30.

Hambach, U., R. Rolf, and M. Weidenfeller (2008), Rock magnetic evidence for the Plio-/Pleistocene palaeoclimatic change and for Pleistocene climatic cyclicity recorded in Upper Rhine Graben sediments, paper presented at EGU General Assembly, Vienna.

Knipping, M. (2008), Early and Middle Pleistocene pollen asssemblages of deep core drillings in the northern Upper Rhine Graben, Germany, Netherlands Journal of Geosciences, 87(1), 51-65.

Rolf, C., U. Hambach, and M. Weidenfeller (2008), Rock and palaeomagnetic evidence for the Plio-Pleistocene palaeoclimatic change recorded in Upper Rhine Graben sediments (Core Ludwigshafen Parkinsel), Netherlands Journal of Geosciences, 87(1), 41-50.

Rolf, C., U. Hambach, E.-M. Hagedorn, M. Weidenfeller, and D. Ellwanger (2005), Rock and palaeomagnetic evidence for the Plio/Pleistocene palaeoclimatic change recorded in Upper Rhine Graben sediments (Bohrung Ludwigshafen-Parkinsel), paper presented at 65. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, Graz, 20.-25.02.2005.

Letzte Änderung 27.07.2012