Rolf, Christian; Hambach, Ulrich; Weidenfeller, Michael (2021): Rock and palaeomagnetic evidence for the Plio-Pleistocene palaeoclimatic change recorded in Upper Rhine Graben sediments (Core Ludwigshafen-Parkinsel) [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.931710

In the area of Ludwigshafen (Germany; Upper Rhine Graben (URG); Fig. 1) we sampled a core (P34) which was recovered during the exploration for groundwater resources. The core comprises 300 m of Quaternary and Tertiary sediments (Fig. 2). Rockmagnetic parameters measured are: NRM (natural remanent magnetization); characteristic remanent magnetization (ChRM, could be isolated using demagnetization experiments (alternating field and thermal) Fig. 3); magnetic susceptibility measured on core and discrete samples compared with interpretation of polarity (Fig. 5); as demonstrated in figure 6, a clear correlation of heavy mineral data (Hagedorn & Boenigk, 2008; doi:10.1016/j.quascirev.2005.01.018) and susceptibility data is apparent; the so-called S-ratio (Fig. 7a) gives us information about the relative amounts of high-coercivity ('hard') to low-coercivity ('soft') remanence and therefore a fair estimate of the importance of antiferromagnetics (goethite, hematite) versus ferrimagnetics (soft magnetite, iron-sulphides); "saturation"IRM curves (Fig. 7b, c) also show a clear subdivision in soft (above 177 m) and hard (below 177 m) remanence carriers; thermal demagnetization of "S"IRM identifies greigite or (Ti) -magnetite (Fig. 8a) for the upper (alpine influenced) part of the drill whereas the lower Pliocene part is dominated by greigite (Fig. 8b); alternating field (AF) demagnetization of samples from the upper part often show acquisition of significant gyroremanent magnetization (Fig. 10a), a typical property of greigite (Snowball, 1997; doi:10.1111/j.1365-246X.1997.tb04498.x); we used a technique after Van Velzen and Zijderfeld (1992; doi:10.1111/j.1365-246X.1992.tb00715.x) detecting greigite instead of pyrrhotite (Fig. 10b); Combination of different parameters in biplots can help to separate various magnetic components (Fig. 11 a+b). We applied this method by combining anhysteretic remanent magnetization (ARM) and IRM measurements in different ways. ARM against IRM (Fig. 11a) demonstrates high concentration differences for samples from the upper part (above 177 m) of the profile and narrow plotting (low concentration variations) for samples of the lower part (below 177 m); A similar plot, the relation of ARM normalized by IRM and ARM, emphasizes this result (Fig. 11b). Again, two different clusters (high coercivity mineral (goethite) in the lower and low coercivity mineral (greigite) in the upper part of the profile) are obvious (with the exception of some samples in a mixed zone).