A 62 kyr geomagnetic palaeointensity record from the Taymyr Peninsula, Russian Arctic

• Published in: Geochronology
• Main Authors: Scheidt, Stephanie, Lenz, Matthias, Egli, Ramon, Brill, Dominik, Klug, Martin, Fabian, Karl, Lenz, Marlene M., Gromig, Raphael, Rethemeyer, Janet, Wagner, Bernd, Federov, Grigory, Melles, Martin
• Format: Text
• Language: English
• Published: 2022
• Subjects: Arctic; Taymyr; Magnetic susceptibility; Taymyr Peninsula; Siberia
• Online Access: https://doi.org/10.5194/gchron-4-87-2022; https://gchron.copernicus.org/articles/4/87/2022/

This work presents unprecedented, high-resolution palaeomagnetic data from the sedimentary record of Lake Levinson-Lessing, the deepest lake in northern central Siberia. Palaeomagnetic analyses were carried out on 730 discrete samples from the upper 38 m of the 46 m long core Co1401, which was recovered from the central part of the lake. Alternating field demagnetization experiments were carried out to obtain the characteristic remanent demagnetization. The relative palaeointensity is determined using the magnetic susceptibility, the anhysteretic remanent magnetization, and the isothermal remanent magnetization for normalization of the partial natural remanent magnetization. The chronology of Co1401 derives from correlation of the relative palaeointensity of 642 discrete samples with the GLOPIS-75 reference curve, accelerated mass spectrometer radiocarbon ages, and optically stimulated luminescence dating. This study focuses on the part > 10 ka but also presents preliminary results for the younger part of the core. The record includes the geomagnetic excursions Laschamps and Mono Lake and resolves sufficient geomagnetic features to establish a chronology that continuously covers the last ∼ 62 kyr. The results reveal continuous sedimentation at high rates between 45 and 95 cm kyr −1 . The low variability of the magnetic record compared to datasets of reference records with lower sedimentation rates may be due to a smoothing effect associated with the lock-in depths. Because Co1401 was cored without core segment overlap the horizontal component of the characteristic remanent magnetization can only be used with caution. Nevertheless, the magnetic record of Co1401 is exceptional as it is the only high-resolution record of relative palaeointensity and palaeosecular variations from the Arctic tangent cylinder going back to ∼ 62 ka.