Late Weichselian palaeomagnetic secular variation from the Torreberga basin, south Sweden

Abstract

Three 6 m long sediment profiles from the Torreberga basin (55°37′N, 13°14′E) in south Sweden have been analysed palaeomagnetically. The sediment successions cover the period 12 800-10 000 years B.P. which almost corresponds to the entire Late Weichselian (13 000-10 000 years B.P. sensu Mangerud et al.). The sediments were recovered with a Russian peat corer, a method which allows the declination to be determined in absolute degrees. Around the mean declination two maxima with an intervening minima is recorded, with a peak to peak amplitude of 60°. In the inclination records more variation can be seen, however, the amplitudes are much smaller. The mean inclination is 5° lower than expected with respect to the site latitude. On a general trend of gradually steeper inclination upcore 5 maxima and 5 minima are found. The peak to peak amplitudes range between 5° and 14°. The amplitudes of both parameters are comparable in magnitude to those documented in other records of Late Quarternary age from, e.g., North America or of Holocene age from Europe. The records show that there is no evidence of any geomagnetic excursion between 12 800 and 10 000 years B.P., as previously discussed in the literature, but the field has been of normal polarity. The palaeomagnetic records from the Torreberga basin, which give consistent and repeatable values, must so far be considered to be the best and most detailed European palaeomagnetic record from this period.