A Late Devensian Lateglacial palaeomagnetic record from Llyn Gwernan, North Wales: comparison with other NW European records

Palaeomagnetic analysis of 222 specimens from a high-resolution Late Devensian Lateglacial sedimentary sequence at Llyn Gwernan, North Wales has provided the first detailed record of geomagnetic secular variation for the Lateglacial period in Britain. This provides the opportunity to extend the British Holocene Geomagnetic Master Curve possibly as far back as 15 000 yr BP. The declination log records six well-defined oscillations with peak-to-peak amplitudes of 20-30". The inclinations are shallower than expected for this latitude (52"44'N) which are probably due to the magnetic recording process although low geomagnetic inclinations are not ruled out. The inclination log defines a number of relatively smooth swings with peak-to-peak amplitudes of 10-20". No evidence for any geomagnetic excursions (such as the Gothenburg 'Flip') was found. The Llyn Gwernan Lateglacial palaeomagnetic record is compared with the published palaeomagnetic records for a number of European sites. Correlations between records suggest that the ages of the Llyn Gwernan palaeomagnetic features, derived from a series of radiometric radiocarbon measurements, are in general compatible with those of the European sites. Discrepancies between the records are probably due to errors in radiocarbon dating of Lateglacial sediments and variability of the palaeomagnetic recording process and do not represent spatially-variable geomagnetic field behaviour