The full programme book (PDF) - Royal Geographical Society

T6
Testing modes of interglacial sea level variability, using estuarine deposits from the
North Sea basin
N.L.M.Barlow 1 *, A.J. Long 1 , W.R. Gehrels 2 and M.H. Saher 2
1 Department of Geography, Durham University, South Road, Durham, DH1 3LE
2 Environment Department, University of York, Heslington, York, YO10 5DD
Many reconstructions of relative sea-level change from previous interglacials in locations
distant from the former great ice sheets are characterised by high-frequency (submillennial),
large-amplitude (several meter) fluctuations. These are especially notable
when sea level rose close to and above present-day levels. Fluctuations of this nature
were once thought to exist in the Holocene as well but revolutions in the methods of
quantitative sea-level reconstruction from estuarine sequences, and an improved
understanding of local, regional and global processes, now mean that large oscillations
are only rarely recognised within the Holocene. It is therefore essential that the apparent
differences in the mode of Holocene and previous interglacial sea-level variability are
demonstrated to be real and not merely an artefact of the methods of reconstruction. RSL
reconstructions from temperate latitudes have been important in understanding the modes
of post-LGM sea-level change and similar records are required from previous interglacials
to understand the nature of former sea level highstands.
We present the results of an ongoing research programme (as part of the iGlass
consortium) designed to assess the mode of sea-level variability during the late
Pleistocene interglacials. We do this by applying litho- and bio-stratigraphical
(foraminifera and pollen) methods of sea-level reconstruction that are common to
Holocene sea-level studies to intertidal deposits from around the North Sea, most notably
from the Nar Valley. Stratigraphical investigations are supported by AAR and U-Th
dating. Our results, though preliminary, fail to record multiple abrupt sea-level oscillations
during previous interglacials. We explore the implications of this work for our
understanding of ice sheet and sea-level variability during previous warm periods.
Sea level, estuarine, interglacial, foraminifera, pollen, AAR, North Sea