Abstract. We assess the disputed phase relations between forcing and
climatic response in the early Pleistocene with a spliced Gelasian
(∼2.6–1.8 Ma) multi-proxy record from the southern North
Sea basin. The cored sections couple climate evolution on both land and sea
during the intensification of Northern Hemisphere glaciation (NHG) in NW
Europe, providing the first well-constrained stratigraphic sequence of the
classic terrestrial Praetiglian stage. Terrestrial signals were derived from
the Eridanos paleoriver, a major fluvial system that contributed a large
amount of freshwater to the northeast Atlantic. Due to its latitudinal
position, the Eridanos catchment was likely affected by early Pleistocene
NHG, leading to intermittent shutdown and reactivation of river flow and
sediment transport. Here we apply organic geochemistry, palynology, carbonate
isotope geochemistry, and seismostratigraphy to document both vegetation
changes in the Eridanos catchment and regional surface water conditions and
relate them to early Pleistocene glacial–interglacial cycles and relative
sea level changes. Paleomagnetic and palynological data provide a solid
integrated timeframe that ties the obliquity cycles, expressed in the
borehole geophysical logs, to Marine Isotope Stages (MIS) 103 to 92,
independently confirmed by a local benthic oxygen isotope record. Marine and
terrestrial palynological and organic geochemical records provide high-resolution reconstructions of relative terrestrial and sea surface
temperature (TT and SST), vegetation, relative sea level, and coastal
influence. During the prominent cold stages MIS 98 and 96, as well as 94, the record
indicates increased non-arboreal vegetation, low SST and TT, and low
relative sea level. During the warm stages MIS 99, 97, and 95 we infer
increased stratification of the water column together with a higher
percentage of
arboreal vegetation, high SST, and relative sea level maxima. The early
Pleistocene distinct warm–cold alterations are synchronous between land and
sea, but lead the relative sea level change by 3000–8000 years. The
record provides evidence for a dominantly Northern Hemisphere-driven cooling that leads the
glacial buildup and varies on the obliquity timescale. Southward migration of
Arctic surface water masses during glacials, indicated by cool-water
dinoflagellate cyst assemblages, is furthermore relevant for the discussion
on the relation between the intensity of the Atlantic meridional overturning
circulation and ice sheet growth.
Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing
