Combined palynological and organic geochemical reconstruction of marine and terrestrial climate of the Early Pleistocene in northwest Europe

Large scale Northern Hemisphere glaciations started during the Pliocene-Pleistocene transition (~2.6Ma). Two marine cores from the northwestern part of the Dutch North Sea basin contain ancient Eridanosdelta sediments covering this transition. Paleomagnetic data, dinoflagellate cyst and foraminiferal proxies have provided a solid integrated timeframe. Gamma ray and magnetic susceptibility logs show obliquity cycles that correlate with Marine Isotope Stages 103 to 94. Therefore, these cores are well suited for coupled climate reconstruction of the terrestrial and marine environments during Early Pleistocene.

Palynological results show dominant open heath,- and grasslands during glacials, and more forested landscapes during interglacials. Interglacial periods show enhanced occurrences of Pediastrum, a fresh water algae, linked to increased fresh water influx.
Long chain alkenones are present in part of the cores. Sea surface temperature (SST) reconstructions based on these compounds show a clear coupling to gamma ray log and palynology and show a ~6ºC SST difference between glacials and interglacials.
Analyses of the distribution of glycerol dialkyl glycerol tetraether membrane lipids of soil bacteria are underway to reconstruct terrestrial mean annual air temperatures (MAT) and fluvial input of soil organic matter. Preliminary results indicate fluctuations of ~4ºC in MAT over glacial-interglacial cycles.