Abstract
We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (ĝ1/4 2.6-1.8ĝ€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.
| Original language | English |
|---|---|
| Pages (from-to) | 397-411 |
| Number of pages | 15 |
| Journal | Climate of the Past |
| Volume | 14 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 23 Mar 2018 |
Funding
Acknowledgements. We are grateful for the constructive comments of Stijn de Schepper and David Naafs and an anonymous referee that helped to improve the paper. We gratefully acknowledge the support in providing the offshore samples to this study and permission to publish from Wintershall Noordzee B.V. and project support from partners Chevron Exploration and Production Netherlands B.V., Total E&P Nederland B.V., Dana Petroleum Netherlands B.V., Oranje-Nassau Energie B.V., and Energie Beheer Nederland (EBN). Arnold van Dijk is thanked for running C / N and stable isotope analyses and Giovanni Dammers for processing palynological samples. The work was partly supported by funding from the Netherlands Earth System Science Center (NESSC) through a gravitation grant (NWO 024.002.001) from the Dutch Ministry for Education, Culture, and Science to Jaap S. Sinninghe Damsté, Gert-Jan Reichart, and Lucas Lourens.
