Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

Abstract

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 evPublished by Copernicus Publications on behalf of the European Geosciences Union. 398T. H. Donders et al.: Land-sea coupling of early Pleistocene glacial cycles idence 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.

Extensive marine-terminating ice sheets in Europe from 2.5 million years ago

“…The regional seismic mapping presented above has been tied chronostratigraphically to borehole data in the southern North Sea and forms the dating framework. Seismic horizons defining the prograding clinoforms in the SE of the central North Sea have been traced back across the shelf and tied into the most detailed Plio-Pleistocene chronology for the North Sea (see Methods) ( 16 , 31 ). Supporting data come from the Josephine and Aviat wells ( Fig.…”

“…The basin-scale seismic stratigraphic framework and relative chronology were calibrated to five absolute ages (2.58, 2.43, ~2.15, 1.94, and 1.78 Ma ago) dated using magnetostratigraphy and an additional age, ~2.35 Ma ago, dated using palynology correlated to the global oxygen isotope curve in borehole A15-03 in the southern North Sea ( 31 ). Corroboration comes from the Josephine and Aviat wells (22/07a-5Z and 22/07a-6Z) in the central North Sea ( Fig.…”

Dinoflagellate fossils: Geological and biological applications

“…Dinocyst stratigraphy for the Neogene in northern latitudes, and more precisely for the Oligocene-Miocene, is discussed in Schreck et al (2017) and Bijl et al (2018), respectively. Also, phase relationships between climate forcing and paleoecological responses across the Pliocene (De Schepper et al, 2015), Plio-Pleistocene climate transition (Hennissen et al, 2016), or Pleistocene glacial-interglacial stages (Donders et al, 2018) have also recently been discussed even if ecological optima of extinct species are not always well known, challenging the use of quantitative sea-surface reconstructions (cf. following chapter 3 of this manuscript).…”

The palaeontology and dating of the ‘Weybourne Crag’, an important marker horizon in the Early Pleistocene of the southern North Sea basin

“…Tzedakis et al, 2015), has been crucial in enabling correlation of the terrestrial pollen record with the marine isotope stratigraphy and in understanding phase relationships between the two (e.g. Donders et al, 2018). Shallow-marine sequences also offer opportunities for linking marine biostratigraphical schemes with terrestrial records, such as those based on mammal biostratigraphy.…”