Integrated chronostratigraphy of the Pliocene-Pleistocene interval and its relation to the regional stratigraphical stages in the southern North Sea region

Abstract

Time-stratigraphic interpretations of Late Pliocene to Early Pleistocene sediments from onshore locations and from marginal marine settings of the North Sea Basin often refer to the subdivision of the Dutch and British ’Quaternary’ regional stratigraphic stages. Since age control for these stages and their stage boundaries are based on relative dating methods, in this study pollen, dinoflagellate cysts and foraminiferal assemblages were investigated to correlate the regional stratigraphic stages independently to the global chronostratigraphy and the paleomagnetic timescale. The data were obtained from eight boreholes located in the depocentre setting of the Late Pliocene North Sea Basin comprising a 1000 m thick sedimentary succession. The British Gedgravian and Waltonian stages, the Dutch Reuverian to Brunssumian as well as published foraminiferal zones (NSB 14, FB and the lower part of the FA2 zone) fall within the Zanclean and Piacenzian. The lower boundaries of the Pre-Ludhamian and Pretiglian stages and of the NSB 14 to 15 zones are close to the paleomagnetic Gauss-Matuyama boundary. The Pre-Ludhamian, Ludhamian, Thurnian and the Pretiglian, Tiglian A and Tiglian B stages presumably cover the marine isotope stages 103 to 95. It is proposed that the Ludhamian, Thurnian and the Tiglian A were short lasting, warm, periods during which sea level highstand facilitated sedimentary deposition at the marginal areas of the North Sea Basin. The lower boundary of the paleomagnetic Olduvai subchron is situated in the Tiglian Cl-4b stage while the TC4c stage is found within the Olduvai subchron. Foraminiferal NSB 15 and NSB 16 zone as well as the upper part of the FA2 and FA1 zone fall within the Gelasian and cover the Matuyama chron as well as the lower part of the Olduvai subchron. Comparison with formerly dated North Sea sediments shows a good agreement between foraminiferal zonations on a broader scale but significant differences in absolute ages occur. Strontium isotope values indicate approximately 1 Ma younger ages as expected from our chronostratigraphic model. This discrepancy is explained by the dominance of freshwater from river discharge contributing high amounts of eroded material to the basin, leading to an increase of the 87Sr/86Sr ratio in the shelf-sea water.

Neogene stratigraphy of the Langenboom locality (Noord-Brabant, the Netherlands)

“…Sea surface temperature estimates based on 5 18 0 ratios indicate very low temperatures of 4.5 -8.3° C. This contradicts temperature estimates based on dinocysts from our samples as well as previous estimates for the southern North Sea Basin during the Early Pliocene, that show higher than modern values (Johnson et al, 2000;Kuhlmann et al, 2006). Johnson et al (2000), comparing growth increment lengths and stable isotope values of both modern and Zanclean Aequipecten opercularis, concluded that cryptic diagenesis caused these aberrant isotope Netherlands Journal of Geosciences -Geologie en Mijnbouw | 87 -2 N G estimates.…”

“…Louwye et al (2004) show that the last occurrence of M. choanophorum is associated with the Kruisschans Member in Belgium. Kuhlmann et al (2006) show that the L0D of Barssidinium spp. falls within the Piacenzian (circa 2.6 Ma).…”

The early Quaternary North Sea Basin

“…The chronostratigraphy of Kuhlmann et al (2006) in Dutch exploration well A15-03 (55°18′N, 3°48′E; Fig. 1) can be correlated to the work of Köthe (2007Köthe ( , 2012 and Thöle et al (2014) in the German sector of the North Sea, Nielsen et al (2008) and Rasmussen et al (2005) in the Danish sector, and Noorbergen et al (2015) onshore Netherlands (Table 1; Harding 2015).…”

“…The base Quaternary stratigraphic surface, taken as 2.58 Ma, was correlated to a well-defined and continuous seismic reflection trough using the Dutch North Sea well A15-03, for which very detailed bio-and magneto-stratigraphic dating is available in the public domain (Kuhlmann et al 2006; see discussion below). The horizon was picked at the well tie and then mapped down the depositional dip of the clinoforms into the basin, which minimized correlation errors to about half the dominant wavelength (20 -35 m), using a diminishing grid size (200 m then 100 m then 50 m), which was then propagated in full three dimensions (Hart 1999).…”

“…The sediment was mostly sourced from the Rhine-Meuse and Baltic river systems of northern Europe and Scandinavia (Bijlsma 1981;Overeem et al 2001;Busschers et al 2007). The timing of onset of glaciation in the Quaternary remains unclear, although there is growing evidence for several ice sheet advances during the Middle and Late Pleistocene, sourced from the UK and Scandinavian landmasses (Graham et al 2011), and evidence for iceberg scouring even in the southern North Sea Basin since the onset of the Quaternary (Kuhlmann et al 2006;Stuart & Huuse 2012;Dowdeswell & Ottesen 2013;Ottesen et al 2014).…”