Latitudinal variability in the Quaternary development of the Eurasian ice sheets—Evidence from the marine domain

Berit Oline Hjelstuen,Hans Petter Sejrup

doi:10.1130/g48106.1

Abstract

Abstract Here we present the first compilation of sediment volumes, sedimentation rates, and chronology of Quaternary sediment packages along the entire marine margin of the Eurasian ice sheets (EurIS; British–Irish, Kara–Barents Sea–Svalbard, and Fennoscandian). This compilation allows for a subdivision of the EurIS development into three phases (2.6–1.5 Ma, 1.5–0.78 Ma, and 0.78–0 Ma). At the start of the Quaternary, sedimentation rates increased, relative to pre-Quaternary rates, by an order of magnitude. This abruptness in rate change excludes tectonic raising of landmasses as the main factor, but more likely reflects climate change through increased glacial erosion. The sediment distribution data suggest that the Kara–Barents Sea–Svalbard Ice Sheet (KBSIS) already was quite large at the beginning of the Quaternary, and well before 1.5 Ma it extended to the shelf edge and coalesced with the Fennoscandian Ice Sheet (FIS), which prior to 1.5 Ma most likely was located near the coast. Large ice streams and intense glacial erosion characterized the KBSIS in the 1.5–0.78 Ma time period, whereas the FIS at that time extended farther out on the continental shelf. After 0.78 Ma, a north-south change in EurIS development occurred. In the FIS and the British–Irish Ice Sheet (BIIS), large ice streams developed and shelf-edge glaciations occurred nearly 1 m.y. later compared to the KBSIS. The FIS and BIIS also repetitively coalesced in the North Sea. A significant drop in sediment input along the KBSIS marine margin, to the lowest Quaternary level, suggests a less erosive KBSIS.

Highlights

At the Pliocene-Pleistocene boundary, the global climate cooled from temperatures 3–4 °C higher than today, transitioning into a 2.6 m.y. period—the Quaternary—characterized by increasingly colder climate, larger climate variability, and extensive glaciations (e.g., Lisiecki and Raymo, 2005; De Schepper et al, 2014)
Volume estimates of such sediment accumulation along the marine margin of the paleo–Eurasian ice sheets (EurIS; British–Irish, Kara–Barents Sea–Svalbard, and Fennoscandian) (Fig. 1) have been essential in detailing the development of glaciations through the Quaternary and in evaluating the role of tectonic uplift versus climate cooling in shaping northwestern European landscapes (Dowdeswell et al, 2010; Steer et al, 2012; Andersen et al, 2018)
Further growth of the Kara–Barents Sea–Svalbard Ice Sheet (KBSIS) through Northern Hemisphere glaciation (NHG) phase I gave rise to an ice sheet that extended to the shelf edge in the southwestern Barents Sea

Summary

INTRODUCTION

At the Pliocene-Pleistocene boundary, the global climate cooled from temperatures 3–4 °C higher than today, transitioning into a 2.6 m.y. period—the Quaternary—characterized by increasingly colder climate, larger climate variability, and extensive glaciations (e.g., Lisiecki and Raymo, 2005; De Schepper et al, 2014). Marine depocenters that formed adjacent to continental ice sheets during the Quaternary reflect climate changes, ice sheet dynamics, the intensity of erosion, and the effect of uplift and subsidence in onshore and offshore catchment areas (Vorren et al, 1998; Nielsen et al, 2005; Fjeldskaar and Amantov, 2017) Volume estimates of such sediment accumulation along the marine margin of the paleo–Eurasian ice sheets (EurIS; British–Irish, Kara–Barents Sea–Svalbard, and Fennoscandian) (Fig. 1) have been essential in detailing the development of glaciations through the Quaternary and in evaluating the role of tectonic uplift versus climate cooling in shaping northwestern European landscapes (Dowdeswell et al, 2010; Steer et al, 2012; Andersen et al, 2018). The 2.6 and 0.78 Ma phase boundaries are linked to paleomagnetic datum levels (Matuyama-Gauss and Brunhes-Matuyama reversals, respectively), identified in a number of deep-sea and continental-shelf cores along the northwestern European margin (Fig. S1 and Table S1 in the Supplemental Material1), whereas the 1.5 Ma boundary is based on biostratigraphy and extrapolation between the top Olduvai (1.77 Ma) and base Jaramillo (1.0 Ma) magnetic excursion events

QUATERNARY DEVELOPMENT OF THE EURIS MARGIN

DATA AND METHODS

SEDIMENTATION RATE AND VOLUME ESTIMATES