Rapid and sustained environmental responses to global warming: the Paleocene–Eocene Thermal Maximum in the eastern North Sea

Abstract

Abstract. The Paleocene–Eocene Thermal Maximum (PETM; ∼ 55.9 Ma) was a period of rapid and sustained global warming associated with significant carbon emissions. It coincided with the North Atlantic opening and emplacement of the North Atlantic Igneous Province (NAIP), suggesting a possible causal relationship. Only a very limited number of PETM studies exist from the North Sea, despite its ideal position for tracking the impact of both changing climate and NAIP activity. Here we present sedimentological, mineralogical, and geochemical proxy data from Denmark in the eastern North Sea, exploring the environmental response to the PETM. An increase in the chemical index of alteration and a kaolinite content up to 50 % of the clay fraction indicate an influx of terrestrial input shortly after the PETM onset and during the recovery, likely due to an intensified hydrological cycle. The volcanically derived zeolite and smectite minerals comprise up to 36 % and 90 % of the bulk and clay mineralogy respectively, highlighting the NAIP's importance as a sediment source for the North Sea and in increasing the rate of silicate weathering during the PETM. X-Ray fluorescence element core scans also reveal possible hitherto unknown NAIP ash deposition both prior to and during the PETM. Geochemical proxies show that an anoxic to sulfidic environment persisted during the PETM, particularly in the upper half of the PETM body with high concentrations of molybdenum (MoEF > 30), uranium (UEF up to 5), sulfur (∼ 4 wt %), and pyrite (∼ 7 % of bulk). At the same time, export productivity and organic-matter burial reached its maximum intensity. These new records reveal that negative feedback mechanisms including silicate weathering and organic carbon sequestration rapidly began to counteract the carbon cycle perturbations and temperature increase and remained active throughout the PETM. This study highlights the importance of shelf sections in tracking the environmental response to the PETM climatic changes and as carbon sinks driving the PETM recovery.

The interplay between siliciclastic and carbonate depositional systems: Maastrichtian to Danian basin‐floor sediments of the mid‐Norwegian Møre Basin

“…A more local influence from bottom currents, such as reworking of the turbidite deposits (Faugères & Mulder, 2011; Rebesco et al., 2014) or of the hemipelagic suspension fall‐out appears more likely. The Early Palaeocene increasingly warmer and wetter climate (Stokke et al., 2021 and references within) is likely to have caused elevated weathering and runoff rates in the sediment source areas (e.g. Sømme et al., 2019).…”

Large Igneous Province Control on Ocean Anoxia and Eutrophication in the North Sea at the Paleocene–Eocene Thermal Maximum

“…The PETM was a complex event: in addition to global temperature increase (Dunkley Jones et al, 2013), some sea surface temperature and continental proxies hint to a transient warming prior to the CIE onset (Secord et al, 2010; Paleoceanography and Paleoclimatology 10.1029/2023PA004756 Sluijs et al, 2007), while marine environments display highly variable regional and local water column salinity and stratification (Sluijs & Brinkhuis, 2009). Areas proximal to the NAIP emplacement area, such as the North Sea, may have faced far more direct and local consequences to the tectonic uplift and sill intrusions, such as precursor cooling from volcanic SO 2 injections (Stokke et al, 2021), which are not observed in other distal locations globally. Alternatively, the tectonic uplift resulting from NAIP emplacement might have caused an episodic cooling event by modifying the positioning of the Northern Hemisphere jet stream (Vickers et al, 2024).…”

“…Previous records of bottom water oxygen depletion in the North Sea region are not sufficiently resolved to identify whether basin restriction facilitated, or drove, the observed anoxia/euxinia around the PETM onset (e.g., Schoon et al., 2015; Stokke et al., 2021). The exact phasing between the emplacement of the NAIP, North Sea basin restriction, primary productivity and runoff changes and bottom water anoxia/euxinia has not yet been robustly determined, mainly due to the lack of high‐resolution records from high quality core material.…”

Stratigraphic expression of the Paleocene-Eocene Thermal Maximum climate event during long-lived transient uplift—An example from a shallow to deep-marine clastic system in the Norwegian Sea

“…The short-lived PETM climate event lasting 100-200 kyr is known to have been associated with significant global warming (Sluijs et al, 2007), changes in the hydrological cycle and increasing sediment supply to North Atlantic basins (e.g., Dypvik et al, 2011;Kender et al, 2012;Pogge von Strandmann et al, 2021;Rush et al, 2021;Stokke et al, 2021;Jin et al, 2022).…”

“…Studies of the PETM suggest that this hypothermal event was associated with increased onshore weathering rates, higher seasonal variability in fluvial discharge and change in sediment delivery to shallow and deepwater basins (Pujalte et al, 2015;Carmichael et al, 2017;Rush et al, 2021;Jin et al, 2022), producing a stratigraphic response that can be distinguished from more long-term tectonic forcing (Samanta et al, 2016). Even though the PETM has been recognized several places in wells and outcrops in the North Atlantic (e.g., Beerling and Jolley, 1998;Dypvik et al, 2011;Harding et al, 2011;Kender et al, 2012;Eldrett et al, 2014;Stokke et al, 2021;Jolley et al, 2022), little is known about how the PETM influenced the dynamics of sedimentary systems in this region. However, recent studies from the North Sea suggest increased sediment supply and a change in depositional style during the event (Sømme et al, 2019;Vieira and Jolley, 2020;Jin et al, 2022).…”