Abstract. The mid-Piacenzian Warm Period (mPWP; 3264–3025 ka) represents the most
recent interval in Earth's history where atmospheric CO2 levels were
similar to today. The reconstruction of sea surface temperatures (SSTs) and
climate modelling studies has shown that global temperatures were 2–4 ∘C warmer than present. However, detailed reconstructions of
marginal seas and/or coastal zones, linking the coastal and continental
climate evolution, are lacking. This is in part due to the absence of
precise age models for coastal sedimentary successions, as they are
generally formed by dynamic depositional systems with varying sediment and
freshwater inputs. Here, we present a multi-proxy record of Pliocene climate
change in the coastal southern North Sea basin (SNSB) based on the
sedimentary record from borehole Hank, the Netherlands. The marginal marine
setting of the Hank borehole during the late Pliocene provides an excellent
opportunity to correlate marine and terrestrial signals due to continental
sediment input mainly derived from the proto-Rhine–Meuse River. We improve
the existing low-resolution palynology-based age model for the Hank borehole
using stable oxygen and carbon isotope (δ18O and
δ13C) measurements of the endobenthic foraminifera species Cassidulina laevigata, integrated
with biochrono- and seismostratigraphy. Identification of hiatuses and
freshwater effects in the record allows us to isolate glacial–interglacial
climate signals in order to tune the endobenthic oxygen stable isotope record to a
global benthic δ18O stack. This results in a tuned age
framework for the SNSB for the late Pliocene (∼3190–2770 ka). Our multi-proxy climate reconstruction for the interval which covers
part of the mPWP (∼3190–3000 ka) shows a strong agreement
between lipid biomarker and palynology-based terrestrial temperature
proxies, which suggest a stable climate, 1–2 ∘C warmer than
present. In the marine realm, however, biomarker-based SSTs show a large
range of variation (10 ∘C). Nevertheless, the fluctuation is
comparable to other SST records from the North Atlantic and Nordic Seas,
suggesting that a common factor, possibly ocean circulation, exerted a
strong influence over SSTs in the North Atlantic and the North Sea at this
time.
Supplementary material to "A new age model for the Pliocene of the Southern North Sea Basin: evidence for asynchronous shifts of marine and terrestrial climate"
