Microfauna- and sedimentology-based facies analysis for palaeolandscape reconstruction in the back-barrier area of Norderney (NW Germany)

Abstract

Palaeolandscape reconstructions at the German North Sea coast are essential for the understanding of coastal changes and dynamic landscape-forming processes. This study contributes to reconstructing Holocene coastal changes in the back-barrier area of the East Frisian island of Norderney and draws conclusions on the local palaeogeography. Five sediment cores were analysed in terms of sedimentology (grain-size distribution), geochemistry (TOC, TIC, N, C/N), microfauna (foraminifers and ostracods) and 13 radiocarbon dates. In order to identify driving environmental factors and support the facies interpretation, multivariate statistics (PCA) were carried out. Additional cores from the surrounding area (WASA Project and ‘Landesamt für Bergbau, Energie und Geologie’ (LBEG) Hannover) enabled correlation of the investigated cores over a transect of ~6 km, showing six depositional environments, which can be used for landscape reconstruction. Deposition starts with periglacial (aeolian and glaciofluvial) Pleistocene sediments, with subsequent pedogenesis followed by swamp conditions that develop into a salt marsh. The overlying tidal-flat sediments are partially cut by (fossil and recent) channel deposits. A hiatus at the base of the tidal-flat deposits that spans some 3000 years hints at their reworking caused by a combination of antrophogenic coastal protection measures and the impact of storms. Furthermore, based on the profile correlation and the age data, a widespread salt-marsh area with a minimum age of ~4000 cal BP is defined for the ‘Hohes Riff’ in the southwestern back-barrier of Norderney Island.

Insights into Holocene relative sea‐level changes in the southern North Sea using an improved microfauna‐based transfer function

“…The sample from N44 originates from a salt-marsh layer with a very high organic content (peat), hence, typical calcareous microfauna could have been dissolved (cf. Elschner et al, 2021), possibly biasing the calculation by the TF. Therefore, these samples are not expected to be reliable and were not integrated into the error envelope.…”

“…Microfaunal, sedimentological and geochemical investigations were performed for 137 samples from seven sediment cores (for details see S1.1 (suppl.)) for facies interpretation (see also Elschner et al, 2021). Core VVC17 was analysed as described in Bulian et al (2019).…”

A new ΔR value for the southern North Sea and its application in coastal research

“…Reported 14 C ages of two bivalves collected in AD 1889 with resulting regional offset ΔR from the global marine calibration curve Marine20. Please note that an earlier reported value of ΔR based on the Marine13 calibration curve (Reimer et al, 2013) is 74 ± 16 14 C years (Elschner et al, 2020 a This sample was dated with improved precision using two cathodes at the AMS laboratory in Poznań (573 ± 26 and 511 ± 27 14 C years, respectively). living position.…”

“…basal peats; Meijles et al, 2018), dating of marine material is inevitable when reconstructing the dynamics of the sedimentation processes of the overlying marine sediments (e.g. Elschner et al, 2020). Here, terrestrial material is sparse or reworked, and often marine organisms that build calcium carbonate shells are the only available material for 14 C dating.…”

The WASA core catalogue of Late Quaternary depositional sequences in the central Wadden Sea – A manual for the core repository

“…After the macroscopic description, one core half was sampled for in-depth analysis with regard to the specific disciplines involved in the project. Samples were taken at both regular and irregular intervals, depending on the specific research questions or approaches for each discipline, namely for grain size analysis (for method see Elschner et al, 2021), gravel component analysis (for method see Schaumann et al, 2021), C/N and TOC (Elschner et al, 2021), 14 C-datings (Enters et al, 2021;Scheder et al, 2021;Schlütz et al, 2021), palynology (Schlütz et al, 2021), diatoms (Bulian et al, 2019), foraminifers and ostracods (Scheder et al, 2019(Scheder et al, , 2021Haynert et al, 2020), and taphonomy. Additionally, down core scanning was applied on most of the intact core halves for magnetic susceptibility, and XRF (for methods see Lee et al, 2021).…”