Late Quaternary glacier and sea‐ice history of northern Wijdefjorden, Svalbard

Abstract

The deglaciation history and Holocene environmental evolution of northern Wijdefjorden, Svalbard, are reconstructed using sediment cores and acoustic data (multibeam swath bathymetry and sub‐bottom profiler data). Results reveal that the fjord mouth was deglaciated prior to 14.5±0.3 cal. ka BP and deglaciation occurred stepwise. Biomarker analyses show rapid variations in water temperature and sea ice cover during the deglaciation, and cold conditions during the Younger Dryas, followed by minimum sea ice cover throughout the Early Holocene, until c. 7 cal. ka BP. Most of the glaciers in Wijdefjorden had retreated onto land by c. 7.6±0.2 cal. ka BP. Subsequently, the sea‐ice extent increased and remained high throughout the last part of the Holocene. We interpret a high Late Holocene sediment accumulation rate in the northernmost core to reflect increased sediment flux to the site from the outlet of the adjacent lake Femmilsjøen, related to glacier growth in the Femmilsjøen catchment area. Furthermore, increased sea ice cover, lower water temperatures and the re‐occurrence of ice‐rafted debris indicate increased local glacier activity and overall cooler conditions in Wijdefjorden after c. 0.5 cal. ka BP. We summarize our findings in a conceptual model for the depositional environment in northern Wijdefjorden from the Late Weichselian until present.

The Novel Hydroxylated Tetraether Index RI‐OH′ as a Sea Surface Temperature Proxy for the 160‐45 ka BP Period Off the Iberian Margin

“…(2015) found the smallest RI‐OH′ and largest RI‐OH residuals at the lowest SSTs and recommended to use RI‐OH′ rather than RI‐OH for polar oceans. Consequently, all subsequent validations of the RI‐OH′ paleothermometer focused on polar oceans (Allaart et al., 2020; Kremer et al., 2018; Liu et al., 2020; Park et al., 2019; Vorrath et al., 2020; J. Wu et al., 2020; see also Fietz et al., 2020 for a review). While the Iberian Margin is not presently under the influence of (sub)polar waters, it was during Heinrich events when the Polar Front reached this margin (Bard, Arnold, Maurice, et al., 1987; Eynaud et al., 2009).…”

“…In temperate and polar oceans, the only two global core top studies to date have shown that RI‐OH and RI‐OH′ increase with increasing SST (Fietz et al., 2020; Lü et al., 2015). Only a few recent studies have used RI‐OH (Davtian et al., 2019; de Bar et al., 2019) and RI‐OH′ (Allaart et al., 2020; Fietz et al., 2020; Kremer et al., 2018; Vorrath et al., 2020; J. Wu et al., 2020) as SST proxies in sedimentary archives.…”

“…Perceptually uniform color maps are used in this study to prevent visual distortion of the data (Crameri, 2018a(Crameri, , 2018b. de Bar et al, 2019) and RI-OH′ (Allaart et al, 2020;Fietz et al, 2020;Kremer et al, 2018;Vorrath et al, 2020; as SST proxies in sedimentary archives.…”

A Driftwood‐Based Record of Arctic Sea Ice During the Last 500 Years From Northern Svalbard Reveals Sea Ice Dynamics in the Arctic Ocean and Arctic Peripheral Seas

“…Therefore a direct comparison is not applicable to our spatiotemporal record, which targets naturally felled wood only. Other proxy‐based reconstructions of sea ice, such as those derived from the IP 25 biomarker, also suggest variability in sea ice cover during the Late Holocene associated with intermittent warm sea surface temperatures (Allaart et al., 2020; Jernas et al., 2013; Müller et al., 2012; Pawłowska et al., 2020; Sarnthein et al., 2003). Records of brine formation can be interpreted as a proxy for sea ice cover above basins, with a varied Late Holocene record from Storfjorden (Figure 1) suggesting episodic fluctuations between intense and reduced brine formation and concurrent sea ice cover variability (Rasmussen & Thomsen, 2014).…”

The Billefjorden Fault Zone north of Spitsbergen: a major terrane boundary?

“…2). Allaart et al (2020) reported north-south-trending ridges on bathymetric data in northern Wijdefjorden, but these consist either of recent glacial deposits following the trend of the fjord and are associated with a flat-lying top-basement reflection (Allaart et al 2020, figure 5) or of tightly folded, subvertical basement units of the Atomfjella Antiform (Manby 1990;Witt-Nilsson et al 1998). Based on these observations, we discuss three possible scenarios for the Billefjorden Fault Zone north of Wijdefjorden.…”