Agderia – a postglacial lost land in the southern Norwegian North Sea

Abstract

Large continental shelf areas, presently submerged, were dry land during the last glacial maximum and early postglacial time. These 'lost worlds' are of outstanding interest because they are believed to have played a central role in animal and plant biogeography, and particularly human migration and cultural development. The large postglacial land area in the North Sea, known as Doggerland, has been studied in the British, Dutch and Danish sectors, but there is a gap in our knowledge in the Norwegian sector. By the compilation and interpretation of recent geophysical data (3D seismic data, high-and ultrahigh-resolution seismics, and bathymetry) and core data (sedimentology, micro-and macropaleontology, palynology, radiocarbon dating) we review the present knowledge about postglacial paleogeography in this area. In our limited core material, the terrestrial phase is represented by a hiatus or possibly by glaciolacustrine sediments, capped by 0.4-2.6 m of marine Holocene sand. We document marine transgression in the area at around 10-11 kyr cal BP. By analogy with similar areas such as Beringia, and with reference to archeological finds in Vest-Agder, Norway, we suggest the name Agderia for the Norwegian part of Doggerland. Agderia -a postglacial lost land in the southern Norwegian North Sea Introduction Large areas of the continental shelves around the world were dry land during the Last Glacial Maximum (LGM), and were flooded during the sea-level rise in the latest Pleistocene or Early Holocene. It is becoming clear that these areas played fundamental roles for the dispersal and evolution of plants, animals and humans in the Quaternary. Prominent examples of such 'lost lands' are Sundaland, connecting the Malay Peninsula to Borneo, Java and Sumatra (Bird et al., 2005); Beringia, connecting Asia to America over the Bering Strait (West, 1996), and Doggerland ( Fig. 1), forming a land bridge from Great Britain to mainland Europe (Gaffney et al., 2009). Gaffney et al. (2007) published a comprehensive study of the paleolandscapes of Doggerland in the southern North Sea. Their 23,000 km 2 study area is located in the UK sector of the North Sea focusing on the Doggerbank (Fig. 1). Their study used a combination of industry 3D seismic data, high-resolution seismic and other geophysical data, and shallow cores and metadata from the British Geological Survey and other public sources. The integrated interpretation revealed a large prehistoric

Characterization of a glacial paleo-outburst flood using high-resolution 3-D seismic data: Bjørnelva River Valley, SW Barents Sea

“…The imaged channel belt cannot be a tunnel valley system formed at the base of an ice stream, nor be a submarine channel system. Tunnel valleys are typically elongated, subglacial channels over several kilometers long, forming canyon morphologies and anastomosing networks that are several hundred meters deep and more than 2 km wide (Ó Cofaigh, 1996; Huuse and Lykke-Andersen, 2000; Stackebrandt, 2009; Stewart and others, 2013; Hammer and others, 2016; Reinardy and others, 2017). Subglacial meltwater channels in Antarctica are further documented to both deepen and becoming increasingly focused in the downstream segment (Anderson and Fretwell, 2008; Simkins and others, 2017).…”

“…Subsequent classification by analysis of the geometries of these landforms can be interpreted in terms of hydrodynamic regime, typically characterized by a set of characteristic geomorphic elements. As such, we will be able to differentiate between glacial drainage systems and depositional environments, and determine if Bjørnelva River Valley is a tunnel valley or a braided river channel belt (Boyd and others, 1988; Piotrowski, 1994; Ó Cofaigh, 1996; Huuse and Lykke-Andersen, 2000; Kelly, 2006; Hammer and others, 2016; Castelltort, 2018). In addition, we characterize the architecture and infill of Bjørnelva River Valley based on attribute analysis of high-resolution 3-D seismic data, which can also be used to distinguish between a subglacial, submarine or subaerial origin.…”

Evidence of an ice-dammed lake outburst in the North Sea during the last deglaciation

“…2), and penetrates 37 m into the sediments. The upper 12 m of this boring has been subdivided into five units based on grain size and various geotechnical parameters (Hammer et al, 2015). LN-BH3/4 is located in a water depth of 109 m at the northern tip of the Ling Bank, and information on grain size and shear strength are available from this borehole (Reinardy et al, 2017).…”

“…Especially, the Dogger and Ling banks (Figs. 1 and 2) must have been sub-aerially exposed for a considerable time span, and these now "lost lands" have attracted strong interest as they in post-glacial time may have been sites for early settlements (e.g., Coles, 2000;Hammer et al, 2015). It has been suggested that an ice-dammed lake has occupied the region south of Dogger Bank during various glacial stages, including Marine Isotope Stage (MIS) 12, MIS 6 and MIS 2 (e.g., Hijma et al, 2012;Murton and Murton, 2012).…”

Norway: Submerged Stone Age from a Norwegian Perspective

“…Elsewhere, deep waters cover such early sites, making archaeological examination more difficult. On the southern side of the Norwegian trench there is a potential for finding sites predating the Holocene (Hammer et al 2016). Initial investigations (Hafeez et al 2012;Glørstad and Kvalø 2012;Glørstad et al 2017) have, however, revealed that finding such sites involves considerable challenges.…”