Postglacial, relative shore-level changes in Lillebælt, Denmark

The brackish Baltic Sea and the more saline Kattegat are connected by three straits, Lillebælt, Storebælt and Øresund (Fig. 1). Of the three straits, Lillebælt is the narrowest, with 700 m at its narrowest point, widening out towards the south to around 25 km (Fig. 2). In the narrow parts of Lillebælt, water depths around 30–50 m are common. In the northern part of Lillebælt the depth is 16–18 m and in the southern part the depth is around 35 m. Storebælt and Øresund have played important roles as outlets during the history of the Baltic Sea, and their histories have been much discussed (Björck 1995; Bennike et al. 2004). In contrast, Lillebælt has received little attention. In this paper we present 11 new radiocarbon accelerator mass spectrometry (AMS) ages and propose a curve for Holocene relative shore-level changes in Lillebælt. We use the term shore-level changes rather than sea-level changes because we have constructed both lake-level and sea-level changes

A new Middle Pleistocene interglacial occurrence from Ejby, Sjælland, Denmark

Despite more than a century of investigations, parts of the Quaternary stratigraphy of Denmark with their fragmented record of deposits remain ambiguous. Here we describe a newly found interglacial clay deposit from Ejby on Sjælland, Denmark, from a borehole at 55.695°N, 11.839°E (terrain elevation 5.7 m above sea level). We place the new occurrence on record and provide details of the macrofossil analysis of the sample. The clay contains remains of the present-day temperate bivalve Corbicula fluminalis and the caddis fly Hydropsyche contubernalis – both inhabiting rivers. The presence of C. fluminalis indicates that the deposit most probably is of Middle Pleistocene age, older than the last interglacial, the Eemian

Chemical Analyses of Archaeological Bone-Samples: Evidence for High Lead Exposure on the Faroe Islands

Chemical Analyses of Archaeological Bone-Samples: Evidence for High Lead Exposure on the Faroe Islands

Glacial Rock Flour as Soil Amendment in Subarctic Farming in South Greenland

Agriculture in subarctic regions is limited by a short and cold growing season. With warming in the region, the number of growing days and, consequently, the potential for agricultural intensification and expansion may increase. However, subarctic soils are typically acidic, low in plant-available nutrients, and coarsely textured, so they require soil amendment prior to intensification. This is the case in South Greenland, where we tested the use of glacial rock flour (GRF) produced by glaciers as a soil amendment. An experiment was made on a farm in South Greenland during the 2019 summer to quantify the short-term effect of applying GRF to a field dominated by perennial timothy grass. Three treatments were compared to control sites (n = 5): 20 t GRF ha−1 without conventional NPK-fertilizer, as well as 20 and 40 t GRF ha−1 in combination with 25% NPK-fertilizer. The experiment showed no significant response in biomass production (aboveground and belowground) for the plots treated with GRF only. The low rate of GRF combined with 25% NKP showed a marked and significant increase in yield in contrast to a high GRF rate with NPK, which resulted in a significant reduction in yields. The chemical composition of the plants versus soil and GRF showed that the plant uptake of nutrients was significantly higher for NPK-fertilized plots, as expected, but no differences were found between GRF-treated plots and the control plots with respect to nutrient availability or pH in the soil. We conclude that adding water and fertilizer has the potential to increase yields in South Greenland, but applying glacial rock flour as a short-term agricultural supplement needs to be further investigated before it can be recommended

Late glacial to early Holocene development of southern Kattegat

The Kattegat region is located in the wrench zone between the Fennoscandian shield and the Danish Basin that has repeatedly been tectonically active. The latest ice advances during the Quaternary in the southern part of Kattegat were from the north-east, east and south-east (Larsen et al. 2009). The last deglaciation took place at c. 18 to 17 ka BP (Lagerlund & Houmark-Nielsen 1993; Houmark-Nielsen et al. 2012) and was followed by inundation of the sea that formed a palaeo-Kattegat (Conradsen 1995) with a sea level that was relatively high because of glacio-isostatic depression. Around 17 ka BP, the ice margin retreated to the Øresund region and meltwater from the retreating ice drained into Kattegat. Over the next millennia, the region was characterised by regression because the isostatic rebound of the crust surpassed the ongoing eustatic sea-level rise, and a regional lowstand followed at the late glacial to Holocene transition (Mörner 1969; Thiede 1987; Lagerlund & Houmark-Nielsen 1993; Jensen et al. 2002a, b)

Holocene insect remains from south-western Greenland

Remains of plants and invertebrates from Holocene deposits in south-western Greenland include a number of insect fragments from Heteroptera and Coleoptera. Some of the finds extend the known temporal range of the species considerably back in time, and one of the taxa has not previously been found in Greenland either fossil or extant. The fossil fauna includes the weevil Rutidosoma globulus which is at present extremely rare in Greenland. Its rarity might indicate that it is a recent immigrant, but the fossil finds provide a minimum date for its arrival at around 5840 cal. years B.P. Other remains of terrestrial insects complement the scarce fossil Greenland record of the species concerned

Holocene relative sea-level changes in the Qaqortoq area, southern Greenland

We present results from an investigation of relative sea-level changes in the Qaqortoq area in south Greenland from c. 11 000 cal. yr BP to the present. Isolation and transgression sequences from six lakes and two tidal basins have been identified using stratigraphical analyses, magnetic susceptibility, XRF and macrofossil analyses. Macrofossils and bulk sediments have been dated by AMS radiocarbon dating. Maximum and minimum altitudes for relative sea level are provided from two deglaciation and marine lagoon sequences. Initially, relative sea level fell rapidly and reached present-day level at ∼9000 cal. yr BP and continued falling until at least 8800 cal. yr BP. Between 8000 and 6000 cal. yr BP, sea level reached its lowest level of around 6-8m below highest astronomical tide (h.a.t.). At around 3750 cal. yr BP, sea level has reached above 2.7m below h.a.t. and continued to rise slowly, reaching the present-day level between ∼2000 cal. yr BP and the present. As in the Nanortalik area further south, initial isostatic rebound caused rapid isolation of low elevation basins in the Qaqortoq area. Distinct isolation contacts in the sediments are observed. The late Holocene transgression is less well defined and occurred over a longer time interval. The late Holocene sea-level rise implies reloading by advancing glaciers superimposed on the isostatic signal from the North American Ice Sheet. One consequence of this transgression is that settlements of Palaeo-Eskimo cultures from ∼4000 cal. yr BP may have been transgressed by the sea

Neoglacial and historical glacier changes around Kangersuneq fjord in southern West Greenland

The Nuup Kangerlua region in southern West Greenland became eglaciated in the early Holocene and by the mid-Holocene, the margin of the Inland Ice was located east of its present position. Discussion of late Holocene changes in the frontal positions of outlets relies on descriptions, paintings, photographs, maps, data from investigations of Norse ruins, aerial photographs and satellite images.The Kangiata Nunaata Sermia glacier system has receded over 20 km during the last two centuries, indicating a marked response to climatic fluctuations during and since the Little Ice Age (LIA). A large advance between 1700 and 1800 was followed by rapid recession in the first half of the 1800s. Limited data from c. 1850–1920 indicate that although the long-term position of the glacier front remained c. 10–12 km behind the LIA maximum, the late 1800s and the early 1900s may have seen a recession followed by an advance that resulted in a pronounced moraine system. The ice-dammed lake Isvand formed during the LIA maximum when meltwater from the western side of Kangiata Nunaata Sermia drained to the Ameralla fjord in the west. This is in contrast to the drainage pattern before the 1700s, when water probably drained to Kangersuneq in the north. Thinning of Kangiata Nunaata Sermia resulted in total drainage of Isvand between 2000 and 2010 and the discharge of water through Austmannadalen has now returned to the same level as that in medieval times.Other outlets in the region, such as Akullersuup Sermia and Qamanaarsuup Sermia have varied in phase with Kangiata Nunaata Sermia, but with amplitudes of only a few kilometres. In contrast, Narsap Sermia has been nearly stationary and Kangilinnguata Sermia may have advanced until the middle of the 1900s.Lowland marine outlets in south-western Greenland were characterised by large amplitude changes during the Neoglacial. Extreme examples, in addition to Kangiata Nunaata Sermia, are Eqalorutsit Killiit Sermiat at the head of Nordre Sermilik fjord in southern Greenland and Jakobshavn Isbræ in Disko Bugt, central West Greenland. The Neoglacial advances appear to have occurred at different times, although this may in part reflect the limited information about fluctuations prior to the 1930s. The differences could also reflect variations in mass balance of different sectors of the ice sheet, different subglacial dynamics or topographical factors. The lowland areas are separated by uplands and highlands that extend below the marginal part of the Inland Ice; in such areas, the outlets have been advancing almost up to the present, so that the position of the glacier front around AD 2000 broadly coincides with the LIA maximum. Charting the fluctuations of the outlets thus illustrates the large variability of the glaciers’ response to changing climate but it is notable that the number of advancing outlets has decreased markedly in recent years

The Storebælt gateway to the Baltic

The present-day Storebælt (Great Belt), the waterway between the islands of Fyn and Sjælland (Fig. 1), contains deeply incised valleys, locally more than 50 m deep, and is of crucial importance to the water exchange between the fully marine Kattegat and the brackish Baltic Sea. The role of this important gateway changed significantly during the late and post-glacial period (since 15000 B.P.), when the Baltic Basin experienced alternating freshwater, brackish and marine conditions as a result of changes in relative sea level (Figs 2, 3). The importance of the Storebælt in understanding the dynamics of the Baltic Basin is reflected in the large number of studies carried out (see Bennike et al. 2004). The first detailed sedimentological and stratigraphic studies in the Storebælt area that demonstrated the presence of early Holocene freshwater deposits below the seabed were those of Krog (1960, 1965, 1971), who also presented the first shore-displacement curve for the area (Krog 1979)