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The coastal cliff section at Kas Hoved in northern Denmark represents one of the largest exposures of marine interglacial deposits in Europe. High-resolution analyses of sediments, foraminifera, ostracods, and stable isotopes (oxygen and carbon) in glacial-interglacial marine sediments from this section, as well as from two adjacent boreholes, are the basis for an interpretation of marine environmental and climatic change through the Late Elsterian-Holsteinian glacial-interglacial cycle. The overlying glacial deposits show two ice advances during the Saalian and Weichselian glaciations. The assemblages in the initial glacier-proximal part of the marine Late Elsterian succession reveal fluctuations in the inflow of sediment-loaded meltwater to the area. This is followed by faunal indication of glacier-distal, open marine conditions, coinciding with a gradual climatic change from arctic to subarctic environments. Continuous marine sedimentation during the glacial-interglacial transition is presumably a result of a large-scale isostatic subsidence caused by the preceding extended Elsterian glaciation. The similarity of the climatic signature of the interglacial Holsteinian and Holocene assemblages in this region indicates that the Atlantic Ocean circulation was similar during these two interglacials, whereas Eemian interglacial assemblages indicate a comparatively high water temperature associated with an enhanced North Atlantic Current. The foraminiferal zones are correlated with other Elsterian-Holsteinian sites in Denmark, as well as those in the type area for the Holsteinian interglacial in northern Germany and the southern North Sea. Correlation of the NW European Holsteinian succession with the marine isotope stages MIS 7, 9 or 11 is still unresolved.

A multiproxy study of Eemian Stage sediments in two core records, Licze and Obrzynowo, in the Gulf of Gdansk area of northern Poland, shows that the brackish-marine interglacial conditions were determined partly by regional environmental changes and partly by local changes of the river outflow from the Vistula into the southern Baltic Sea. Correlation of the sediments with the Eemian is based on pollen analysis of the Obrzynowo record, showing the presence of regional pollen zones (RPAZ) E2–E6, combined with previously published pollen analyses from Licze (RPAZ E1–E7). A floating chronology is established on the basis of correlation with the annually laminated Bispingen sequence. Diatoms, foraminifera and ostracods are used as marine environmental proxies at both sites. An indication of marine conditions as early as pollen zone E1 or E2 at Licze and close to the E2–E3 boundary at Obrzynowo reflects the rapid relative sea-level rise in the area, which proceeded through ∼3000 years. A major salinity increase c. 1100 years after the beginning of the Eemian (early pollen zone E4) at both sites may be related to the opening of the Danish Straits. The Obrzynowo site became isolated from the sea at c. 3500 years (early pollen zone E5), whereas marine conditions continued at Licze until c. 7000 years, that is, throughout pollen zone E5. Gradually shallower water after c. 5000 years presumably resulted from progradation of the rivers combined with isostatic rebound of the area before final isolation from the sea at c. 7000 years.

Knudsen, K. L., Jiang, H., Kristensen, P., Gibbard, P. L. & Haila, H. 2011: Early Last Interglacial palaeoenvironments in the western Baltic Sea: benthic foraminiferal stable isotopes and diatom-based sea-surface salinity. Boreas, 10.1111/j.1502-3885.2011.00206.x. ISSN 0300-9483. Stable isotopes from benthic foraminifera, combined with diatom assemblage analysis and diatom-based sea-surface salinity reconstructions, are used for the interpretation of changes in bottom- and surface-water conditions through the early Eemian at Ristinge Klint in the western Baltic Sea. Correlation of the sediments with the Eemian Stage is based on a previously published pollen analysis that indicates that they represent pollen zones E2–E5 and span ∼3400 years. An initial brackish-water phase, initiated c. 300 years after the beginning of the interglacial, is characterized by a rapid increase in sea-surface and sea-bottom salinity, followed by a major increase at c. 650 years, which is related to the opening of the Danish Straits to the western Baltic. The diatoms allow estimation of the maximum sea-surface salinity in the time interval of c. 650–1250 years. After that, slightly reduced salinity is estimated for the interval of c. 1250–2600 years (with minimum values at c. 1600–2200 years). This may be related to a period of high precipitation/humidity and thus increased freshwater run-off from land. Together with a continuous increase in the water depth, this may have contributed to the gradual development of a stratified water column after c. 1600 years. The stratification was, however, particularly pronounced between c. 2600 and 3400 years, a period with particularly high sea-surface temperature, as well as bottom-water salinity, and thus a maximum influence of Atlantic water masses. The freshwater run-off from land may have been reduced as a result of particularly high summer temperatures during the climatic optimum.

Erbs-Hansen, D. R., Knudsen, K. L., Gary, A. C., Jansen, E., Gyllencreutz, R., Scao, V. & Lambeck, K. 2011: Late Younger Dryas and early Holocene palaeoenvironments in the Skagerrak, eastern North Atlantic: a multiproxy study. Boreas, 10.1111/j.1502-3885.2011.00205.x. ISSN 0300-9843 A high-resolution study of palaeoenvironmental changes through the late Younger Dryas and early Holocene in the Skagerrak, the eastern North Atlantic, is based on multiproxy analyses of core MD99-2286 combined with palaeowater depth modelling for the area. The late Younger Dryas was characterized by a cold ice-distal benthic foraminiferal fauna. After the transition to the Preboreal (c. 11 650 cal. a BP) this fauna was replaced by a Cassidulina neoteretis-dominated fauna, indicating the influence of chilled Atlantic Water at the sea floor. Persisting relatively cold bottom-water conditions until c. 10 300 cal. a BP are presumably a result of an outflow of glacial meltwater from the Baltic area across south-central Sweden, which led to a strong stratification of the water column at MD99-2286, as also indicated by C. neoteretis. A short-term peak in the C/N ratio at c. 10 200 cal. a BP is suggested to indicate input of terrestrial material, which may represent the drainage of an ice-dammed lake in southern Norway, the Glomma event. After the last drainage route across south-central Sweden closed, c. 10 300 cal. a BP, the meltwater influence diminished, and the Skagerrak resembled a fjord with a stable inflow of waters from the North Atlantic through the Norwegian Trench and a gradual increase in boreal species. Full interglacial conditions were established at the sea floor from c. 9250 cal. a BP. Subsequent warm stable conditions were interrupted by a short-term cooling around 8300–8200 cal. a BP, representing the 8.2 ka event.

Lithostratigraphy and chronostratigraphy of samples from 18 deep boreholes in Vendsyssel have resulted in new insight into the Late Weichselian glaciation history of northern Denmark. Prior to the Late Weichselian Main advance c. 23-21 kyr BP, Vendsyssel was part of an ice-dammed lake where the Ribjerg Formation was deposited c. 27-23 kyr BP. The timing of the Late Weichselian deglaciation is well constrained by the Main advance and the Lateglacial marine inundation c. 18 kyr BP, and thus spans only a few millennia. Rapid deposition of more than 200 m of sediments took place mainly in a highly dynamic proglacial and ice-marginal environment during the overall ice recession. Mean retreat rates have been estimated as 45-50 m/yr in Vendsyssel with significantly higher retreat rates between periods of standstill and re-advance. The deglaciation commenced in Vendsyssel c. 20 kyr BP, and the Troldbjerg Formation was deposited c. 20-19 kyr BP in a large ice-dammed lake in front of the receding ice sheet, partly as glaciolacustrine sediments and partly as rapid and focused sedimentation in prominent ice-contact fans, which make up the Jyske As and Hammer Bakker moraines. In the northern part of central Vendsyssel, at least four generations of north-south orientated tunnel valleys are identified, each generation related to a recessional ice margin. This initial deglaciation was interrupted by a major re-advance from the east c. 19 kyr BP, which covered most of Vendsyssel. An ice-dammed lake formed in front of the ice sheet as it retreated towards the east; the Morild Formation was deposited here c. 19-18 kyr BP. Related to this stage of deglaciation, eight ice-marginal positions have been identified based on the distribution of large tunnel-valley systems and pronounced recessional moraines. The Morild Formation consists of glaciolacustrine sediments, including the sediment infill of more than 190 m deep tunnel valleys, as well as the sediments in recessional moraines, which were formed as ice-contact sedimentary ridges, possibly in combination with glaciotectonic deformation. The character of the tunnel-valley infill sediments was determined by proximity to the ice margin. During episodes of rapid retreat of the ice margin, tunnel valleys were quickly abandoned and filled with fine-grained sediments in a distal setting. During slow retreat of the ice margin, tunnel valleys were filled in an ice-proximal environment, and the infill consists of alternating layers of fine- to coarse-grained sediments. At c. 18 kyr BP, Vendsyssel was inundated by the sea, when the Norwegian Channel Ice Stream broke up, and a succession of marine sediments (Vendsyssel Formation) was deposited during a forced regression. (Less)

The Quaternary sedimentary succession in Vendsyssel, northern Denmark, contains a unique, high-resolution record of the last interglacial and glacial periods. There is still much debate, however, about the timing and ice extent in this southwestern part of the Scandinavian Ice Sheet, particularly during the Middle Weichselian. In this study, a detailed lithostratigraphical subdivision is established for the Late Saalian to Middle Weichselian Skaerumhede Group on the basis of numerous, up to 250 m deep, boreholes in Vendsyssel. The sediments mainly consist of marine clays, glaciolacustrine sediments and tills, and the total thickness of the Skaerumhede Group is up to 140 m. Marine intervals have been used as stratigraphical marker units to separate the formations indicative of ice-sheet activity in Vendsyssel, and the timing of the events has been constrained by a large number of optically stimulated luminescence (OSL) and radiocarbon ages. The Skaerumhede Group is subdivided into seven formations and two members, reflecting shifts between marine and terrestrial sedimentation caused by fluctuations of the Scandinavian Ice Sheet and changes in sea level. The lowermost Skaerumhede Till Formation was deposited directly on top of the bedrock during the Warthe advance c. 160-140 kyr BP. Above, there are fine-grained marine sediments, subdivided into the Lower, Middle and Upper Skaerumhede Clay Formations. The marine formations are separated by the Br circle divide nderslev Formation related to the Sunds circle divide re ice advance from the north c. 65-60 kyr BP, and the Asted Formation, deposited during the Ristinge advance from an east-southeastern direction c. 55-50 kyr BP. The uppermost formation in the group is the L circle divide nstrup Klint Formation, which is an upwards-coarsening sequence of mainly glaciolacustrine sediments deposited prior to the Kattegat advance c. 30-29 kyr BP. The new evidence from Vendsyssel has shown that the Skaerumhede Group covers a large area, and that it can be used as a regional stratigraphical marker horizon. Furthermore, it contributes to a better understanding of the timing and extent of glacial events during the Late Saalian to Middle Weichselian in southwest Scandinavia.

The marine Quaternary of Vendsyssel has been studied in a series of new boreholes in the area, and the climatic development is discussed on the basis of foraminiferal assemblages and stable isotopes. The foraminiferal zones are correlated with previously published records from northern Denmark, and the spatial local and regional distribution is discussed in details based on the new evidence. The new data show that the marine sedimentation in Vendsyssel was not continuous from the Late Saalian to the Middle Weichselian, as previously thought. For example, there is indication of a hiatus at our key site, Asted Vest in the central part of Vendsyssel, at the transition between regional foraminiferal zones N4 and N3, i.e. at the Late Saalian (MIS 6) - Eemian (MIS 5e) transition. The hitherto most complete Early Weichselian succession (zone N2) in Vendsyssel is presented from Asted Vest. Deposits from the Early Weichselian sea-level lowstands (MIS 5d and 5b) may, however, be missing in parts of the area. Two major breaks in the marine deposition during the Middle Weichselian represent glacial advances into northern Denmark. The first event occurred just after deposition of the regional foraminiferal zone N2 (late MIS 4), and the second event in the middle part of zone N1 (early MIS 3). Zone N1 is succeeded by a series of non-marine units deposited during the sea-level lowstand of the Weichselian maximum glaciation (late MIS 3 and MIS 2), including deeply incised tunnel valleys, which have been refilled with non-marine sediments during the Late Weichselian. Vendsyssel was inundated by the sea again during the Late Weichselian, at c. 18 kyr BP. Subsequently, the marine conditions were gradually changed by forced regression caused by local isostatic uplift, and around the Weichselian-Holocene transition most of Vendsyssel was above sea level. A continuous deposition across the Late Weichselian-Holocene boundary only occurred at relatively deep sites such as Skagen. The environmental and climatic indications for Vendsyssel are in accordance with the global sea-level curve, and the Quaternary record is correlated with the oxygen isotope record from the NorthGRIP ice core, as well as the marine isotope stages. (Less)

A high-resolution diatom record from core MD99-2275 reveals a series of palaeoceanographic changes on the North Icelandic shelf since about 9000 cal. yr BP. The influence of relatively warm high-salinity Atlantic water-masses of the IC was strong in the study area during the Holocene Climate Optimum (8760 (base of record) to c. 5300 cal. yr BP) and peaked between c. 8000 and 7000 cal. yr BP. There is a general cooling trend from c. 7000 cal. yr BP to the present, which is indicated by an increase in the influence of cold Polar water-masses from the EGC and the EIC and a decrease in the influence of the IC. A major change in diatom assemblages at around 5300 cal. yr BP indicates a palaeoceanographic shift on the North Icelandic shelf in the mid-Holocene. In addition, several abrupt palaeoceanographic changes are distinguished. Enhanced influence of Polar waters is reflected during the intervals 8120–8000, 6650–6100, 4300–4100, 3000–2700, 1300–1100 and 600–200 cal. yr BP. The palaeoceanographic indication of the diatom record of core MD99-2275 is consistent with the indication of other environmental parameters from the same core, such as benthic and planktonic foraminifera as well as magnetic properties, and the results are also consistent with palaeoclimatic records from adjacent areas around Iceland and in the North Atlantic region.

Isoleucine epimerization (alle/Ile) ratios have been measured on foraminiferal tests from interglaical sites in the southern North Sea region. In order to evaluate the possibilities of this amino acid method on benthic foraminifera, sites were chosen from areas where the stratigraphy was already well known. The study demonstrates that the isoleucine epimerization reaction in benthic foraminifera can be used for correlation and as a means of relative age estimation within a limited geographic area. Previous suggestions of a Holsteinian age for the Rugȧrd, Tornskov, and Wacken sites are supported for the Kås Hoved site. The age of most presumed Eemian sites is supported by the amino acid results; the Reighton site also seems to belong in this interglacial.

Benthic foraminiferal faunas suggesting interglacial climatic conditions are present in several shallow drillings in the North Sea and in northern Jutland. Denmark. The interglacial deposits in six of the cores arc correlated by means of isoleucine epimerization, paleomagnetic data and environmental inferences. Four episodes of interglacial circulation are recorded in sediments of Brunhes age and one warm episode is found just below the Brunhes Matuyama boundary. The Holocene and Eemian faunas of the North Sea are richer in species and individuals and contain more thermophilous species than the older interglacial faunas. However. a much more northern distribution of Bulimina marginata in sediments of Eemian age suggests that oceanic circulation was different during this period than during the Holocene. Sediments of the three other Brunhes interglacials (the Holsteinian, the Norwegian Trench and the Devils Hole Interglacial) and the Leerdam Interglacial record periods of relatively cooler conditions and possibly reduced inflow of Atlantic water.

A new stratigraphic framework is proposed for the Quaternary of a portion of central West Greenland, based primarily on faunal and geochronologic studies of shallow shelf deposits. Twenty‐four occurrences of pre‐Holocene deposits were already known in West Greenland and data from 18 new sites are presented, together with new information on some of the previously described localities. Four pre‐Holocene marine events are described. The interglacial Ivnaarssuit and Nordre Laksebugt marine events are considered to be Middle Pleistocene in age. The interstadial Laksebugt marine event is considered to be late Middle Pleistocene, whereas the Svartenhuk marine event is correlated with the last interglacial. For the last glacial period an extensive ice shelf is proposed west of Disko. The oldest postglacial deposits are dated at 10,470 ± 130 14C‐years BP.

Foraminifera from four boreholes through Quaternary deposits at Roar, Skjold and Dan in the central North Sea have been examined. Shallow marine Eemian deposits were represented over the whole area, and at Roar marine deposits from an older glacial period were found below the Eemian. A glaciolacustrinc sequence occurred above the Eemian in all the boreholes, and at Roar this unit was succeeded by marine sediments containing arctic to boreo-arctic foraminiferal faunas. Both the non-marine and overlying marine units are referred to the Weichselian. Marine Flandrian deposits occur in the upper part of the borings and the faunal succession through this sequence is described.

The study of a c. 18 m thick Late Weichselian- Early Holocene (isotope stage 2/1) marine succession (original water depth 100–150 m) from the Skagen 3 borehole, northern Denmark, has led to a better understanding of the palaeoenvironmental changes during the last deglaciation. The palaeoenvironmental interpretation is based on benthic foraminifera, stable isotope composition and lithology, whereas the chronostratigraphy and sedimentation rates are based on AMS radiocarbon dates. Marine conditions were established in the area at between 15 000 and 14 500 BP (reservoir corrected 14C years), and the first influence of Atlantic water masses imported through the Norwegian Channel is registered from 13 100 BP to 10 900BP (the Bolling- Allerrad interstadial complex). This was followed by the Younger Dryas cooling event between 10 900 and 10 100 BP. The hydrographic change at the Pleistocene-Holocene transition after the Younger Dryas occurred in two stages. Arctic/subarctic deep-water assemblages persisted continuously at Skagen after the first stage at 10 200 BP, while cold boreal assemblages existed in shallower water environments in the Kattegat-Skagerrak basin during the same period of time. The slight warming in the early Holocene seems to have been interrupted by a short-term cooling at about 9700–9600 BP. Finally, at 9600 BP the arrival of warm Atlantic water masses created full-interglacial conditions in the whole region.

Knudsen, Karen Luise: The Lundergard Clay and its Foraminifera, a new formation in the marine Quaternary of Denmark. Boreas, Vol. 1, pp. 289–297. Oslo, 1st December, 1972. Samples from marine Quaternary clay deposits at Lundergard in Vendsyssel have been analysed for their content of Foraminifera. The clay, which is called the Lundergard Clay, contains a typical arctic foraminifer fauna with Quinqueloculina stalkeri and Elphidium ustulatum as characteristic species. To attempt an age determination of the Lundergard Clay, the fauna is compared with foraminifer assemblages from other marine Quaternary deposits of Vendsyssel and adjacent areas. The deposit may represent a hitherto unknown facies of the Older Yoldia Clay of Vendsyssel, which is supposed to be of Weichselian interstadial age, or it may be older and can perhaps be correlated with the Holderness Basement Till of Saale interstadial age.

Examination of a 10 m piston core from the eastern Kattegat revealed marine sediments spanning a period from the late Middle Weichselian to the Early Holocene. The oldest marine unit in the core is 14C-dated to about 30,000–36,000 years BP. These sediments represent the Middle Weichselian Sandnes/Denekamp-Hengelo Interstadial (upper part of stable isotope stage 3) and can be correlated to marine deposits from several localities in the Kattegat region by means of foraminifera. The Late Weichselian deposits comprise sediments from the Oldest Dryas Stadial and the Allerod Interstadial. The intervening periods are not represented in the sequence (hiatuses). Sediments from the latest part of the Early Holocene Preboreal period succeeding the Allerod sequence indicate a considerable hiatus spanning 2000–3000 years around the Weichselian/Holocene boundary. The late Preboreal faunas document a high freshwater inflow during this period, and stable conditions seem not to have been reached in the area until a few hundred years later, in the Boreal period. Comparison with boxcore material from the same site documents a reduction of the energy level of the bottom currents some time between c. 8000 and 800 years BP.

One profile and four short borings were analyzed. A marine Quaternary deposit, here called the Hostrup Clay, was found. The two dominant species in the Hostrup Clay were Elphidium excavatum, forma clavata and Cassidulina crassa, whereas characteristic accessory species were Protelphidium orbiculare in the lower clayey part of the deposit, and Buccella frigida, Elphidiuni albiumbilicatum, and E. subarcticum together with P. orhiculare in the upper more sandy part. The Hostrup Clay faunas were compared with assemblages from other marine Quaternary deposits. The present deposit is probably correlatable with the lower part of the marine sequence of the Inder Bjergum borings at Ribe, which is supposed to be of Holsteinian Interglacial age. However, as the foraminiferal faunas indicate a climatic succession from arctic to probably boreo-arctic conditions, the Hostrup Clay, together with the corresponding cold part of the marine Quaternary sequence in the Ribe-Esbjerg region, may represent the Lateglacial part of the preceding Glacial Period, i.e. the Elsterian.

New palaeoenvironmental data from the Lateglacial in Southwest Iceland add to the record of climatic events during deglaciation of the region. Recently exposed sediments on the north coast of Seltjarnarnes Peninsula in the Reykjavik area, Southwest Iceland, contain evidence of marine deposition during the Bolling Interstadial. The glaciomarine sediments contain both slightly reworked marine macrofossils and microfossils indicating normal marine salinity and subarctic climate conditions. Previous sedimentological studies and radiocarbon dating of the sporadic sediments covering the lava bedrock in Reykjavik have revealed lateglacial marine units from the Allerod, the Allerod—Younger Dryas transition, the Younger Dryas and from the Preboreal. Until now, the only Bolling evidence has consisted of scattered radiocarbon-dated redeposited shell fragments. From the Bollagardar deposits we report the first faunas dated to the Bolling chronozone preserved in marine sediments in the Reykjavik area. Recently published work in Hvalfjordur and Borgarfjordur, West Iceland, has shown that sea level was relatively high during the Bolling and that deglaciation was rapid. Bolling, Allerod and Younger Dryas deposits in the coastal areas of the Reykjavik region accumulated in a relatively open marine environment in oceanographic conditions similar to the present ones. Combined previous and present results indicate that several episodes of glaciomarine deposition occurred.

Knudsen, K. L. & Larsen, N. K. 2009: Quaternary of Vendsyssel, northern Denmark - Introduction. Boreas, 10.1111/j.1502-3885.2009.00100.x. ISSN 0300-9483.

Different topics of Quaternary geology were dealt with at a symposium arranged in 1986 in Arhus, Denmark: (1) reviews on recent Quaternary research in the Nordic countries, (2) studies of stratigraphy and geological processes in the Fennoscandian Border Zone, which demonstrate that the Quaternary deposition pattern is highly influenced by tectonic movements, and (3) Quaternary research as it can be applied to geotechnical investigations in the search for raw materials, in connection with pollution, and with conservation.