Weichselian before 15,000 years B.P. at Jæren-Karmø in southwestern Normay

On the basis of studies of many stratigraphical profiles, together with radiocarbon dates, Thorium-Uranium dates and amino-acid dates, the following preliminary stratigraphy is proposed: (1)Late Weichselian. Stavanger Stadial. The glacier covered the coast and deposited the upper drift sheet. - (2) Middle Weichselian.(a)Sandnes Interstadial (30,000?-39,000 years B.P.). Thick units of marine deposits underlie the Stavanger Stadial drift. The lithology, the foraminiferal fauna, the molluscan fauna and the pollen flora all record cold, partly near-ice environment during their deposition. Elements of a boreal type foraminiferal fauna suggest that certain phases of the Sandnes Interstadial could have been slightly warmer. The shore level was very high. (b) Jæren Stadial (40,000? 1000 years B.P.). Tills and glaciomarine deposits at several locailites are correlated with a Jæren Stadial. (c) Nygaard Interstadial (41,000–50,000? years B.P.). Marine deposits representing a low shore-level phase, record cool to cold conditions. - (3)Early Weichselian. (a) Karmøy Stadial (older than 47,000 years B.P.). Gravelly and very bouldery tills at low stratigraphical levels in several prifles are correlated with a Karmøy Staidial.(b) Older deposits. Marine deposits which lie below the Karmøy Stadial till and on top of Eemian deposits at Bø II on Karmøy are being studies.     

Late Weichselian and Holocene shoreline displacement in the Trondheimsfjord area, central Norway

Shoreline displacement data from the Trondheimsfjord area have been collected and a synthesis of the Late Weichselian and Holocene relative uplift is presented. The isobase direction is N 30–35°E during the whole period. The gradients of the shorelines are 1.7? m/km at 11,800 years B.P., 1.3 m/km at 10,000 years B.P., gradually decreasing towards the present with a value of 0.2 m/km at 5,000 years B.P. Some irregularities in the shoreline gradient curve in the Late Weichselian and Preboreal chronozones may be ascribed to crustal readjustments by faults. An interpolation of the 9,500 years B.P. shoreline to the Ångermanland and Baltic area shows a relative uplift at 11,800 years B.P. of 400–450 m in the central area of glaciation. The island of Hitra was probably deglaciated at about 12,000 years B.P. and Ørlandet/Bjugn somewhat later. The Younger Dryas ice marginal deposits at Tautra have been deposited early in this chronozone, and deposits proximal to this at Hoklingen and Levanger were probably deposited in the late part of the same chronozone.     

Weichselian in Sweden before 15,000 B.P.

A brief summary is given of the present state of knowledge about the Weichselian glaciations and interstadials in sweden. The following stages are discussed: (1) The first Weichselian glaciation (W1). This glaciation has not been identified. Probably only northern Sweden was ice-covered. (2) The Jämtland Interstadial , dated at > 50,000 B.P. and correlated with the Finnish Peräpohjola and the Danish Brörup Interstadials. - (3) The second Weichselian glaciation (W II). There are several uncertainteis concerning this glaciation. Sweden was probably ice-covered down to the latitude of Stockholm. – (4) A Middle Weichsedlian interstadial , or complex of interstadials. Some radiocarbon dates indicate, although very uncertain, that most of Sweden may have been free of ice some time rather well known. – Some main problems which have to be investigated are also identified.     

Aspects of the Weichselian chronology in central East Greenland

From central East Greenland, C₁₄ ages between 19,500 > 40,000 years B.P. have been obtained for six samples of marine bivalve shells. The ages seem to be consistent with geological observations and form the basis for a tentative chronology for the Weichselian ice age in the region. It appears that the maximum glaciation during Weichselian times was attained more than 40,000 years ago, and that since then ice-free areas have existed. This assumption agrees with evidence of botanical refugia in the region, and the restricted glacier activity especially during the Upper Pleniglacial (ca. 30,000–15,000 years B.P.) is explained by a reduced supply of moisture. A comparison with evidence from other parts of Greenland indicates that different glacial histories can be expected for different sectors of the Greenland Inland Ice.     

A Middle Weichselain ice-free period in Western Norway: the Ålesund Interstadial

Seven localities with fossil-bearing tills were found in the Ålesund area. Fifteen radiocarbon dates of marine shells in the tills all gave ages between 28,000 and 38,000 years B.P. In spite of a general scepticism to shell dates giving high finite ages, these ages may be accepted mainly because of the quality of the shells, the geological situation in which they were found, and identical results for different fractions. The ice-free period is named the Ålesund Interstadial. and its Middle Weichselian age is also suggested by amino acid D/L ratios in shells, compared with Late Weichselian and Eemian ratios. Shell and foraminifera faunas suggest arctic conditions with the Atlantic water present during the optimal period. The tills are non-sorted, compacted and interpreted to be basal tills. Their age is bracketed between c. 28,000 and 12,800 years B.P.     

Late Weichselian glaciation and deglaciation of Forlandsundet area, western Spitsbergen, Svalbard

Late Weichselian glacier limits for the Forlandsundet area, western Spitsbergen are reconstructed from the stratigraphic distribution of tills and deglacial deposits, variations in the altitude of the marine limit, distribution of pre-Late Weichselian raised beach deposits, and the rare occurrence of moraines and striated bedrock. The Late Weichselian glaciation was primarily a local event with fjord outlet-glaciers expanding no more than 15 km beyond their present position; cirque glaciers were similar to their neoglacial limits. A previously reconstructed ice sheet centered over the Barents Shelf had little direct influence on the glaciation of the Forlandsundet area. Glacier retreat began at or prior to 10.5 ka ago and possibly as early as 13 ka ago with fjords mostly, and perhaps rapidly deglaciated by 10 to 9 ka ago.     

Late Pleistocene-Holocene planktic foraminifera of the western equatorial Pacific

Planktic foraminiferal assemblages were studied qualitatively and quantitatively in 13 samples obtained at 3 cm intervals throughout the uppermost Pleistocene-Holocene deposits of Box core 123 (Eurydice Expedition, western equatorial Pacific Ocean). Absolute ages of these samples have previously been determined by the ¹⁴C method; the lowest sample dated from approximately 16,000 B.P. A curve based on the ratio between specimens of warm and warm-temperate vs. cold and cold-temperate water assemblages suggests that two temperature drops occurred during this time-span: at 11,OOO B.P. and around 4,000–2,OOO B.P. The former drop corresponds to the onset of the Younger Dryas cooling. An unexpectedly high dominance of Globigerinita clarkei (up to 60%, on the average 48.5%) was observed throughout the entire core. Isolated, small-sized and poorly developed specimens of typical cold water foraminifera were present in the materials investigated; their origin is most probably due to advection via equatorward subsurface currents.     

Amino acid ratios in Quaternary molluscs and foraminifera from western Norway: correlation, geochronology and paleotemperature estimates

Isoleucine epimerization (alle/Ue) ratios in the pelecypod Mya truncata and benthic foraminifer Cibicides lobalulus from emerged marine units in western Norway allow construction of a regional relative chronostratigraphy for the Ecmian and Weichselian. Two in situ interglacial sections are considered correlative by the similar biostratigraphy and alle/Ile ratios in C. lobalulus. Overlying sediments at the two sites are of both marine and glacial origin. Neither site contains a complete Weichselian record, but allelic ratios, lithostratigraphy and fauna! changes suggest at least four stadial and three interstadial events occurred along the western Norwegian coast during Early and Middle Weichselian time. Kinetic data defining the relationship between the isoleucine epimerization rate constant and temperature for the species studied allow the estimation of paleotemperatures for samples of known age. Accepting published age estimates for the Eemian interglacial beds, the average Weichselian temperature in western Norway is calculated to have been ca. 4°C below the average Holocene temperature, whereas the last interglacial was 1 to 2°C warmer that the Holocene. The limited temperature depression over this region during the Weichselian implies that coastal western Norway was ice-covered only about 30% of this period, and that Atlantic water, although not necessarily in a warm surface current as today, entered the Norwegian Sea during much of marine isotope stage 5 and intermittently during stage 3. Interpolated amino acid ages date interstadial events at ca. 94 ka, 78 ka and 52 ka, B.P., whereas glacial events are dated ca. 103 ka and bracketed by limiting dates between 78 and 89 ka, between 52 and 63 ka and less than 36 ka B.P.     

Late Quaternary foraminiferal stratigraphy from western Svalbard

In the lower part of sections at Skilvika and Linneelva, western Svalbard, marine silts and sands characterized by infinite radiocarbon ages (<40,000 BP) on shells are found. These sediments are covered by at least one basal till of Late Weichselian age. The till is overlain by marine sediments from the last deglaciation (12,800-10,000 BP) which contain shallow-water, subarctic foraminiferal assemblages, similar to modern near-glacial faunas from western Svalbard. The most common foraminifera in all zones in the sub-till sediments are Cassidulina reniforme, Astrononion gallowayi and/or Elphidium excavatum . The richest zones at both localities are found in the sub-till units and contain more than 20 foraminiferal species, including some boreal-arctic species. These faunal assemblages are similar to the living faunas on the west coast of Svalbard. Faunas from the postglacial climatic optimum are not yet described. We suggest that the foraminiferal assemblages in the sub-till sediment reflect Early or Middle Weichselian interstadial environments, although an Eemian interglacial cannot be excluded.     

The last glaciation of Germania Land and adjacent areas,northeast Greenland

A profile across the unglaciated coast of northeast Greenland at 77°N was studied with regard to the Quaternary stratigraphy and glacial history. The Germania Land peninsula is characterised by till-covered lower ground which contrasts sharply with the blockfields and extensive gelifluction deposits of its higher altitudes. Two glaciations are distinguished. The older one extended over the entire area and had its margin on the continental shelf. The younger one, of Late Weichselian age, reached the present coastline and several mountains and high plateaus on western Germania Land formed nunataks. The Late Weichselian glaciation was more extensive and occurred later on the Germania Land peninsula than on the coast further south. Radiocarbon dates suggest that the glacier margin rested to the east of the present coastline until ca. 10 000 yr BP. This correlates with the Late Weichselian Milne Land Stage, which is found as a late glacial readvance along the coast of East Greenland. A series of recessional moraines formed during the deglaciation were probably caused by glacier dynamics, as opposed to being of climatic origin.     

Eemian and Weichselian correlation problems in Finland

The Quaternary stratigraphy in Finland is discussed on the basis of an example from the Oulainen area of Ostrobothnia. Organogenic deposits found beneath till at this site are correlated with the Eemian Interglacial on biostratigraphical evidence. This is confirmed by TL dates of 97,000 ± 18,000 B.P. and 150,000 ± 30,000 B.P., whereas a finite radiocarbon date of 63,200 +⁵⁵⁰⁰ -₃₂₀₀ B.P. is probably too young. Correlation of the Weichselian stratigraphy is based on deep-sea oxygen isotope data, in which the variations in isotope ratios are assumed to reflect global changes in climate and fluctuations in the volume of the ice-caps. It is concluded on the latter grounds that Finland must have been free of ice at two periods during the Early Weichselian but at least for the most part covered by ice thereafter up to the final deglaciation. The sediments attributed to the only known Weichselian interstadial in Finland, the Perapohjola Interstadial, are taken to correspond most probably to the Brørup, although some may represent the Odderade, Information on the Weichselian till stratigraphy in the Oulainen area is largely confined to the deglaciation phase, the relatively complex nature of which suggests that complete reconstruction of the earlier phases of the Weichselian in an area such as Finland, located towards the centre of the ice sheet, is scarcely feasible by the methods currently available.     

Late Weichselian vegetation, climate, and floral migration at Sandvikvatn, North Rogaland, southwestern Norway

Pollen analysis from Sandvikvatn has elucidated the local Late Weichselian vegetational and climatic history since deglaciation about 14,000 B.P. The pleniglacial period, the first of three climatic main periods and ending c. 13,600 B.P., is an Artemisia -dominated pioneer vegetation on disturbed mineral soils. The Late Weichselian Interstadial (13,600-11,000 B.P.) comprises a Salix -shrub consolidation phase and, from 12,900 B.P., a birch-forest optimum phase. In the Younger Dryas Stadial (11,000–10,100 B.P.) the Artemisia -dominated pioneer vegetation returns. Three climatic oscillations are demonstrated at intervals of about 500 years within the Interstadial. The oldest two, about 12,500 and 12,000 B.P., could both have been connected with the 'Older Dryas'. Cold winters and strong winds, causing soil erosion and drought, are suggested as important factors during the climatic periods unfavourable to woody vegetation. In the pleniglacial and Younger Dryas periods the winds are assumed to be katabatic. During the whole Late Weichselian southern species dominate locally. A northwards spread is demonstrated for the majority of the local late-glacial taxa, including the endemic Primula scandinavica and also Papaver radicatum and Aconitum , both previously discussed as part of the hypothesis of Weichselian ice-free refugia.     

Palaeoenvironments of a complete Eemian sequence at Mommark, South Denmark: foraminifera, ostracods and stable isotopes

A new investigation of the coastal cliff section at Mommark in southern Denmark has revealed a complete Eemian interglacial sequence for the first time in the southwestern Baltic area. Environmental changes through the lacustrine and marine interglacial deposits are discussed on the basis of foraminiferal assemblages and stable isotope composition as well as ostracods. In general, the assemblages indicate relatively high temperatures throughout the Eemian, and the Lusitanian foraminiferal species Pseudoeponides falsobeccarii Rouvillois has been reported for the first time from the Eemian of northwest Europe. A floating chronology of the deposits is based on a previously published correlation of the local pollen stratigraphy with annually laminated sequences in northern Germany. An initial early Eemian lacustrine phase, with ostracodal indication of deposition in a large freshwater lake, lasted until c. 300 years after the beginning of the interglacial, i.e. to the transition between the regional pollen zones E2 and E3. After that, marine conditions persisted almost throughout the interglacial, and the Cyprina Clay was deposited. The foraminiferal and ostracodal assemblages indicate that relatively deep water prevailed in the area until c. 6000 years after the beginning of the interglacial. However, both the foraminiferal assemblages and the oxygen isotope results show that a trend from relatively high salinity to lower salinity conditions had begun already at about 4000 years. After c. 6000 years the fauna indicates a gradual change to shallower water and further reduction in salinity, the latter also being reflected by a general decrease in the oxygen isotope values. The marine deposition ended at c. 10 600 years after the beginning of the Eemian, i.e. within the topmost part of pollen zone E7. This was succeeded by a late Eemian and early Weichselian freshwater phase.     

Eemian crustal deformation in the eastern Baltic area in the light of the new sites at Peski, Russia and Põhja-Uhtju, Estonia

Several Eemian (Mikulino) marine deposits are known from the northwestern part of Russia and from Estonia. The best-known deposits are situated at Mga, Russia and at Prangli, Estonia. Two new sites with clayey and silty deposits covered by till were studied for pollen and diatoms at Peski, Russia and Põhja-Uhtju, Estonia. At Peski, the deposit representing the Eemian Interglacial is 3.8 m thick at the depth of 13.4–9.6 m above present sea-level. At Põhja-Uhtju, the deposit representing the Eemian is 3.5 m thick at the depth of 47.9–51.4 m below present sea-level. Although Peski is situated at a higher altitude than Põhja-Uhtju at present, the diatom stratigraphy at these sites indicates deeper and more saline conditions in the Peski area than at Põhja-Uhtju during the Eemian. This result is similar to some previous studies, which indicate, that although the Russian deposits (e.g. Peski, Mga) are now at a higher altitude than those in Estonia (Põhja-Uhtju and Prangli), the diatoms in the Russian deposits are indicative of a considerable depth of water during the time of deposition. These deposits suggest that the Eemian shore levels ascend from Estonia eastwards, while the Late Weichselian and Holocene shorelines tilt downwards in the same general direction. The present material from Estonia and northwestern part of Russia shows marked differences between the Eemian and Late Weichselian/Holocene crustal deformations, which probably resulted from different ice loads during the final glaciation phases and probably also from different deglaciation patterns during the Saalian and Late Weichselian.     

Early and Late Weichselian chronology and birch assemblages in Denmark

Biostratigraphy and chronostratigraphy of the Early and Late Weichselian substages in Denmark are discussed and a more complete terminology than previously used is proposed. The size variation in Weichselian birch pollen assemblages was compared with subrecent samples. Mean pollen size and variance of the parent species were determined and the proportions of the parent species were calculated. The results confirm earlier conclusions. Percentage frequency-curves for Betula nana and B. pubescens in Late Weichselian pollen diagrams were calculated.     

Late Quaternary Variations in the Level of Paleo-Lake Malheur, Eastern Oregon

The highest shoreline features of paleo-Lake Malheur are undated gravelly barrier beaches south of Harney Lake that lie ca. 3.5 m higher than the hydrographic outlet of Harney Basin at Malheur Gap (1254 m). The earliest Quaternary record for Lake Malheur consists of occurrences of water-deposited tephra dated to ca. 70,000–80,000 yr ago. The next identified lake interval is dated by shells with ages of ca. 32,000 and 29,500 yr B.P. No dates are available for the terminal-Pleistocene Lake Malheur. Lake(s) were present between ca. 9600 and 7400 yr B.P., although periodic low levels or desiccation are suggested by a paleosol dated as ca. 8000 yr B.P. The lake system probably dried further after 7400 yr B.P., although dates are lacking for the period between ca. 7400 and 5000 yr B.P. Dune deposits on the lake floor are ca. 5000 yr old and indicate generally dry conditions. Fluctuating shallow lakes have probably characterized the last 2000 years. A date of 1000 yr B.P. gives a maximum age for beach deposits at 1254 m, near the basin threshold elevation. Thus, the Malheur Lake system may have drained to the Pacific Ocean by way of Malheur Gap during the latest Holocene.     

A Late Weichselian find of polar bear (Ursus maritimus Phipps) from Denmark and reflections on the paleoenvironment

The mandible of a polar bear (Ursus maritimus Phipps) found in about 1920 at Kjul Å, North Jutland, and described by Nordmann & Degerbol in 1930. has been ^l4C dated to 11.100 ± 160 B.P. It is so far the only find of polar bear in Denmark. Comparison with recent ¹⁴C datings of Swedish and Norwegian polar bears shows that the Danish specimen was a member of a southern Scandinavian Late Weichselian population. The contemporaneous Zirphaeu sea deposits can be regarded as the boreal-arctic shallow water equivalent of the arctic Upper Saxicava sand deposits from northern Jutland. The polar bear mandible, however, was deposited on land, as was the metacarpal bone of a brown bear ( Ursus arctos ) from the nearby Nr. Lyngby locality of Allerød age. The overall picture of the Late Weichselian mammal fauna in Denmark shows a mixed composition of different ecotypes. Their sympatric occurrence points at a unique environment not comparable to any now existing, and probably related to the very low latitude of the Weichselian ice sheet.     

Late Pleistocene environmental changes indicated by fossil insect faunas of the English Midlands

Twenty-five fossil insect assemblages are described from discrete lenses of or-ganic material in a gravel sequence at Four Ashes. The youngest date of 30,500 years B.P. obtained on the organic materialhas confirmed that the till overlying the gravels is Late Devensian (Weichselian) in age. The analyses of the insect faunas have shown conclusively for the first time the existence of climatic changes in one geographic area during the Early and Middle Devensian in Britain. Some of the earliest insect faunas can be correlated with the Brorup Interstadial, when boreal forests existed in the English Midlands. It is suggested that a cold period prior to 43,000 years ago (but post-Brorup) may have caused the elimination of the trees, because around 40,000 years ago the insects indicate that there was a rapid climatic amelioration when it was warm enough for trees to grow again in that area. Around 36,000 years ago there was another climatic deterioration when the thermophilous insect species were replaced by a large number of arctic stenotherms and a tundra type of environment. This cold period lasted for at least 6,000 years and probably became increasingly severe with the approach of the main Devensian ice advance sometime after 30,500 years B.P.     

Late Quaternary environmental history of central Prins Karls Forland, western Svalbard

This paper presents the results from stratigraphic and geomorphologic investigations in the Poolepynten area, Prins Karls Forland, western Svalbard. Field mapping, soil profile development and ¹⁴C dating reveal the existence of at least two generations of raised beach deposits. Well-developed raised beaches rise to the Late Weichselian marine limit at 36 m a.s.l. Discontinuous pre-Late Weichselian beach deposits rise from the Late Weichselian marine limit to approximately 65 m a.s.l. Expansion of local glaciers in the area during the Late Weichselian is indicated by a till that locally overlies pre-Late Weichselian raised beach deposits. Stratigraphic data from coastal sections reveal two shallow marine units deposited during part of oxygen isotope stage 5. The two shallow marine units are separated by a subglacially deposited till that indicates an ice advance from Prins Karls Forland into the Forlandsundet basin some time during the latter part of stage 5. Discontinuous glaciofluvial deposits and a cobble-boulder lag could relate to a Late Weichselian local glacial advance across the coastal site. Late Weichselian/early Holocene beach deposits cap the sedimentary succession. Palaeotemperature estimates derived from amino acid ratios in subfossil marine molluscs indicate that the area has not been submerged or covered by warm based glacier ice for significant periods of time during the time interval ca. 70 ka to 10 ka.