The history of this volume goes back to a 1973 INQUA congress in New Zealand, where an INQUA Commission of Stratigraphy working group on major subdivisions of the Pleistocene was established. The Pleistocene series/epoch was hitherto generally subdivided into the Lower/Early, Middle and Upper/Late Pleistocene (see, among others, Zeuner, 1935, 1959) but the boundaries between these subseries/subepochs were not formally defined. The boundary between the Early and Middle Pleistocene was, in the European literature, put at the base of the Cromerian Complex (Zagwijn, 1963) or at the Brunhes/Matuyama magnetic boundary (Richmond, 1996).

A historical outline of the Eemian research in the Netherlands is presented as an introduction to recent research in the type area. At the end of the 19th and during the first part of the 20th century, Eemian sediments were recognized because of the presence of lusitanian and mediterranean mollusc species. From 1930 onwards, pollen analysis made it possible to identify also non-shell-bearing deposits and to equate them with the Eemian. At the same time this technique proved a valuable tool for understanding the vegetation development during this interglacial. Pollen zonation offered a unique possibility for the correlation of terrestrial sequences in North-West Europe.

The type area of the Eemian, near Amersfoort, was described by Harting in 1874 and was comprehensively restudied by Zagwijn (1961). A pollen zonation was introduced as a standard for the Netherlands, allowing the correlation of pollen records from both marine and non-marine depositional environments. This enabled a more detailed temporal resolution, resulting in a better understanding of the distribution of the various environments in the type area.

In the northern and central parts of the Netherlands, the identification of the marine sequence was, apart from the occurrence of the specific mollusc fauna, facilitated by the presence of a till of Saalian age underlying the Eemian deposits. The presence of deep glacial basins in these areas enabled the deposition and preservation of a complete Eemian record in a marine setting. Sediment accumulation in the basins began immediately following deglaciation at the end of the Saalian. The Eemian type sections at Amersfoort are situated near the margin of one of these basins.

Recent research of the Eemian focused on the integration of lithostratigraphic evidence and information on the sedimentary environment as derived from diatoms, dinoflagellates, foraminifers, molluscs and pollen.

During its maximum extension, the Saalian ice cap reached into the central Netherlands, where glacier tongues excavated over 100 m deep basins in the unconsolidated Middle and Early Pleistocene sediments. The basins are filled by relatively thick successions of Late Saalian, Eemian and Weichselian sediments. The fill of the Amsterdam glacial basin is among the best known and studied in the Netherlands. The Late Saalian sediments consist mainly of warves and ill-bedded clays and silts with, along its southern margin, influxes of sands from the surrounding ice-pushed ridges. During deposition of these sediments, the Amsterdam basin formed part of a large lake extending into the present North Sea. Draining of this lake at the end of the Late Saalian left small, shallow pools at the site of the glacial basins.

Late Saalian and Eemian sediments are probably separated by a short break, although sedimentation may have been continuous in the deepest part of the basin. The Eemian deposits consist in main lines of a thin, diatom-rich sapropel at the base, overlain by an up to 30 m thick clay-rich sequence covered by a wedge of sand that measures more than 20 m in the northern part of the basin and that peters out southwards. As appears from the fauna, most of the clays were deposited in a lagoonal setting shielded behind a threshold and/or barrier. The rate of sediment supply was low so that lagoonal conditions were maintained over a long timespan. Sands derived from the surrounding ice-pushed ridges and transported by longshore drift and tidal currents formed a spit at the northern margin of the basin, which moved southward after eustatic sea-level rise stabilized and the lagoon was filled by clay. Loading of this clay-rich sequence by the spit and its washover fans induced subsidence, however, because of compaction, so that marine conditions were maintained until after the Eemian highstand. Fluvial and eolian sediments of Weichselian age, locally reaching a thickness of almost 10 m, eventually levelled the Amsterdam glacial basin.

The Amsterdam glacial basin was a major sedimentary sink from late Saalian until late Eemian (Picea zone, E6) times. The basin’s exemplary record makes it a potential reference area for the last interglacial stage. The cored Amsterdam-Terminal borehole was drilled in 1997 to provide a record throughout the Eemian interglacial. Integrated facies analysis has resulted in a detailed reconstruction of the sedimentary history.

After the Saalian ice mass had disappeared from the area, a large, deep lake had come into being, fed by the Rhine river. At the end of the glacial, the lake became smaller because it was cut off from the river-water supply, and eventually only a number of shallow pools remained in the Amsterdam basin. During the early Eemian (Betula zone, El), a seepage lake existed at the site. The lake deepened under the influence of a steadily rising sea level and finally evolved into a silled lagoon (late Quercus zone, E3). Initially, the lagoon water had fairly stable stratification, but as the sea level continued to rise the sill lost its significance, the lagoon becoming well mixed by the middle of the Corylus/Taxus zone (E4b). The phase of free exchange with the open sea ended in the early Carpinus zone (E5), when barriers developed in the sill area causing the lagoon to become stratified again. During the Late Eemian (late E5), a more dynamic system developed. The sandy barriers that had obstructed exchange with the open sea were no longer effective, and a tidally-influenced coastal lagoon formed.

The Eemian sedimentary history shown in the Amsterdam-Terminal borehole is intimately connected with the sea-level history. Because the site includes both a high-resolution pollen signal and a record of sea-level change, it has potential for correlation on various scales. Palaeomagnetic results show that the sediments predate the Blake Event, which confirms that this reversal excursion is relatively young. The U/Th age of the uppermost part of the Eemian sequence is 118.2±6.3 ka.

In order to obtain a better understanding of the infilling of the Saalian glacial basins during the Eemian, particularly following the recent research in the Amsterdam Basin (Terminal borehole), it was necessary to re-investigate the type locality of the Eemian at Amersfoort. Both published and unpublished data from various biota (diatoms, foraminifers, molluscs, ostracods, pollen) provide new information on the changing sedimentary environments during the Eemian. Although the organic and clastic sediments of the infilling represent nearly all the pollen zones, the sedimentary sequence at Amersfoort is discontinuous: four breaks at least are recognised at the type locality.

The successive sedimentary environments and the breaks in the record are linked with the transgression of the Eemian sea, the topographic position at the margin of an ice-pushed ridge, and the changes in hydrodynamic conditions. Local conditions, such as a sandy sea bed, shallow water and a reduced water exchange near the North Sea margin, influenced the salinity of the basin. Rib counts of Cerastoderma edule shells indicate a higher salinity at the end of the Taxus (E4b) and the beginning of the Carpinus (E5) zones than that present in the modern North Sea. Local conditions were responsible for the higher salinity following the climate optimum.

During the Abies phase (the later part of regional pollen zone E5), the sea level had already fallen. The change from eu-trophic peat growth (with Alnus and Salix) to an oligotrophic Ericaceae/Sphagnum community at the end of the Eemian resulted from the change from a marine to a fresh-water environment, probably coherent with a deterioration of the climate.

Many small deposits of Eemian age, including the stratotype, are found right across the North European plain. In adjacent areas, this interglacial is known by local names such as Ipswichian (Britain), Luhe or Ribains (France), Riss-Würm interglacial (Alps) and Mikulinian (Poland and Russia). It correlates primarily with MIS 5e of the deep-sea stratigraphy, though boundaries may not be exactly the same. Basins containing Eemian sediments rest directly on morainic deposits of all three Saalian ice advances, which must all, therefore, fall within MIS 6.

Indicator species of both plants and animals suggest that mean July temperatures in the early-temperate part of the interglacial were warmer than during the Holocene. For many years, palynologists have recognised a very uniform succession of temperate tree acme pollen zones and a substantial late-temperate expansion of Carpinus as hallmarks of this interglacial across much of northern Europe. In southern England, however, deposits with a similar pollen signature are being recognised on stratigraphie and palaeontological grounds as characterising not only the Ipswichian but also the previously poorly-defined interglacial stage correlating with MIS 7. High Carpinus values are known from these latter sites and from the Le Bouchet inter-glacial of the French Massif Central, also clearly correlated with MIS 7. Thus stratigraphie confusion and misinterpretations may have occurred at supposedly Eemian/Ipswichian sites unrelated to the glacial stratigraphy or to deep continuous records.

The uniformity and rapid development of Eemian vegetational successions may be ascribed to (1) rapid warming and the lack of any late-glacial climatic oscillation on the scale of the Younger Dryas, (2) the development of an open marine connection in the first half of the interglacial from the English Channel across the North and Baltic Seas to the White Sea and the Arctic Ocean, and (3) the occurrence of Saalian per-glacial refugia for Carpinus, not only in the Balkans but also on the Iberian peninsula, permitting much more rapid northward colonisation of Europe during this interglacial.

The question of climatic events within the Eemian is far from settled. Not only is the ice-core evidence ambiguous and awaiting further clarification, but the scale and synchroneity of proposed events at different continental sites in both northern and southern Europe show no clear pattern at present; clearly there is a need for more detailed investigation and interpretation. Likewise there is ongoing debate about the duration of this interglacial and its detailed correlation with the deep-sea core record and events within the North Atlantic Ocean.

The vegetational and climatic developments during the Riss-Würm interglacial in the area on the northern flank of the Alps are reviewed. Reforestation seems to have begun over the whole region with a dwarf-shrub and ensuing shrub phase, leading to birch and/or pine woodland. The rise in summer temperatures, which δ180 values suggest to have been a two-stage event, permitted the immigration and expansion of more demanding trees (elm, oak, lime, ash, ivy, hazel, yew, etc.). Following the thermal maximum, which took place during the hazel and yew biozones, hornbeam dominated the forests in the alpine foreland, whilst fir/spruce forests formed the dominant vegetation at sites closer to the Alps or at a higher altitude. A marked climatic deterioration can only be recognised towards the end of the interglacial, which led to extensive spruce/pine and, finally, almost pure pine forests.

Shells belonging to the bivalve genus Corbicula occur commonly in Pleistocene interglacial deposits in NW Europe. These have usually been identified as C. fluminalis, a modern species described from the Euphrates river, although the veracity of this specific attribution remains equivocal. Corbicula has nowadays a southern distribution, and laboratory studies indicate that it is thermophilous. It is also tolerant of brackish water, one of several attributes that make this an effective colonizer.

In NW Europe, Corbicula is known from the Lower Pleistocene but is absent from the Cromerian Complex, occuring again in the three interglacials following the Anglian/Elsterian. It appears to be unknown from the last interglacial, except as derived fossils.

Assemblages of fossil coleoptera (beetles) have been obtained from eight sites in southern England that date from the early phase (Pinus — Quercetum mixtum — Corylus pollen assemblage zone) of the Eemian (Ipswichian) interglacial Stage. Altogether 294 different species have been identified from these sites. They represent a wide spectrum of habitat requirements; terrestrial, aquatic, carnivorous and phytophagous species and many more with subtle dependences of specialist biotopes. Almost all of them live today in central and southern Europe and some are restricted to regions well south of the British Isles.

By using mutual climatic range methods, the thermal climate of the early phase of the Eemian Interglacial has been estimated quantitatively, showing that mean July temperatures were about 4°C above those of southern England today. Mean winter temperatures were not much different from those nowadays. This phase was probably the thermal maximum of the Eemian Interglacial. Precipitation levels are difficult to quantify but were adequate to maintain flowing rivers in England throughout the year. These results are in agreement with the presence of other fossils, both plants and animals, in the same deposits.

The knowledge of the Eemian fauna of central Europe is based on the fossil record from a number of sites located in the eastern part of Germany. The faunas with different deer species as well as Sus scrofa, Palaeoloxodon antiquus, Stephanorhinus kirchbergensis and Glis glis indicate a forested environment alternating during the climatic optimum of the Eemian s.s. with areas with a more open environment inhabited by species such as Cricetus cricetus, Equus sp. (or Equus taubachensis), Equus hydruntinus and Stephanorhinus hemitoechus. Characteristic for the Rhine valley fauna are Hippopotamus amphibius and the water buffalo (Bubalus murrensis); both species are absent in the eastern German faunas with an Eemian age.

Taking into account the short period of time covered by the Eemian s.s., the amount of data on the Eemian mammalian fauna is remarkably large. There is, however, still an ongoing debate on whether the stratigraphical position of a number of faunas are of Eemian or ‘intra-Saalian’ age. Furthermore, there are faunal assemblages or stratigraphically isolated finds referred to the Eemian without indisputable evidence. This is particularly the case in the Rhine valley, where most of the so-called Eemian fossils come from dredged assemblages. The picture of the evolution of the Eemian fauna and its geographical variation is consequently still incomplete.

The relevance of a study of the Eemian occupation of Europe lies largely in the discussion on the environmental tolerances of early humans and in the limits encountered during the reconstruction of Palaeolithic habitats. The traditional vision is reviewed; then follows a discussion of Gamble’s studies (1986, 1987) in which he postulated an absence of human occupation in North-Western Europe during the Eemian. Gamble’s explanatory models and the reactions to his work are presented. Finally, the relation is considered between the distribution pattern of sites, the former dispersal of early humans across the European landscape, and the implications of this evidence for hypotheses of environmental tolerances of Palaeolithic humans.

During the last decades a considerable amount of data on mammals from Mikulino (=Eemian) deposits of the central and southern parts of the Russian Plain has been produced. Mammuthus primigenius (the early type), Palaeoloxodon antiquus (the advanced form), Arvicola ex gr. terrestris, Eolagurus cf. luteus and Lagurus cf. lagurus characterize this period. The so-called ‘Shkurlatian mammal assemblage’ was distinguished on the basis of a number of Eemian faunas.

The age of the mammal localities was established by using various geological and palaeontological evidence, together with the results of palaeomagnetic studies and absolute dating. The evolutionary level of the diagnostic species allows correlations between localities from different parts of the Russian Plain that have varying taphonomical conditions. The mammal- and malacofauna of the Mikulino Interglacial can also be used as a basis for correlations between the Karangat marine strata of the Black Sea and the continental deposits (alluvial sediments of the second terrace of the Sudost’ River and the Salyn phase of the Mezin fossil pedocomplex (see Dodonov et al., this volume). Forest, forest-steppe and steppe zone landscapes have been reconstructed for the central and southern parts of the Russian Plain on the basis of the Eemian faunas.

The records of the last interglacial in several palaeogeographical zones and various sedimentary environments from Central Asia to the Black Sea shoreline are presented. The last interglacial is characterized in the study areas by a two- or three-unit stratigraphical complex with both terrestrial and marine formations. Finds of significant small mammalian remains, together with a characteristic mollusc fauna in the Karangatian marine sediments, provide key levels for biostratigraphical correlation between the marine and continental deposits. New U/Th dates allow the correlation of the Karangatian transgression with δ18O substage 5e.

For more than one century, the textural B-horizon of the last interglacial soil and its cover deposits have been standing out in Europe as an important pedostratigraphic marker. The complexity of this horizon was well illustrated since the seventies, though its pedological and stratigraphic significance remained doubtful. Macro-, meso- and micromorphological data gathered by the authors at various key-sites in Europe and the sequential correlation principle have resulted in a better understanding of the high complexity of the pedosedimentary and stratigraphical evolution of the last interglacial and early glacial loess succession. The present study identifies four megacyclic pedosedimentary intervals that show a general trend towards dry and continental climatic conditions.

A consistent correlation exists between pedosedimentary evolution and vegetation, as recorded in the Grande Pile pollen record. The picture obtained in the present study is similar for both the Western and the Eastern European loess palaeosol successions. The so-called ‘last interglacial soil’, with three major soil-forming processes, belongs to the Eemian and Saint-Germain I (MIS substages 5e and 5c), whereas the humiferous sediments and soils on top are linked to Melisey II, Saint-Germain II and Ognon I (MIS substages 5b and 5a).The overlying loess, colluvial sediments and humiferous soils that end the palaeosol succession belong to the Ognon II and III interstadials; they record the onset of the early Pleniglacial (MIS stage 4) characterized by a significant increase in aeolian sedimentation.

The current status of knowledge concerning the Eemian interglacial in Sweden is surveyed, and comparisons are made with northern and western Finland. The course of shore displacement is fragmentarily known for Sweden, since brackish-marine sediments have been identified, on the basis of diatom analysis, at only few sites. In Finland, on the other hand, a shoredisplacement curve has been constructed for the Eemian Baltic Sea in Ostrobothnia, central western Finland.

The vegetation history is summarised for the southernmost part of Sweden, and can be correlated with that documented in Denmark. For the central part of Sweden, information is sparse, but the composition of the forests has been outlined for most of the interglacial, although information on regional pollen assemblage zones E3 and E4 (early-temperate substage) are mainly missing. A more complete picture of the interglacial vegetational history is known from Ostrobothnia in Finland. The thermophilous indicators Viscum, Ilex, Hedera and Osmunda grew far North during the Eemian. Corylus and Carpinus expanded much further to the North than during the Holocene. In Swedish and Finnish Lapland, the vegetation history is similar except that Larix was common in Finland during the Eemian, but its presence has so far not been confirmed in Sweden.

Eemian deposits relocated during the Weichselian glaciation contain pollen and diatoms that can be used for reconstruction of the Eemian environment. No clear indication of a rapid climatic deterioration during the Eemian has been found so far in either Swedish or Finnish sequences.

The marine Eemian (marine oxygen-isotope substage 5e: MIS 5e) is represented by shallow-water deposits in southern and western Denmark, while relatively deep-water environments occurred to the north and north-east, where complete interglacial successions seem to be present. We present an overview of the marine Eemian deposits in Denmark, and discuss in more detail indications of climate variability, both for the late Saalian and within the Eemian.

High-resolution pollen, dinocyst and isotopie profiles covering the marine isotope stage 5 (MIS 5) are presented from core MD952042 (Tagus abyssal plain, 37°47'N, 10°09'W). Both marine and terrestrial proxies indicate the occurrence of a Bølling-Allerød-Younger Dryas-like event at the beginning of MI substage 5e. The terrestrial Eemian stage coincides with both the lightest oxygen isotope values of substage 5e and the heavier ones approaching the 5e/5d transition. Accordingly, the Eemian is not equivalent to MI substage 5e, as the Holocene is not equivalent to MIS 1.

Remarkably, both pollen and dinocyst data reflect the same climatic pattern on land and ocean, and they evidence a succession of climatic events that the isotope signal does not identify. The Eemian began with a Mediterranean vegetation that was gradually replaced by Eurosiberian formations indicating a change from Mediterranean to oceanic climates. In the middle of the Eemian, warming conditions were interrupted by an event corresponding to a slight cooling resulting from an increase in precipitation over land and ocean. Finally, a warming trend characterised the last phase of the Eemian. The occurrence of small climatic changes during this interglacial is inconsistent with the dramatic variability suggested by the GRIP ice-core record.

The extent of regional variability in vegetation development in mainland Greece during the last interglacial is considered. Three pollen sequences – Ioannina (northwest Greece),Tenaghi Philippon (northeast Greece) and Kopais (central Greece) – all located in different environmental settings, extend into the last interglacial. Examination of the vegetation histories of the three sites during the last interglacial reveals the influence of local climatic conditions with closed mixed forests in the northwest, becoming progressively more open and less diverse farther to the east and south. All three sequences contain a number of similar trends, however, in the expansion of certain taxa. In addition, they also show the presence of a two-step late glacial interval, a short episode of forest reduction in the second part of the interglacial and a final small expansion of tree populations at the very end of the interglacial. Comparison with other European records shows a number of common features, but also suggests differences consistent with the particular environmental setting of the Greek sites.