Temperate Stage Research Articles

Palaeoenvironmental history of the Middle Pleistocene deposits at Gilson, Warwickshire, England: part of the High Speed Two railway route alignment

ABSTRACTThe investigation of a hillside at Gilson (Lat. 52.510341, Long. ‐1.718313), southwest of Coleshill, Warwickshire (within the High Speed Two railway ‘Delta Junction’ compound), England, has yielded evidence of sedimentation during a temperate stage. The site's stratigraphy starts with the aggregation of cold‐climate sand and gravels deposited during the Anglian Stage within the proto‐Tame and proto‐Blythe palaeovalleys. A warm‐climate period is recorded by the infill of organic material representing the second half of the Hoxnian interglacial Stage. Picea, Abies and Pinus dominate vegetation within a swamp‐like environment, before a Pinus forest develops in the upper part of the organic sequence. The following cold‐climate period saw incision and aggregation of the surrounding region throughout much of the Wolstonian and Devensian Stages, where much of the overlying silt, sand and gravel were reworked under intense periglacial conditions. Presented here is a geophysical examination of the shallow basin by ground‐penetrating radar undertaken to understand the spatial distribution and stratigraphical history of the basin. The deposits at Gilson provide a valuable stratigraphic marker in the glacial sequence of the English West Midlands and are correlated to similar deposits at neighbouring Quinton and Nechells. At these regional sites organic accumulation occurred for most of the temperate stage, infilling lake basins. These sequences indicate an environment dominated by pollen of Abies, Quercus, Ulmus and Corylus woodland vegetation. These assemblages differ markedly from those typically found in the last interglacial and confirm correlation to the Middle Pleistocene Hoxnian interglacial Stage (c. MIS 11c).

The Middle Pleistocene to early Holocene subsurface geology of the Norderney tidal basin: new insights from core data and high-resolution sub-bottom profiling (Central Wadden Sea, southern North Sea)

AbstractPleistocene strata of the Wadden Sea region are mostly covered by an up to 10m thick sediment wedge deposited during the Holocene transgression. However, tidal inlets cut deep into the Holocene succession, causing Middle Pleistocene to early Holocene glacial and interglacial deposits to outcrop at the channel bottom. To investigate how the lithological properties and/or morphologies of these deposits affect the development of Holocene tidal inlets (e.g. limiting erosional processes), we analysed a series of eight cores to verify three high-resolution sub-bottom transects – and thus – to extend point-based data over a broader area. Furthermore, eight additional new cores (16 WASA cores in total), and 14 reinterpreted cores from the LBEG (Geological Survey of Lower Saxony) log database, were correlated to generate three short cross-sections at the transition from the tidal inlet (Riffgat channel) to the island of Norderney, revealing a number of new aspects for the reconstruction of the Pleistocene palaeoenvironments, i.e. the last two glacials (Saalian and Weichselian) and interglacials (Holsteinian? and Eemian). A succession of Middle Pleistocene lacustrine delta deposits, belonging either to the Holsteinian or the Dömnitz temperate stage, suggests the presence of Elsterian tunnel valleys located below the island. Furthermore, we verified the presence of an Eemian mixed tidal-flat system overlain by an Eemian sand tidal flat below the western head of Norderney which is, in contrast to suggestions from previous studies, not fully eroded in this area. Finally, we demonstrate that the Saalian moraine (Drenthe Main Till) functions as a limiting constraint in the vertical development of the Holocene/modern Riffgat channel. Our results provide a better understanding of the Quaternary stratigraphy of the central Wadden Sea as well as the influence of the subsurface geology on the architecture and evolution of tidal channels.

Stratigraphic revision of the Quaternary material from the vicinity of Belgrade and the Serbian segment of the Tisza valley analysed by V.D. Laskarev

In his studies of the Quaternary deposits in the vicinity of Belgrade and Vojvodina, V.D. Laskarev clearly identified the main Quaternary facies and lithostratigraphic units (loess series, Corbicula fluminalis beds, Holocene sands, etc.). Since the period of the publication of his research, there has been development in Quaternary stratigraphy and palaeogeography. In compliance with these changes, the following elements of his studies should be corrected:1) The age of the loess series in the Zemun Loess Plateau and the Belgrade Plateau corresponds to the younger part of the Middle and Late Pleistocene.2) The Pleistocene Corbicula beds represent temperate fluvial stages of the younger part of the Lower and Middle Pleistocene. The Viviparus boeckhi Horizon was defined as a subunit of the Pleistocene Corbicula beds that corresponds to the younger part of the Lower Pleistocene fluvial temperate stages. The Makiš beds should be defined as a local term for the Pleistocene Corbicula beds in the Sava valley (in the vicinity of Belgrade).3) Laskarev generally recognized the main features of the Quaternary palaeogeographic evolution; however, they cannot be applied to the whole area of the Serbian segment of the Pannonian Plain.There are still no reliable geological data for the Lower and Middle Pleistocene parts of the Quaternary geological sections such as the Zrenjanin–Titel Loess Plateau. It is evident that up to now the Pleistocene Corbicula beds have not been identified in the basement of the Titel Loess Plateau, only the aeolo-lacustrine and lacustrine–palustrine silts underlying the loess series.4) Geomorphological investigations have identified four terraces in the valley of the Danube and the Tisza in Vojvodina. In this case, the first terrace level of Laskarev should be divided into the lower Ia or t1 and upper Ib or t2 terraces.

Age and palaeoenvironment of the enigmatic Arternian Interglacial — Evidence from the Muschelton at Voigtstedt/Hackelsberg (Thuringia, Central Germany)

The Arternian Interglacial has been established on the basis of a pollen record within the Muschelton (=Shell Clay) horizon near Voigtstedt (type locality) in the surroundings of Artern in Central Germany. This horizon is older than the early Middle Pleistocene Voigstedt/Lehmzone (=Loam Zone) layers, which overlie the Muschelton. Due to the lack of a comprehensive fossil record, the age of the Arternian Interglacial has long been disputed, as has its palaeoenvironmental conditions. Here we present the results of new interdisciplinary studies from new exposures of the Muschelton at Voigtstedt/Hackelsberg. Palaeomagnetic screening revealed dominantly reversed polarity of the Muschelton, partly overprinted by normal magnetisations. Fossil content consists of identifiable plant, mollusc, ostracod, fish, small and large mammal remains.The stratigraphic range of the recorded taxa, in combination with the palaeomagnetic reverse polarity and amino acid racemization studies, indicate an Early Pleistocene age for the Arternian Interglacial, within the range of MIS (marine isotope stages) 29–21 (c. 990–810ka). In contrast to interpretations in former studies, our investigations of the Muschelton from Voigtstedt/Hackelsberg do not indicate subarctic climate prior to or following a clearly separated interglacial. As evidence for high summer temperatures was present throughout the Muschelton sequence, the changes between cold and temperate stages in the pollen record can be best explained by changes in continentality. This result confirms climatic inferences for pollen records of other Early and early Middle Pleistocene sites in Central Europe.

A new Middle Pleistocene interglacial record from Denmark: Chronostratigraphic correlation, palaeovegetation and fire dynamics

Previously only three terrestrial interglacial periods were known from southern Scandinavia, all of which could be relatively easily correlated within the central European stratigraphical framework. Here, we present a new interglacial–interstadial pollen, plant macrofossil and charcoal record from Trelde Klint, Denmark, and analyse its biostratigraphy, correlation with other European records, vegetation development, fire dynamics and absolute dating. Except for a slight truncation of the early part of the record, the pollen stratigraphy exhibits a full interglacial succession, including temperate trees (Quercus, Ulmus and Tilia) during its mesocratic stage. Macrofossil analysis allowed identification to species level for Quercus robur, Picea abies and two mosses. Conifers (Pinus and Picea) dominate the pollen record of the interglacial sequence, and the occurrence of Larix pollen in the top part of the interglacial record as well as in the interstadial sediments is especially indicative of this interglacial. The overall diversity of tree genera is rather low. These biostratigraphical features suggest that Trelde Klint is unique among Danish records, but it is similar to records from northern Germany. Numerical analyses (REVEALS and DCA) indicate that forests during the temperate stage were dense and that vegetation openness increased only towards the end of the interglacial, accompanied by increased fire occurrence. A short interstadial sequence with a dominance of Pinus and Betula and the presence of Larix is present above the interglacial deposit. We argue that lack of attention to differences in fire regimes may hamper understanding of between‐site correlations of interglacial pollen records. OSL dating, using a novel feldspar technique, yields an average age of 350±20 ka for the sandy sediments above the interglacial layers at Trelde Klint, suggesting that the whole interglacial–interstadial succession belongs to Marine Isotope Stage 11.

Testing the correlation of fragmented pollen records of the middle and late Pleistocene temperate stages

Testing the correlation of fragmented pollen records of the middle and late Pleistocene temperate stages

Ipswichian (Eemian) floodplain deposits and terrace stratigraphy in the lower Great Ouse and Cam valleys, southern England, UK

Gao, C. & Boreham, S. 2010: Ipswichian (Eemian) floodplain deposits and terrace stratigraphy in the lower Great Ouse and Cam valleys, southern England, UK. Boreas, 10.1111/j.1502-3885.2010.00191.x. ISSN 0300-9483. Thick argillaceous deposits named the Mannings Farm Beds recently uncovered in the third terrace at Mannings Farm near Willingham, Cambridgeshire contain a pollen sequence covering the transitions from Ipswichian/Eemian substages I to II and II to III, when oak and hornbeam expanded, respectively. This is the longest record hitherto obtained in Britain, providing important insight into the major forest successions in this temperate stage. The frequent occurrence of Ipswichian deposits in the third terrace suggests the development of an extensive floodplain on the valley bottom, similar to the case for the present-day lower Great Ouse and Cam. The Mannings Farm Beds testify to a complete interglacial sequence emplaced between cold-climate gravels that was directly associated with the terrace development. The third terrace developed during the Ipswichian and the preceding and succeeding cold stages. Major river downcutting, which shaped the third terrace, occurred during the Early Devensian/Weichselian. Previously reported interglacial fossils from this terrace that are inconsistent with an Ipswichian affinity are probably reworked material derived from pre-Ipswichian interglacial deposits, or their significance as biostratigraphical indicators needs to be confirmed. The second and first terraces developed from the late Early Devensian onwards. Ipswichian deposits filling flood-scoured deep channels in bedrock are preserved locally below these low terraces.

The molluscan fauna of the Cromerian type site at West Runton, Norfolk

An updated and revised list of the non-marine molluscs of the West Runton Freshwater Bed (WRFB), the type site of the Cromerian Stage, is presented. A minimum total of 73 species is now known, consisting of 46 aquatic and 27 terrestrial taxa. The molluscan fauna suggests a sluggish, base-rich, stream choked with aquatic vegetation, upstream of any brackish influence. The banks were bordered with marshland. Sandy facies with a greater proportion of fluvial species indicate more active flow within small channels. Four aquatic and 5 terrestrial species no longer live in the British Isles, and 3 (6.5%) of the aquatic species (Tanousia runtoniana, Borysthenia goldfussiana and Pisidium clessini) are extinct. The Cromerian molluscan fauna lacks southern thermophiles and, apart from the extinct taxa, is remarkably similar to modern faunas from eastern England. Indeed, 91% of the species of aquatic mollusc found in the WRFB still inhabit East Anglia. A number of the species that no longer live in Britain have ranges that are central or eastern European, implying that the climate may have been more continental. The stratigraphical ranges of both B. goldfussiana and T. runtoniana extend into the late Early Pleistocene in The Netherlands, and in Britain they seem to occur only in temperate stage deposits falling within the early part of the ‘Cromerian Complex’ or earlier.

Climate change since 11.5 ka on the Diancang Massif on the southeastern margin of the Tibetan Plateau

The Diancang Massif is located in a region linking the Tibetan and Yungui Plateaus. Climatically, it is in a transition belt between the south and middle subtropical zones, controlled by Indian monsoon and westerlies. Thus, this study provides more evidences on the evolution of Indian monsoon since the Holocene. We reconstruct the history of climate on the Diancang Massif since 11.5 ka, using integrated correlation of glacial activities, early human settlement sites, and climate proxies abstracted from variations in grain size, magnetic susceptibility, geochemical composition, and pollen in lacustrine sediments. Six climatic stages have been identified. Stage I, from 11.5 ka to 9.0 ka, is a relatively wet period, corresponding to the onset of the Holocene; from 9.5 ka to 6.0 ka, the climate is arid; a cold period follows from 6.0 ka to 5.3 ka, and this is succeeded by a temperate stage from 5.3 ka to 4.0 ka; from 4.0 ka to 0.73 ka the climate is again arid. Compared with other regions dominated by the Indian monsoon, there is a delay in response of the climate on the Diancang Massif to the onset of the Holocene.

Aminostratigraphy of Middle and Late Pleistocene deposits in The Netherlands and the southern part of the North Sea Basin

A review of all available amino acid racemization D (alloisoleucine)/L (isoleucine) data from the whole shell of four molluscan species from Late and late Middle Pleistocene deposits of the Netherlands is presented. The data allow the distinction of 5 aminostratigraphical units, NAZ (Netherlands Amino Zone) A–E, each representing a temperate stage. The zones are correlated with marine isotope stages 1, 5e, 7, 9, and 11 respectively. Apart from NAZ-D (MIS 9), in all aminozones the marine transgression reached the present-day onshore area of the Netherlands. The transgression during NAZ-C (Oostermeer Interglacial: MIS 7) seems to be at least as widespread as its counterpart during NAZ-B (Eemian: MIS 5e) in the southern bight of the North Sea Basin. The stratigraphic position of the Oostermeer Interglacial is just below deposits of the Drente phase of the Saalian and because of this position the interglacial marine deposits have formerly erroneously considered to be of Holsteinian age. Neede, the ‘classic’ Dutch Holsteinian site, is dated in NAZ-E (MIS 11), like Noordbergum. Although the validity of these zones has been checked with independent data, some overlap between succeeding zones may occur. The relation between amino acid data from elsewhere in the North Sea Basin and the Netherlands amino zonation is discussed. The deposits at the Holsteinian stratotype Hummelsbüttel in North West Germany are dated in NAZ-D. This interglacial correlates with MIS 9. The Belvédère Interglacial, which is of importance for its archaeology, is in NAZ-D (MIS 9) and therefore of Holsteinian age as well. The lacustroglacial ‘pottery clays’ in the Noordbergum area are deposits from two glacial stages, which can be correlated with MIS 8 and 10 (the Elsterian). The pottery clay that is considered equivalent to the German ‘Lauenburger Ton’ correlates with MIS 10.

Calibration of decomposition of serine to alanine in Bithynia opercula as a quantitative dating technique for Middle and Late Pleistocene sites in Britain

The concentration ratio of the amino acids alanine and serine in calcite opercula of freshwater gastropods of genus Bithynia has been assessed as an age proxy for British Middle and Late Pleistocene sites. Due to decomposition of peptide-bound serine within intra-crystalline protein molecules, alanine/serine ratios increase with sample age, enabling resolution of the marine oxygen-isotope stage of almost all sites and substage resolution for some sites. However, slight overlaps are evident in alanine/serine ratios between some sites from late in one temperate stage and early in the next; this effect results from the low decomposition rates during cold stages, combined with an evident slight dependence of decomposition rates on site conditions. The technique, which can be extended to the Early Pleistocene without technical refinements, is amenable to quantitative calibration using a first-order rate equation, making it feasible in future to present results as numerical ages, subject to an assumed temperature history. Most Pleistocene sites investigated are shown using this technique to have the same ages as previously deduced using biostratigraphy. However, the serine–alanine ages obtained preclude glaciation of southeast England during MIS 16 or of central England during MIS 10.

Evidence from coleopteran assemblages for a short but intense cold interlude during the latter part of the MIS11 Interglacial from Quinton, West Midlands, UK

A sequence of fossiliferous organic sediments spanning the whole of an interglacial has been investigated from Quinton, near Birmingham, United Kingdom This interglacial can be correlated on palynological grounds with the Hoxnian Interglacial of England; equivalent to the Holsteinian Interglacial of central Europe and to Marine Isotope Stage 11. A pollen diagram and coleopteran spectrum were obtained from the same series of samples. By using the mutual climatic range method on the coleopteran assemblages, it has been possible to quantify the thermal climatic conditions at this time. They show clear evidence for a sudden and intense climatic oscillation during the late temperate stage of the interglacial—named the Quinton Cold Interlude. At this time mean temperatures of the warmest month (July) declined suddenly by at least 5°C and mean temperatures of the coldest months (January and February) by more than 10°C. Subsequently cool-temperate conditions returned. The pollen diagram through this interval shows little or no response to this climatic event. It is too early yet to generalise about the regional significance of the Quinton Cold Interlude but a similar climatic oscillation also occurs towards the closing stage of the MIS11 Interglacial at Hoxne, Norfolk, UK, suggesting that the cold interlude was at least regional in extent. A short climatic oscillation of similar intensity has also been interpreted from coleopteran evidence towards the end of the MIS13 Interglacial at Waverley Wood Farm Pit, Warwickshire, UK, indicating that such events may characterise the later stages of other interglacials. These severe climatic oscillations towards the end of interglacials may have relevance to our understanding of the closing phase of the present interglacial.

Marine Isotope Stage 9 environments of fluvial deposits at Hackney, north London, UK

Middle Pleistocene deposits at Hackney, north London comprise a thick unit of organic sands and silts occupying a channel near the confluence of the River Thames in south-eastern England and its left-bank tributary the River Lea. They represent a short time interval, perhaps no more than a few years, within a late Middle Pleistocene interglacial. The organic sediments are overlain by unfossiliferous sands and gravels indicating deposition on the floodplain of a braided river under cool or cold climatic conditions. The fossil plant, insect, mollusc and vertebrate remains from the interglacial deposits all indicate climatic conditions with summers warmer than the present in SE England, and winters with a similar thermal climate. The biostratigraphic evidence suggests that the time period represented by the organic unit is part of MIS 9, although the geochronological evidence for such an age is inconclusive. The palaeontological evidence strongly suggests that this temperate stage was warmer than the succeeding temperate stage MIS 7 or the Holocene, and approaching the Ipswichian (MISs 5e) in its warmth. The multidisciplinary description of the Hackney deposits is one of the first to reconstruct terrestrial conditions in Marine Isotope Stage 9 in Western Europe.

The Duration of Forest Stages in Southern Europe and Interglacial Climate Variability

Foraminiferal oxygen isotope and pollen analyses from a deep-sea sequence off southwest Portugal show that the duration of temperate stages on land over the past 350,000 years varied considerably. The record shows forest contractions during intervals of low ice volume, coeval with declines in atmospheric methane, after which tree populations did not always recover. What emerges is that, although the broad timing of interglacials is consistent with orbital theory, their specific duration may be dictated by millennial variability. This complicates the prediction of the natural duration of interglacials, at least until the origin of this climate variability is understood.

Palaeotemperature calculations from the Praetiglian/Tiglian (Plio–Pleistocene) pollen record of Lieth, northern Germany: implications for the climatic evolution of NW Europe

The temperature evolution during the Praetiglian and Tiglian (Plio–Pleistocene) of northern Germany and the southern North Sea area is reconstructed based on the pollen record from Lieth, northern Germany. The examined record covers the time span from approximately 2.6 to 1.7 Ma. Calculations of the temperatures of the warmest (MTW) and coldest (MTC) months are presented utilizing the mutual climatic range principle. The thermal resolution of the reconstruction is increased through the calculation of most likely intervals for actual temperature ranges. For the analyzed pollen record, the MTW and MTC resolution reaches up to 1.5 °C using 100% most likely intervals and up to 1 °C using 70% most likely intervals. A seasonality index is calculated as a further tool for evaluating the climate development. The results indicate that cold and temperate stages during the Praetiglian and Tiglian were characterized by strong variations in winter temperatures in combination with relatively constant summer temperatures. Seasonality was highest during cold stages and lowest during the thermal optima of temperate stages. These seasonality variations are attributed to sea level changes as expressed in the North Sea Basin. Low seasonalities, which tend to co-occur with periods of high sea level, are interpreted to represent increased maritime influence. The seasonality variations may also be related to changes in Atlantic Ocean circulation and a southward shift of the polar front. The comparison of temperature calculations from Lieth with pollen-based temperature estimates for corresponding time intervals from the Netherlands reveals similarities and differences. For cold periods, the quantitatively obtained temperatures from Lieth are generally more extreme than the estimates from the Netherlands. These contrasts are too high to result solely from differences in the evaluation methods as can be shown through the application of our quantitative approach to pollen spectra from the Netherlands. Hence, the observed temperature contrasts between northern Germany and the Netherlands also reflect a temporary climate differentiation between these regions during cooler periods of the Praetiglian and Tiglian. The differentiation may be due to the respective vicinities of these regions to the North Sea.

Establishing a terrestrial chronological framework as a basis for biostratigraphical comparisons

The palynological signature of interglacial deposits in the fragmentary European terrestrial record has often been used as the basis for determining their chronostratigraphical position and ultimately their age. This has placed emphasis on the presence/absence and abundance of certain characteristic taxa, but given the lack of continuous stratigraphies and independent chronologies, it has been difficult to assess the extent to which this strategy has produced reliable schemes. Here, an alternative approach is adopted whereby a chronological framework is developed for long and continuous pollen sequences from southern Europe. This in turn allows the emergence of a complete stratigraphical scheme of major vegetation events for the last 430 thousand years (ka) and the evaluation of the stage record of different taxa and their potential diagnostic value for biostratigraphical correlation. The comparison shows distinct similarities among some temperate stages of the terrestrial equivalent complexes of Marine Isotope Stages (MIS) 5 and 7 and also of MIS 9 and 11, but examination of combined records of taxa provides a possibility to differentiate between individual stages. A numerically-derived dichotomous key for the terrestrial stages based on the palynological records of 10 taxa is presented. Carpinus, Fagus, Abies, Pterocarya and Buxus emerge as the best ‘indicator pollen types’ because of their variable behaviour from one stage to the next, possibly a result of their late expansion within a temperate stage or reduced genetic variability. The analysis shows that the palynological signature of a temperate deposit can constrain the range of chronostratigraphical possibilities, but vegetation and palynological variability arising from local factors could result in difficulties in making a definite assignment at individual sites.

Current understanding of Pleistocene temperate stages in Ireland

Research on Irish Pleistocene temperate stages has been dominated by investigation of deposits with very similar floristic records, collectively termed the Gortian and traditionally correlated with the continental Holsteinian. Recently detailed investigation of interglacial material from Cork Harbour suggested the Gortian group may contain floristically similar deposits of different ages. The pollen record had Gortian/Holsteinian characteristics and dating (by measurement of uranium thorium disequilibrium and amino acid racemization) suggested that the deposits were younger than Stage 11 (correlated with the Holsteinian by Reille and de Beaulieu (Reille, de Beaulieu, Quat. Res. 44 (1995) 205)). The suggestion that there may have been more than one Holsteinian-style temperate stage in Europe might explain the floristic similarity of Gortian and Holsteinian deposits and the apparent younger age of the Cork deposits. The lack of a last interglacial stratotype is the most outstanding problem in Irish Quaternary studies. The pollen content of sediments at Fenit, Co. Kerry, dated to ca 118 ka BP, suggested they may represent a cool temperate phase at the end of the last interglacial. Recently investigated sub-drumlin, organic-rich deposits at Knocknacran, Co. Monaghan are also possibly last interglacial in age and these are discussed in detail here.

The mammalian faunas of Pakefield/Kessingland and Corton, Suffolk, UK: evidence for a new temperate episode in the British early Middle Pleistocene

It has been recognised for some time that early Middle Pleistocene mammal faunas in Britain can be divided into an earlier group with Mimomys savini (e.g. West Runton Freshwater Bed—WRFB), and a later group with Arvicola terrestris cantiana (Boxgrove, Westbury, Ostend), representing two or more temperate/interglacial stages. On the basis of the available early Middle Pleistocene non-marine molluscan faunas, Meijer and Preece (in: C. Turner (Ed.), The Early Middle Pleistocene in Europe, Balkema: Rotterdam, 1996, pp. 53–82.) and Preece (Quaternary Science Reviews 20 (2001)) recognised three biostratigraphic groups, representing at least three temperate stages. These are largely compatible with the vertebrate faunas, but new evidence presented here strongly indicates that Pakefield/Kessingland represents an additional, hitherto unrecognised temperate stage with Mimomys savini, younger than the WRFB but older than Little Oakley, Boxgrove and Westbury.New exposures and finds from the Cromer Forest-bed Formation at Pakefield, Suffolk have prompted a fresh look at the palaeontology of Pakefield/Kessingland and also Corton, which has a similar lithostratigraphic and biostratigraphic sequence. The large-mammal fauna (at least in part pollen substage II) includes Hippopotamus sp., Palaeoloxodon antiquus, and Megaloceros dawkinsi—none of which has so far been found in the WRFB—strongly suggesting that the Suffolk sites represent a distinct stage. Further, no records of ‘southern’ European plant, invertebrate or vertebrate taxa have been found in the WRFB, whereas the plants Trapa natans and Salvinia natans—indicating summers warmer than now—are known from Pakefield/Kessingland and Corton, providing corroborative evidence for a stage distinct from the Cromerian s. s.

Significance of Two New Pleistocene Plant Records from Western Europe

The first records of extinct Caulinia goretskyi (Dorofeev) Dorofeev (synonym Najas goretskyi Dorofeev) in western Europe and of Potamogeton occidentalis M.H. Field sp. nov. were obtained from plant macrofossil analyses of Middle Pleistocene temperate stage deposits exposed at Trez Rouz, Brittany, France. Palynological assemblages recovered suggest correlation with the Holsteinian Stage. This discovery greatly expands the western limit of the paleogeographical distribution of Caulinia goretskyi. The record of Potamogeton occidentalis indicates an affinity with the eastern Asiatic flora, as the fruits resemble those of the extant Potamogeton maackianus A. Bennett. Other extinct Pleistocene species related to P. maackianus have been described, and it is possible to follow the development of this group through the Pleistocene in the European fossil record. These new finds illustrate the importance of a complete paleobotanical approach (both plant macrofossil and palynological analyses). The plant macrofossil assemblages not only provide detailed insight into local vegetation and environment, because they are often not transported long distances (in temperate areas) and can frequently be identified to species level; they can also offer the opportunity to investigate Pleistocene evolutionary trends.

Middle Pleistocene deposits at La Côte, Val-de-Lans, Isère department, France: plant macrofossil, palynological and fossil insect investigations

Plant macrofossils, pollen and spores, and Coleoptera remains were analysed from high altitude, lacustrine, interglacial deposits collected from La Côte, Val-de-Lans, Isère, western French Alps. The investigation concentrated on the second half of the temperate stage (locally called the La Côte Interglacial Stage). Palaeoecological, palaeoenvironmental and quantitative climatic reconstructions for the termination of the interglacial period and the onset of cold conditions are presented. Because the different fossils were affected in varying ways by taphonomic processes they provide a range of complementary data about the palaeoenvironment, and illustrate the importance of multi-disciplinary studies. As conditions became cooler at the end of the temperate stage the lake levels fluctuated, and the water's trophic status changed. The occurrence of Pterocarya and the dominance of Abies support a correlation with the temperate Holsteinian Stage (oxygen isotope stage 11). At the top of the core an interstadial event characterised by Pinus, Picea and Betula is represented. This could have occurred either directly after the La Côte Interglacial Stage or the event may have occurred during the following cold La Bourne Stage after a hiatus. The climate fluctuations represented at the end of the La Côte Interglacial Stage in the Val-de-Lans basin prompt comparisons with the end of the Eemian Stage (Late Pleistocene) and suggest that such oscillations are characteristic for the end of temperate stages. An understanding of the changes represented here aids the evaluation of present trends as we possibly enter the final phases of the Holocene Stage. Sites of this age and located at this altitude are rare in Europe; therefore, it is proposed that the La Côte site should be considered as a high altitude, alpine parastratotype for the Holsteinian Stage in western Europe.