Temperate Stage Research Articles

Morphology and palaeoenvironment of brood cells of Quaternary ground-nesting solitary bees (Hymenoptera, Apidae) from Fuerteventura, Canary Islands, Spain

On Fuerteventura, the abundance of in situ brood cells of ground-nesting solitary bees in Pleistocene and early Holocene loessic palaeosols and calcretes, and the presence of several taxa of land snails, living species of which occur today in the Mediterranean region and northwest Africa, indicates a semiarid climate, probably with hot, dry summers. Large-scale nesting by solitary bees may have occurred early during European temperate stages.

Foraminiferal isoleucine epimerization determinations from the Nar Valley Clay, Norfolk, UK: implications for Quaternary correlations in the southern North Sea basin

Fully temperate freshwater, brackish and marine sediments overlying Anglian till and glacilacustrine sediments in the Nar Valley area of northwest Norfolk, UK, have been attributed to the Middle Pleistocene Hoxnian temperate stage on palynological grounds, and basal peats associated with this sequence have been recently correlated with oxygen isotope stage 9 on the basis of a series of 230Th/238U dates (mean 317±14 ka). At Tottenhill these sediments (Nar Valley Freshwater Beds, Nar Valley Clay) underlie a deltaic complex attributed to the Wolstonian ice margin. The lithostratigraphical relations between the major formations in the Nar Valley, and the pollen stratigraphy of the fully temperate sequence, are very similar to the Pleistocene sequence in the Inner Silver Pit area of the southern North Sea, and correlation has been proposed between the successions described from these two localities. However, the Inner Silver Pit sequence has yielded aminostratigraphic data consistent with isotopic stage 11.Benthic foraminiferal assemblages and foraminiferal amino-acid determinations have been investigated from the Nar Valley Clay in order to test further the palaeoenvironmental setting of the sequence and to help resolve the age of the sequence and correlation with the Inner Silver Pit interglacial. The foraminiferal assemblages support previous sedimentological and palaeontological evidence for a transgressive tendency within this sequence. Multiple isoleucine epimerization determinations on Ammonia beccarii and Aubignyna perlucida from five levels within the Nar Valley Clay give mean aIle/Ile ratios of 0.135 and 0.111, respectively. The A. beccarii ratios are much lower than mean aIle/Ile ratios on equivalent species from the interglacial sequence in the Inner Silver Pit (upper Sand Hole Formation), which are close to 0.2, and the two datasets fail to overlap at the 1σ level. The new aminostratigraphic ratios indicate correlation of the Nar Valley Clay with oxygen isotope stage 9, and therefore support the pre-existing 230Th/238U data.These results suggest that two temperate stages of Hoxnian palynological affinity are present in the Quaternary record of East Anglia and the southern North Sea basin, a conclusion consistent with independent new U-series data from other Hoxnian sites in East Anglia. An alternative model in which the amino-acid ratios are explained as a function of different post-depositional thermal histories, related to length of cover by ice and water, is discussed but considered unlikely. The conclusions have important implications for the timing and number of glacial events in and around the southern North Sea basin, and help to resolve discrepancies in relative sea-level histories and biogeography in temperate sequences hitherto accommodated within a single stage.

Late and Middle Pleistocene deposits at Somersham, Cambridgeshire, U.K.: a model for reconstructing fluvial/estuarine depositional environments

Gravel quarries at Somersham, Cambridgeshire, have yielded evidence for a Pleistocene channel of the R. Great Ouse, containing temperate stage sediments between cold stage sediments. In the earlier cold stage, fluviatile gravels and floodplain loessic sediment accumulated. In the later cold stage a further series of gravel units and floodplain sediments were deposited, together with lake sediments. The lake sediments are associated with Lake Sparks, dammed by Late Devensian ice in the Wash at ca. 18.5kaBP. The lake sediments overlie gravels with a radiocarbon date from an organic horizon indicating a Middle Devensian age. Clast lithological analyses from the earlier and later gravels suggest that reworking of gravels has occurred within a relatively stable catchment. The petrography of the earlier cold stage loessic sediment and temperate stage fine sediment indicates an Anglian affinity, which conflicts with the biostratigraphic interpretation. Pollen and macroscopic plant remains from sediments of both cold stages and from the temperate stage indicate, respectively, assemblages with a typical full-glacial aspect with a rich flora of shrubs and open ground herbs(including an assemblage at ca. 18ka), and temperate freshwater and marine-influenced organic sediments. On the basis of pollen analysis these are ascribed to substages Ip II and III of the Ipswichian Stage(O.I.S. 5e), with a Pinus-Quercus-Corylus biozone in the former and a biozone with Carpinus in the latter. Marine-influenced sediments, at −3.7 to −0.3m OD, indicate transgression in Ip II and regression in Ip III.Molluscan assemblages from the temperate stage and the later cold stage are described; two are from the Late Devensian, at a time near the maximum extension of ice into the Wash. Foraminifer and ostracod faunas are described from post-Ipswichian sediments and may be reworked. Radiocarbon dates confirm the age of the later gravel suite as Devensian and a calibration of the measurements is given. Amino acid ratios from Corbicula fluminalis valves from temperate stage sediments are reported, with measurements from different parts of the valve; the results tend to support an Ipswichian age. TL measurements of the earlier cold stage loessic sediment and associated sand indicate a pre-Ipswichian age for the sediments. The earlier cold stage is correlated with the pre-Ipswichian cold stage, the Wolstonian of Mitchell et al.(1973); problems with this correlation are discussed.Various periglacial phenomena, including thermal contraction networks and cracks, diapirs, involutions and coversand are associated with the Devensian sequence. The complex environmental history, based on stratigraphy and palaeontology, is described, and related to other nearby sites in southern Fenland.

Comment on D. M. Wilkinson (1997). ‘Plant colonization: are wind dispersed seeds really dispersed by birds at larger spatial and temporal scales?’

(it was probably rightly excluded, owing number of pollen grains counted in each (1997). ‘Plant colonization: are to ‘its water dispersal strategy’ (Wilkinson, spectrum), and so is inherently as inwind dispersed seeds really 1997: 62; but see Chambers & Elliott, 1989)); consistent measure; whereas the ‘rational dispersed by birds at larger spatial whereas had Corylus been excluded (on the limit’ (the rise to higher percentage values) and temporal scales?’ grounds of incomplete separation from Myis still a relative, rather than an absolute,

A middle pleistocene shallow marine interglacial sequence, inner silver pit, southern north sea: pollen and dinoflagellate cyst stratigraphy and sea-level history

The Sand Hole Formation is a Pleistocene seismic–stratigraphic unit of restricted distribution in the Inner Silver Pit, southern North Sea. Pollen and dinoflagellate cyst analyses of this formation, penetrated by British Geological Survey borehole 81/52A and three juxtaposed vibrocores, enables division of the formation into two sequences of contrasting palaeoclimatic affinity. The lower sequence contains poorly-preserved pollen assemblages of low concentration dominated by residual reworked elements, and is coincident with cold, shallow marine dinoflagellate cyst and foraminiferal assemblages. This sequence overlies till and glacimarine sediments of the Anglian/Elsterian Swarte Bank Formation, and is also interpreted as late Anglian/Elsterian in age. The upper sequence contains well-preserved, high concentration, pollen spectra recording the latter half of an interglacial stage with Hoxnian affinities. The strong terrigenous signal preserved in this sequence suggests a subtidal depositional setting within a region of freshwater influence; correlation of the vibrocores with the longer record preserved in borehole 81/52A indicates that interglacial sedimentation rates increase southwards towards a suggested terrigenous source in the Wash area. The first half of the interglacial cycle is missing, indicating that a hiatus is present between the two sequences preserved within the Sand Hole Formation, but the termination of the interglacial is clearly preserved. The spatial and temporal distribution of the sediments and bounding unconformities in the region are consistent in recording the transgressive ravinement surface, highstand systems tract and subsequent regression within an interglacial eustatic cycle. The character, age and elevation of the preserved facies is typical of a glacio-isostatically controlled emergence cycle and lends support to the notion that this temperate stage (oxygen isotope stage 9) immediately followed extensive glaciation during the late Anglian/Elsterian.

Palynology, aminostratigraphy and U-series dating of marine gortian interglacial sediments in cork harbour, Southern Ireland

Palynological analysis, amino acid epimerization analysis and uranium thorium disequilibrium age determination of three Irish interglacial cores support the suggestion that there may have been more than one Holsteinian-style temperate interval in Europe. The cores were taken from estuarine deposits beneath glacial diamicton in Cork Harbour, southwest Ireland. The pollen records an incomplete temperate stage. The biotic signature is similar to those from several interglacial sites in Ireland and is considered part of the Gortian group. The pollen signature is Holsteinian/Hoxnian in character. Amino acid epimerization analysis suggests the deposits to be Oxygen Isotope Stage 7 in age, whereas uranium–thorium disequilibrium suggests a minimum Stage 5 age. Possible correlatives of the Gortian group in Europe are suggested.

The Gortian temperate stage

Interglacial sediments assigned to the Gortian temperate stage are recorded at eleven sites throughout Ireland but they remain undated by absolute means. However, the unique vegetational assemblages found within the Gortian appear to belong to the Middle Pleistocene on biostratigraphic grounds. The Gortian vegetational records are reviewed and a summary of the possible age of the interglacial is presented along with recent work that has been carried out on stratigraphically important sites within Ireland.

Late Pleistocene deposits at Block Fen, Cambridgeshire, England

AbstractOrganic sediments in a gravel quarry at Block Fen, Cambridgeshire, form a sheet dividing lower from upper gravels. Analyses of pollen, macroscopic plant remains and molluscs from these organic sediments are presented. They indicate the presence of temperate freshwater and slightly brackish fine floodplain sediments, which, on the basis of the palaeobotany, are correlated with the temperate Ipswichian Stage. The freshwater sediments, ascribed to Ipswichian substage IIb, occur at ca. −3 m OD. Marine‐influenced tidal sediments, ascribed to Ipswichian substage III, occur at ca. −6 m OD. No evidence was found for the presence of more than one temperate stage in the sequence. The lower gravels are then correlated with the cold Wolstonian Stage and the upper gravels with the cold Devensian Stage. In contrast to the woodland environments indicated by the palaeobotany of the Ipswichian organic sediments, post‐Ipswichian pollen diagrams and macroscopic plant remains in the upper suite of sands and gravels indicate open tree‐less vegetation typical of the cold Devensian Stage. They also contain a typical cold‐stage mollusc fauna. The sediments containing these floras and faunas are associated with thermal contraction cracks, indicating the presence of permafrost. The final sand and gravel aggradation in the Devensian forms the Block Fen Terrace, near 0 m OD. The evidence indicates that it is younger than the lacustrine sediments resulting from the blocking of the Fenland at the Wash by Late Devensian ice at ca. 18.5 ka BP.The sequence at Block Fen is related to nearby Ipswichian and Devensian sediments at Chatteris, March, Wimblington and Mepal, and to deposits at Wretton on the east margin of Fenland. The correlation permits an outline reconstruction of the history of the valley carrying the River Great Ouse between the Isle of Ely and the Chatteris and March ‘islands’ from the time of a gravel aggradation before the Ipswichian to the Flandrian. The reconstruction shows the time and level of the Ipswichian marine incursion into the Middle Level of Fenland and the extent of aggradation and erosion in the Devensian.

The holocene sedimental characteristicand paleoclimatic evolution of Ebinur Lake, XinJiang

On the basis of lacustrine sedimentary profile of Ebinur Lake, sequences of evolution of paleoclimate and paleoenvironment in Ebinur Lake area have been rebuilt by analysing the sedimentary stratigraphy, bio-stratigraphy and geochemistry as well as the chronological records. The results show that, during the last 10 ka years, the general change trends of the paleoclimate in E-binur Lake area can be divided into three stages: (1) 10. 2 – 8.3 ka B. P., a warm-cool dry climate stage; (2) 8.3–3.5 ka B. P., a warmer moist climate stage (specially, 7.3–6.4 ka B. P., a relatively stable humid temperate stage); (3) 3.5 ka B. P. —present, adraught temperate climate stage, similar to the present climate. In addition, there existed clearly several times of secondary undulations of dry-humid climate, i.e. 8.3 ka and 7.3 ka for dry climate

Malacological evidence relating to the insularity of the British Isles during the Quaternary

Abstract The marine molluscan faunas from different temperate stages of the Pleistocene of the North Sea vary enormously both in terms of species richness and in the diversity of their biogeographical composition. The marine assemblages from the Middle Tiglian, Eemian and Holocene have all yielded c. 100 species or more, including many with southern or ‘Lusitanian’ affinities. It is thought that during these stages the Strait of Dover was open, allowing entry of these southern taxa into the southern North Sea. Conversely, the temperate stages from the Late Tiglian up to and including the Holsteinian have yielded relatively impoverished faunas (no more than about 40 species) virtually lacking any of the southern elements. During these stages it would appear that the Strait of Dover was closed, so preventing the spread of marine molluscs into the North Sea. Examination of the history of fluvial molluscs (particularly prosobranchs and larger bivalves) on either side of the English Channel supports this interpretation. Fluvial provinciality is recognized during the stages when Britain is thought to have become an island. Non-provinciality, pointing to fluvial exchange, occurs during the other stages.

The floristic record of Ireland’s Pleistocene temperate stages

Abstract The unique flora of Ireland, that includes plants with Atlantic, amphi-Atlantic and Mediterranean affinities, has attracted the attention of many biogeographers. Using a database, this paper compiles the Irish Pleistocene plant fossil record and examines the disappearances of some taxa and the continuity of others. A retreat of some plants to the east since the Tertiary, movement of arctic-alpine species to the north and to the mountains, and the long continuity of Atlantic and amphi-Atlantic taxa, including some not present in Britain, can be identified. The flora of the Irish Middle Pleistocene Gortian temperate stage is examined and its uniqueness, and the long continuity of certain taxa, are discussed. The long record of Atlantic and amphi-Atlantic species, as well as wetland and aquatic taxa, suggests the possibility of proximal refugia for some plants. The implications for in situ survival and for migration during and after cold stages are discussed in the light of the compiled fossil record.

Palaeotidal modelling of continental shelves: marine implications of a land-bridge in the Strait of Dover during the Holocene and Middle Pleistocene

Abstract Numerical models of the tide on the NW European continental shelf are useful in predicting basic tidal dynamics (amplitude, current, bed stress, mixing) from bathymetry, coastline configuration and a known ocean tide at the shelf edge. Using the M 2 constituent of the ocean tide, a numerical model has been used to investigate the tidal regime of the English Channel/southern North Sea at successive stages during the Holocene transgression, and also during the maximal sea-levels of Middle Pleistocene temperate stages, by incorporating palaeogeographical interpretations of geological data from these time-slices. Prior to the breaching of the Strait of Dover in the early Holocene, the Southern Bight of the North Sea was a quiet, shallow embayment of low M 2 tidal amplitude (<0.5 m); following breaching it attained the present state of vigorous tidal action with mean amplitudes of around 2 m. Changes in sediment transport paths and shelf-sea fronts are also indicated. Models of the Middle Pleistocene interglacial English Channel incorporate modified palaeobathymetries to compensate for tectonic uplift in the central Channel area over the past 400 000 years. These models indicate increased seasonal stratification in the Channel compared with the present mixed condition. This is in agreement with independent evidence from coccolith assemblages contained within sediments of the same age from the central Channel area.

Palaeontology and taphonomy of Late Quaternary fossil assemblages at Somersham, Cambridgeshire, England, and the problem of reworking

AbstractAssemblages of foraminifers, ostracods and molluscs from temperate Ipswichian Stage (last temperate stage) sediments and overlying cold Devensian Stage (last cold stage) sediments at Somersham in the southern Fenland of Cambridgeshire have been analysed. The Ipswichian sediments contain faunas consistent with temperate brackish water conditions under tidal influence. The Devensian assemblages were recovered from a series of sands and gravels laterally accreting in a channel cutting into Ipswichian sediments. In contrast to the Ipswichian faunas, the faunas of particular Devensian samples show a complex mixture of temperate freshwater, brackish and marine taxa. The molluscs are mainly freshwater, with few land snails; they occur together with foraminifers and ostracods. Freshwater, brackish water and marine ostracods are present with foraminifers. A sample of Devensian fine laminated sediment in the channel was analysed for pollen; only abundant pre‐Quaternary spores were present, with abundant foraminifers in the same sample. The taphonomy of the assemblages and the difficulties of their interpretation in environmental terms are discussed. The importance of taphonomy in assessing environments, climate, range of taxa and dating is stressed.

A hominid tibia from Middle Pleistocene sediments at Boxgrove, UK.

Fossil hominids from the earlier Middle Pleistocene of Europe are very rare and the Mauer mandible is generally accepted as the most ancient, with an estimated age of 500 kyr. We report here on the discovery of a human tibia, in association with stone tools, from calcareous silts at the Lower Palaeolithic site of Boxgrove, West Sussex, UK (Fig. 1). The silt units are correlated by mammalian biostratigraphy to an, as yet unnamed, major temperate stage or interglacial that immediately pre-dates the Anglian cold stage. Accordingly, the temperate sediments are equated with oxygen isotope stage 13 (ref. 6) and are therefore roughly coeval with the Mauer mandible. The massive tibia is the oldest hominid fragment from the British Isles and provides the first information about the manufacturers of the early Acheulian industries of Europe. It is assigned to Homo cf. heidelbergensis.

Climatic deterioration and the end of the Gortian Interglacial in sediments from Derrynadivva and Burren Townland, near Castlebar, County Mayo, Ireland

AbstractPollen and macrofossil analyses of two sequences of organic sediment in western Ireland have allowed the recognition of the latter parts of the Gortian Interglacial, a Middle Pleistocene temperate stage. The palaeobotanical information from the two sites identifies the preservation of partial sequences from the Gortian Interglacial (believed to be the equivalent of the Hoxnian Stage of Britain and the Holsteinian of Europe). The pollen and macrofossil data from one of the sites, Derrynadivva, span the middle and latter parts of the temperate stage. The results show that fire influenced the vegetation throughout the middle part of the temperate stage, and the termination of the organic depositional sequence appears to have been due to environmental deterioration. The former is identified through the abundant occurrence of charcoal in the sediments, whereas the latter is apparent in the sediment sequence and in the reworking of thermophilous pollen types into the upper part of the deposit. The second site, Burren Townland, records only part of the later zones of the interglacial, but the ericaceous assemblages of the latter part of the Gortian Interglacial are well developed and well preserved. Macrofossil analyses and scanning electron microscopy work on the pollen at the latter site has allowed the recognition of Rhododendron ponticum, adding to previous records of this species, which now has a very disjunct European distribution.

A uranium‐thorium dated late Eemian or early midlandian organic deposit from near Kilfenora between Spa and Fenit, Co. Kerry, Ireland

AbstractThis paper discusses the dating of stratigraphically important Quaternary sequences from a site near Fenit, Co. Kerry, which have been the subject of debate since they were first described by Mitchell in 1970. The overall stratigraphy of the Quaternary deposits have been investigated and detailed analyses of the organic material carried out. Pollen from biogenic sediments have been analysed and samples of peat dated using the uranium‐thorium disequilibrium method. The pollen assemblages match no others previously recorded in Ireland and appear to represent a cool temperate phase following the last interglacial. The uranium‐thorium dates of between 114000 and 123 000 yr BP indicate that the deposit dates from Oxygen Isotope Stage 5, possibly post‐dating the last temperate stage (the Eemian Stage interglacial; Oxygen Isotope Substage 5e). The dating of this deposit and the realisation that it is not penultimate temperate stage (Gortian) in age invalidates much recent speculation on the age of the Gortian interglacial.

The middle pleistocene deposits of Waverley Wood Pit, Warwickshire, England

AbstractA complex of channels underlying the Baginton‐Lillington Gravel (Baginton Formation) at Waverley Wood Quarry, Warwickshire is described. Fossil pollen and plant macrofossils, Coleoptera, Ostracoda, Mollusca and Mammalia are described from the channel‐fill deposits. Consideration of all the evidence allows the identification of four separate stages of channel fill which largely occurred under a cool temperate climate. At the top of Channel 2 evidence for a cold, continental climatic episode can be recognised, suggesting that the whole complex was deposited under a fluctuating climate at the end of a temperate stage. At two levels in the channels human artefacts were recovered confirming the presence of Palaeolithic people in Warwickshire during the deposition of the sediments. Amino‐acid geochronology suggests an age within the ‘Cromerian Complex’ Stage for the channels. The small vertebrate and molluscan faunas indicate that the deposits are no older than the latter part of the ‘Cromerian Complex’ Stage of East Anglia. The regional stratigraphic significance of the Waverley Wood succession is outlined.

A resedimented interglacial peat ball containing Carpinus pollen within a glacial efflux sequence, Blackwater, Co. Wexford: evidence for part of the last interglacial cycle in Ireland?

This paper records the find of a reworked ball of detrital peat that was glacially eroded from terrestrial deposits located to the east or northeast, and subsequently became entombed within a complex deltaic deposit, which was associated with a major glacial efflux venting into standing water during the Late Devensian (Midlandian). The pollen content of the detrital peat is unlike other assemblages in the Irish Pleistocene record, and it represents a temperate stage deposit with a background of thermophilous tree taxa ( Quercus, Fraxinus and Acer ) along with important contributions of the pollen of Pinus, Betula, Picea and Carpinus . The pollen assemblage is unlike any known Gortian assemblages and it is most similar to assemblages recorded from the Late Pleistocene of northwest Europe, in particular those from the latter parts of the Eemian Interglacial. Although the limited data collected preclude a firm correlation to any particular Late Pleistocene stage, it is the first deposit of its kind reported from Ireland and it provides an important indication of the possibility of finding further post-Gortian temperate stage deposits.

The margin of a Middle Pleistocene ice advance at Tottenhill, Norfolk, England

AbstractExposures at Tottenhill quarry, west Norfolk, are described. Detailed sediment logs, lateral sediment distribution and facies relationships are presented, together with palaeocurrent measurements and pebble counts. It is concluded that the sequence represents a delta-like subaquatic fan accumulation that was deposited by glacier meltwater at the eastern margin of the present Fenland. The ice must have entered the area from the west to northwest. An arctic leaf flora is associated with still water pool sediments within the fan sequence. Pollen assemblages appear to be largely derived by reworking from underlying in situ temperate stage sediments which are correlated with the Hoxnian Stage.The age of the deposits is discussed and it is concluded that the glaciation concerned must date from the early part of the Wolstonian Stage on the basis of the previously established stratigraphical sequence in the area.

The fauna and flora of the March Gravels at Northam Pit, Eye, Cambridgeshire, England

AbstractInvestigations of the March Gravels of Northam Pit, Eye, Cambridgeshire, have provided previously undescribed molluscan, ostracod and foraminiferal faunas together with pollen spectra, which enable a detailed palaeoenvironmental synthesis to be developed. The sediments were laid down in brackish-water conditions and a temperate environment, during a Late Pleistocene temperate stage.