middle pleistocene deposits at frog hall pit stretton on dunsmore warwickshire english midlands and their implications for the age of the type wolstonian organic sediment from frog hall pit near coventry has produced pollen plant macrofossil insect ostracod and molluscan data indicative of the early part of a temperate episode in the middle pleistocene the regional stratigraphy and clast lithological characteristics of the gravels underlying the temperate deposits show that the whole sequence at the site post dates the major glaciation the wolstonian sensu mitchell et al 1973 of the midlands amino acid d l ratios from molluscan shells give mean values of 0 24 which is consistent with an age in oxygen isotope stage 9 and comparable with those from the hoxnian interglacial of east anglia this age estimate for the frog hall organic deposit places a minimum age on the wolstonian glaciation of the midlands in oxygen isotope stage 10 and therefore close in time to the anglian oxygen isotope stage 12 cold stage 1997 john wiley sons ltd

a uranium thorium dated late eemian or early midlandian organic deposit from near kilfenora between spa and fenit co kerry ireland this 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 123000 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

comment on numerical 230 th u dating and a palynological review of the holsteinian hoxnian interglacial by geyh and muller

age dating and the orbital theory of the ice ages development of a high resolution 0 to 300 000 year chronostratigraphy using the concept of orbital tuning a continuous high resolution deep sea chronostratigraphy has been developed spanning the last 300 000 yr the chronology is developed using a stacked oxygen isotope stratigraphy and four different orbital tuning approaches each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data each approach yields a separate chronology the error measured by the standard deviation about the average of these four results which represents the best chronology has an average magnitude of only 2500 yr this small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used excellent convergence between chronologies developed using each of five different paleoclimatological indicators from a single core is also obtained the resultant chronology is also insensitive to the specific indicator used the error associated with each tuning approach is estimated independently and propagated through to the average result the resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr in excellent agreement with the 2500 yr estimate transfer of the final chronology to the stacked record leads to an estimated error of 1500 yr thus the final chronology has an average error of 5000 yr

borehole guided avo analysis of p p and p s reflections quantifying uncertainty on density estimates seismic properties of isotropic elastic formations are characterized by the three parameters acoustic impedance poisson s ratio and density whilst the first two are usually well estimated by analysing the amplitude variation with angle ava of reflected p p waves density is known to be poorly resolved however density estimates would be useful in many situations encountered in oil and gas exploration in particular for minimizing risks in looking ahead while drilling we design a borehole seismic experiment to investigate the reliability of ava extracted density receivers are located downhole near the targeted reflectors and record reflected p p and converted p s waves a non linear wide angle based bayesian inversion is then used to access the a posteriori probability distributions associated with the estimation of the three isotropic elastic parameters the analysis of these distributions suggests that the angular variation of reflected p s amplitudes provides additional substantial information for estimating density thus reducing the estimate uncertainty variance by more than one order of magnitude compared to using only reflected p waves

correlation of european glaciations and their relation to the deep sea record north european scandinavian glaciations quaternary glaciations in europe may be studied in two areas the first area from west to the east corresponds with the area of scandinavian glaciations that formed coherent ice sheets from northwestern europe as far as the ural mountains correlations from north to south involve comparison of stratigraphic sequences from the area of the scandinavian glaciations by way of the extraglacial zone to the mountain glaciations of the alpine chain a stratigraphic review of the different areas is given in preceding chapters correlation of scandinavian glaciations has in general more basic information available and the nature of the glacial deposits makes correlation easier but stratigraphic comparison of that area with the alps faces difficulties and is possible in rough outline only many problems persist in the alpine area and are derived from surviving quadriglacial concepts which contrast with generally accepted polyglacial schemes correlation of european glaciations and their relation to the deep sea record

correlation of the eemian and the weichselian with deep sea oxygen isotope stratigraphy abstract the eemian interglacial was defined in the netherlands and is correlated all over northern europe it is now demonstrated that the eemian was the last interglacial in europe thus it is obvious that it should correlate with either the entire stage 5 in the deep sea oxygen isotope stratigraphy or with parts of stage 5 several observations prove that the eemian correlates with substage 5e the two other peaks in stage 5 correlates with the warm interstadials brorup and odderade in northern europe

late quaternary evolution and sea level history of a glaciated marine embayment bantry bay sw ireland ireland experienced a spatially complex pattern of relative sea level rsl changes and shoreline development caused by the interplay of isostatic and eustatic ice equivalent sea level processes since the last glacial maximum lgm using a combination of high resolution marine geophysical data vibrocores foraminiferal analysis and 10 ams radiocarbon dates we reconstruct the late quaternary evolution and rsl history of bantry bay a large 40 km long 5 10 km wide embayment in sw ireland the data indicate two infill phases one before and one after the lgm separated by glacial and lowstand sediments the pre lgm history is not dated and the depositional history is inferred a large sediment lobe formed at the outer edge of bantry bay as a lowstand ice proximal glacimarine outwash system as the ice retreated after the lgm at a sea level ca 80 m lower than present iceberg scour immediately west of this location likely relate to the break up of the local kerry cork ice cap long curvilinear ridges seen both offshore and on top of the sediment lobe probably formed as shoreface ridges under stronger than present tidal currents during a period of rsl stability pre 14 6 ka cal bp a subsequent infill phase is characterised by a basin wide erosional ravinement surface and the deposition of inter and sub tidal estuarine sediments although our data support the general trends our stratigraphic and radiocarbon data suggest a higher sea level between 11 and 13 5 ka cal bp than predicted by existing glacial isostatic adjustment models

an analysis of eemian climate in western and central europe on the basis of 31 pollen diagrams and additional data for botanical macrofossils an analysis is made of the last interglacial eemian climatic history in western and central europe the main tool for this analysis is the climatic indicator species method only selected woody species are used for the quantification of data partial climatic range diagrams are presented for abies alba acer monspessulanum acer tataricum buxus sempervirens tilia tomentosa the problem of time correlation and pollen zonation of the eemian is discussed the climatic analysis itself is based on an improved version of the indicator species method in this version not every site is analysed for its climatic values instead maps and tables on the migrational history of hedera ilex buxus abies and species of acer tilia and abies are the basis for climatic maps showing respectively january and july isotherms for the periods of the corylus zone e4a and the carpinus zone e5 it is concluded that mean january temperatures were as much as 3 c higher at amsterdam the netherlands than at present and mean temperatures in july were 2 c higher however the thermal maximum in winter was later zone e5 than the summer thermal maximum zone e4a winter temperatures changed parallel to rise and fall of global sea level precipitation changes are more difficult to estimate in the first part of the eemian precipitation must have been relatively low but from zone e4b onward it increased to higher values reaching 800 mm and probably substantially more in zones e5 and e6 hence the eemian climate was in its beginning relatively more contintental and later from e4b onward more oceanic however as compared with the holocene the eemian climate was generally speaking more oceanic

shear wave velocity and density estimation from ps wave avo analysis application to an obs dataset from the north sea s wave velocity and density information is crucial for hydrocarbon detection because they help in the discrimination of pore filling fluids unfortunately these two parameters cannot be accurately resolved from conventional p wave marine data recent developments in ocean bottom seismic obs technology make it possible to acquire high quality s wave data in marine environments the use of s waves for amplitude variation with offset avo analysis can give better estimates of s wave velocity and density contrasts like p wave avo s wave avo is sensitive to various types of noise we investigate numerically and analytically the sensitivity of avo inversion to random noise and errors in angles of incidence synthetic examples show that random noise and angle errors can strongly bias the parameter estimation the use of singular value decomposition offers a simple stabilization scheme to solve for the elastic parameters the avo inversion is applied to an obs data set from the north sea special prestac

looking ahead with vertical seismic profiles several operations enhance our ability to predict the subsurface below the bottom total depth td of the well when applied to zero offset vertical seismic profiling vsp data other key issues regarding the use of vsp data in this fashion are resolution and look ahead distance an impedance log is the most useful form for presenting vsp data to look ahead of the drill bit the vsp composite trace must first tie reliably to the surface seismic section and to the well log synthetic seismogram the impedance log is obtained by inverting this vsp composite trace however before performing the inversion we need to 1 correct the composite trace for attenuation effects below td and 2 input velocities to provide low frequency information an exponential gain function applied to the vsp data below td adequately compensates for the loss of amplitude caused by attenuation a calibration of the seismically derived velocities with vsp velocities yields the necessary low frequency information these concepts ar

quaternary glaciations in southern fennoscandia evidence from southwestern norway and the northern north sea region abstract based on records from the northern north sea and southern norway quaternary fennoscandian glaciations are described and discussed maximum glaciation defined as the presence of shelf edge glaciation an ice stream flowing out of the norwegian channel and most likely an ice divide over the central part of fennoscandia sweden gulf of bothnia occurred for the first time in the late cenozoic at ca 1 1 myr the fedje glaciation this glaciation was followed by a ca 600 kyr period with at least two glaciations with ice extension somewhat larger than the younger dryas event in the region the first maximum glaciation of the bruhnes chron was during isotope stage 12 and was followed by repeated maximum glaciations within each of the light isotopic stages until stage 2 during the weichselian the southwestern part of the fennoscandian ice sheet reached maximum position three times sometime between 22 and 28 37 and 50 and 60 and 80 ka limited glaciations probably occurred during stadials between the early and middle weichselian interstadials between 500 ka and 1 1 myr and most likely also prior to 1 1 myr deep norwegian sea ice rafted detritus ird records reflecting contributions from several different ice sheets fennoscandian barents sea iceland and greenland each with large variations in history of ice extent to their respective margins yet to some degree they reflect the glaciation of the northern north sea region with an increasing ird input around 1 1 myr and a relatively low input of north sea components during some cycles around the b m boundary maximum glaciations occurred during insolation minima in the earlier part of the middle pleistocene however not all such minima are reflected by maximum glaciation in southern parts of fennoscandia the relatively poor chronological control and non continuous character of the data on weichselian interstadials stadials precludes a clear relationship to atmospheric changes recorded in greenland ice cores as well as to precession and or obliquity cycles in insolation

description and esr dating of the holsteinian interglaciation abstract the classical region of the holsteinian interglacial is in the vicinity of hamburg and the lower elbe it is defined on the basis of pollen and is clearly distinguishable from the eemian interglacial hallik 1960 muller 1974 the holsteinian interglacial is represented by a sequence of sediments up to 100 m in thickness these consist of limnic fluvial and marine beds and show a transgression up to the height of present sea level twenty seven molluscs from holsteinian deposits were used for esr dating the ages show that the holsteinian may be correlated with stage 7 of the deep sea record v28 238 shackleton and opdyke 1973

late middle pleistocene sea level change in the southern north sea the record from eastern essex uk abstract litho and biostratigraphical data from a complex of buried channels in eastern essex are combined with palaeosalinity data to reconstruct the estuary of the thames during the late middle pleistocene two models of relative sea level change are proposed for the anglian elsterian ipswichian eemian interval the first invokes a complex marine incursion during a single interglacial event the second describes two marine transgressions during two separate interglacial stages the models are placed in the wider context of the shallow marine record of the southern north sea

amino acid geochronology its impact on our understanding of the quaternary stratigraphy of the british isles this review aims to act as a brief primer to amino acid racemization and protein breakdown as well as to document the major applications and results of amino acid dating on british quaternary sediments amino acid results from fossil shells have had far reaching effects in developing our current understanding of british quaternary stratigraphy and its links to continental europe and the marine record to appreciate the potential for amino acid geochronology the technique s limitations and recent developments are discussed as well as the future of the field copyright 2009 john wiley sons ltd

current understanding of pleistocene temperate stages in ireland abstract 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

sedimentary history of za hajovnou cave moravia czech republic a unique middle pleistocene palaeontological site za hajovnou cave in the javoricko karst moravia czech republic has a rich record of middle pleistocene typical holsteinian flora and fauna dominated by bear ursus deningeri sedimentological geochemical mineralogical geophysical palynological and zoopalaeontological analyses of the sediments along with u th dating of flowstones place the deposits into a numerical timeframe the cave origin dates to a period before the mid miocene badenian transgression the oldest fluvial deposits are lower pleistocene spanning the brunhes matuyama boundary the later terrestrial deposits range from middle pleistocene to holocene the most important result of u th dating is that the main holsteinian senso lato fossil bed can be correlated with mis 9 the lower fossil bed is probably mis 11 and the upper fossil bed mis 5e this represents one of the still relatively few numerically dated holsteinian sites contradicts the global chronostratigraphical correlation table that places the holsteinian only in mis 11 and supports the concept that the holsteinian is not a single unit and likely not confined to a single interglacial c 2013 elsevier ltd and inqua all rights reserved

amino acid geochronology and the british pleistocene secure stratigraphical framework or a case of circular reasoning aminostratigraphy is central to the recently revised correlation of quaternary deposits in the british isles providing a link between terrestrial deposits and marine oxygen isotope stages the central tenet of british aminostratigraphy however that shells from the same interglacial yield very similar ratios so that the characteristic ratios from different interglacials are distinct remains uncertain the data available suggest that amino acid ratios from different interglacials do not fall into discrete groups but overlap considerably it is therefore not valid to assign individual shells to oxygen isotope stages simply on the basis of their amino acid ratios which means that filtering data to remove high or low values on the assumption that they represent reworked shells is unacceptable the range of characteristic ratios assigned to british warm stages may have been underestimated and the degree of separation between them overestimated amino acid ratios should be treated as sample data that are naturally variable copyright 2002 john wiley sons ltd

aminostratigraphy of european marine interglacial deposits molluscan fossils collected from shallow water marine sediment across nw europe and nearby arctic regions have been analysed for the extent of isoleucine epimerization dl ratio in indigenous protein residues the dl ratios confirm that essentially all classical eemian sites from nw europe are of the same age and are correlative with the type locality near amersfoort in the netherlands shells from interglacial marine sediment beneath the type weichselian till in poland also correlate with the type eemian site dl ratios in holsteinian marine shells 0 29 are substantially higher than in their eemian counterparts 0 17 late cromerian shells yield even higher ratios 0 46 dl ratios in late glacial shells 0 06 and middle weichselian shells 0 09 permit differentiation from modern 0 01 and last interglacial material based on the position of the matuyama brunhes boundary and the differences in dl ratios the eemian must correlate with isotope substage 5e whereas the holsteinian is most likely substage 7c possibly stage 9 but certainly younger than stage 11 intra saalian warm periods may be terrestrial equivalents of the younger substages of stage 7 extensive pre eemian marine sediments along the sw coast of denmark previously correlated with the holsteinian are shown to be of late cromerian age the underlying till there is the first widespread evidence of a pre elsterian till in nw europe dl ratios in molluscs from last interglacial sites along the arctic coast of the ussr the arctic islands and eastern greenland are substantially lower than in their european counterparts due to their low thermal histories the combined mid and high latitude data are used to develop a predictive model for the expected dl ratio in any of several moderate epimerization rate taxa for last interglacial sites with mean temperatures between 20 and 15 c not all sites could be unambiguously assigned to an established interglacial the fjosanger norway and margareteberg sweden sites previously thought to be eemian yield dl ratios higher than in secure nearby eemian material it is yet unresolved whether these are aberrant sites or if they predate the last interglacial in situ shoreline deposits encountered in borings in sw belgium and in exposures on the belgium coastal plain contain molluscs that yield dl ratios intermediate between secure eemian and late weichselian ratios raising the possibility that a late stage 5 high sea level event attained near modern levels in the southern north sea basin resolution of these uncertainties is the focus of future work

numerical 230th u dating and a palynological review of the holsteinian hoxnian interglacial abstract earth scientists increasingly consider the holsteinian interglacial and mis 11 as synonyms despite the limited number of numerical dates and ambiguous stratigraphic and palynological correlation with the numerical marine isotope timescale hence we present new tims 230th u dates from two fen peat layers of the holsteinian reference site at bossel in northern germany and re evaluate published numerical data from two sites with hoxnian deposits in england a new method for the calculation of methodically controlled minimum 230th u ages mcma was developed the synopsis of the 230th u dates allows a correlation of both the holsteinian and hoxnian interglacials to mis 9 this correlation is supported by supplementary 230th u dates of fen peat from several pre eemian but non holsteinian sites in germany there is palynological evidence for a reliable correlation between precisely investigated and numerically dated holsteinian deposits in poland germany england sw ireland and france an apparently contradictory palynological correlation from the french central massif is discussed

the beginning of the ice age in europe and its major subdivisions abstract the time range of the quaternary is discussed in terms of the view that this period is essentially the one in the earth s history in which during certain intervals inland ice developed in the northern hemisphere this process first became evident about 2 3 ma bp since then the quaternary thus defined has witnessed many climatic variations although for practical reasons it is not feasible to assign the status of stage to each distinclty warm or cold phase climatic change is nevertheless the most appropriate basis for world wide correlation it seems possible to use both climatic change and other correlation parameters to arrive at a practicable subdivision of the quaternary period into stages before about 1 ma vegetational succession during interglacials in western europe differed from that seen in later times a possible cause for this divergence is discussed in the later part of the quaternary after about 1 ma two distinct types of warm temperate intervals occurred one associated with high sea levels and an oceanic climate the other showing lower sea levels and a cooler and more continental climate the difference between these two types is shown by comparison of the distribution of abies during these time intervals

the gortian temperate stage abstract 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

volcanic maars long quaternary sequences and the work of the inqua subcommission on european quaternary stratigraphy abstract for several years the inqua subcommission on european quaternary stratigraphy seqs has been actively fostering debate on the stratigraphy and typification of the middle pleistocene in europe palynological investigations of deep sediment cores from maar lakes in italy and the french massif central have now provided a stratigraphical framework conclusively correlated with the deep ocean record confirming the occurrence of two clearly temperate intervals between the holsteinian and eemian interglacials this places interglacial deposits from localities such as schoningen pritzwalk domnitz wacken and maastricht belvedere into a clearer perspective all major saalian glacial advances probably relate to oxygen isotope stage 6 reasons for the relative paucity of continental interglacial deposits equivalent to oxygen isotope stages 7 and 9 are discussed these stages were not preceded by major glacial events in northern europe so suitable basins of deposition were largely absent in contrast fluvial erosion was very active with much downcutting and drainage re organisation finally evidence from the sea surface temperature record of the norwegian sea does suggest a less powerful pattern of oceanic circulation in the north atlantic during these interglacial intervals within the saalian complex stage when compared to those of the eemian and holocene this difference would certainly have affected environments on the adjacent european continent

dagmar cave czech republic moravian karst a unique palaeontological site of the cromerian interglacial abstract dagmar cave czech republic is the first locality in the moravian karst where sediments of cromerian age have been discovered and it is the first locality with such a large number of species of molluscs of this age it was originally a swallow hole initiated in the neogene which has since accumulated sediments basal sediments are palaeontologically sterile stream boulders originating from weathered lower carboniferous rock after this fossiliferous loamy sediments were carried in from the entrance by streams and or gravity molluscan and vertebrate assemblages along with palynological remains are indicative of interglacial conditions faunal analysis determined that this could only consist of one interglacial either cromerian iii or iv this is the first record of middle pleistocene molluscan fauna in the moravian karst palynology demonstrated a humid and thermophilic vegetation typical of a cromerian interglacial with forest and probably water and an open grassy bushy area close to the cave the age is constrained by a mis 7 u th date 182 ka on the calcite flowstone that overlies the interglacial material and underlies the palaeontologically more sterile upper sediments

sudden changes in north atlantic circulation during the last deglaciation sudden changes in the flow of warm atlantic surface waters into the norwegian sea occurred frequently during the last deglaciation typically involving shifts in sea surface temperature of 5 c in fewer than 40 years these led to equally large and rapid changes in atmospheric temperatures and to shifts in atlantic deep thermo haline circulation and ice sheet melting rates

palynology aminostratigraphy and u series dating of marine gortian interglacial sediments in cork harbour southern ireland abstract 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 role of the deep ocean in north atlantic climate change between 70 and 130 kyr ago the suggestion1 that changes in north atlantic deep water nadw production are linked through surface heat flux to the atmospheric temperature over greenland is supported by earlier indications2 3 that nadw production decreased during glacial times and by the subsequent finding4 6 that it declined during the younger dryas cool period at the end of the last glaciation changes in north atlantic surface temperatures have been found7 to mirror high frequency temperature changes recorded in greenland ice cores over the past 80 kyr but the connection to abyssal circulation has yet to be established except for one or two isolated oscillations8 9 here we present carbon and oxygen isotope analyses of benthic foraminifera in a high resolution north atlantic deep sea sediment core for the period 70 130 kyr ago these data allow us to reconstruct the history of nadw production which shows a close correlation with greenland climate variability for much of this time interval suggesting that the climate influence of nadw variability was widespread we see no evidence however for changes in nadw production during substage 5e the eemian interglacial period in contrast with recent ice core data10 which suggest severe climate instability in greenland during this time period our results may support suggestions based on data from a second ice core that this apparent instability is an artefact caused by ice flow11 alternatively the eemian climate instability may have had a different origin from the subsequent climate events

iron and manganese speciation and cycling in glacially influenced high latitude fjord sediments west spitsbergen svalbard evidence for a benthic recycling transport mechanism abstract glacial environments may provide an important but poorly constrained source of potentially bioavailable iron and manganese phases to the coastal ocean in high latitude regions little is known about the fate and biogeochemical cycling of glacially derived iron and manganese in the coastal marine realm sediment and porewater samples were collected along transects from the fjord mouths to the tidewater glaciers at the fjord heads in smeerenburgfjorden kongsfjorden and van keulenfjorden along western svalbard solid phase iron and manganese speciation determined by sequential chemical extraction could be linked to the compositions of the local bedrock and hydrological weathering conditions below the local glaciers the concentration and sulfur isotope composition of chromium reducible sulfur crs in kongs and van keulenfjorden sediments largely reflect the delivery rate and isotope composition of detrital pyrite originating from adjacent glaciers the varying input of reducible iron and manganese oxide phases and the input of organic matter of varying reactivity control the pathways of organic carbon mineralization in the sediments of the three fjords high reducible iron and manganese oxide concentrations and elevated metal accumulation rates coupled to low input of fresh organic matter lead to a strong expression of dissimilatory metal oxide reduction evidenced in very high porewater iron up to 800 m and manganese up to 210 m concentrations in kongsfjorden and van keulenfjorden sediment reworking by the benthic macrofauna and physical sediment resuspension via iceberg calving may be additional factors that promote extensive benthic iron and manganese cycling in these fjords on going benthic recycling of glacially derived dissolved iron into overlying seawater where partial re oxidation and deposition occurs facilitates the transport of iron across the fjords and potentially into adjacent continental shelf waters such iron dominated fjord sediments are likely to provide significant fluxes of potentially bioavailable iron to coastal waters and beyond by contrast low delivery of reducible iron oxyhydr oxide phases and elevated organic carbon mineralization rates driven by elevated input of fresh marine organic matter allow organoclastic sulfate reduction to dominate carbon remineralization at the outer smeerenburgfjorden sites which may limit iron fluxes to the water column

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 230 th 238 u 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 1 level the new aminostratigraphic ratios indicate correlation of the nar valley clay with oxygen isotope stage 9 and therefore support the pre existing 230 th 238 u 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

land sea correlations in the pleistocene based on isoleucine epimerization in non marine molluscs the correlation between the oxygen isotope stratigraphy of the oceans and continental stratigraphic records is one of the main challenges for quaternary research most continental classifications however are based on techniques and hypotheses that predate recent advances nevertheless the deep sea oxygen isotope global stratigraphic framework has been extended to the continents by means of some long sequences1 but these are exceptional and regional geology is unsatisfactorily classified for correlation with the oxygen isotope signal because successive geological events produced similar evidence homotaxis geochronometric dating is essential for correlation but available methods are highly site regional or sample specific fortunately non marine molluscs are ubiquitous in time and space and here we use the time dependent epimerization of l isoleucine in these fossils to subdivide the pleistocene of the british isles and to identify more events than recognized by the existing classification2 by calibrating the relative aminostratigraphic scale with independent dating methods we have set up a geochronology which is the basis for land sea correlations back to oxygen isotope stage 15

u series dating of hoxnian interglacial deposits at marks tey essex england a u th dating study was carried out on the authigenic carbonate component of interglacial lake sediments at marks tey essex england isochron methods were necessary because of the presence of non carbonate detritus calculated dates around the limit of the u th method were obtained for two horizons error limits were determined by monte carlo sampling from the normal distributions of errors in the isotope ratios comparison of the resulting empirical distribution functions with the marine oxygen isotope time scale indicates with 87 confidence that the marks tey sediments correlate with ois 11 or some older stage as the marks tey deposits rest without stratigraphical break on anglian till and can be firmly correlated with the hoxnian interglacial type site at hoxne suffolk england this result implies that the anglian glaciation took place in ois 12 acid the hoxnian stage of the british chronostratigraphy commenced in ois 11 copyright c 1999 john wiley sons ltd

climatic deterioration and the end of the gortian interglacial in sediments from derrynadivva and burren townland near castlebar county mayo ireland pollen 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

vegetation and climate during warmer intervals in the late pleistocene of western and central europe abstract many warmer intervals occurred during the last interglacial glacial cycle 130 10 ka in europe the vegetational record shows several types of such intervals among which the forest periods of the eemian interglacial and the amersfoort brorup interstadials of the early weichselian are of special interest a series of map reconstructions is used to present some of the relevant vegetational and paleoclimatic characterizations they represent two types of temperate intervals occurring in the late pleistocene in europe one with a rather uniform distribution of vegetation types a warmer oceanic climate and a high sea level the other type shows strong vegetation gradients both north south and east west a more continental climate and a relatively low sea level inland ice probably persisted in the far north during this last type of interval it is suggested that these two types of interglacial occurred throughout the pleistocene

an osl dated middle and late quaternary sedimentary record in the roer valley graben southeastern netherlands abstract well dated terrestrial sedimentary sequences are important to evaluate the influence of quaternary climate change on continental landscape evolution the roer valley graben southeastern netherlands contains a 35 m thick sedimentary record of middle and late quaternary fluvial aeolian and organic deposits sediment provenance depositional processes and the continuity and timing of deposition were reconstructed sedimentary and geochemical data reveal a change from a fluvial depositional environment to a dominance of aeolian deposits this change may be related to increased tectonic uplift and the onset of large scale volcanism in the ardennes eifel region between 800 and 500 ka the main source of aeolian sediments are quaternary rhine deposits that crop out to the northwest of the study area sedimentation and preservation in the roer valley graben took place under humid surface conditions these conditions occurred 1 in a periglacial climate with permafrost 2 at the transition from a warm temperate to a cool climate dates from two internally consistent quartz optically stimulated luminescence osl age series in the roer valley graben correspond well with the ages of related terrace deposits in the orbitally tuned meuse river terrace flight the osl dates confirm the presence of organic deposits reflecting marine oxygen isotope stage mis 9 or 11 and mis 5e this long terrestrial sequence thus provides input for the fragmentary middle pleistocene record of northwestern europe and forms a possible link between the glacial history of northern europe and the long lake and loess records of eastern and southern europe