causes consequences and chronology of large magnitude palaeoflows in middle and late pleistocene river systems of northwest europe this study examines the record of high palaeoflow phases in river systems in northwest europe investigating their causes whether due to unique events such as the formation of the dover strait or as characteristic consequences of climate change examining their consequences with regard to landscape evolution and possible effects on climate and determining the chronology of key events large magnitude palaeoflows more than an order of magnitude larger than present day flood peaks are shown to be characteristic of rivers in this region at particular times within the pleistocene these events the most recent of which were during heinrich events 2 and 1 at 25 and 17 ka were evidently caused by the combined effects of glacial outwash rainfall snowmelt and melting of permafrost in some proportion they released such large volumes of water that the thermohaline circulation of the atlantic ocean and thus the climate may well have been affected these large magnitude palaeoflows are thus a significant aspect of the pleistocene earth system that has hitherto gone unquantified

middle pleistocene interglacial deposits at barling essex england evidence for a longer chronology for the thames terrace sequence results are presented from a multidisciplinary study of fossiliferous interglacial deposits on the northern side of the thames estuary these fill a channel cut into london clay bedrock and overlain by the barling gravel a thames medway deposit equivalent to the lynch hill and corbets tey gravels of the middle and lower thames respectively the channel sediments yielded diverse molluscan and ostracod assemblages both implying fully interglacial conditions and a slight brackish influence pollen analysis has shown that the deposits accumulated during the early part of an interglacial plant macrofossils particularly the abundance of trapa natans reinforce the interglacial character of the palaeontological evidence a beetle fauna which includes four taxa unknown in britain at present has allowed quantification of palaeotemperature using the mutual climatic range method tmax 17 to 26 c tmin 11 to 13 c a few vertebrate remains have been recovered from the interglacial deposits but a much larger fauna as well as palaeolithic artefacts is known from the overlying barling gravel the age of the interglacial deposits is inferential the geological context suggests a late middle pleistocene interglacial part of the post diversion thames system and therefore clearly post anglian this conclusion is supported by amino acid ratios from the shells of freshwater molluscs the correlation of the overlying barling gravel with the lynch hill corbets tey aggradation of the thames valley constrains the age of the barling interglacial to marine oxygen isotope stages 11 or 9 the presence of corbicula fluminalis and pisidium clessini confirms a pre ipswichian marine oxygen isotope substage 5e age and their occurrence in the early part of the interglacial cycle at barling precludes correlation with marine oxygen isotope stage 11 as these taxa occur only later in that interglacial at sites such as swanscombe and clacton thus by process of elimination a marine oxygen isotope stage 9 age would appear probable

3 d numerical simulations of earthquake ground motion in sedimentary basins testing accuracy through stringent models summary differences between 3 d numerical predictions of earthquake ground motion in the mygdonian basin near thessaloniki greece led us to define four canonical stringent models derived from the complex realistic 3 d model of the mygdonian basin sediments atop an elastic bedrock are modelled in the 1d sharp and 1d smooth models using three homogeneous layers and smooth velocity distribution respectively the 2d sharp and 2d smooth models are extensions of the 1 d models to an asymmetric sedimentary valley in all cases 3 d wavefields include strongly dispersive surface waves in the sediments we compared simulations by the fourier pseudo spectral method fpsm the legendre spectral element method sem and two formulations of the finite difference method fdm s and fdm c up to 4hz the accuracy of individual solutions and level of agreement between solutions vary with type of seismic waves and depend on the smoothness of the velocity model the level of accuracy is high for the body waves in all solutions however it strongly depends on the discrete representation of the material interfaces at which material parameters change discontinuously for the surface waves in the sharp models an improper discrete representation of the interfaces can cause inaccurate numerical modelling of surface waves for all the numerical methods considered except sem with mesh of elements following the interfaces a proper implementation of interfaces requires definition of an effective medium consistent with the interface boundary conditions an orthorhombic effective medium is shown to significantly improve accuracy and preserve the computational efficiency of modelling the conclusions drawn from the analysis of the results of the canonical cases greatly help to explain differences between numerical predictions of ground motion in realistic models of the mygdonian basin we recommend that any numerical method and code that is intended for numerical prediction of earthquake ground motion should be verified through stringent models that would make it possible to test the most important aspects of accuracy

a catastrophic origin for the palaeovalley system of the eastern english channel abstract the partially infilled valley system found in the floor of the eastern english channel is not typical of a normal river system and a catastrophic flood which modified a former fluvial system is invoked the breaching of a permafrost sealed chalk barrier at the site of the present dover strait in late quaternary times permitted the scouring of the exposed channel floor modification of the palaeovalley system and the creation of the hurd deep the flood waters involved in this short lived event were released from a lake developed between an ice front in the central north sea and the northern limb of the weald artois anticlinorium a number of related consequences are described including complexities in the late quaternary successions bordering the north sea and sea floor features in the north sea and western english channel

the holstein interglaciation time stratigraphic position and correlation to stable isotope stratigraphy of deep sea sediments marine molluscan shells from para type and other loclities of the holsteinian interglaciation were dated by thu and the electron spin resonance esr method to more than 350 000 and 370 000 yr b p beyond the limit of thu dating the high age estimate is corroborated by a kar age of 420 000 yr b p determined from volcanic ash near the base of the ariendorf paleosol in the middle rhine valley believed to be a pedostratigraphic equivalent of the holsteinian shells from the herzeele marine unit iii an equivalent of the wacken domnitz warm stage in northern france and subsequent to the holsteinian revealed ages between 300 000 and 350 000 yr b p a correlation of these two warm stages with marine oxygen isotope stages 11 and 9 on the specmap and cartune time scales is suggested from the benthic oxygen isotope record one may infer that no exceptionally high global sea level rise corresponds to the large transgressions of the holstein sea in northern germany therefore a significant proportion of the transgression was probably the result of an unusually large local glacial isostatic depression caused by the extreme buildup of ice during the preceding elster glaciation stage 12 according to the deep sea record it lasted approximately 50 longer than the subsequent cold stage 10 the outstanding soil formation with braunlehm and the well developed thermal optimum of the holsteinian are tentatively related to a phase of minimum sea ice cover in the norwegian greenland sea as deduced from long benthic carbon isotope records from the central atlantic

palaeolithic archaeology and the british quaternary sequence abstract studies within the last two decades culminating in the recent publication of the i g c p project 24 quaternary glaciations in the northern hemisphere sibrava et al 1986 have amplified changed or questioned much of the accepted sequence in britain during the middle and late pleistocene this review takes the chronology of events as now seen and relates it to the evidence for the palaeolithic period prior to that in the reach of radiocarbon dating it would indicate that there was considerable human activity in britain before the hoxnian stage and that acheulian hand axe industries of considerable refinement were present and that these industries occurred before or co existed with non hand axe clactonian industries only the latter can be demonstrated as having been present during the earlier part of the hoxnian interglacial acheulian industries occur in various forms from towards the close of this interglacial and during the long period before the ipswichian stage it is not possible to demonstrate a human presence during the ipswichian interglacial as represented by the type site and artifacts occur very sparsely if at all in sediments attributed to other warm periods or the period between the hoxnian and ipswichian stages levallois technique is not found as a significant element of flint industries until the latter part of this period during the first half of the devensian stage flint industries with distinctive hand axes and levallois flakes occur and can be described as mousterian of acheulian tradition

determining finite difference weights for the acoustic wave equation by a new dispersion relationship preserving method numerical simulation of the acoustic wave equation is widely used to theoretically synthesize seismograms and constitutes the basis of reverse time migration with finite difference methods the discretization of temporal and spatial derivatives in wave equations introduces numerical grid dispersion to reduce the grid dispersion effect we propose to satisfy the dispersion relation for a number of uniformly distributed wavenumber points within a wavenumber range with the upper limit determined by the maximum source frequency the grid spacing and the wave velocity this new dispersion relationship preserving method relatively uniformly reduces the numerical dispersion over a large frequency range dispersion analysis and seismic numerical simulations demonstrate the effectiveness of the proposed method

accelerated uplift resulting from anglian glacioisostatic rebound in the middle thames valley uk evidence from the river terrace record abstract a relatively simple analysis of the terraces of the middle thames valley reveals a complex sequence of responses to late anglian late middle pleistocene drainage disruption a decrease in the amounts of vertical incision separating the later post anglian terraces strongly suggests a major change in the rate of incision in the middle thames area in the post anglian a late anglian and early post anglian incision rate of 1 45 m ka 1 was quickly replaced by incision at a rate of 0 089 m ka 1 in the later post anglian period the lower incision rate of the later post anglian compares favourably with previous estimates of regional uplift two plausible explanations for the enhanced incision in the late anglian and early post anglian are recognized one related to ponding of the river by anglian ice and the other to glacio isostatic rebound in the latter case the mismatch between expected and actual heights of late anglian deposits would suggest glacio isostatic uplift of the order of 22 25 m

incised palaeo channels of the late middle pleistocene thames age origins and implications for fluvial palaeogeography and sea level reconstruction in the southern north sea basin abstract multidisciplinary investigations of the infills of steeply incised buried channels on the coast of essex england provide important insights into late middle pleistocene climate and sea level change and have a direct bearing on the differentiation of mis 11 and mis 9 in terrestrial records new data are presented from rochford and burnham on crouch where remnants of two substantial palaeo channels filled with interglacial sediment can be directly related to the terrace stratigraphy of the thames the sediments in both channels accumulated in an estuarine environment early in an interglacial when mixed oak forest was becoming established lithological evidence suggests that the interglacial beds post date the brackish water infill of an older palaeo channel ascribed to the hoxnian and correlated with part of mis 11 and pre date terrace gravels barling gravel ascribed to mis 8 an mis 9 attribution is supported by molluscan biostratigraphy palaeo salinity and amino acid racemization data the relative sea level record in this area thus includes evidence for two major marine transgressions during mis 11 and mis 9 with local maxima of 10 m o d both are associated with sediments that show hoxnian palynological affinities the wider significance of these findings and of an intermediate phase of pronounced fluvial incision during mis 10 is discussed

analysis of river lateral channel movement using quantitative geomorphometric indicators qara sou river iran qara sou river a permanent river in ardabil province iran has recently undergone changes by anthropogenic factors in this research through geomorphometric quantitative methods we have tried to carefully investigate lateral channel movement of qara sou river during the last 12 years so as to provide a comprehensive understanding of these changes and their calculation methods using gis techniques the study area is located 31 km away from qara sou river from the vicinities of qadilou village to the surroundings of la l ganj village the most important geomorphometric indices used in this paper include total bankline change e normalized lateral movement rate n width change dw true migration m and lateral stability index the results of river lateral movement indices show the high level of total bankline change e and low level of true migration m indices this is due to changes in the width change of qara sou river during the last 12 years in fact farming activities and encroachments in bed and riparian of qara sou river have caused channelization of the channel accelerating flooding around the river in addition the results revealed that high mobility in total bankline change e and normalized lateral movement rate n of qara sou river was not related to lateral migration of the river but it had a strong connection with width changes of the channel the calculated true migration rate in the study area for qara sou river was about 0 36 m per year during the last 12 years

climate and related controls on interglacial fluvial sedimentation in lowland britain lewin john gibbard p l 2002 climate and related controls on interglacial fluvial sedimentation in lowland britain sedimentary geology 151 3 4 pp 187 210 rae2008

biostratigraphic and aminostratigraphic constraints on the age of the middle pleistocene glacial succession in north norfolk uk considerable debate surrounds the age of the middle pleistocene glacial succession in east anglia following some recent stratigraphical reinterpretations resolution of the stratigraphy here is important since it not only concerns the glacial history of the region but also has a bearing on our understanding of the earliest human occupation of north western europe the orthodox consensus that all the tills were emplaced during the anglian marine isotope stage mis 12 has recently been challenged by a view assigning each major till to a different glacial stage before during and after mis 12 between trimingham and sidestrand on the north norfolk coast datable organic sediments occur immediately below and above the glacial succession the oldest glacial deposit happisburgh till directly overlies the sidestrand unio bed here defined as the sidestrand hall member of the cromer forest bed formation dating of these sediments therefore has a bearing on the maximum age of the glacial sequence this paper reviews the palaeobotany and describes the faunal assemblages recovered from the sidestrand unio bed which accumulated in a fluvial environment in a fully temperate climate with regional deciduous woodland there are indications from the ostracods for weakly brackish conditions significant differences are apparent between the sidestrand assemblages and those from west runton the type site of the cromerian stage these differences do not result from contrasting facies or taphonomy but reflect warmer palaeotemperatures at sidestrand and a much younger age this conclusion is suggested by the higher proportion of thermophiles at sidestrand and the occurrence of a water vole with unrooted molars arvicola rather than its ancestor mimomyssavini with rooted molars amino acid racemisation data also indicate that sidestrand is significantly younger than west runton these data further highlight the stratigraphical complexity of the cromerian complex and support the conventional view that the happisburgh till was emplaced during the anglian rather than the recently advanced view that it dates from mis 16 moreover new evidence from the trimingham lake bed sidestrand cliff formation above the youngest glacial outwash sediments briton s lane formation indicates that they also accumulated during a middle pleistocene interglacial probably mis 11 all of this evidence is consistent with a short chronology placing the glacial deposits within mis 12 rather than invoking multiple episodes of glaciation envisaged in the new glacial stratigraphy during mis 16 12 10 and 6 copyright 2009 john wiley sons ltd

pre weichselian quaternary glaciations of the british isles the netherlands norway and adjacent marine areas south of 68 n implications for long term ice sheet development in northern europe within this paper we review the pre weichselian glacial history of northern europe focussing on evidence from the british isles netherlands norway and adjacent marine areas that record the activity of the british bis and scandinavian sis ice sheets the objective of the paper is to examine the long term evolution of the two ice sheets in order to determine their level of synchronicity and their relationship to the plio pleistocene record of northern hemisphere glaciation geological evidence demonstrates striking long term similarities between the behaviour of the bis and sis with a step wise intensification in the glacial signal 1 first ice rafted debris ird input onto the continental margin at ca 2 7 2 6 ma and restricted glaciation prior to ca 1 1 ma 2 initiation of more lowland style glaciation from 1 1 ma 3 repeated shelf edge glaciations from 0 45 ma these steps coincide with a major intensification of the northern hemisphere climate signal at the beginning of the quaternary and the mid pleistocene transition temporal and spatial variabilities in the behaviour of different sectors of the bis and sis appear to reflect regional scale geographic latitude elevation climatic moisture temperature and glaciological deformable beds controls that modulate the build up of ice volume in the main ice accumulation areas relative to global climate forcing and its subsequent lateral expansion 2010 nerc

the margin of a middle pleistocene ice advance at tottenhill norfolk england exposures 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

differentiation of mis 9 and mis 11 in the continental record vegetational faunal aminostratigraphic and sea level evidence from coastal sites in essex uk multidisciplinary investigations of the vegetational faunal and sea level history inferred from the infills of buried channels on the coast of eastern essex have a direct bearing on the differentiation of mis 11 and mis 9 in continental records new data are presented from cudmore grove an important site on mersea island that can be linked to the terrace sequence of the river thames the vegetational history has been reconstructed from a pollen sequence covering much of the interglacial represented the temperate nature of the climate is apparent from a range of fossil groups including plant remains vertebrates especially the rich herpetofauna molluscs and beetles which all have strong thermophilous components the beetle data have been used to derive a mutual climatic range reconstruction suggesting that mean july temperatures were about 2 c warmer than modern values for southeast england whereas mean january temperatures may have been slightly colder the sea level history has been reconstructed from the molluscs ostracods and especially the diatoms which indicate that the marine transgression occurred considerably earlier in the interglacial cycle than at the neighbouring hoxnian site at clacton there are a number of palynological similarities between the sequence at cudmore grove and clacton especially the presence of abies and the occurrence of azolla filiculoides megaspores moreover both sites have yielded palaeolithic archaeology indeed the latter is the type site of the clactonian flake and core industry however the sites can be differentiated on the basis of mammalian biostratigraphy new aminostratigraphic data as well as the differences in the sea level history the combined evidence suggests that the infill of the channel at cudmore grove accumulated during mis 9 whereas the deposits at clacton formed during mis 11 the infill of a much later channel yielding non marine molluscs and vertebrates including hippopotamus appears to have formed during the ipswichian mis 5e this evidence is compared with other important sites of late middle pleistocene age in britain and elsewhere on the continent and the importance of a multidisciplinary approach is stressed

a chronological framework for the british quaternary based on bithynia opercula the british quaternary spanning roughly the past 2 6 million years is unmatched for the biodiversity and abundance of its fossil localities and its record of climatic contrasts however with all but the most recent deposits beyond radiocarbon range and with no readily datable volcanic rocks it has been difficult to get accurate dates for many british pleistocene deposits penkman et al have developed new analytical methods based on the intra crystalline proteins of stable biominerals in the opercula shell closure of the freshwater gastropod bithynia common in quaternary deposits they obtain confident assignments for various strata to global marine isotope stages securely placing britain s rich record of faunal and archaeological change into a broader context marine and ice core records show that the earth has experienced a succession of glacials and interglacials during the quaternary last 2 6 million years although it is often difficult to correlate fragmentary terrestrial records with specific cycles aminostratigraphy is a method potentially able to link terrestrial sequences to the marine isotope stages mis of the deep sea record1 2 we have used new methods of extraction and analysis of amino acids preserved within the calcitic opercula of the freshwater gastropod bithynia to provide the most comprehensive data set for the british pleistocene based on a single dating technique a total of 470 opercula from 74 sites spanning the entire quaternary are ranked in order of relative age based on the extent of protein degradation using aspartic acid asparagine asx glutamic acid glutamine glx serine ser alanine ala and valine val this new aminostratigraphy is consistent with the stratigraphical relationships of stratotypes sites with independent geochronology biostratigraphy and terrace stratigraphy3 4 5 6 the method corroborates the existence of four interglacial stages between the anglian mis 12 and the holocene in the terrestrial succession it establishes human occupation of britain in most interglacial stages after mis 15 but supports the notion of human absence during the last interglacial mis 5e 7 suspicions that the treeless optimum of the upton warren interstadial at isleworth pre dates mis 3 are confirmed this new aminostratigraphy provides a robust framework against which climatic biostratigraphical and archaeological models can be tested

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

late middle pleistocene pollen biostratigraphy in britain pitfalls and possibilities in the separation of interglacial sequences abstract recent work on late middle pleistocene interglacials in britain has shown that sites formerly attributed to the hoxnian include representatives of two different interglacials which have been correlated with oxygen isotope stages 11 and 9 palynology has long been used to characterize and correlate temperate sequences in britain however the quality of the palynological record is considerably better in lacustrine sequences than in fluvial and estuarine sediments the former have longer sequences and higher resolution whereas more rapid deposition in fluvial and estuarine environments leads to sequences representing only fragments of interglacials the latter type of site however is more likely to have multi proxy evidence and to be readily fitted into a stratigraphical framework the problems are reviewed in the light of new work in the west midlands where some of the most complete british late middle pleistocene lacustrine sequences are preserved lacustrine sites here have a strong affinity with hoxnian sites of the type area in east anglia a critical question remains as to whether the two interglacials conflated under the term hoxnian can be separately characterized in terms of their pollen assemblages details of lacustrine sequences in the north birmingham area and east anglia show remarkable similarities perhaps suggesting that the same interglacial is recorded in all of them as many of these sites are thought to be kettle holes or glacially overdeepened basins the first interglacial following the anglian glaciation is the most likely to be represented suggesting that all the lacustrine hoxnian sites might date from ois 11 in areas not glaciated since the anglian interglacials after ois 11 are likely to be represented only by fragmentary non lacustrine sequences difficult if not impossible to separate using palynology alone

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

major river systems of central and southern britain during the early and middle pleistocene central and southern britain was drained by two main river systems during the larger part of the early and middle pleistocene the thames and bytham rivers evidence for these rivers and their quaternary history is represented by their sediments the kesgrave and bytham sands and gravels respectively the geomorphological position of the sediments biostratigraphy and amino acid geochronology evidence from the earlier parts of the early pleistocene tiglian c4b and earlier indicates low energy river systems and marine conditions over much of east anglia for most of the early pleistocene tiglian c4c to the cromerian complex the ancestral thames was the main river with at its maximal extent a catchment that extended into wales and across east anglia and what is now the north sea to join the ancestral rhine during this period glaciers in the uplands of wales and periglacial mass movement elsewhere supplied material to the catchment and it was at this time that the bulk of the sorted quaternary ssediments of lowland britain were deposited the bytham river system has no successor because the landscape now in existence has been fundamentally altered by glacial erosion this catchment drained most of midland england and joined the thames in central east anglia initially the bytham river was a tributary of the thames but over time it extended its catchment and at the beginning of the cromerian complex it became the main river of southern britain with the anglian glaciation 01 stage 121 the bytham river was destroyed and the thames was diverted to its present route through london

flow in the lower continental crust as a mechanism for the quaternary uplift of south east england constraints from the thames terrace record abstract the sequence of terraces of the river thames in south east england has been shown to date from the early pleistocene onwards and to provide an indication of the quaternary uplift history of the region using this evidence supplemented by altitudes of pliocene and early pleistocene marine sediments we have determined the pliocene and quaternary uplift histories of five representative localities clacton colchester and dartford for the lower thames and cookham and reading for the middle thames these uplift histories have been modelled using a physics based technique which calculates the isostatic response involving flow in the lower continental crust induced by cyclic loading at the earth s surface our results suggest that the late pliocene and early pleistocene part of the uplift history of our study region was initiated following the deterioration in climate starting at 3 1 ma which marked the start of upland glaciation elsewhere in europe the later increase in uplift rates in the middle pleistocene followed the start of intensified cyclic loading by very large continental ice sheets during and after oxygen isotope stage ois 22 at 0 87 ma dartford cookham and reading in the interior of south east england are all shown to have begun to uplift quite rapidly at rates of up to 0 1 mm a 1 following the start of forcing at 3 1 ma they have since uplifted by distances which increase gradually westward from 200 to 250 m of which a uniform 70 m has occurred since ois 22 at 0 87 ma in contrast clacton and colchester near the present north sea coastline experienced slow subsidence until the late early pleistocene but have nonetheless uplifted since ois 22 by similar distances to the other sites

the late middle pleistocene biostratigraphy of the thames valley england new data from eastern essex abstract coring investigations at east hyde near tillingham essex have revealed a sequence of fluvial and estuarine deposits infilling a channel incised into london clay these deposits are of thames origin and were deposited after the river s diversion into eastern essex late in the anglian stage the detailed litho and biostratigraphy of the deposits are described ostracod and molluscan data confirm that the lower parts of the sequence accumulated in a quiet fluvial environment rich in aquatic vegetation the upper sediments accumulated in an inner estuarine environment under conditions of rising sea level pollen assemblages from both units show strong biostratigraphical affinities with the hoxnian stage particularly with the hoxnian late temperate substage ho iii the sequence has also yielded a rare assemblage of freshwater fluvial molluscs the rhenish fauna which migrated into the thames following a link with the rivers of continental europe the occurrence of theodoxus serratiliniformis is exceptionally rare representing only the second record of the species in the entire british pleistocene the molluscan assemblages show striking similarities with those at clacton in northeast essex and swanscombe kent and provide strong evidence that the three sites are contemporaneous and were connected in the same fluvial system the timing of the migration of the rhenish fauna into britain and the implications for sea level reconstruction in the southern north sea region are discussed the episode of major climatic warmth and high eustatic sea level represented at east hyde is correlated with stage 11 of the deep sea record

middle pleistocene interglacial thames medway deposits at clacton on sea england reconsideration of the biostratigraphical and environmental context of the type clactonian palaeolithic industry abstract in 1987 an archaeological investigation was undertaken during redevelopment of the erstwhile butlin s holiday camp at clacton on sea on the grounds that the middle pleistocene clacton channel deposits containing the type clactonian palaeolithic industry were known to extend beneath the site excavations for a storm drain allowed sampling at points along a longitudinal traverse of the main clacton channel analysis of these samples has provided new palaeontological information including data pertaining to the rise in relative sea level during the interglacial represented systematic studies of molluscs and ostracods the latter undertaken at clacton for the first time have been particularly valuable information from the butlin s site supplements evidence previously gathered from the west cliff section and from other localities at clacton the calcareous clay marl that underlies the clacton golf course extends beneath butlin s where it was found to be part of the freshwater beds not the estuarine beds as hitherto supposed the clacton estuarine beds restricted to the eastern end of the site have their base just below 2 m o d implying that their superposition upon the clacton freshwater beds occurred when relative sea level in this area was close to present ordnance datum correlation of the clacton channel deposits with the interglacial immediately following the anglian elsterian stage appears secure equivalence with oxygen isotope stage 11 of the oceanic sequence is most probable a borehole survey and subsequent excavation revealed a holocene sequence of unlithified tufa and organic sediments beneath part of the site

crustal uplift in southern england evidence from the river terrace records abstract much of the past work on the quaternary rivers of northwest europe has been concerned with river terraces which characterise almost every valley while these terraces are undoubtedly striking features of the landscape the incision achieved by quaternary rivers is equally significant in terms of river behaviour and for an understanding of the factors affecting landform development during the quaternary this paper examines the incision achieved during the quaternary by the thames in both its upper and lower catchments and by the hampshire avon in southern england valley incision rates of ca 0 07 0 10 m ka 1 have been identified although in the lower catchment of the thames these have been enhanced by additional incision in response to glacio isostasy and valley shortening a model is proposed in which regional uplift is recognized as the primary cause of incision by these quaternary rivers possible mechanisms for regional uplift are considered

differentiation of the british late middle pleistocene interglacials the evidence from mammalian biostratigraphy abstract acknowledgement of the climatic complexities of the marine oxygen isotope 18o record has inspired fresh investigations into methods of identifying and separating interglacial deposits on land biostratigraphical analysis of fossil mammalian assemblages particularly those from long fluvial sequences has proved to be a uniquely valuable technique in the differentiation of the various temperate episodes of the late middle pleistocene in britain thereby enabling a sequence of diagnostic mammalian assemblage zones to be established the scheme has provided an important means of correlation between geographically distant localities and between different types of depositional environment using mammalian biostratigraphical information this paper explores the evidence for three post anglian interglacials prior to the last ipswichian interglacial correlated with stages 11 9 and 7 of the oxygen isotope record and presents the case for the recognition of much smaller scale environmental and climatic oscillations within these interglacials possibly corresponding to marine isotopic substages

the fluvial cycle at cold warm cold transitions in lowland regions a refinement of theory abstract a previously established non linear theory of river cyclicity as a response to climate change states that short phases of fluvial instability occur both at the transition from relatively warm temperate to cold periglacial and from relatively cold to warm periods such instability typically starts with vertical erosion successively followed by sedimentary fill of the erosive scar in spite of frequent confirmation of this theory by geomorphological reconstructions a few problems arise first there are fewer incision phases than climatic transitions secondly remnants of erosion at cold warm transitions are scarce in contrast to obvious erosion relics at warm cold transitions furthermore it appears that the incision style is strikingly different at both kinds of climatic transitions similarly the long stable phases are also expressed in terms of different floodplain development in cold and warm periods these arguments require a modification of the general non linear theory at the transition from relatively temperate to colder conditions rivers transformed gradually from a regular low energy single channel course to a periodically high energy multi channel type the latter braided type is characterized by intense lateral movement rather than by deep vertical erosion this results in a well expressed morphology of wide extensive floodplains and terraces in contrast the linear and constrained meandering channels incise with small width depth ratio and build floodplains of limited lateral extent consequences are twofold 1 the spatial limitation of the deeply incised meandering valleys at the beginning of warm periods counts against their recognition 2 relatively strong lateral migration of the braided rivers removes most traces of previous meandering systems which contrasts with the limited lateral activity of confined meandering channels it means that in a warm cold warm alternation generally only one phase of vertical erosion is preserved the one that is caused by the high energy braided river at the start of the cold period

middle pleistocene lacustrine deposits in eastern essex england and their palaeogeographical implications investigations in quarry exposures in the asheldham gravel and related deposits of southeast essex are described section logging mapping and borehole investigations are supported by clast lithological heavy and clay mineralogical determinations the sediments are derived from reworking of local thames basin materials fine sediment being predominantly from the london clay the sequence is shown to represent an aggradation that began as the fluvial infilling of the river medway valley the river thames diverted into this valley by glaciation further west overwhelmed the medway reworking the deposits the valley was subsequently drowned and fine laminated lake sediment was initially deposited this was during a period when the valley was drowned by the glacial lake ponded in the southern north sea basin by the anglian elsterian ice sheet progradation by a braid delta complex advanced along the valley and subsequently fluvial deposition returned valley widening and straightening accompanied the delta progradation the deposits were dissected by deep fluvial valleys infilled by hoxnian interglacial sediments the asheldham gravel is therefore placed in the anglian elsterian stage

terrestrial environments during mis 11 evidence from the palaeolithic site at west stow suffolk uk abstract multidisciplinary investigations of the sequence at beeches pit west stow suffolk uk have a direct bearing the age of the hoxnian interglacial and its correlation with the continental holsteinian and with the global marine record at this site glacial deposits till and outwash gravels referable to the anglian lowestoft formation fill a subglacial channel cut in chalk bedrock above these glacial deposits a series of interglacial sediments occurs consisting of limnic tufaceous and colluvial silts lacking pollen but rich in shells ostracods and vertebrates lower palaeolithic flint artefacts of acheulian character have also been recovered including refitting examples charred material is abundant at certain horizons and many of the bones have been burned several discrete areas of burnt sediment are interpreted as hearths the molluscan fauna comprises some 78 taxa and includes species of considerable zoogeographical and biostratigraphical importance the land snail assemblage from the tufa consists of woodland taxa with no modern analogue including species that are either extinct e g zonitoides sepultus or which no longer live in britain e g platyla polita p similis neniatlanta pauli this is also the type locality of retinella lyrodiscus skertchlyi which belongs to a subgenus of zonitid land snail now living only on the canary islands there are indications from this fauna the lyrodiscus biome that the climate was wetter and perhaps warmer than the present day the vertebrate fauna is also noteworthy with species of open habitats such as rabbit oryctolagus cf cuniculus and of closed forest such as squirrel sciurus sp and garden dormouse eliomys quercinus present at different times the occurrence of southern thermophiles such as aesculapian snake zamenis longissimus indicates temperatures warmer than those of eastern england today the upper levels include much material reworked from the interglacial sediments although there is clear faunal evidence for climatic deterioration both the molluscan and vertebrate faunas suggest correlation of the interglacial sediments with the hoxnian uranium series dates from the tufa 455 ka bp tl dates from burnt flints 414 30 ka bp and a range of amino acid racemization data all support correlation of this interglacial with mis 11 however four osl dates from sand beneath the interglacial sequence yield a mean age of 261 31 ka bp far younger than all other age determinations and far younger than implied by the biostratigraphy archaeologically the site is unusual in showing prolonged human occupation within closed deciduous forest and evidence for controlled use of fire in a lower palaeolithic context biostratigraphical correlations with other lower palaeolithic sites support the suggestion that acheulian and clactonian industries both occurred in southern britain during the same substage of the hoxnian although not necessarily at precisely the same time the characteristics of the mis 11 interglacial in britain are discussed in the light of evidence from beeches pit and elsewhere

catastrophic flooding origin of shelf valley systems in the english channel britain became geographically isolated from continental europe when high interglacial seas flooded the shallow english channel and north sea shelf areas but a tenuous link remained the weald artois chalk ridge between southeast england and northwest france just how this isthmus was breached making britain an island has been a matter of conjecture a new bathymetric map of the sea floor may solve the mystery it reveals a large bedrock floored valley containing landforms including grooves and streamlined islands consistent with a megaflood event caused when a rock dam at the dover strait breached draining a large pro glacial lake in the north sea basin a hypothesis for the permanent isolation of britain from mainland europe during interglacial high sea levels has been confirmed gupta et al analysed a new regional bathymetric map of part of the area finding a valley with landforms indicating large scale subaerial erosion by high magnitude water discharges they suggest breaching of a rock dam at the dover strait instigated drainage of a large lake in the north sea basin megaflood events involving sudden discharges of exceptionally large volumes of water are rare but can significantly affect landscape evolution continental scale drainage patterns and climate change1 it has been proposed that a significant flood event eroded a network of large ancient valleys on the floor of the english channel the narrow seaway between england and france2 3 4 this hypothesis has remained untested through lack of direct evidence and alternative non catastrophist ideas have been entertained for valley formation5 6 here we analyse a new regional bathymetric map of part of the english channel derived from high resolution sonar data which shows the morphology of the valley in unprecedented detail we observe a large bedrock floored valley that contains a distinct assemblage of landforms including streamlined islands and longitudinal erosional grooves which are indicative of large scale subaerial erosion by high magnitude water discharges our observations support the megaflood model in which breaching of a rock dam at the dover strait instigated catastrophic drainage of a large pro glacial lake in the southern north sea basin2 we suggest that megaflooding provides an explanation for the permanent isolation of britain from mainland europe during interglacial high sea level stands7 and consequently for patterns of early human colonisation of britain together with the large scale reorganization of palaeodrainage in northwest europe4

age limits on middle pleistocene glacial sediments from osl dating north norfolk uk the lowland region of north norfolk contains some of the best preserved evidence for glacial deposition during the middle pleistocene in northwest europe despite the importance of these deposits there is limited chronological control and it is debated whether they belong to a single glaciation equated to the anglian glaciation marine isotope stage 12 or represent deposition over a number of middle pleistocene cold stages in order to develop an improved chronology for glaciation in this region we obtained 18 samples for optical stimulated luminescence osl dating from glacial outwash facies samples of coarse grained quartz sand were measured using the sar single aliquot regenerative dose protocol the low radioactive isotope concentrations in sediments of this region enable the traditionally accepted age limit of luminescence dating to be extended the form of the dose response curves pre heat plateaux tests and dose recovery experiments also indicate that laboratory doses can be reliably measured in these samples age overestimation due to partial bleaching is thought to be insignificant the osl ages suggest that the glacial sediments studied were deposited during mis 12 rather than in different post mis 12 stages

earthquake ground motion in the mygdonian basin greece the e2vp verification and validation of 3d numerical simulation up to 4 hz n a low seismicity context the use of numerical simulations becomes essential due to the lack of representative earthquakes for empirical approaches the goals of the euroseistest verification and validation project e2vp are to provide 1 a quantitative analysis of accuracy of the current most advanced numerical methods applied to realistic 3d models of sedimentary basins verification and 2 a quantitative comparison of the recorded ground motions with their numerical predictions validation the target is the euroseistest site located within the mygdonian basin greece the site is instrumented with surface and borehole accelerometers and a 3d model of the medium is available the simulations are performed up to 4 hz beyond the 0 7 hz fundamental frequency thus covering a frequency range at which ground motion undergoes significant amplification the discrete representation of material heterogeneities the attenuation model the approximation of the free surface and nonreflecting boundaries are identified as the main sources of differences among the numerical predictions the predictions well reproduce some but not all features of the actual site effect the differences between real and predicted ground motions have multiple origins the accuracy of source parameters location hypocentral depth and focal mechanism the uncertainties in the description of the geological medium damping internal sediment layering structure and shape of the sediment basement interface overall the agreement reached among synthetics up to 4 hz despite the complexity of the basin model with code to code differences much smaller than predictions to observations differences makes it possible to include the numerical simulations in site specific analysis in the 3d linear case and low to intermediate frequency range

geomorphic and sedimentary response of rivers to tectonic deformation a brief review and critique of a tool for recognizing subtle epeirogenic deformation in modern and ancient settings abstract rivers are extremely sensitive to subtle changes in their grade caused by tectonic tilting as such recognition of tectonic tilting effects on rivers and their resultant sediments can be a useful tool for identifying the often cryptic warping associated with incipient and smaller scale epeirogenic deformation in both modern and ancient settings tectonic warping may result in either longitudinal parallel to floodplain orientation or lateral normal to floodplain orientation tilting of alluvial river profiles alluvial rivers may respond to deformation of longitudinal profile by 1 deflection around zones of uplift and into zones of subsidence 2 aggradation in backtilted and degradation in foretilted reaches 3 compensation of slope alteration by shifts in channel pattern 4 increase in frequency of overbank flooding for foretilted and decrease for backtilted reaches and 5 increased bedload grain size in foretilted reaches and decreased bedload grain size in backtilted reaches lateral tilting causes down tilt avulsion of streams where tilt rates are high and steady down tilt migration combing where tilt rates are lower each of the above effects may have profound impacts on lithofacies geometry and distribution that may potentially be preserved in the rock record fluvial sedimentary evidence for past tilting is traditionally based on the assumption that depositional features reminiscent of modern fluvial tectonic effects are evidence for past tectonic effects where it is closely associated with historically active structures or where non tectonic causes cannot be invoked however caution must be exercised when using these effects as criteria for past or current tectonic warping as these effects may be caused by non tectonic factors these non tectonic causes must be eliminated before tectonic interpretations are made

sedimentology palaeontology and archaeology of late middle pleistocene river thames terrace deposits at purfleet essex uk middle pleistocene fluvial deposits of the corbets tey formation at purfleet essex provide evidence of an un named and previously poorly recognized interglacial thought to corrrelate with oxygen isotope stage ois 9 previous attributions of the sediments to the ipswichian last interglacial stage are refuted new investigations have yielded rich molluscan mammalian and ostracod assemblages that indicate fully temperate conditions and the distal influence of marine transgression pollen analyses suggest a previously unrecorded phase of interglacial vegetational development clast composition geomorphological evidence and the occurrence of molluscs that favour large rivers all point to deposition by the thames rather than in a minor tributary as suggested previously three separate palaeolithic industries in stratigraphical superposition are recognized at purfleet these being clactonian acheulean and levallois purfleet is therefore a key locality in the understanding of the early human occupation and exploitation of southern britain as well as for the interpretation and correlation of the terrace sequence in the thames valley

uplift driven valley incision and climate controlled river terrace development in the thames valley uk abstract the sequence of terraces of the river thames in southeast england has previously been shown to span the period from the earliest pleistocene to the present this terrace sequence contains biostratigraphical and sedimentary evidence that testifies to the high amplitude climatic changes of the quaternary large scale fluvial incision resulting in basin wide terrace formation appears to have been concentrated at the warming limbs of the major climatic glacial interglacial cycles when sediment supply was greatly reduced this incision and subsequent valley floor widening created the accommodation space for the later aggradation of the terrace sediments during the following warm cold transitions and during the cold stages when high sediment supply conditions prevailed although the timing of terrace aggradation may be controlled by climate change the progressive valley incision recorded by terrace staircases cannot easily be explained in terms of quaternary climatic change alone and recently developed models suggest that long term incision by the thames has been driven by uplift this paper presents an overview of the available terrace data and tabulates incision amounts and rates between key stratigraphic horizons superimposed upon these broad changes revealed by the complex internal sedimentary architecture of many terrace sediments are the geomorphological system responses to both higher frequency climate driven changes and more localized intrinsic fluvial system adjustments

fluvial deposition on periodically emergent shelves in the quaternary example records from the shelf around britain abstract this paper explores the record of fluvial sedimentation on continental shelves during the quaternary in areas that are shallow seas in the present day during episodes of higher global ice volume than the present which account for a large proportion of quaternary time large parts of the shelf were dry land drained by rivers the latter included extensions of still existing rivers as well as complete systems that are now lost beneath holocene interglacial seas in areas where extensive epi continental seas have formed during interglacials there is considerable potential for large areas of submerged fluvial sediments to survive on the shelf providing evidence of former river courses and for the evolution of these rivers during the late cenozoic examples of now submerged fluvial systems from the shelf to the south and east of britain are examined submerged terraces of the extended river thames have been mapped beneath the southern north sea in the area offshore from the thames estuary further offshore however all evidence of former sub aerial drainage during the last glacial has been removed by erosion and it is uncertain whether the thames and rhine which would have joined in this area flowed northwards to the north sea or southwards to the english channel although the latter is regarded as more likely the rhine thames is just one example of the very large system that would have existed only during low stands their concentrated freshwater output having a potentially significant effect on ocean systems

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

thermoluminescence dating of the holsteinian marine formation of herzeele northern france thermoluminescence dating of potassium feldspar coarse grains from the fossiliferous holsteinian marine formation of herzeele at the southern limit of the north sea basin yields a minimum age of 228 30 ka a tentative correction for the long term fading of the tl signal in potassium feldspar is proposed assuming a lifetime of 711 ka this correction would yield a preliminary age estimate of 271 36 ka these results support a minimum oxygen isotope stage 7 age but do not preclude at this stage of our research a possible correlation with late oxygen isotope stage 9 these results are in agreement within the error of the method with independent absolute dates u th and esr obtained on in situ marine shells which range from 225 ka to 348 ka this study provides evidence of the reliability of tl age estimates on potassium feldspar coarse grains from shallow marine sediments older than the last interglacial

the chronology palaeogeography and archaeological significance of the marine quaternary record of the west sussex coastal plain southern england u k abstract the quaternary sediments of the west sussex coastal plain have produced a wide range of floral faunal and archaeological remains these sediments consist of marine sands and gravels exhibiting transgressive and regressive trends which occur from present day sea level to c 43 0 m o d and are overlain by terrestrial silts and cold climate periglacial sediments at the present day coastline channel fill deposits occur below modern beach levels new field observations coupled with a re investigation of old sites and literature suggest that five discrete high stands of sea level may be preserved in the area of the west sussex coastal plain age estimates for these deposits suggest that they span large parts of the middle and upper pleistocene oxygen isotope stages 13 to 5 conformable relationships between many of the marine and terrestrial sediments suggest that the potential exists within the area to correlate the marine and terrestrial quaternary stratigraphic records in addition sediments associated with two of these high sea level stands are associated with extensive buried landsurfaces covering large areas of the coastal plain at some locations these intact landsurfaces are associated with evidence for human activity and represent stratigraphic and cultural resources of international importance