self weight consolidation of soft soils an experimental and theoretical study soil is laid down by sedimentation through water passing through the phases of a fluid supported suspension through a loose structure to a soft soil the stiffness of which then gradually increases under additional load consolidation is caused by the self weight of the soil and while the sediment is soft is accompanied by large strains to predict magnitudes and rates of movement the physical processes must be understood and used as the basis of a theoretical model this paper describes laboratory experiments on the development and consolidation of a soft soil in settling columns with measurement of density using an accurate non destructive x ray technique total stress pore pressure and settlement the results are compared with an earlier theoretical model modifications made to the model in the light of observed experimental features allow it to be used to predict the laboratory consolidation le sol est depose par sedimentation a travers l eau il a d abord la forme d une suspension soutenue

a middle pleistocene shallow marine interglacial sequence inner silver pit southern north sea pollen and dinoflagellate cyst stratigraphy and sea level history abstract the sand hole formation is a pleistocene seismic stratigraphic unit of restricted distribution in the inner silver pit southern north sea pollen and dinoflagellate cyst analyses of this formation penetrated by british geological survey borehole 81 52a and three juxtaposed vibrocores enables division of the formation into two sequences of contrasting palaeoclimatic affinity the lower sequence contains poorly preserved pollen assemblages of low concentration dominated by residual reworked elements and is coincident with cold shallow marine dinoflagellate cyst and foraminiferal assemblages this sequence overlies till and glacimarine sediments of the anglian elsterian swarte bank formation and is also interpreted as late anglian elsterian in age the upper sequence contains well preserved high concentration pollen spectra recording the latter half of an interglacial stage with hoxnian affinities the strong terrigenous signal preserved in this sequence suggests a subtidal depositional setting within a region of freshwater influence correlation of the vibrocores with the longer record preserved in borehole 81 52a indicates that interglacial sedimentation rates increase southwards towards a suggested terrigenous source in the wash area the first half of the interglacial cycle is missing indicating that a hiatus is present between the two sequences preserved within the sand hole formation but the termination of the interglacial is clearly preserved the spatial and temporal distribution of the sediments and bounding unconformities in the region are consistent in recording the transgressive ravinement surface highstand systems tract and subsequent regression within an interglacial eustatic cycle the character age and elevation of the preserved facies is typical of a glacio isostatically controlled emergence cycle and lends support to the notion that this temperate stage oxygen isotope stage 9 immediately followed extensive glaciation during the late anglian elsterian

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

new evidence for complex climate change in mis 11 from hoxne suffolk uk the climatic signal of marine isotope stage mis 11 is well documented in marine and ice sheet isotopic records and is known to comprise at least two major warm episodes with an intervening cool phase terrestrial records of mis 11 though of high resolution are often fragmentary and their chronology is poorly constrained however some notable exceptions include sequences from the maar lakes in france and tenaghi philippon in greece in the uk the hoxnian interglacial has been considered to correlate with mis 11 new investigations at hoxne suffolk provide an opportunity to re evaluate the terrestrial record of mis 11 at hoxne the type hoxnian interglacial sediments are overlain by a post hoxnian cold temperate sequence the interglacial sediments and the later temperate phase are separated by the so called arctic bed from which cold climate macroscopic plant and beetle remains have been recovered the later temperate phase was deposited during an episode of boreal woodland and is associated with the artefacts a diverse vertebrate fauna and molluscs new amino acid geochronological data and biostratigraphical considerations suggest that the post hoxnian sequence correlates with late substages of mis 11 the paper further investigates the correlation of the sequence at hoxne with the palynological sequences found elsewhere in europe and adjacent offshore areas

marine isotope stage 11 palaeoclimates palaeoenvironments and its role as an analogue for the current interglacial abstract interglacials of the quaternary period are currently the focus of a great deal of attention within the scientific community this is primarily because they play a vital role in distinguishing between natural and human climate change in the current interglacial and in understanding how the holocene would evolve in the absence of anthropogenic greenhouse warming in this respect marine isotope stage 11 mis 11 ca 410 000 yr bp is one of the key interglacial stages of the past 450 000 yr the pattern of insolation variability that occurs during mis 11 matches that which occurs in the holocene more closely than in any other warm stage of the past half a million years in addition there is now an extensive range of evidence for mis 11 palaeoclimates and palaeoenvironments from marine ice core lacustrine and terrestrial sequences the aim of this paper is to provide a comprehensive review of the current state of our understanding of mis 11 this is the first paper to provide a detailed review of mis 11 that incorporates the wide range of marine ice core long lacustrine and terrestrial records that have been generated over the last ten years since the last major overview crucially it is the first review of mis 11 that incorporates a detailed synthesis of the high resolution terrestrial sequences of western and central europe this paper therefore provides a holistic integration of a diverse range of proxies and archives to provide a detailed understanding of the expression of mis 11 in the earth system in particular the review focuses on 1 the climatic background of mis 11 2 the robustness of the identification of mis 11 in a diverse range of sequences 3 the climatic structure of mis 11 4 the magnitude of warmth that occurred in this warm stage 5 mis 11 sea level magnitude and variability 6 the duration of mis 11 7 evidence for abrupt climatic events within the interglacial of mis 11 and 8 precipitation patterns and trends during this interglacial the paper concludes by considering how useful mis 11 is as an analogue for holocene climates and compares it with other proposed analogues such as mis 19 with particular reference to the early anthropogenic hypothesis

timing of massive fleuve manche discharges over the last 350 kyr insights into the european ice sheet oscillations and the european drainage network from mis 10 to 2 continuous high resolution mass accumulation rates mar and x ray fluorescence xrf measurements from marine sediment records in the bay of biscay ne atlantic have allowed the determination of the timing and the amplitude of the fleuve manche channel river discharges during glacial stages mis 10 mis 8 mis 6 and mis 4 2 these results have yielded detailed insight into the middle and late pleistocene glaciations in europe and the drainage network of the western and central european rivers over the last 350 kyr this study provides clear evidence that the fleuve manche connected the southern north sea basin with the bay of biscay during each glacial period and reveals that fleuve manche activity during the glaciations mis 10 and mis 8 was significantly less than during mis 6 and mis 2 we correlate the significant fleuve manche activity detected during mis 6 and mis 2 with the extensive saalian drenthe substage and the weichselian glaciations respectively confirming that the major elsterian glaciation precedes the glacial mis 10 in detail massive fleuve manche discharges occurred at ca 155 ka mid mis 6 and during termination i while no significant discharges are found during termination ii it is assumed that a substantial retreat of the european ice sheet at ca 155 kyr followed by the formation of ice free conditions between the british isles and scandinavia until termination ii allowed meltwater to flow northwards through the north sea basin during the second part of the mis 6 we assume that this glacial pattern corresponds to the warthe substage glacial maximum therefore indicating that the data presented here equates to the drenthe and the warthe glacial advances at ca 175 160 ka and ca 150 140 ka respectively finally the correlation of our records with odp site 980 reveals that massive fleuve manche discharges related to partial or complete melting of the european ice masses were synchronous with strong decreases in both the rate of deep water formation and the strength of the atlantic thermohaline circulation fleuve manche discharges over the last 350 kyr probably participated with other meltwater sources in the collapse of the thermohaline circulation by freshening the northern atlantic surface water

the middle pleistocene fluvial sequence at uichteritz central germany chronological framework paleoenvironmental history and early human presence during mis 11 abstract the site of uichteritz saxony anhalt germany is a quaternary gravel quarry hosting several middle pleistocene fluvial units of the saale river this fluvial archive contains detailed information on 1 the timing of middle pleistocene fluvial aggradation and erosion periods in the region 2 the driving forces for those alternations as well as 3 early human presence indicated by the presence of lower paleolithic stone artefacts here we establish a luminescence based numerical chronology at uichteritz additionally geophysical sedimentological and micromorphological analyses were applied to obtain information on depositional and post depositional processes of the fluvial sequence our results point to several fluvial aggradation periods between ca 420 and 180 ka a first fluvial unit was deposited during the late elsterian period followed by formation of a luvisol during mis 11 and its fluvial reworking at the transition from mis 11 to mis 10 and or during early mis 10 these mis 10 11 deposits with an age of about 400 ka also contain reworked lower paleolithic stone artefacts that document the initial appearance of humans in northwestern central europe during mis 11 after a period of fluvial incision during mis 10 which was accompanied by a change in the course of the saale river several stacked fluvial sequences of the saalian main terrace smt formed between mis 8 and mis 6 mainly during cold climatic periods our age estimates confirm the correlation of the elsterian ice advances with mis 12 and the saalian ice advances with later mis 6

fluvial deposits as an archive of early human activity progress during the 20 years of the fluvial archives group fluvial sedimentary archives are important repositories for lower and middle palaeolithic artefacts throughout the old world especially in europe where the beginning of their study coincided with the realisation that early humans were of great antiquity now that many river terrace sequences can be reliably dated and correlated with the globally valid marine isotope record potentially useful patterns can be recognized in the distribution of the find spots of the artefacts that constitute the large collections that were assembled during the years of manual gravel extraction this paper reviews the advances during the past two decades in knowledge of hominin occupation based on artefact occurrences in fluvial contexts in europe asia and africa as such it is an update of a comparable review in 2007 at the end of igcp project no 449 which had instigated the compilation of fluvial records from around the world during 2000 2004 under the auspices of the fluvial archives group an overarching finding is the confirmation of the well established view that in europe there is a demarcation between handaxe making in the west and flake core industries in the east although on a wider scale that pattern is undermined by the increased numbers of lower palaeolithic bifaces now recognized in east asia it is also apparent that although it seems to have appeared at different places and at different times in the later lower palaeolithic the arrival of levallois technology as a global phenomenon was similarly timed across the area occupied by middle pleistocene hominins at around 0 3 ma

how normal faulting and sedimentation interact to produce listric fault profiles and stratigraphic wedges abstract in a series of scale experiments we generated listric normal faults by extending models composed of colored sand layers deposited at regular time intervals throughout deformation during syntectonic sedimentation progressive bulk extension along a single set of faults caused domino type tilting of fault blocks underlying tilted faults propagated upwards with constant dips into newly sedimented layers hence fault profiles become progressively more listric tilting of the free surface resulted in asymmetrical depressions and in fan shaped deposits stepwise or continuous geometric models of domino tilting and synchronous sedimentation yield the same structural and stratigraphic features as observed in the sand models the continuous geometric model shows that a critical parameter governing fault curvature is the ratio r between rates of bulk strain and sedimentation both types of models reveal that synchronous sedimentation and bulk extension are capable by themselves of generating listric normal faults

pollen analytical biostratigraphy of the last five climatic cycles from a long continental sequence from the velay region massif central france in the volcanic region of velay massif central france lake sediment sequences derived from maar craters situated close to one another ribains praclaux and lac du bouchet have been correlated on the basis of tephrostratigraphical analyses this has enabled the construction of a sequence 2980 pollen spectra that begins during the glaciation preceding the holsteinian and ends in the present this sequence covers the period from 450 ka i e from the end of marine oxygen isotope stage 12 to the present time and includes five climatic cycles the study of a second core from the praclaux site completed the long velay sequence the biostratigraphy of the whole sequence is described in detail and illustrated by a synthetic and simplified pollen diagram thirteen temperate forest episodes interglacials or interstadials and as many cold periods glacials or stadials are defined each temperate episode is characterised by particular forest development and vegetation dynamics and all of them with the exception of the holocene begin and end with a pinus forest the vegetation dynamics observed during the holocene resemble more closely those recorded during the interstadials than during the interglacials copyright 2000 john wiley sons ltd

inverse procedure for calibrating parameters that control land subsidence caused by subsurface fluid withdrawal 1 methods 1 land subsidence prediction depends on a selected theoretical model and the calibration of its parameter values an inverse model is developed that calibrates five parameters of a compacting confined aquifer system k v vertical hydraulic conductivity of the aquitards s skv aquitard nonrecoverable skeletal specific storage s ske aquitard recoverable skeletal specific storage ssk skeletal specific storage of the aquifer and p max 0 initial preconsolidation stress within the aquitards this inverse model combines a procedure for finding an initial set of parameter values and an inverse adjustment procedure initial values are estimated by using a new graphic method for the analysis of field data the follow up inverse procedure is a computer algorithm that combines the newton raphson method with helm s one dimensional finite difference subsidence model compac compac offers two options a constant parameter simulation and a stress dependent parameter simulation the classical least squares criterion is employed as the objective function of this inverse procedure three characteristics of the objective function are considered this inverse model is applied to calculations of an idealized compacting confined aquifer system using helm s model this investigation shows that the final values for the five parameters lead to simulated compaction error of less than 1 this contrasts to the initial error of more than 60 these results indicate that the proposed inverse procedure model can be applied to actual field data

measurement of diagenetic compaction strain from quantitative analysis of fault plane dip we developed a new technique for quantifying the amount of porosity loss during diagenetic transformation of opal a to opal ct the technique is based on 3d seismic data from offshore norway where the widely developed biosiliceous sediments of the brygge formation are deformed by a polygonal fault system evidence is shown from two study areas that the dip of the polygonal fault planes reduces abruptly across the opal a to opal ct diagenetic boundary suggesting that the fault planes were passively rotated into shallower dips due to diagenesis the reduction of fault plane dip was used to quantify the vertical compaction strain due to diagenesis using an independent assessment of the magnitude of the porosity loss we are able to validate the method based on fault plane dips and also to evaluate whether the porosity loss results in an exclusively vertical strain additionally the impact of silica diagenesis on the shear strength of the sediments and fault growth is investigated we present evidence suggesting that deviations from classical mohr coulomb behaviour may be expected during the combined processes of diagenesis and porosity collapse and may indeed be sufficient to promote continued fault growth

volume change during sediment diagenesis and the development of growth faults abstract the stress system induced the weight of a sediment and the pore fluid it contains termed the passive stress system is capable of deforming the sediment this volumetric deformation is examined with respect to the evolution of porosity and permeability during burial the effect of this self deformation on the shape of growth faults and normal faults in extensional terrains is considered

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

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

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

structural stratigraphic models for extensional basins of half graben type abstract the equations describing subsidence in isostatically compensated basins formed by lithospheric stretching can be modified to define a notional depth to decollement which relates subsidence to the stretching factor in much the same way as the depth to a physical sole fault relates subsidence to extension in uncompensated thin skinned basins for a constant density basin fill this notional depth to decollement corresponds to the level of no vertical motion within the lithosphere in general the physical sole to a system of detached normal faults will not lie at the notional depth to decollement and must move vertically during extension this vertical movement must be implicitly corrected for before area bed length balancing is used to determine the depth to a physical sole fault the notional depth to decollement has been calculated numerically for an extensional basin loaded by sediments which follow a north sea shaly sand compaction law and increases with from 5 to 9 km a set of model half grabens has been constructed by combining subsidence curves generated by this shaly sand model with geometric relationships inherent in the rotated planar domino mechanism of upper crustal faulting for comparison a similar set of half grabens was constructed for an uncompensated basin with a sole fault at 7 5 km depth in both cases large fault to fault spacings give rise to large basement relief and consequent footwall uplift and erosion small fault spacings give rise to simple listric growth faults intermediate values generate more complex uplift subsidence histories which are capable of giving rise to such commonly observed features as rounded eroded fault block shoulders local regression followed by onlap or exponentially increasing subsidence at the crest of the fault block

the geometrical evolution of normal fault systems abstract the purpose of this paper is to examine the kinematic behaviour of normal fault systems and see what general conditions govern their geometrical evolution we pay particular attention to seismological and surface data from regions of present day active normal faulting as the instantaneous three dimensional geometry at the time of fault movement is better known in active regions than in areas where the faults are now static most normal faults are concave upward or listric this shape can be produced by geometric constraints either because the faults reactivate curved thrusts or because they must be curved to accommodate rotations another effect which will produce curved faults is the variation of rheology with depth brittle failure at shallow depths produces less fault rotation than does distributed creep in the lower part of the crust an important geometric feature of normal faulting is the uplift of the footwall the amount of such uplift is related not only to the elastic properties of the lithosphere but also to the throw and dip of the fault a striking feature of active normal faults is that they occur in groups in which all the faults dip in the same direction this behaviour arises because the faults cannot intersect if they do one must cease to be active the rotation which such fault systems produce reduces the dip of the faults until a new steeply dipping fault is formed once a new fault cuts pre existing faults the earlier faults become locked and a new set of faults must propagate rapidly across the whole region involved many of these geometric constraints also apply to thrust faulting

on changes in porosity and volume during burial of argillaceous sediments abstract the porosity and hence volume of argillaceous sediments is determined by 1 the magnitude of the effective stress acting within the sediment 2 the previous stress history of the sediment and 3 at shallow depths of burial by features such as the mineralogy and the nature of the depositional environment stress paths and the critical state diagrams for a number of clays are used to investigate the range of porosities possible in argillaceous sediments as the effective stresses increase it is found that all porosity effective stress curves converge at large stresses the change in porosity is strongly dependent on the mean effective stress but largely independent of the deviatoric stress and thus is largely independent of the nature of the stress field acting on the basin compressional extensional etc because of the dependence of porosity on the mean effective stress no simple relationship exists between porosity and depth of burial but in the absence of overpressured pore fluids and assuming the sediment is not overconsolidated it is possible to contour the porosity effective stress diagram in terms of burial depths these data should assist in recalculating stratigraphic thicknesses for basin reconstruction and stratigraphic correlation studies

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

balanced cross section construction from seismic sections in areas of extensional tectonics abstract the application of the technique of balanced section construction initially developed for areas of compressional folding and faulting is reviewed with reference to extensional tectonics a number of examples are discussed where these techniques have been successfully applied in the north sea the interpretation of geoseismic sections is considered to be greatly assisted by careful application of geometrical balance and a consideration of strain even in areas of low crustal extensions the nature of seismic sections however places limitations on the validity of balancing which must be borne in mind with such interpretations and wherever possible the balancing of a geoseismic section should be confirmed by complete depth conversion the rapid testing of the integrity of the geoseismic section by attempting to balance the section at the interpretational phase can eliminate many problems as well as allowing the fullest use to be made of the geophysical information

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

revision of the late middle pleistocene stratigraphy and palaeoclimate in poland abstract the aim of this paper is a critical verification of the late middle pleistocene stratigraphy in poland in connection with stratigraphical schemes in the neighbouring countries although a terrestrial record of the middle pleistocene is almost complete in western and southern europe it is full of gaps in central and eastern europe eight key sites in poland and one in belarus were selected to compile environmental and palaeoclimate data for a revised stratigraphy from the termination of mis 12 to mis 6 and the chronology was based on correlation with oxygen isotope stratigraphy and osl ages the late middle pleistocene record starts with the holsteinian lake sequences some of which have been initiated already at the end of mis 12 persisted through mis 11 and terminated in mid mis 10 in the examined sites mis 11 is represented also by deposits of meandering rivers in a temperate climate in contrast there is no evidence for deposition in most of mis 10 and in mis 9 a warmer and presumably wet episode at the beginning of mis 8 lead to local erosion followed by development of small lakes modest ice sheet advance into central europe occurred in the second part of mis 8 as reflected by a till glaciofluvial and glaciolacustrine deposits and presumably also by permafrost and ice wedges in western belarus mis 7 seems to have been generally warm and wet when small lakes and meandering rivers could develop such mild conditions were interrupted with cool and probably drier episodes when braided rivers and limited pedogenesis occurred saalian ice sheet cover of central europe in mis 6 was widespread but even more importantly in this stage periglacial environments were dominant as shown by continuous permafrost intensive aeolian activity and development of ice wedges and involutions braided rivers developed during short wetter intervals

kinematic analysis of a growth fault system in the niger delta from restoration in map view by restoring six stratigraphic markers in map view we have studied the kinematics of a growth fault system involving a major fault its antithetic and a faulted roll over located within the niger delta offshore nigeria restoration yields for each marker the horizontal displacements due to normal faulting and the associated fields of block rotation about vertical axes as expected for a continuous history of growth faulting the amount of extension computed for each stratigraphic marker increases with depth from the fields of finite displacement and block rotation we find that horizontal extension perpendicular to fault traces is associated with a minor amount of bulk left lateral wrenching accommodated by counterclockwise rotation of blocks because the overall deformation differs from a plane strain balancing of cross sections alone would lead to some errors we also computed incremental displacement fields for time intervals between successive stratigraphic markers according to our results during the first stages of growth faulting displacement occurred only on the major faults whereas during later stages larger horizontal displacements were accommodated by numerous small faults probably responsible for the collapse of the roll over

fluid flow pathways in actively deforming sediments the role of pore fluid pressures and volume change abstract the manner in which sediments respond to burial and shear depends largely on the ease with which fluids can escape rapid increase of overburden pressure or shear prevents efficient dewatering and can lead to the generation of excess pore fluid pressures a principal control on the development of overpressure and hence mechanical strength is the sediments permeability observations from modern plate margin accretionary prisms indicate that many faults are associated with both overpressuring and efficient fluid flow that operates in pulses indicative of permeability that is constantly changing we present the results of laboratory experiments exploring how the permeability of sediment retrieved from the barbados accretionary prism and laboratory analogues varies with progressive strain volume changes are linked to permeability fluctuations and the drainage capacity of the material we investigate the importance of the previous stress history imparted on the sediment and quantify the extent to which different deformation structures can acts as conduits for fluid flow under conditions of fluctuating effective stress material that has been initially consolidated and then subjected to reduction of effective stress either by raised fluid pressure or reduction of load inducing overconsolidation dilates during shear zone formation and displays an increase in permeability during strain shear fabrics can localise flow further where the principal mode of deformation is intensely localised and brittle and effective stress approaches zero conversely normally consolidated sediments deform by bulk volume loss without generating discrete fabrics and hence do not enhance flow under reduced effective stress conditions permeability can increase during strain by up to one order of magnitude when deformation results in sudden porosity collapse and pore water expulsion microstructural analysis and permeability testing before during and after shear have helped constrain the principal factors that control the evolution of flow conduits in fine grained low permeability sediments

volume changes during diagenesis abstract the literature pertaining to volume change during diagenesis of clastic sediments is reviewed with respect to the problem of calculating pre and syn compaction thicknesses of sediments for basin reconstruction and stragraphic correlation studies four major mechanisms for volume change are identified mechanical compaction mechanical dissolution chemical dissolution and phase change the first two of these are found to be strongly dependent on the effective stress whilst the latter two show at least a pressure dependence quantification of the relationships between porosity and depth of burial of a sediment seems to be possible only for specific examples of the first of these processes at present this quantification is dealt with in the accompanying related publication

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

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

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

on the hydro mechanical behaviour of remoulded and natural opalinus clay shale the geo energy sector makes use of advanced technologies such as shale gas extraction co2 sequestration and nuclear waste geological disposal that rely on the exploitation of shale formations due to the great depths involved in these applications and the difficulties in retrieving intact samples remoulded shale specimens are often adopted for hydro mechanical testing remoulded and intact shales may substantially differ in their hydro mechanical behaviour due to the particular structure of the natural material which is the result of diagenesis and burial history this paper presents an experimental campaign aimed at i characterizing the role of diagenesis and depth for opalinus clay shale and their impact on the hydro mechanical behaviour of the material and ii understanding how representative the behaviour of the remoulded material is with respect to that of the natural shale in this paper the hydro mechanical behaviour of remoulded and intact specimens from the opalinus clay shale formation is investigated by means of a comprehensive oedometric testing campaign the effects of depth and diagenesis on the material behaviour are analysed by testing intact specimens that come from two different sites and depths of the considered shale formation the results highlight a considerably greater stiffness for the natural opalinus clay with respect to the remoulded specimens when the same vertical effective stress is considered together with a significantly lower porosity for the former which is shown to be the result of diagenetic processes rather than solely mechanical compaction a lower swelling sensitivity is also manifested by the natural material with respect to the remoulded specimens as a result of the formation of bonding on the other hand the diagenetic processes do not seem to have a strong impact on the permeability of the material finally creep effects are reduced when diagenesis occurs while they become more relevant when the material is disturbed or remoulded the obtained results provide significant insight into the roles of depth diagenesis and structural disturbance on the hydro mechanical behaviour of the opalinus clay shale

displacive widening of calcite veins in shale insights into the force of crystallization abstract the geometry microtextures and c axis fabrics of calcite beef veins in the lower jurassic black shales wessex basin uk were characterized to investigate the mechanism responsible for widening following fracture propagation isolated beef veins exhibit planar tapering tips whereas closely spaced veins are characterized by blunt tips vein surfaces are generally smooth and flat however circular ridges appear on vein surfaces that protrude into the host clays where there are solid inclusions below or above the ridges fossils with well preserved morphologies which are separated by subvertical calcite fibers are observed on both the lower and upper surfaces of single veins the shale laminations around beef veins are folded and parallel to vein margins the beef veins commonly contain blocky zones of small equant calcite crystals pyrite and organic matter the fibers exhibit a preferred subvertical c axis orientation whilst crystals in the median zones and blocky zones have random c axis orientations the different crystal sizes morphologies and c axis orientations of the fibers from the blocky crystals suggest that the fibers grew without competition with each other under a nonhydrostatic stress field the displacive widening of calcite beef veins which is evident from vein interactions and deformation of individual fossil skeletons demonstrates that fibers grew incrementally because the crystallization pressure of calcite exceeded the overburden load the force of crystallization is suggested to be responsible for the c axis orientations of calcite fibers whereby crystals with free surfaces normal to c axis orientations grew preferentially the present study suggests that the fibrous widening of calcite veins in shale postdates their initiation and may result from displacive crystallization rather than fluid overpressure