coastal sedimentation in east sussex during the holocene abstract lithostratigraphic and biostratigraphic evidence is presented which suggests that shoreward movement of sediment resulting in the formation of a barrier beach has been the dominant method of accretion in the eastbourne area with longshore drift probably being of only secondary importance a model of coastal evolution for this area has been constructed it appears that distinct phases of accretion have occurred during the holocene as well as a change in the type of sediment transported into this area originally of silty clay then sand and finally of gravel a distinct coarsening upwards in the sedimentary sequence is apparent a loss of sediment since the 18th century has resulted in the erosion of eastbourne s beaches this current episode of erosion may have important implications for land use the study of iron age forest clearance in the combe haven valley of east sussex exemplifies the inter relationship of sedimentation between river and coastal systems at the heart of this relationship is the hypothesis that forest clearance resulted in a substantial release of colluvial material and a concurrent increase in river discharge biostratigraphic evidence supported by radiocarbon dating suggests that the development of the floodplain in the combe haven valley may be directly linked to forest clearance and that the estuary of this river was modified by the increase in discharge due to reduced evapotranspiration and increased run off causing a marine incursion into the lower course of the combe haven valley the results from the two areas discussed suggest cyclic erosion phases associated with a change from one sediment type to another

diatom records and sedimentary responses to sea level change during the last 8000 years in roudsea wood northwest england diatom biostratigraphies are recorded in close stratigraphical intervals from two sites in roudsea wood northwest england these diatom sequences are used to reconstruct sediment surface elevation which is then compared with the mid and late holocene sea level history of the region four new sea level index points are added to the sea level data base for the region and the sea level history is subjectively divided into three time periods for discussions the established model of sediment surface elevation for roudsea wood suggests that the sedimentary responses to the changing sea level have varied through time and appeared as site dependent in roudsea wood valley a site sheltered from the estuary the sedimentary equilibrium was not reached until the end of the first period around 6200 yr bp coincided with the development of a sand barrier across the mouth of the valley in roudsea marsh a site opened to the estuary the sedimentary equilibrium was reached as late as the end of the second period aro

holocene relative sea level changes and coastal vegetation history at kentra moss argyll northwest scotland abstract a late holocene fall in relative sea level in northwest scotland from ca 1 3mm yr 1 to ca 1 0 mm yr 1 is interpreted from lithostratigraphic biostratigraphic chronostratigraphic and numerical analyses of fossil tidal marsh and acidic peat bog communities elevated by isostatic uplift pollen diatom and stratigraphic data from contemporary depositional environments are used to define the indicative range 0 2 m and reference water level mean high water of spring tides or highest astronomical tide of thirteen dated sea level index points no holocene intertidal sediments are recorded above 7 7 m od and all sea level index points are younger than ca 4 kyr b p in parts of kentra moss beyond the limit of holocene intertidal clastic sedimentation raised bog communities were established by at least 8 3 kyr b p these age and altitude parameters differ from those interpolated for the main postglacial shoreline but support a regional model in which isostatic uplift continues at present in the kentra moss area

a geotechnical correction for post depositional sediment compression examples from the forth valley scotland fine grained sediments usually suffer post depositional compression compaction which reduces bed thickness and lowers the elevations of sample positions and marker horizons this reduction has been calculated for two general cases using geotechnical theory and a correction decompaction factor is presented that can be applied to many field situations its use is illustrated by two examples from the clay sediments of the claret formation of the forth valley in the first the correction is calculated for 14c samples from the bothkennar research site near grangemouth and the effect on the reconstruction of water depths is discussed in the second example corrections are obtained for published sea level index points from former shorelines in the forth valley using a method for a postiori estimation of geotechnical data general conclusions are drawn between the size of the correction and the sample position relative to the local depocentre some applications to palaeotidal modelling are also suggested 1998 john wiley sons ltd

a comparison of late holocene and twentieth century sea level trends from the uk and north sea region summary a comparison has been made of secular trends in sea level from the twentieth century and late holocene period determined from tide gauge and geological data respectively for 18 sites from the uk and north sea region in the main the two data sets of trends are well correlated with a small number of possible exceptions although even these are consistent with the general correlation within the errors the tide gauge trends are systematically larger than the long term sea level trends inferred from geological data by approximately 1 0 0 15 mm yr 1 statistical error only which can be interpreted as an estimate of the regional eustatic rate of sea level change for the twentieth century there is no evidence in the region for an acceleration of sea level trends in recent decades and this rate can consequently be inferred to be the current eustatic trend

the stratigraphy depositional environment and dating of a possible tidal surge deposit in the beauly firth area northeast scotland the stratigraphic setting pollen and diatom content and radiocarbon age of a thin minerogenic layer predominantly composed of grey micaceous silty sand are described from two sites located near the head of the beauly firth scotland the layer resulted from a short lived incursion of marine water which flooded subtidal intertidal saltmarsh and reedswamp environments during the mid holocene comparisons with other sites in eastern scotland indicate this incursion may have been caused by a north sea storm surge event of considerable magnitude

the role of relative sea level rise and changing sediment supply on holocene gravel barrier development the example of porlock somerset uk the holocene development of the coastal system at porlock has been driven by variations in the rate of relative sea level rise providing a long term control on longshore sediment supply which in t

holocene crustal movements and sea level changes in great britain crustal downwarping has occurred throughout southern and south eastern england and most of wales for at least the last 4000 years but the type of movement in some areas of southern and eastern england is more complicated than simple linear subsidence highest estimated rates of subsidence since 4000 bp are for the thames estuary and norfolk up to 2 mm yr glacio isostatic processes have resulted in uplift in northern england and mainland scotland the rates of uplift have decreased throughout the holocene estimates for the present range from zero in south lancashire and the tees estuary to over 1 mm yr though less than 2 mm yr in central scotland over 400 sea level index points from the databank of 904 cases collected for igcp project 200 are grouped into 15 main areas and used to investigate the nature of crustal movements in great britain since 8800 bp but there are significant deficiencies in available data which constrain the analysis

late quaternary sea level changes crustal movements and coastal evolution in northumberland uk northumberland lies in the transition between holocene emergence and submerg ence and is thus a critical zone for testing models of isostatic rebound we have collected data from this area to reconstruct relative sea level changes and lateral coastline movements for the last 14000 y these are deposits from tidal marsh back barrier wetland and terrestrial environ ments producing 47 sea level index points from 12 sites there is no unequivocal evidence for late devensian sea levels above present and the reliable sea level index points are restricted between 26 m and 12 5 m relative to present and 9 0 2 5 kyr cal bp analysis of these quantifies differential responses to glacio and hydroisostatic rebound with the northern sites recording a mid holocene sea level maximum ca 2 5 m above present whereas the southern sites show a maximum ca 0 5 m above present these observations show a reasonable fit with the predictions from quantitative models of glacio and hydroisostatic rebound but there is currently no unique solution of earth and ice model parameters that will explain all the sea level observations copyright 2000 john wiley sons ltd

salt marsh aggradation in response to late holocene sea level rise at amherst point nova scotia canada a radiocarbon 14c chronology determined for plant macrofossils in exposed salt marsh sediments at amherst point nova scotia canada shows that the edge of the high salt marsh aggraded 7 5 m since 900 bc equivalent to a mean rate of 25 9 cm 100 yr 1 four phases of rapid aggradation 900 600 bc 100 bc ad 200 ad 700 1100 and ad 1600 to present were interspersed with three phases of slower aggradation 600 100 bc ad 200 700 and tentatively ad 1100 1600 the stepped pattern of marsh aggradation probably resulted from eustatic sea level fluctuations superimposed on background signals of crustal subsidence and tidal range expansion because the rate of high salt marsh aggradation lagged or exceeded the rate of higher high water hhw increase at various times the high salt marsh aggradation trend only approximates the trend of hhw increase the eustatic sea level fluctuations are estimated to have a range of at least 0 8 m

holocene relative sea level changes on the margin of a glacio isostatically uplifted area an example from northern caithness scotland evidence is presented for holocene relative sea level changes on the margin of a glacio isostatically uplifted area the lower wick river valley northern caithness scotland lithostratigraphic b

holocene relative sea level change and crustal movement in the southwestern netherlands abstract sea level data collected by jelgersma 1961 from zeeland in the southwestern netherlands show an anomalously high time depth position with respect to sea level curves established for the rest of the netherlands until now it was not clear whether this was related to differential crustal movements a higher tidal range and or to groundwater influenced peat growth above contemporaneous sea level new radiocarbon dates from the base of the basal peat in zeeland and the adjacent estuarine flood plain of the river scheide in belgium have a considerably lower time depth position than the original data of jelgersma 1961 comparison of the lowest mean sea level msl time depth points from the study area with a reference msl error band for the western netherlands yields a maximum crustal uplift of zeeland relative to the western netherlands of about 0 17 m 1000 yr over the last 8000 yrs cal b p a regional msl envelope for the southwestern netherlands has been constructed by correcting the reference msl error band with this maximum rate of relative uplift the new regional maximum msl error band plots significantly below the zeeland curve and the zeeland data points of jelgersma 1961 1966 but is still higher than msl curves established for the rest of the netherlands the remaining vertical distance of the data of jelgersma to the new zeeland msl error band is attributed to early basal peat growth above contemporaneous msl primarily due to a groundwater gradient effect on the gently inclined pleistocene subsoil the sea level index points with the lowest time depth position all come from locations close to or within the late pleistocene palaeovalley of the river scheide this was probably due to the slope of the regional groundwater table towards the palaeovalley resulting in better drainage conditions on the valley sidewalk peat could only develop under the direct influence of the river water level which was controlled by sea level rise this suggests that comparable palaeovalleys on other coastlines of the north sea or elsewhere offer considerable potential for sea level research if the topography of the compaction free substratum is well known

patterns of isostatic land uplift during the holocene evidence from mainland scotland preliminary results of a lengthy and detailed investigation into middle and late holocene raised shorelines in mainland scotland indicate that three shorelines are sufficiently widely distributed to permit an examination of their extent and of the patterns of uplift which they indicate the shorelines are the storegga tsunami shoreline reached at c 7100 14c years bp at the culmination of the main postglacial transgression and the blairdrummond shoreline reached after the main postglacial shoreline at c 2000 4200 14c years bp at the time of a tsunami believed to have been caused by the second storegga submarine slide the main postglacial shoreline reached at c 5800 6850 14c years bp the main postglacial shoreline previously believed to be the highest holocene raised shoreline in scotland is now believed to be overlapped around the periphery of the uplifted area by the later blairdrummond shoreline isobase models based upon quadratic trend surface analysis of available comparable height dat

evaluating late holocene relative sea level change in the somerset levels southwest britain holocene relative sea level rsl change is investigated at nyland hill somerset levels the lithostratigraphy comprises turfa peat underlying marine clay both onlapping a sloping upper palaeozoic basement the altitude of the peat clay contact ranges from 2 42 to 4 52 m od becoming lower down basement slope yet 14c dates of three samples taken laterally along the contact at different altitudes yield similar ages 3640 3330 3715 3460 3725 3465 cal yrs bp suggesting either very rapid instantaneous rsl rise or sediment compaction biostratigraphic data indicate a gradual transition to marine conditions across the peat clay contact therefore the height difference is interpreted as evidence for significant compaction we consider 4 64 m od the minimum pre compaction altitude indicating maximum observed compaction of 2 22 m the clay surface reclaimed during roman occupation represents an anthropogenically induced negative tendency and is dated chemostratigraphically to 1776 46 using a da

rapid coastal change during the mid to late holocene the record of barrier estuary sedimentation in the romney marsh region southeast england a common problem facing sea level researchers lies in determining the cause of rapid changes observed in coastal stratigraphic sequences such changes are commonly ascribed to the interaction of processes that operate over differing temporal and spatial scales i e rapid local and regional sea level trends and storm magnitude frequency at least some of the difficulty in distinguishing between these processes lies in the often limited stratigraphic database upon which palaeoenvironmental reconstruction is based here we present the results of detailed morphostratigraphic and micropalaeontological investigations from a series of sites located at the interface between the protective gravel barrier complex of dungeness and the barrier estuary sediments of romney marsh england a period of rapid coastal regression is identified between c 4500 and 3000 cal yrs bp during which time the sea level continued to rise but was outpaced by sediment accretion and peat accumulation a subsequent acceleration in th

the last ice sheet in north west scotland reconstruction and implications recent models of the last scottish ice sheet suggest that nunataks remained above the ice surface in areas peripheral to the main centres of accumulation this proposition has been investigated on 140 mountains over an area of 10 000 km2 in nw scotland outside the limits of the later loch lomond readvance in this area there is evidence for a single high level weathering limit that separates glacially eroded terrain from higher areas of in situ frost debris this limit occurs at altitudes ranging from 425 to 450 m in the outer hebrides to 950 m on the mainland and is best developed on lithologies that resisted breakdown after ice sheet downwastage interpretation of this weathering limit as a periglacial trimline cut by the last ice sheet at its maximum thickness is supported by 1 joint depth and schmidt hammer measurements that indicate significantly more advanced rock breakdown above the weathering limit 2 a much greater representation of gibbsite a pre late devensian weathering product in the clay fraction of soils above the limit 3 cosmogenic isotope dating of the exposure ages of rock outcrops above and below the limit 4 the sharpness of the limit at some sites and its regular decline along former ice flowlines and 5 shear stress calculations based on the inferred altitude and gradient of the former ice surface reconstruction of the ice surface based on trimline evidence indicates that the mainland ice shed lay near or slightly east of the present watershed and descended northwards from 900 m to ca 550 m at the north coast independent dispersion centres fed broad ice streams that occupied major troughs on skye an ice dome 800 m deflected the northwestwards movement of mainland ice but the mountains of rum were over ridden by mainland ice up to an altitude of ca 700 m the outer hebrides supported an independent ice cap that was confluent with mainland ice in the minches extrapolation of the trimline evidence indicates that most reconstructions of ice extent are too conservative and suggests that low gradient ice streams extended across the hebridean shelf offshore wider implications of this research are 1 that blockfields and other periglacial weathering covers are not all of the same age or significance depending on the resistance of different lithologies to frost weathering 2 that the contrasting degree of glacial modification in the western and eastern highlands of scotland may reflect a former cover of predominantly warm based ice in the former and predominantly cold based ice in the latter and 3 that the approach and techniques developed in this study have potential application for constraining ice sheet models not only in areas peripheral to the main centres of ice accumulation in britain and ireland but also in other mountain areas where nunataks protruded through warm based late pleistocene ice masses

late devensian and holocene relative sealevel changes at loch nan eala near arisaig northwest scotland pollen diatom radiocarbon and lithostratigraphical data from isolation basins in northwest scotland are used to quantify the reference water tide level indicative range and age of differenty types of isolation and connection contacts tendencies of sea level movement and relative sea level changes from the mid lateglacial interstadial 11 8 ka bp to the late holocene are constructed from these data relative sea level fell continuously from 17 8 m od at 11 8 ka bp to ca 5 2 m od at 10 1 ka bp from an unkown minimum between 10 ka and 9 ka bp relative sea level then rose to 6 3 m od at 8 3 ka bp the maximum holocene sea level occurred within the range 6 6 m od to 9 3 m od between 6 6 ka bp and 4 0 ka bp before falling to present isobase age altitude and quantitative rebound models for northwest scotland are tested using these sealevel data but none of the published models shows close agreement with the new results

magnitude and frequency of extra tropical north atlantic cyclones a chronology from cliff top storm deposits cliff top storm deposits ctsds are known to occur on cliffs at elevations of up to 50 m above sea level at exposed sites on the deep water coasts of the british isles eye witness accounts and time series field mapping of ctsds demonstrate their formation over the historical period and their continued modification during major storms with ctsds burying a range of modern human derived debris older deposits show surface lichen growth and weathering effects that relate to the relative age of ctsds over longer time spans buried sand and peat deposits provide dates on phases of ctsd emplacement and mobilisation and so provide an indication of the frequency and timing of the most severe storms two adjacent sites in shetland provide a combination of 14c dates on peat buried beneath storm deposited boulders 14c dates on marine shells buried inside ctsd boulder ridges and optically stimulated luminescence osl ages on sands intercalated with storm derived boulders although the precision is low this evidence identifies phases of exceptional storm activity spanning approximately 400 550 700 1050 1300 1900 and since 1950 ad by the very nature of cliff top erosion and deposition these records are fragmentary yet the timeline of major storms recorded in the shetland cliffs matches fairly well with the more general record of storminess in the north atlantic derived from the sea salt record in the gisp2 ice core as such ctsds represent an overlooked archive of storm sedimentation with the potential to elucidate local storm chronologies as well as informing debate surrounding the palaeo tempestology and impact of major cyclones and hurricanes

basaltic tephra from monogenetic marcath volcano central nevada abstract monogenetic volcanic eruptions are generally assumed to last to tens of years and produce frequent intermittent explosive activity that creates eruption columns up to 10 km in elevation although this view fits the historically observed eruptions few data have been collected about the range of durations and eruption sizes possible from monogenetic events examining other eruption deposits can help clarify the range of eruption styles and sizes possible from future explosive monogenetic eruptions the 38 ka marcath event at lunar crater volcanic field nevada produced a scoria cone two tephra fall deposits and a lava field we reconstruct the activity that produced the largest tephra fall deposit explosive activity produced an eruption column up to 7 km and a volume of about 0 018 km 3 the marcath tephra forming activity was small compared to other characterized scoria cones post eruptive remobilization of the deposit has occurred especially around the margins through both fluvial and eolian processes and has likely removed at least 0 001 km 3 of fine material from the distal portions of the deposit

the use of bomb spike calibration and high precision ams 14c analyses to date salt marsh sediments deposited during the past three centuries abstract a combination of bomb spike calibration and conventional calibration of ams 14c dating has been used to determine a detailed age depth model for a 1 m sediment section collected from a salt marsh in poole harbour southern england these data were compared with the chronology obtained from 210pb analysis and 137cs age markers we report post bomb values of over 1 46 f14c 146 modern 14c and both the rising and falling limbs of the atmospheric bomb spike are identified five pre bomb samples were analysed using multi target high precision 2 ams analysis and after the replicates were combined the one sigma uncertainty was as low as 9 14c yr on some ages these data and an additional three normal precision pre bomb 14c samples were calibrated using calib 5 0 and the chronology constrained using the prior knowledge of independent age markers obtained from the analysis of pollen and spheroidal carbonaceous particle scps no agreement was found between the 14c bomb spike dates and the crs 210pb chronology modelled for this sequence in addition poor agreement was found between the signal of the 1960s weapons test fallout indicated by the 14c bomb spike dates and the timing suggested by the 137cs data this disagreement is attributed to the influence of the local discharge of 137cs from the former ukaea site at winfrith we use our new chronology to confirm the existence of an acceleration in sedimentation rates in poole harbour during the last 100 yr previously reported for this site by long et al long a j scaife r g edwards r j 1999 pine pollen in intertidal sediments from poole harbour uk implications for late holocene sediment accretion rates and sea level rise quaternary international 55 3 16 and conclude that bomb spike 14c calibration dating may offer a more robust alternative to the use of 210pb chronologies for dating sediment deposition in salt marsh environments in addition we demonstrate how the use of high precision ams analysis has the potential for reducing some of the uncertainties involved in the high resolution dating of recent salt marsh sediments

sedimentary evolution of the north norfolk barrier coastline in the context of holocene sea level change holocene sediments of the north norfolk coast nnc between weybourne and hunstanton have been studied using geophysical sedimentological biofacial and dating techniques new cores and refraction seismic data have defined the topography of the pre holocene surface and show that the nnc sediment prism is underlain by an east west trending quaternary trough probably a palaeo river valley the age of the holocene fill has been dated using radiocarbon and luminescence dates while sedimentation rates were constrained by and compared with modern rates using radionuclide data the holocene sediments are divided into a sandy barrier lithofacies association lfa and a muddy silty peat back barrier lfa the oldest holocene sediments are peats formed on an undulating till surface these peats were forming by 11 10 cal ka bp and continued to form until at least 7 cal ka bp in a number of places as holocene sea level rose marine mudflat and saltmarsh environments began to form between 7 and 6 cal ka bp east of holkham and around 6 cal ka bp or younger west of holkham a marked erosion surface between the barrier and back barrier lfa in the holkham to burnham overy area is imperfectly dated at 3 cal ka bp but suggests the sediment prism has thinned by about 3 km over 6 to c 3cal ka bp this surface probably records the westward progress of laterally migrating tidal channels that caused back barrier sediment erosion along with shoreface processes as sea level rose small scale regressive and transgressive saltmarsh sequences occur at different elevations along strike but cannot be correlated suggesting that the control on saltmarsh and mudflat development is autocyclic rather than allocyclic generally transgressive and regressive events are related to disposition of coastal barriers and these are superimposed on a general facies evolution governed by regional sea level change predictions about how this barrier coastline might respond to increased rates of regional sea level change caused by global warming or climatic events like increased storminess require an understanding of how specific segments of the coastline have responded over millennial time scales this longer term evolution provides the baseline information for decision making and management strategy it is likely that sandy sediment supply is limited on the nnc and this implies that the barriers will continue to move landward probably at increased rates relative to today suggesting that parts of the nnc will become more vulnerable to erosion and flooding

a review of the trends observed in british isles mean sea level data measured by tide gauges summary this report presents an up to date review of the british isles bi mean sea level msl data set obtained from tide gauges and of the long term secular trends in bi msl the data are of mixed quality and not as copious as one would like for scientific analysis given the complexity of long term sea and land level changes around bi coasts nevertheless the small number of very long records can be studied evectively and indicate that twentieth century secular trends in bi msl are consistent with those obtained from nw europe as a whole and with the bottom range of estimates for global average msl change during the past 100 years century timescale low frequency accelerations in msl of the order of 0 4 0 8 mm yr 1 century 1 are obtained from the three longest records which are also similar to estimates from mainland europe sea level indices for the bi are constructed which can provide responsible agencies with a guide to the average state of bi sea level combined ocean tide and storm surge tide surge numerical modelling is demonstrated to be a valuable tool in understanding part of the variability of msl around the bi although modelling of long term changes is limited at present by the lack of adequate meteorological data sets from before 1955 nevertheless it is shown that even if a complete meteorological modelling data set were available it would not be able to account for all of the msl variability finally recommendations are made for the development of tide gauge and global positioning system gps recording in the bi for the purpose of long term msl monitoring in the next century

holocene sea level change and coastal evolution in the humber estuary eastern england an assessment of rapid coastal change new stratigraphic data collected from six sites in the humber estuary establish a record of holocene relative sea level rsl change and enable testing of four possible causes of rapid coastal change sea level rise changes in sedimentation storm surge history and human impact mean high water of spring tides mhwst in the humber rose from c 9 m od at 7500 cal yrs bp to 0 m od by 4000 cal yrs bp at an average long term rate of c 3 9 mm yr 1 after this the rate of rise gradually decreased to c 1 mm yr discrete episodes of rapid rsl rise are not identified although their absence may reflect limited data availability however we do observe two episodes of rapid coastal change in the humber estuary the first occurs between c 3200 and 1900 cal yrs bp as marine conditions expand to their holocene maximum and then contract this pattern of coastal development differs from that in the east anglian fenlands suggesting local processes control sedimentation at one or both of these sites the sec

late devensian and holocene records of relative sea level changes in northwest scotland and their implications for glacio hydro isostatic modelling raised tidal marshes and isolation basins lakes that were once connected to the sea in northwest scotland record changes in relative sea level following deglaciation during the late devensian to the present the kentra to arisaig area which was covered by relatively thick ice c 900 m at the last glacial maximum lgm shows a regression from a marine limit between 36 5 m od and 40 m od at c 15 9 kyr cal bp range 15 6 16 3 kyr cal bp through to an early holocene minimum a range of sites in the same area record a mid holocene maximum indicative of mean sea level c 6 5 m above present the maximum is not a well developed and short duration highstand as predicted by a number of models but is an extended period 8 0 5 0 kyr cal bp with sea level within c 1 m of the maximum sites to the north in kintail show no late devensian record because much of the area lies within the younger dryas ice limit the altitude of the mid holocene maximum in kintail is not well constrained but occurred 7 9 8 1 kyr cal bp further north sites on the applecross peninsula record a late devensian fall in sea level and a holocene maximum for mean sea level no higher than c 3 0 m above present in coigach the furthest north of the new sites and well outside the younger dryas ice limit there is no evidence recorded of late devensian sea levels above present the holocene maximum here was around c 2 5 m above present these observations of sea level change all standardised to change in mean sea level relative to present constrain the glacio hydroisostatic rebound model parameters earth models comprising three mantle layers with lateral viscosity and elastic parameters give a satisfactory description of rebound the parameters h lithosphere thickness 65 km g 6 upper mantle viscosity 4 1020 pa 14c seconds and g lower mantle viscosity 1022 pa 14c seconds give the best overall agreement but discrepancies between observations and predictions remain an increase of 10 in ice thickness north of the great glen compared to the previous optimum ice model provides good agreement for many sites but important discrepancies remain for the northern sites and indicate inadequacies in the model of the british ice sheet several alternative ice models are examined but the various combinations of earth and ice model illustrate the non uniqueness of the solution a combination of more extensive ice limits especially onto the hebridean shelf and west shetland shelf and some changes to ice thicknesses over the mainland should produce a better agreement but the spatial coverage of observations remains a limitation to producing a unique solution the characteristics of the holocene highstand age duration and amplitude at the di erent sites refutes the assumption that globally deglaciation ceased abruptly 7000 yr ago the observations are consistent with an ice model that includes c 3 m of melting over the last 7000 yr 2000 elsevier science ltd all rights reserved

global meltwater discharge and the deglacial sea level record from northwest scotland quantitative models of earth ice sheet ocean interactions predict that periods of rapid eustatic sea level rise indicating enhanced meltwater discharge to the oceans should be manifest in the relative sea level histories from sites within the limits of late devensian ice sheets analysis of a record of relative sea level change for the last 16000 calendar years from northwest scotland constrains the magnitude and timing of two major pulses of meltwater ca 14000 and ca 11300 cal yr bp inferred from coral records the ca 14000 cal yr bp event saw a temporary doubling of the flux of meltwater but existence of the second major event at ca 11300 cal yr bp is not supported by the data from northwest scotland copyright 1999 john wiley sons ltd

holocene tides of the wash u k the influence of water depth and coastline shape changes on the record of sea level change abstract tidal simulations are conducted using a numerical model to investigate the relative influence of water depth and coastline shape changes on the holocene tides of the wash tidal input to this model is obtained by running a nested series of models commencing with a model of the northeast atlantic results of both types of simulations are compared with those of other simulations incorporating all the palaeogeographic information available on both past water depths and coastline shapes around the wash the model employs six harmonic tidal constituents to obtain mean high water of spring tides mhwst altitudes the wash was a depositional embayment during the holocene and results of model simulations are compared with sea level indicators in the stratigraphy which record past mhwst altitudes tidal simulations for water depths reduced by 2 5 and 10 m compared with present sea levels generally give lower tidal amplitudes around the wash than found at present mhwst altitudes simulating the coastline shape for 3000 4000 and 5000 yrs b p utilising present water depths show similar patterns of tidal changes to those obtained from the palaeogeographic simulations however reduced water depth tidal simulations accord more closely with the palaeogeographic simulation results in terms of the magnitude of changes to mhwst altitudes than the palaeocoastline simulations this is due to the fact that the rise in mean sea level during the holocene is far greater than any change in the amplitude of tides in the wash palaeogeographic simulation model results for mhwst agree within experimental errors with sea level curve altitudes reasons for discrepancies include inaccuracies in model parameters or measurement errors in obtaining mhwst altitudes from the stratigraphy overall tidal heights increase with sea level rise towards the present day alterations to coastline shape and non uniform water depth changes for example due to sediment movements or coastal defence schemes must be taken into consideration when assessing changes to the tidal regime for different sea levels in coastal embayments in order to determine both the pattern and magnitude of tidal changes this applies to both past and possible future tidal simulations

holocene sedimentation on the north norfolk barrier coast in relation to relative sea level change fourteen distinct sedimentary environments have been recognised in the surface sediments of the intertidal zone of the north norfolk coast nine of these can be distinguished in borehole samples on the basis of sedimentological and micro palaeontological characteristics they comprise gravel channel sand intertidal sand intertidal silty sand intertidal mud and marsh creek lower salt marsh upper salt marsh dune sand and peat sediment accumulations have been penetrated to a depth of 8 m od and basal peats dated by 14c back to 8410 50 years bp an overall rate of sediment accumulation and subsidence of about 1 m per thousand years is indicated there is considerable persistence of sedimentary environments in the same areas during up building but some erosion and roll over of the coastal barrier system has occurred evidence of positive and negative sea level tendencies are present in the record but the main development of the tract is determined by sediment supply to the beach and marshes positive sea level tendencies occur at c 6610 5970 4630 and 2790 bp negative sea level tendencies occur at 4520 to 4450 and possibly 3470 bp

origin abundance and storage of organic carbon and sulphur in the holocene humber estuary emphasizing human impact on storage changes an organic carbon corg and sulphur s storage inventory for holocene sediments in the humber estuary is established sources of organic matter and their variation over time are identified and with chronological control the importance of estuarine sediments as corg and s stores is demonstrated humber holocene sediments are grouped into seven widespread environmental facies with statistically significant geochemical data sets 1 oak hazel fenwood ohf 2 alder carr ac appearing as peats in core 3 river channel muds or sands rcm s 4 high saltmarsh hsm 5 low saltmarsh lsm 6 intertidal mudflat itmf and 7 a sandy facies s carbon nitrogen and sulphur cns abundances show that these facies have diagnostic geochemical signatures and 13c values for bulk organic matter exhibit a range of average values 28 terrestrial peats 27 hsm and 24 5 itmf reflecting the up core transition from terrestrial peats through saltmarshes to more open marine mudflat environments as regional sea level rose chronology and average sedimentation rates are partly constrained by radiocarbon dates palaeomagnetic techniques helped define discrete sediment packages and discontinuities time gaps although the humber holocene sediment record is not continuous long term sedimentation rates about 1 mm a 1 show that sediment accretion kept pace with regional sea level rise between 6 and 2 cal ka bp this sedimentation rate combined with core evidence to allow a geographic reconstruction of the palaeo humber 3 2cal ka bp is used to calculate storage values for corg and s in the various environments of the palaeo humber comparison of the corg and s sedimentation and storage terms for the palaeo humber with modern values highlights the impacts of reclamation and commercial urban development in the estuary in the last 300 years ohf and ac peats which were the largest corg and s stores in the palaeo estuary are now absent reclaimed while saltmarshes are no longer widespread conservative calculations show a net decrease in corg deposition from about 3 2 105 tonne in the palaeo estuary to no more than 2 5 103 tonne today a 99 reduction in potential corg storage capacity the total modern yearly s deposition is approximately 2 of its value 2ka ago removal of saltmarsh and associated brackish freshwater wetland suggests that suspended sediment and associated corg and s are currently bypassing former holocene storage areas and may be impacting north sea biogeochemical cycling

modeling the contribution of m2 tidal amplification to the holocene rise of mean high water in the gulf of maine and the bay of fundy abstract increase in the m2 principal lunar semi diurnal component of the tidal range is an important contributor to the postglacial rise of the high tide level in the gulf of maine and the bay of fundy in addition to relative sea level rise the increase occurred as the shape of this semi enclosed embayment changed with sea level rise and its natural period approached resonance with the m2 tide a three dimensional tide model 3dens predicts the following m2 tidal ranges averaged for the gulf of maine bay of fundy as a percentage of the present range 54 59 at 7000 yrs b p 73 at 5000 yrs b p 78 at 4000 yrs b p 85 at 3000 yrs b p 94 at 2000 yrs b p and 98 at 1000 yrs b p with a predicted sea level rise of 0 15 0 90 m by the year 2100 m2 tidal range may increase 0 3 1 9

global to local scale parameters determining relative sea level changes and the post glacial isostatic adjustment of great britain abstract observations of relative sea level rsl change in great britain since 16 kyr bp and models of post glacial isostatic adjustment provide constraints on reconstructions of the british and antarctic ice sheets from the last glacial maximum to the present we use the global model from an earlier investigation modified ice 4g vm2 with lithospheric thickness 90 km which gives good rsl fits globally as well as for much of the british data a revised ice model for great britain that fits with recently published observations on ice limits and heights fails to explain all the misfits between rsl observations and predictions much more significant improvements result from models that incorporate a different chronology for the partial deglaciation of antarctica while keeping the total ice melt 17 m the same as in ice 4g vm2 the results suggest antarctic melting of 3 m ice equivalent sea level by 15 kyr bp only 1 m contribution to the 24 m rise of mwp1a with the major melting 12 5 kyr bp and a small amount of melting 1 0 0 3 m between then and 3 or 2 kyr bp these modifications produce rsl predictions for barbados that show the major changes in rate of sea level rise but with an offset up to 1 kyr compared to the observations possible explanations that remain to be investigated further are a delay in the melting of ice from some other region a reduction in the total melt derived from antarctica and a refinement of the 1 kyr temporal resolution assumed in the construction of the theoretical solution

late quaternary sea level changes and crustal movements in eastern england and eastern scotland an assessment of models of coastal evolution abstract the most comprehensive records of late quaternary coastal environmental change in eastern england and eastern scotland are obtained from the intercalated semi terrestrial peats and intertidal silts clays and sands that have accumulated in estuaries and coastal lowlands radiocarbon dated sea level index points from sites in north east england are evaluated with reference to first a conceptual model of coastal sedimentary environments and second a model of pollen assemblages in holocene coastal environments analysis of these new data indicates differential crustal uplift within north east england of ca 0 2 mm yr for the last 4000 to 5000 radiocarbon years this pattern of uplift is consistent with models of holocene crustal deformation in scotland and england the uplift is attributable to the combined effects of ice unloading and water loading

middle and late holocene sea level changes in eastern maine reconstructed from foraminiferal saltmarsh stratigraphy and ams 14c dates on basal peat abstract a relative sea level history is reconstructed for machiasport maine spanning the past 6000 calendar years and combining two different methods the first method establishes the long term 10 3 yr trend of sea level rise by dating the base of the holocene saltmarsh peat overlying a pleistocene substrate the second method uses detailed analyses of the foraminiferal stratigraphy of two saltmarsh peat cores to quantify fluctuations superimposed on the long term trend the indicative meaning of the peat the height at which the peat was deposited relative to mean tide level is calculated by a transfer function based on vertical distributions of modern foraminiferal assemblages the chronology is determined from ams 14 c dates on saltmarsh plant fragments embedded in the peat the combination of the two different approaches produces a high resolution replicable sea level record which takes into account the autocompaction of the peat sequence long term mean rates of sea level rise corrected for changes in tidal range are 0 75 mm yr between 6000 and 1500 cal yr b p and 0 43 mm yr during the past 1500 years the foraminiferal stratigraphy reveals several low amplitude fluctuations during a relatively stable period between 1100 and 400 cal yr b p and a sea level rise of 0 5 m during the past 300 years

flandrian sea level changes in the fenland i the geographical setting and evidence of relative sea level changes the flandrian sediments of the fenland record the infilling of the wash embayment on the east coast of england uk since at least 6500 bp changes in sea level have been a major control on the rate and pattern of sediment accumulation new data are presented from the area which together with published information allow the reconstruction of palaeoenvironments from 6500 to 2500 bp the major environmental changes involved alternations between freshwater fen and intertidal marine sedimentation each episode was characterised by transitional changes as vegetation and sediment zones shifted over large areas marine brackish sediments are found up to 45 km inland of the present coast radiocarbon dated sea level index points with relevant stratigraphic and micropalaeontological data ranging from 6415 bp at 8 17m od to 2595 bp at 1 45m od are described

geological impacts on coastal wetland landscapes some general effects of sediment autocompaction in the holocene of northwest europe a simulation model is described providing general insights into autocompaction effects in stratigraphic sequences formed on coastal mudflats and marshes over uneven basements lithological units and buried landscapes are progressively displaced and distorted the synthetic sequences resembling bedding geometries described from the northwest european holocene autocompaction also promotes local deposition rates that may greatly exceed the rates at which accommodation space is created transgressive silts are associated with especially large deposition rates because of the high compressibility of underlying peats the experimental relationships between apparent rates of sea level rise and bed thickness resemble empirical trends for the holocene the latter are however reinforced by an intrinsic lithology related effect not included in the model

late devensian and holocene shorelines of the british isles and north sea from models of glacio hydro isostatic rebound sea level change around the british isles since the time of the last glacial maximum is largely due to of the crustal rebound from the glacial unloading of northern britain and the concomitant melt water loading of the adjacent seas and atlantic ocean minor but not insignificant contributions also result from the rebound caused by the unloading of the distant ice sheets including fennoscandia and north america observations of sea level change for this period constrain the glacio hydro isostatic rebound model parameters describing the effective lithospheric thickness or rigidity and the effective mantle viscosity as well as certain ice sheet characteristics such as the ice thickness at the time of the last glacial maximum the models permit palaeobathymetry and palaeoshorelines to be predicted for the british isles region including the north sea the resulting evolution of the coastlines exhibits a complex behaviour through time one that is quite different from the usual models in which sea level change is assumed to be a function of time only in part this is because of the delayed response of the mantle to the spatially variable and time dependent ice and water loads and in part because the unloading history of the british ice sheet is different from those of the major global ice sheets thus maximum emergence of the north sea occurred after deglaciation had started and lasted for an extended period from about 15 000 to 12 000 radiocarbon years bp during this relative sea level still stand shoreline features could have formed for example along the western edge of the norwegian trough when access to the firths of eastern scotland would have been via a long and shallow marine inlet shoreline retreat across the north sea became relatively rapid after about 10000 years the model predictions for the irish and celtic seas also suggest a complex behaviour with the formation of a wide land bridge between about 20000 and 13 000 years ago the model also suggests that as long as the scottish ice extended across the northern irish sea until about 14 000 years ago there would have been a large freshwater periglacial lake located further south both the predicted sea level height age relations and the shoreline positions are consistent with a large body of observational evidence but some discrepancies occur particularly in northern scotland and ireland where the ice heights may have been somewhat greater than assumed in the model

sea level changes since the last glacial maximum an appraisal of the ipcc fourth assessment report the ipcc fourth assessment report ar4 stated that global sea level rose by about 120 m between the last glacial maximum lgm and 3 2 ka and did not rise again until the late 19th century a review of relevant literature demonstrates that the rise may have been larger by 10 15 m that the timing of stabilisation is poorly constrained within the last 7 ka bp and that the onset of modern rates of sea level rise is not synchronous and uniform across the globe the lgm lowstand as defined in the ar4 is based on the classic barbados sea level history but the sea level curve from this island may not be an accurate eustatic approximation if glacial isostatic adjustment gia processes were significant as suggested by various authors the barbados sea level curve revealed the existence of meltwater pulse mwp 1a at around 14 000 cal a bp questions about the source and causal mechanism of mwp 1a are still being explored by field scientists and gia modellers these problems have direct relevance for contemporary measurements of ice mass changes because space geodetic measurements rely on information provided by gia models to separate land motion from ice mass changes global patterns of holocene sea level change are controlled by regional sea level variability not only through isostatic and tectonic processes but also through steric effects longer wavelength gravitational changes produced by changing ice ocean mass flux and hemispheric scale perturbations in the earth s rotation eustasy is therefore merely a concept not a measurable quantity constraining the late holocene ice melt contribution to global sea level rise and determining regional sea level rise patterns in the 18th and 19th centuries are important future tasks for sea level scientists these will establish the baseline contributions to 20th and 21st century sea level rise and will help to determine the causes of modern rates of sea level rise constraining historical sea level accelerations and short term ice mass flux will aid models of ice sheet dynamics and help to reduce current uncertainties in future sea level predictions the ar4 shows that regional sea level variability is clearly present in sea level change patterns for the past 50 a and an important challenge for the next ipcc assessment is to incorporate this variability into regional future sea level rise scenarios copyright 2009 john wiley sons ltd

interpretation of holocene sea level tendency and intertidal sedimentation in the tees estuary using sediment luminescence techniques a viability study it is demonstrated that detailed examination of the photo and thermoluminescence pl tl of holocene intertidal sediments can reveal important information regarding their depositional history in the context of sea level tendency and storm surge activity the technique is particularly applicable to thick deposits of relatively uniform composition and is demonstrated with a 1 7 m core of marine to brackish water silty clay taken from cowpen marsh in the tees estuary north east england this sedimentary unit is intercalated with an upper and a lower terrestrial peat bed which have been radiocarbon dated to 5250 45 and 7065 45 14c years bp respectively an investigation of the mineral composition and diatom assemblage of the silty clay facies reveals a marked hiatus in deposition towards the top of the minerogenic unit analysis of the luminescence profiles of the sediment illustrates that below this hiatus sedimentation was slow and continuous with approximately 1 0 m of sediment being deposited in 1800 400 years whilst above sedimentation was rapid with 0 7 m of sediment being deposited in 0 200 years it is shown that variations in the luminescence of the sediments can be interpreted in terms of the onset of a positive sea level tendency period coupled with the occurrence of a low frequency extreme water level event

holocene land and sea level changes in great britain analysis of more than 1200 radiocarbon dated samples that constrain relative sea levels in great britain over the past 16 000 yr provides estimates of current land level changes negative of relative sea level change maximum relative land uplift occurs in central and western scotland ca 1 6 mm yr 1 and maximum subsidence is in southwest england ca 1 2 mm yr 1 sediment consolidation arising from autocompaction as the sediment accumulates and from land drainage increases the subsidence in areas with thick sequences of holocene sediments with an average effect equivalent to at least an extra ca 0 2 mm yr 1 land subsidence but more in parts of southeast england 0 5 1 1 mm yr 1 modelled changes in tidal range during the mid to late holocene in eastern england suggest that the calculated rate of land subsidence is overestimated unless such changes are quantified the effect is most significant for large coastal lowlands the fenland and humber ca 0 5 and 0 6 mm yr 1 that were tidal embayments during the mid to late holocene

pine pollen in intertidal sediments from poole harbour uk implications for late holocene sediment accretion rates and sea level rise abstract marked differences exist between long and short term estimates of sea level rise in southern england crucial to resolving these differences is the development of dating techniques capable of bridging the gap between the late holocene radiocarbon chronology and the more recent 210 pb and observational records of sediment accretion and sea level change in this paper we identify an increase in pinus pollen in a sediment core collected from a saltmarsh in poole harbour dorset this has been dated to ca 1750 ad and reflects the historically documented spread of coniferous plantations across the region this biostratigraphic age horizon together with other pollen and radiocarbon data is used to analyse long and short term rates of sediment accretion and sea level change a basal radiocarbon date indicates a rise in relative sea level since 1510 1260 cal yr bc 3130 60 14 c yr bp of 1 99 m at a rate of approximately 0 59 mm a 1 between ca 1750 ad and ca 1890 ad sediment accretion rates rose from 0 29 mm a 1 to 1 14 mm a 1 perhaps reflecting an acceleration in relative sea level rise these rates increased further to 7 17 mm a 1 after ca 1890 ad following the development of a spartina anglica dominated saltmarsh in poole harbour these data demonstrate that caution should be exercised when using sediment accretion rates from saltmarshes recently colonised by s anglica as proxy data for sea level rise

drowned reefs as indicators of the rate of subsidence of the island of hawaii a major submerged terrace whose seaward edge is at about 150 m depth was investigated in 1983 during 10 dives with the hawaii undersea research laboratory hurl submersible makali i off kealakekua bay hawaii the seaward termination of the terrace is a steep wall of reef limestone that extends from 150 to 250 m below sea level three samples of limestone collected from the reef face at depths of 204 219 m yield a weighted average 14 c age of 13 250 s d 380 years before present the 150 m terrace as well as two deeper terraces off northwestern hawaii at depths of 390 pm 50 m and 580 pm 40 m apparently were formed by the interaction of glacioeustatic sea level changes and island subsidence the best fit of depth age and subsidence data indicates that the northwestern coast of hawaii has subsided at an absolute rate of 1 8 to 3 mm yr and that the rate of subsidence has generally increased over the past 0 3 m y each reef terrace grew intermittently for nearly 0 1 m y the 150 m reef ter

on the postglacial isostatic adjustment of the british isles and the shallow viscoelastic structure of the earth summary observations of postglacial relative sea level rsl history at sites beyond the margins of the main accumulations of wu rm wisconsin devensian ice may be invoked to test the accuracy of global models of the glacial isostatic adjustment process the existing database of rsl time series for the british isles forms a continuous network of sites that sample the coasts of scotland england and wales fairly uniformly and which may be especially important in this regard not only are these 14c data for the holocene epoch of very high quality in terms of our knowledge of the coastal environment and relationship to palaeo sea level of each age measurement but they are especially numerous and relate to an island that was itself partly glaciated in the north essentially ice free in the south and located well outboard of the massive ice sheet that covered fennoscandia at the last glacial maximum lgm taken together the time series from 55 distinct locations allow us to perform a fairly stringent test of the recently formulated ice 4g vm2 global model of the isostatic adjustment process even without modification this model has been shown to fit most of the time series in the uk data set rather well in order to satisfy very recently published a priori constraints on the maximum thickness of the scottish ice sheet however we find that the lithospheric thickness the feature of the radial viscoelastic structure to which the rebound data from scotland are most sensitive must be somewhat reduced whereas the assumed thickness of the lithosphere in ice 4g vm2 was near to 120 km best fits to the scottish data require a lithospheric thickness near to 90 km this reduced value for lithospheric thickness agrees exceedingly well with the latest estimates of this earth property based on the inversion of oceanic geoid and topography data as the asymptotic thickness characteristic of the oldest ocean floor this would appear to be the best possible a priori estimate for the thickness of the cratonic lithospheres upon which the largest ice sheets of the late pleistocene are known to have rested we also demonstrate explicitly that inferences of the shallow viscoelastic structure beneath the british isles are strongly influenced by the details of the history of deglaciation at remote locations at antarctica in particular

flandrian relative sea level changes in the ythan valley northeast scotland relict flandrian estuarine deposits in the ythan valley are confined to an area in the lower valley around the present estuary they rest upon a discontinuous layer of peat over an irregular surface of sand and gravel and consist for the most part of a grey silty clay or carse deposit which forms terraces or small areas of carseland at the seaward end of the estuary the grey silty clay contains a layer of grey micaceous silty fine sand which tapers into the basal peat whilst in places the surface of the grey silty clay is covered by peat and or blown sand the vegetational context and age of these deposits have been determined at waterside near the mouth of the present estuary here the grey silty clay accumulated as the result of a marine transgression which began in the early flandrian and culminated between about 6189 95 and some time prior to 4000 80 radiocarbon years b p the carseland surface produced by this phase of accumulation is the highest flandrian estuarine surface in the valley at about 4 5 m o d and is correlated with the main postglacial shoreline elsewhere in eastern scotland withdrawal of the sea from this level may have been interrupted by the formation of a lower carseland surface before present levels were reached though this is far from certain the grey micaceous silty fine sand layer is dated at approximately 6850 140 radiocarbon years b p and is correlated with similar layers that may have been deposited following a storm surge the paper concludes with some considerations on the age and distribution of the main postglacial shoreline in eastern scotland

the back barrier and barrier depositional history of romney marsh walland marsh and dungeness kent england previous stratigraphical investigations of romney marsh have tended to be local in scale and this has hindered efforts to establish a unifying stratigraphical framework for this area this paper addresses this problem by describing the results of a 12 km transect across romney marsh linking previously studied back and fore marsh sites horsemarsh sewer and broomhill respectively and presenting additional pollen diatom and radiocarbon data from an intermediate mid marsh site brookland one main organic unit is recorded across much of romney marsh although its age altitude and composition varies microfossil and radiocarbon data from brookland and elsewhere on romney marsh show that this organic unit accumulated under a general removal and return of marine conditions that took place between ca 5100 and 2000 yr bp a recently proposed model of barrier development is used to investigate the history of back barrier sedimentation in romney and walland marshes this model suggests a three phase life history for gravel barriers which consists of initiation stability and breakdown although there are problems in relating back barrier deposits directly to barrier dynamics nevertheless the romney marsh data do for the most part agree with the expected number and sequence of sea level tendencies predicted by this model the back barrier stratigraphical data suggest that initiation stability and breakdown of the dungeness foreland occurred between ca 6000 and 5000 yr bp 5000 and 2000 yr bp and 2000 yr bp and present respectively

tides in the northeast atlantic considerations for modelling water depth changes abstract a two dimensional tidal model of the northeast atlantic is used to simulate the m 2 s 2 2 m 4 ms 4 and m 6 tides for present sea level and with mean water level lowered or raised by a uniform number of metres over the model area m 2 s 2 tides predict the present spring tidal range although the other constituents are needed to predict spring tides in shallow water areas the accuracy of the assumptions made in modelling is assessed the relative amplitudes of the different tidal constituents vary in a non linear manner depending on model water depth changes in the northeast atlantic tides are relatively minor for tidal simulations with water depths 30 m below to 5 m above present levels however the situation is more complicated in the shallower waters of the northwest european shelf examples are given from a number of locations results from the northeast atlantic model are used to run larger scale models of morecambe bay on the west coast of britain and the wash on the east coast the tidal changes within these embayments highlight the local nature of the variations in the amplitude of different tidal constituents and the importance of the scale at which modelling is carried out

rapid holocene relative sea level changes in gruinart isle of islay scottish inner hebrides litho and biostratigraphic analyses undertaken in the gruinart estuary central islay reveal a detailed sedimentary record of holocene relative sea level changes and high energy flood events during the last 10 000 years during the lateglacial holocene transition relative sea level had fallen to below c 0 5 m od and remained at this depth until c 8830 14c years bp thus the early holocene minimum sea level is here relatively well constrained altitudinally a sustained and largely uninterrupted rise in relative sea level took place after c 8500 14c years bp reaching a maximum altitude of c 4 5 m od and remained at an elevation of c 4 m od until c 2000 14c years bp both the recorded maximum altitude of the main holocene transgression and the late age of the relative marine regression are incompatible with published shoreline uplift isobase models for this area

holocene coastal change and geoarchaeology at howick northumberland uk the recent discovery of one of the earliest mesolithic occupation sites in northern britain at howick on the northumberland coast in association with multiperiod archaeological evidence nearby highlights the importance of uk coastal settings as focii of human occupation through the holocene environmental evidence from a nearby river valley 8 15 m of sediment ranging in age from about 12 000 cal bp to the present records local and regional environmental change twenty four radiocarbon dates based on plant macrofossils provide a strong chronological framework calcareous microfossil assemblages foraminifera ostracods have been recovered from the fine grained sediments recording a change from marine through to brackish and eventually freshwater conditions between about 8200 and 6500 cal bp a preliminary pollen study of the core has permitted a reconstruction of the regional vegetation as it responded to climatic amelioration and human influence upon the landscape radiocarbon dating and sedimentological evidence indicates a major hiatus between approximately 11 000 and 8000 years bp including the period of mesolithic occupation represented by a 30 cm layer of coarse sands and sandstone pebbles probably the result of a significant high energy event dated to about 8300 cal bp although not a typical tsunami deposit the age and context suggests that this may be associated with the storegga slide event already well documented along the eastern coast of scotland the sedimentary and biological remains at howick record environmental change over much of the holocene and are compared with other environmental change records from the region to provide an environmental framework for the archaeology of this coastline

the stratigraphy of flandrian relative sea level changes at a site in tayside scotland peat deposits in a gully at the inland margin of the firth of tay carselands contain a transgressive wedge of estuarine sediments laid down at the culmination of the main postglacial transgression in previous work the sequence of deposits in the gully and their age have been examined at one location the present study both extends and evaluates that previous work employing further field work and laboratory analyses the detailed stratigraphy of the deposits is identified whilst from a borehole close to the limit of the transgressive deposit diatom analysis and geochemical analyses involving the determination of al mg c and 13cpdb are outlined eight 14c assays from peat at the transgressive and regressive contacts in four boreholes along the wedge of estuarine sediments are described whilst the results of diatom analysis are inconclusive the geochemical analyses indicate that the sediment accumulated broadly continuously without major changes in the depositional environment it is concluded that the main postglacial transgression in the gully was at first rapid then slowed and culminated between 6240 80 and 6030 80 or 6170 90 radiocarbon years b p it is subsequently maintained that the geochemical analyses described here may be of value in determining the continuity of transgressive deposits whilst the practice of obtaining multiple radiocarbon assays at such locations should enable assessment of age to be refined this may in turn assist in testing the hypothesis of shoreline diachroneity in glacioisostatically affected areas

late devensian and holocene relative sea level changes in northwestern scotland new data to test existing models abstract pollen diatom lithostratigraphic and radiocarbon data from five sites in northwestern scotland provide new data from an area previously devoid of reliable and precise information on late devensian and holocene sea level changes the sites cover a range of palaeoenvironments indicative of diversity in coastal evolution since deglaciation for each site and palaeoenvironment the reference water tide level indicative range age and tendency of sea level movement of all sea level index points are quantified to enable correlation of the diverse coastal environments the data record patterns of relative sea level change and tendencies of sea level movement from 12 ka bp to 1 ka bp this is the longest and most comprehensive published record of relative sea level change from the area the information is used to test the accuracy of existing models of relative sea level change the results are only broadly consistent with a quantitative rebound model and there is significant disagreement with empirical models during the late devensian and the early holocene

loch lomond stadial and flandrian shorelines in the inner moray firth area scotland morphological mapping and stratigraphical investigations have identified surface and buried relict marine features in the inner moray firth area the features consist of a buried gravel layer formed during the loch lomond stadial a buried beach of early flandrian age and surface beaches and estuarine flats of mid late flandrian age analysis of the altitudes of morphological features has identified two buried and five possibly six surface glacio isostatically tilted raised shorelines the steepest shoreline is associated with the buried gravel layer and slopes down towards n20 e at a gradient of 0 20m km younger shorelines have lower gradients between 0 16 0 03m km the shoreline sequence combined with published data defines relative sea level movements in the area during the last 11000 years the inner moray firth shorelines are correlated with similar features in other areas of scotland which include the main lateglacial main buried and main postglacial shorelines

osl dating of late holocene coastal sediments and its implication for sea level eustacy in hainan island southern china abstract since the sea level rise is not geographically homogeneous but rather shows great regional differences optically simulated luminescence using quartz as a natural dosimeter has proved to be a powerful and reliable dating technique to determine depositional ages of young coastal sediments around the world the samples acquired from one beach ridge and two marine terraces in coastal hainan island southern china are detected osl dating for the investigation of sea level changes the results show 1 coastal sands in hainan island were well bleached before deposition and the quartz osl can date coastal sediments younger than 200 years which could be one of good indicators for paleo relative sea level highstand records 2 three coastal sediments with 4 m 3 7 m and 2 m higher than present sea level were deposited at 2 40 0 05 ka 2 92 0 17 ka and 4 26 0 10 ka respectively which indicate that the height of highstand relative sea level are higher than both mean global sea level eustacy and those records offshore southern china 3 comparisons with tropical cyclones observations around south china sea indicates that the late holocene coastal sediments of hainan island might have been reformed by tropical cyclones with a highstand sea level

holocene sea level changes and crustal movements in morecambe bay northwest england holocene stratigraphy from skelwith pool on the northern side of morecambe bay is described diatom and pollen analyses and radiocarbon dating have been undertaken for three sampling sites from which eight sea level index points have been obtained these index points come from a small homogeneous area and similar palaeoenvironments some published sea level index points from morecambe bay have been re evaluated and validated by means of diatom analysis an enhanced sea level database with 28 index points has been used for the reconstruction of holocene sea level history relative sea level rose rapidly around 6870 6510 bc at a maximum rate of 36 7 mm yr 1 subsequently the rate of sea level change has varied between 8 mm yr 1 and 12 mm yr 1 the rate of relative sea level changes for the last 3500 years is not clear uplift driven by deglaciation is believed to have been interrupted in the early holocene by a rapid rise in relative sea level uplift restarted at 6510 bc but soon declined as glacio isostatic recovery ended around 3800 bc in the morecambe bay area since then crustal movements in the morecambe bay area have been minimal factors affecting the attitudes of the index points such as sediment compaction of the basal peat and variations in palaeotidal range during the holocene have been considered 1996 john wiley sons ltd

holocene relative sea level changes in the inner solway firth abstract bio and lithostratigraphic data from four sites from the inner solway firth allow an accurate reconstruction of holocene rsl changes in the estuary radiocarbon assays give eleven new sea level index points providing a total of 24 reliable index points for the inner solway firth these data show a consistent pattern of rapid rsl rise during the early holocene culminating in a mid holocene sea level maximum then a gradual fall to the present day level detailed analysis of this dataset quantifies for the first time differential crustal movement between the north and south shores of the solway firth these data are used to test the accuracy of quantitative isostatic rebound models of lambeck and peltier and show there is good general agreement between the data and the models especially during the early holocene the models predict the mid holocene sea level peak slightly later than shown by the data c 500 and c 2000 yr this may be partly due to lack of resolution in the models and for the south solway the maximum altitude at this peak is 1 and 2 5 m too high in the two models the data are also compared to the isobase models of the main postglacial shoreline showing slight diachroneity between the north and south shore but otherwise general agreement with the postulated age and indicating that the altitude of this feature is 1 3 m higher than suggested by the models

the lithostratigraphy and biostratigraphy of a holocene coastal sediment sequence in marazion marsh west cornwall u k with reference to relative sea level movements abstract a holocene sedimentary sequence at marazion marsh mount s bay west cornwall u k is examined with reference to coastal evolution and relative sea level change a sample core analyzed in this paper shows the base of the sedimentary sequence rests on weathered bedrock material basal organic rich deposits are overlain by minerogenic materials dominated by sand a sharp contact separates these two sedimentary units changing coastal conditions are reconstructed using lithostratigraphic biostratigraphic and chronometric data from this sequence the lower organic rich unit accumulated between ca 5420 60 and 4380 55 yrs b p substantial changes in the marsh environment involving vegetation succession from initial herb domination to mesophytic woodland and eventually to fen carr reed marsh development is indicated by pollen records from this unit diatom data show increased salinity within the basal sequence as arboreal pollen values decline and fen carr reed marsh becomes established radiocarbon dates from this and other cores from west cornwall are used to construct a local time altitude plot of relative sea level rsl it is concluded that the sediment sequence at marazion marsh appears to have accumulated in an embayed environment the sequence was both indirectly and directly affected by changes in relative sea level position and the influence of protective transgressive coastal morpho sedimentary structures and associated processes of sedimentation during the mid holocene period

flandrian sea level changes in the fenland ii tendencies of sea level movement altitudinal changes and local and regional factors stratigraphic micropalaeontologic and radiocarbon data show that since c 6500 bp the fenland has been influenced by 7 periods of positive sea level tendencies and by 6 periods of negative sea level tendencies despite the numerous problems associated with the reconstruction of past altitudes of sea level the periods of positive sea level tendencies were clearly characterised by a rise in sea level the development of transgressive overlaps and a landward movement of the coastline the periods of negative sea level tendencies were characterised by the development of regressive overlaps a seaward movement of the coastline and a reduced or negative rate of sea level rise the various altitudinal errors do not permit the incontrovertible distinction of periods of falling sea levels all changes within the fenland were not synchronous and local factors influenced the exact nature of each sea level indicator dominant regional and local factors have been identified for different areas and different time periods the chronological and spatial characteristics of the sequences within the fenland are best explained by a palaeocoastline without supratidal barriers controlling sedimentation the data indicate an average crustal subsidence in the fenland of 0 9m 1000 years since c 6500 bp and the pattern of positive and negative tendencies of sea level movement is also seen in the chronologies for north west england and north east scotland

patterns and processes in the development of coastal mire vegetation multi site investigations from walland marsh southeast england abstract the mid and late holocene vegetation of walland marsh situated on the south coast of england is reconstructed through multi proxy pollen plant macrofossil and diatom analyses and radiocarbon dating investigations of an extensive peat layer at five locations these data combined with previous work from southern england and regions bordering the southern north sea are used to assess the processes controlling the development of and successional trends in coastal mire vegetation on walland marsh fen carr vegetation with alnus glutinosa was sustained at sites influenced by the flow of base rich groundwater from the uplands and more widely promoted by rising relative sea level rsl acidophilous vegetation including ombrotrophic bog with sphagnum imbricatum ssp austinii present developed at sites isolated from base rich water spatial isolation was enhanced by the accumulation of peat while vertical isolation was induced by a decline in the rate of rsl rise and at ca 2600 cal yr bp by climate change similar patterns of mire development can be identified in the other areas reviewed vegetation development in coastal lowlands reflects a unique interplay between regional and local processes these processes can only be disentangled by multi site investigations