sea level change along the french atlantic and channel coasts since the time of the last glacial maximum abstract holocene sea level change along the french atlantic and english channel coast is not uniform because of the response of the crust to the changing ice and water loads in late pleistocene and holocene time the pattern of the spatial variability is a north south trend of decreasing sea levels levels at any time this results primarily from the isostatic response to the melting of the fennoscandian ice sheet superimposed upon this is a mainly east west trend resulting from the isostatic response of the crust to the addition of the meltwater into the atlantic ocean the combined effect is that at any time sea levels vary spatially along this coastline by amounts that are predicted to reach 20 m from the time of the last glacial maximum to about 10 000 radiocarbon yr ago about 15 m at 8000 yr ago and about 10 m at 6000 yr ago thus observations of past sea levels should not be combined into a single sea level curve unless first corrected for the glacio hydro isostatic factors alternatively the data should only be used to construct regional curves for relatively short sections of the coastline such as pas de calais and picardie normandie cotes du nord finistere or the vendee and charente maritime region even within such constrained regions the spatial variability may still be of the order of a few meters analysis of the observational data by region indicates that major oscillations in sea level are unlikely to have occurred that levels at no location exceeded the present mean sea level and that there may have been a small 3 m increase in eustatic sea level over the past 6000 yr palaeoshorelines and palaeo water depths for the english channel and the atlantic coast shelf have been predicted using the isostatic and eustatic models and the results indicate that in situ marine deposits older than 6000 7000 yr are unlikely to be found along many sections of the present coastline

major storm periods and climate forcing in the western mediterranean during the late holocene abstract big storm events represent a major risk for populations and infrastructures settled on coastal lowlands in the western mediterranean where human societies colonized and occupied the coastal areas since the ancient times the variability of storm activity for the past three millennia was investigated with a multi proxy sedimentological and geochemical study from a lagoonal sequence mappings of the geochemistry and magnetic susceptibility of detrital sources in the watershed of the lagoon and from the coastal barriers were undertaken in order to track the terrestrial or coastal marine origin of sediments deposited into the lagoon the multi proxy analysis shows that coarser material low magnetic susceptibility and high strontium content characterize the sedimentological signature of the paleostorm levels identified in the lagoonal sequence a comparison with north atlantic and western mediterranean paleoclimate proxies shows that the phases of high storm activity occurred during cold periods suggesting a climatically controlled mechanism for the occurrence of these storm periods besides an in phase storm activity pattern is found between the western mediterranean and northern europe spectral analyses performed on the sr content revealed a new 270 year solar driven pattern of storm cyclicity for the last 3000 years this 270 year cycle defines a succession of ten major storm periods sp with a mean duration of 96 54 yr periods of higher storm activity are recorded from 680 to 560 cal yr bc sp10 end of the iron age cold period from 140 to 820 cal yr ad sp7 to sp5 with a climax of storminess between 400 and 800 cal yr ad dark ages cold period and from 1230 to 1800 cal yr ad sp3 to sp1 little ice age periods of low storm activity occurred from 560 cal yr bc to 140 cal yr ad sp9 and sp8 roman warm period and from 820 to 1230 cal yr ad sp4 medieval warm period

haskell 1935 revisited the haskell 1935 value of 1021 pa s for mantle viscosity is a classic and enduring constraint on the rheology of the earth s interior we revisit this inference using spherically symmetric self gravitating maxwell viscoelastic earth models our inference is based on both forward and inverse analyses of decay times associated with uplift at two sites considered by haskell angerman river sweden and oslo norway rather than the raw relative sea level rsl data at these sites we demonstrate that predictions of the decay time associated with the angerman river data are insensitive to variations in both the late pleistocene ice load history and the lithospheric thickness of the earth model the predictions at oslo are sensitive to both these inputs and hence decay times at this site provide a remarkably robust constraint on mantle viscosity we derive a constraint on the average viscosity of the mantle of 0 65 1 10 1021 pa s where the average resolved by the data encompasses a region which extends from the base of the lithosphere to a depth of near 1400 km this indicates that many previous analyses which have invoked the haskell value of 1021 pa s as a constraint on the average upper mantle i e above 670 km depth viscosity alone have misinterpreted the resolving power of the inference furthermore our analysis indicates that a number of apparently contradictory inferences of viscosity based on fennoscandian data satisfy the new rigorous interpretation of the haskell constraint finally we demonstrate how the ambiguity in the upper mantle lower mantle viscosity contrast associated with the haskell average may be reduced by invoking decay time constraints estimated from rsl curves in hudson bay a preliminary inversion of decay times at angerman river and richmond gulf in hudson bay suggests a contrast of approximately an order of magnitude between the average viscosities of the upper mantle and the top 1000 km of the lower mantle however a conclusive analysis in this regard must await the determination of consistent decay time estimates for the hudson bay region

oxygen isotopes and sea level from the time that detailed oxygen isotope records derived from foraminifera living in the constant temperature environment of the abyssal ocean became available there has been a discrepancy between the ice volume record that these records imply and that derived from the altitude of dated coral terraces around the world here we re examine the data and conclude that the temperature of the abyssal ocean has been an actively varying component of the climate system

multifrequency turam measurements over a sulfide deposit a six frequency electromagnetic em system has been developed and used for a turam type survey over the sulfide deposit of mailaram copper belt in andhra pradesh india turam field strength ratio fsr and phase difference pd are measured in the range 84 to 2688 hz sulfides in this belt occur as thin concentrated lodes which grade into disseminations soil covers a major part of the area interpretation of the results is carried out using a thin sheet model in free space however an attempt has been made to account for finite resistivity of the normal ground by computing turam response of a conducting half space appropriate for the area and subtracting the same from the observed response the results of the survey confirm the known advantage of the turam method viz its greater depth of investigation compared to a method like slingram the normal ground at mailaram is only mildly conducting so that the free air approximation is valid at low frequencies a correction for the finite resistivity of t

the melting history of the late pleistocene antarctic ice sheet spatial and temporal variations in the sea levels of the past 20 000 years around the globe place constraints on the melting history of the major late pleistocene ice sheets the antarctic ice sheets provided a significant contribution to the sea level rise at a rate that was approximately synchronous with the melting of the laurentide ice sheet except for the interval 9 000 6 000 years ago when it may have lagged behind minor melting of the antarctic ice sheet continued throughout the holocene

sea level change along the french mediterranean coast for the past 30 000 years abstract observational evidence for sea level change along the french mediterranean coast has been examined and compared with glacio hydro isostatic models to predict the spatial and temporal patterns of change for about the past 30 000 14c years these predictions are pertinent to discussions of changing ocean volumes during this interval the tectonic stability or otherwise of the coastal areas mantle rheology and the timing of possible human occupation of the now submerged coastal plain and caves such as cosquer cave near marseille the principal results from the analysis are i sea levels along this section of the coast have risen continually since the time of the last glacial maximum lgm and at no time during the holocene has the mean sea level been higher than that of today ii the coast has been tectonically stable between marseille and nice as well as further to the west in roussillon western corsica may have experienced a slow tectonic uplift of between 0 15 0 3 mm year for the past 3000 years but northernmost corsica appears to have been stable during this same interval iii during the lgm sea levels along the coast and immediate off shore areas stood at between 105 115 m below present level the range reflecting the importance of the isostatic contributions during oxygen isotope stage 3 sea levels do not appear to have risen locally above about 60 m iv the rebound parameters describing the mantle rheology and ice sheets required to match the limited observational evidence are consistent with the results of similar analyses carried out for other parts of europe because of its distance from the former northern ice sheets the isostatic factors are particularly sensitive to the value of the lower mantle viscosity v the model predictions for sea level change at the cosquer cave site and for its immediate environments indicate that the cave was last readily accessible before about 10 700 500 14c years about 12 500 500 cal years bp and that the cave entrance was completely flooded by 9000 200 radiocarbon years bp between about 9800 and 10 300 calibrated years bp the cave was above sea level throughout the oxygen isotope stage 3

effects of tidal amplitude on intertidal resource availability and dispersal pressure in prehistoric human coastal populations the mediterranean atlantic transition abstract in this paper i argue that there is a growing body of evidence supporting an increasingly central position of coastal environments in human evolution and dispersals rather than as merely peripheral habitats eustatic fluctuations during glacial cycles have meant that most prehistoric coastlines are now underwater and lack of evidence to date of a close relationship between people and the coast can be most plausibly ascribed to the limited studies so far on submerged sites coastal environments provide high diversity in food resources consisting of multiple ecotones in close proximity which reduces the need to forage widely one of the richest and most easily exploited coastal resources by human populations living on the coast are molluscs from marine rocky intertidal communities which recent evidence has highlighted as important as far back as the middle palaeolithic however the density of these resources is limited by a number of factors and this varies geographically one of the main large scale factors limiting rocky intertidal mollusc densities is tidal amplitude beyond which smaller scale local factors such as exposure to wave action and shore aspect further affect species distributions the area around the strait of gibraltar is used as a case study of an area which is affected by large variations in tidal amplitudes thus allowing for quantitative comparisons between taxonomically and climatically similar regions shorelines along the mediterranean coast with reduced tidal amplitudes exhibit compressed zonations and harbour fewer macro mollusc individuals with the reverse being the case along the atlantic coast which has significantly larger tides data from middle and upper palaeolithic sites along the strait are used to establish harvested species and present day data are used to model the potential distributions and associated variables such as calorific returns of key food species an optimal foraging model is used to explore the effects of differential levels of resource availability along these coastlines results suggest that the nature and variability of the coastline has a direct influence on the tempo and mode of subsistence strategy followed and whether certain strategies can be adopted at all the possible implications of these biogeographical distributions for foraging economics dispersals and social structures in homo are discussed

very high resolution seismo acoustic imaging of seagrass meadows mediterranean sea implications for carbon sink estimates 1 posidonia oceanica is a widespread coastal mediterranean seagrass which accumulates in its subsurface large quantities of organic material derived from its roots rhizomes and leaf sheaths embedded in sandy sediments these organic deposits may be up to several meters thick as they accumulate over thousands of years forming the matte whose high content in organic carbon plays a major role in the global ocean carbon cycle in this study very high resolution seismo acoustic methods were applied to image the subsurface features of a p oceanica seagrass meadow at portlligat cadaques girona spain in the nw mediterranean sea our findings yield fresh insights into the settling of the p oceanica meadow in the study area and define with unprecedented detail the potential volume occupied by the matte a strong reflector located from 4 3 to 11 7 m depth was recognized in several seismo acoustic profiles as the substratum on which p oceanica first settled in the study area a 3d bathymetric model of this substratum allowed us to reconstruct the portlligat palaeo environment prior to the settling of p oceanica which corresponded to a shallow coastal setting protected from the open sea a core drilled in the meadow at portlligat revealed the presence of a 6 m thick dense matte composed of medium to coarse sandy sediments mixed with plant debris and bioclasts radiocarbon datings revealed a constant accretion rate of the matte of about 1 1 m kyr gravelly bioclastic deposits observed at the base of the core correspond to the base of the matte and gave a date of 5616 46 cal yr bp for the first time very high resolution marine geophysical techniques allowed us to accurately define the volume occupied by p oceanicamatte which in the study area reaches up to almost 220 000 17 400 m3 this result is an important step forward in our efforts to estimate the size of the carbon sink represented by p oceanica meadows along the mediterranean coasts significantly contributing to the biosphere carbon cycle

tests of glacial rebound models for fennoscandinavia based on instrumented sea and lake level records summary evidence for changing sea levels in northwestern europe related to glacial rebound is found in both the geological record of the past millennia and in the instrumental records of the past two centuries the latter records are of two types records of sealevel change primarily from the baltic and the gulfs of finland and bothnia and records of the tilting of some of the larger lakes in both finland and sweden the sealevel records are particularly important because of their long duration and high quality their large number and good spatial distribution and the spatially coherent background noise the two instrumental data types are complementary and provide constraints on the upper mantle rheology and on the distribution of ice during the late glacial stage comparisons of the observed rates of change of the water levels with models for glacial rebound yield earth models with a lithospheric thickness of 80 100 km and an uppermantle viscosity of 4 5 1020 pa s evective parameters that are consistent with those obtained from the analysis of the geological evidence for the same region the mareograph results support ice sheet models in which the late weichselian ice thickness over the eastern and southern parts of fennoscandia is relatively thinner than that for the western region also consistent with the interpretation of the geological evidence for sea level change in addition the instrumental records provide constraints on the eustatic sea level change for about the past 100 years a satisfactory separation of the earth rheology parameters from this rate of change can be achieved by estimating the latter only from those records for which the predicted isostatic evects are small a check on these results is possible by using the lake level records to establish constraints on the earth model parameters and the sea level records to constrain also the eustatic change all approaches lead to an average eustatic sea level rise for the past century of about 1 1 0 2 mm yr 1

sea level change glacial rebound and mantle viscosity fornorthern europe northwestern europe remains a key region for testing models of glacial isostasy because of the good geological record of crustal response to the glacial unloading since the time of the last glacial maximum models for this rebound and associated sea level change require a detailed knowledge of the ice sheet geometry including the ice thickness through time existing ice sheet reconstructions are strongly model dependent and inversions of sea level data for the mantle response may be a function of the model assumptions thus inverse solutions for the sea level data are sought that include both ice and earth model parameters as unknowns sea level data from fennoscandia the north sea the british isles and the atlantic and english channel coasts have been evaluated and incorporated into the solutions the starting ice sheet for fennoscandia is based on a reconstruction of a model by denton hughes 1981 that is characterized by quasi parabolic cross sections and symmetry about the load centre both global northwestern europe as a whole and regional subsets of the data solutions have been made for earth model parameters and ice height scaling parameters the key results are as follows 1 the response of the upper mantle to the changing ice and water loads is spatially relatively homogenous across scandinavia the north sea and the british isles 2 this response can be adequately modelled by an effective elastic lithosphere of thickness 65 85 km and by an effective upper mantle viscosity from the base of the lithosphere to the 670 km depth seismic discontinuity of about 3 4 1020 pa s the effective lower mantle viscosity is at least an order of magnitude greater 3 the ice thickness over scandinavia at the time of maximum glaciation was only about 2000 m much less than the 3400 m assumed in the denton hughes model 4 the ice profiles are asymmetric about the centre of the ice sheet with those over the western part being consistent with quasi parabolic functions whereas the ice heights over the eastern and southern regions increase much more slowly with distance inwards from the ice margin

evolution of the rhone delta plain in the holocene abstract the delta plain of the rhone shows many sandy beach ridges cropping out at the surface we propose here a radiocarbon chronology for the accumulation of the sedimentary bodies and an interpretation of the morphology of the mouth lobes that they form morphologies of the lobes depend on four principal factors 1 the variation of the relative sea level which constitutes the morphogenic base level 2 the fluvial input volume of water discharge and sedimentary input number and position of the mouths 3 marine dynamics volume and direction of the longshore drift dominant wave direction 4 the accommodation space created by the rise of relative sea level along with the paleobathymetry onto which the lobe will prograde immediately in front of the delta and at sea our conclusions are the main holocene paleo delta lobes of ulmet and saint ferreol were contemporaneous being deposited from 4000 to 2000 yr bp however the fluvial style of their downstream channel meandering for ulmet channel and linear for saint ferreol and the lobe morphologies of both channels are contrasted rounded in the case of ulmet and elongated for saint ferreol the role of the accommodation space is confirmed by two recent drillholes traversing the entire holocene succession which reveal a prior stage of sedimentary filling in the case of the saint ferreol lobe thus limiting the accommodation space and favouring a rapid and pointed progradation of this lobe the decoupling between hydrological activity and progradation of lobe indicates the complexity of mechanisms in the large catchment basin of rhone however the high rate of progradation of saint ferreol lobe after 2900 bp is probably a consequence of the increase of human activity after this date the variation of relative sea level remains an important factor controlling the evolution of the rhone delta after 6000 bp the local stabilization of the relative sea level between 4585 bp and 3520 bp played an important role in the triggering of coastal progradation saint ferreol lobe eastern margin rhone delta

holocene environmental change and river mouth sedimentation in the baie des anges french riviera abstract river mouths on the steep high relief coast of the french riviera exhibit thick sequences of holocene marine estuarine deltaic and river channel floodplain sediments that overlie basal fluvial pleistocene gravel gravel is uncommon in most of the early to middle holocene aggradational progradational marine estuarine deltaic sediments despite an ample supply from rock units in the steep adjoining uplands river mouth gravel is common only in late holocene river channels and in barrier beaches perched on finer grained nearshore sediments neither downslope grain size fining on alluvial fans nor sediment stacking patterns during sea level base level rise readily account for the lack of early to middle holocene gravel in the river mouth sediment wedges holocene sea level rise led to the storage of fine grained sediments in shallow marine estuarine and deltaic environments in the present coastal zone we infer that humid temperate conditions a dense forest cover landscape stabilization and a regular quiescent river flow regime associated with the atlantic climatic optimum limited gravel supply in the adjoining catchments and gravel entrainment downstream during the early holocene sea level stabilization in the middle and late holocene coincided with a marked change in bioclimatic conditions toward the present mediterranean type regime which is characterized by a less dense forest cover soil erosion and episodic catastrophic floods the late holocene was thus a time of downstream bedload channel aggradation fine grained floodplain and paludal sedimentation and seaward flushing of clasts leading to the formation and consolidation of the gravel barrier beaches that bound the rivermouths and embayments

holocene uplift rates and historical rapid sea level changes at the gargano promontory italy this paper uses a combination of geomorphological and radiometric data from the northern coast of the gargano promontory comprising the fortore river coastal plain and punta delle pietre nere to reconstruct holocene uplift rates the coastal plain consists of a sandy progradational beach sequence that extends seawards from the base of a relict cliff this cliff probably marks the maximum position reached by the holocene transgression altimetric data compared with the age of beach deposits and the available eustatic sea level curves indicate an average holocene uplift rate of 1 5 mm yr 1 a similar uplift rate has been estimated by dating a bioherm constituted of calcareous algae vermetids and subordinately by cladocora caespitosa l which crops out in the locality of punta delle pietre nere this deposit which was previously assigned an interglacial age yielded a mid holocene age by means of th u and 14c age determinations our observations also reveal evidence for coseismic deformation along the northern coast of the gargano promontory during the last millennium vertical displacements of 0 5 m have affected the punta delle pietre nere coastal block and were preceded by periods of slow coastal subsidence which increased rapidly shortly before a major earthquake copyright 2002 john wiley sons ltd

geophysical logs from the toa baja scientific drillhole puerto rico geophysical logs from the toa baja drillhole on the north central coast of puerto rico are used to distinguish the variation in physical properties with depth in this non volcanic island arc massif a marked unconformity separates shallow oligocene to miocene limestones with considerable permeability contrast from a deeper sequence of volcaniclastic rocks with decreasing shaliness a volcanic sill or flow overlying a strongly mineralized zone is found to cause the impedance contrast responsible for the strong seismic reflection anomaly bright spot that was the exploration target

biological evidence of sea level rise during the last 4500 years on the rocky coasts of continental southwestern france and corsica on the rocky coasts of the northwestern mediterranean basin biogenic littoral rims built by the coralline rhodophyte lithophyllum lichenoides develop whose remains may be preserved for millennia when submerged in a rising sea environment these remains can be used as biological indicators of recent sea level variations our survey of the continental coasts of var and bouches du rhone west of marseilles southern france and of northern corsica shows that relative sea level rose about 1 6 m in the study area during the last 4500 years without exceeding the present datum the rate of sea level rise was 0 4 mm per year between 4500 and 1500 yr b p and slowed down to 0 2 mm per year from 1500 yr b p to present time there are also morphological indications of an acceleration of the rate of sea level rise during the last century supporting the evidence of tide gauges regions at the periphery of the above zone alpes maritimes italian border zone and the french and spanish catalonia regions were also surveyed but a weaker development of lithophyllum rims and bad preservation of algal remains led to unconvincing dates which could also be linked to regional tectonic trends

marine continental tephra correlations volcanic glass geochemistry from the marsili basin and the aeolian islands southern tyrrhenian sea italy abstract major minor and trace element analysis of volcanic glass in proximal and distal it is evident that correlation of proximal continental and distal marine tephras at a high level of confidence requires a full complement of major minor and trace element data in conjunction with considerations of the mineralogy and morphology of juvenile deposits these data help define petrological lineages such that precise provenance can be established whilst a precise proximal distal match must be based on identical major minor and trace element concentrations it is clear that resurgent activity from a single volcano can produce magmas with identical compositions in such cases stratigraphic relationships must complement any geochemical study occasionally proximal stratigraphies may be unrepresentative of the complete eruptive history because of a lack of exposure due to burial by more recent effusive and explosive activity or sector collapse which can remove vital stratigraphy particularly on volcanic islands

sea level in roman time in the central mediterranean and implications for recent change instrumental records indicate that ocean volumes during the 20th century have increased so as to raise eustatic sea level by f1 2 mm year and the few available records suggest that this is higher than for the previous century geological data indicate that ocean volumes have increased since the main phase of deglaciation about 7000 years ago but whether this continued into the recent past remains unclear yet this is important for establishing whether the recent rise is associated with global warming or is part of a longer duration non anthropogenic signal here we present results for sea level change in the central mediterranean basin for the roman period using new archaeological evidence these data provide a precise measure of local sea level of 1 35f0 07 m at 2000 years ago part of this change is the result of ongoing glacio hydro isostatic adjustment of the crust subsequent to the last deglaciation when corrected for this using geologically constrained model predictions the change in eustatic sea level since the roman period is 0 13f0 09 m a comparison with tide gauge records from nearby locations and with geologically constrained model predictions of the glacio isostatic contributions establishes that the onset of modern sea level rise occurred in recent time at f100f53 years before present d 2004 elsevier b v all rights reserved

glacial rebound and relative sea level variations a new appraisal summary late pleistocene and holocene changes in sea level at technically stable shorelines contain information on the melting history of the ice sheets and on the response of the earth to changes in surface loads on time scales of 104yr some separation of parameters defining the ice loads and the earth s response can be achieved by examining sea level change at different sites around the world and at different epochs this paper examines the mathematical requirements for obtaining satisfactory solutions for the sea level equation rather than emphasizing results for the earth s response to the surface loads an examination of the equation expressing the sea level variation on a viscoelastic earth indicates that careful consideration needs to be given to both the definition of the ice load and the geometry of the redistributed water load if geophysically significant earth response parameters are to be deduced from observations of relative sea level the spectrum of the 5 x 5 area mean description of the ice load widely used in glacial rebound studies contains significant power at high degrees n 30 and can result in substantial spatial variations in sea level unless a thick lithosphere is introduced in the earth s response function a smoothed 1 1 description of the ice model avoids these high degree oscillations in relative sea level and produces satisfactory sea level results without requiring a thick lithosphere at far field sites the holocene sea levels are sensitive to the earth s response to the meltwater loading in the vicinity of the site and a high degree spatial resolution of coastline geometry is required to model the mantle flow driven by the differential loading about the site at some sites convergence of the solution to the sea level equation is not obtained even when the solution is expanded to degree 180 convergent solutions at lower degrees can be achieved by introducing earth models with a moderately thick lithosphere if high resolution ice and meltwater load models are not used then the tendency will be to overestimate the effective elastic thickness of the lithosphere estimates of mantle viscosity are also of questionable value if these high resolution models are not used a preliminary examination of sea levels at sites in both the near and far field places an upper limit of about 50 80 km on the effective lithospheric thickness these sea level observations are also consistent with an upper mantle viscosity of about 1021 pas with a lower mantle viscosity in the range of 1021 1023pa s

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

ice 3g a new global model of late pleistocene deglaciation based upon geophysical predictions of post glacial relative sea level change a new high resolution global model of late pleistocene deglaciation is inferred on the basis of geophysical predictions of postglacial relative sea level variations in which the ice ocean solid earth interaction is treated in a gravitationally self consistent fashion for the purpose of these analyses the radial viscoelastic structure of the planet is assumed known on the basis of previously published sensitivity tests on solutions of the forward problem only radiocarbon controlled relative sea level histories from sites that were actually ice covered with one or two additions are employed to constrain the model leaving relative sea level rsl data from sites that were not ice covered to be employed to confirm its consistency results for these confirmatory analyses are reported elsewhere here the new deglaciation model referred to as ice 3g is compared to previous models derived by several independent means and tested against a number of additional observations other than sea level histories including geologically controlled retreat isochrones oxygen isotope data from deep sea sedimentary cores and coral terrace elevations the latter two observations strongly constrain the net sea level rise that has occurred since the onset of deglaciation and therefore the mass of ice that melted during the last glacial interglacial transition

refining the eustatic sea level curve since the last glacial maximum using far and intermediate field sites the eustatic component of relative sea level change provides a measure of the amount of ice transferred between the continents and oceans during glacial cycles this has been quantified for the period since the last glacial maximum by correcting observed sea level change for the glacio hydro isostatic contributions using realistic ice distribution and earth models during the last glacial maximum lgm the eustatic sea level was 125 5 m lower than the present day equivalent to a land based ice volume of 4 6 4 9 107 km3 evidence for a non uniform rise in eustatic sea level from the lgm to the end of the deglaciation is examined the initial rate of rise from ca 21 to 17 ka was relatively slow with an average rate of ca 6 m ka 1 followed by an average rate of ca 10 m ka 1 for the next 10 ka significant departures from these average rates may have occurred at the time of the younger dryas and possibly also around 14 ka most of the decay of the large ice sheets was completed by 7 ka but 3 5 m of water has been added to the oceans since that time

holocene relative sea level change isostatic subsidence and the radial viscosity structure of the mantle of northwest europe belgium the netherlands germany southern north sea abstract a comprehensive observational database of holocene relative sea level rsl index points from northwest europe belgium the netherlands northwest germany southern north sea has been compiled in order to compare and reassess the data collected from the different countries regions and by different workers on a common time depth scale rsl rise varies in magnitude and form between these regions revealing a complex pattern of differential crustal movement which cannot be solely attributed to tectonic activity it clearly contains a non linear glacio and or hydro isostatic subsidence component which is only small on the belgian coastal plain but increases significantly to a value of ca 7 5 m relative to belgium since 8 cal ka bp along the northwest german coast the subsidence is at least in part related to the post glacial collapse of the so called peripheral forebulge which developed around the fennoscandian centre of ice loading during the last glacial maximum the rsl data have been compared to geodynamic earth models in order to infer the radial viscosity structure of the earth s mantle underneath nw europe lithosphere thickness upper and lower mantle viscosity and conversely to predict rsl in regions where we have only few observational data e g in the southern north sea a very broad range of earth parameters fit the belgian rsl data suggesting that glacial isostatic adjustment gia only had a minor effect on belgian crustal dynamics during and after the last ice age in contrast a narrow range of earth parameters define the southern north sea region reflecting the greater influence of gia on these deeper older samples modelled rsl data suggest that the zone of maximum forebulge subsidence runs in a relatively narrow wnw ese trending band connecting the german federal state of lower saxony with the dogger bank area in the southern north sea identification of the effects of local scale factors such as past changes in tidal range or tectonic activity on the spatial and temporal variations of sea level index points based on model data comparisons is possible but is still complicated by the relatively large range of earth model parameters fitting each rsl curve emphasising the need for more high quality observational data

late pleistocene and holocene sea level change in greece and south western turkey a separation of eustatic isostatic and tectonic contributions summary sea level change during late pleistocene and holocene times is a combination of eustatic isostatic and tectonic contributions in the central mediterranean sea region of greece and western turkey the isostatic components are important due to the changing gravitational potential of the earth the readjustment of the crust upon the removal of the large ice sheets and the addition of the meltwater into the oceans including the mediterranean changes in relative sea level due to these glacio hydro isostatic adjustments have reached amplitudes of 1 mm yr 1 during the last few thousand years a model for the isostatic contribution to sea level change including the movement of shorelines due to the combined eustatic isostatic changes is developed based on earth model and ice sheet parameters estimated from sea level observations from other areas comparisons of this model with observations of sea level change permit rates of vertical movement to be estimated for late holocene time allowance for the isostatic factors makes a significant difference to these rates the plains of argolis lakonia messinia and navarine in the southern peloponnese for example appear to be tectonically stable on time scales of a few thousand years and longer consistent with the position of the last interglacial shoreline close to the present day sea level the observations here of a rising sea level are largely the consequence of the glacio hydro isostasy and not of a long term tectonic process crete as a whole is subject to tectonic uplift but at variable rates and forms part of an arcuate zone of uplift extending from rhodes and karpathos in the east to kithera in the west at rates that locally exceed 4 mm yr 1 the southern shore of the gulf of corinthos is also subject to uplift at rates approaching 1 5 mm yr 1 these isostatically corrected estimates for the past few thousand years are in agreement with longer term estimates based on the position of the last interglacial shoreline only on the perachora peninsula do the tectonic rates over these two time intervals appear to be in disagreement with the late holocene rates being much higher than the long term rates

the glycymeris query along the coast and shallow shelf of israel southeast mediterranean abstract high concentrations of empty valves of the genus glycymeris are found along the israeli coast both at the water line and in adjacent archeological sites in contrast with the abundance of the empty shells live specimens are rare this discrepancy raises the questions of when and where did glycymeris live on the israeli shelf and why and when did they disappear in this study concentrations of empty shells from contemporary depositional environments were sampled at 13 sites along the waterline and 91 sites on the israeli inner shelf between 3 and 30 m water depth in addition 12 coastal archeological sites were sampled so as to determine the distribution of bivalves in the last few thousands years and a random sample was checked for taphonomic characteristics six valves of glycymeris insubrica were radiocarbon dated glycymeris shells comprise 89 to 100 of the total dead mollusks shells found south of haifa with g insubrica comprising up to 100 of the entire glycymeris assemblage in archeological sites g insubrica is also abundant g insubrica an opportunist species appeared in large numbers 5000 5500 years ago and almost ceased to exist 1500 1000 years ago taphonomic studies based on the present day state of preservation of glycymeris support the observation that they ceased to exist sometime after 2000 years ago the sharp increase in their numbers is attributed to a combination of several factors the inner shelf became oligotrophic 5500 years ago the late holocene sea level rise slowed down considerably and nearly reached its maximum sandy sediments predominated and new habitats were open the near disappearance of g insubrica 1500 to 2000 years ago was probably due to the ongoing impoverishment of nutrient flux and reduction in marine productivity of the eastern mediterranean it may also have been part of the natural succession of populations that replace each other resulting in a distinct community change

on postglacial sea level summary an exact method is presented for calculating the changes in sea level that occur when ice and water masses are rearranged on the surface of elastic and viscoelastic non rotating earth models the method is used to calculate the instantaneous elastic and delayed vi scoelastic sea level changes following the partial melting of late quaternary ice sheets we find that there can be large errors in the usual assumption that changes in sea level are uniform over the ocean basins if a quantity of ice equivalent to a uniform 100 m rise in sea level melts from the laurentide and fennoscandian ice sheets then in the south pacific the instantaneous rise in sea level can be as large as 120m in the north atlantic the instantaneous rise is always less than 100 m there is a zone in the north atlantic with almost no sea level change and near greenland and norway the sea level falls rather than rises by over 100 m one thousand years after the melting a forebulge migrating towards the ice loads causes water to flow from the south pacific into the north pacific suggesting that raised beaches should occur in the south pacific the gravitational attraction of an ice mass upon a nearby ocean tends to hold sea level high in the vicinity of the ice this extra load near the ice may have a significant influence on postglacial isostatic adjustment

glacial rebound of the british isles iii constraints on mantle viscosity summary observations of sea level change since the time of the last glacial maximum provide important constraints on the response of the earth to changes in surface loading on time scales of 103 104 years this response is conveniently described by an effective elastic lithospheric thickness and effective viscosities for one or more mantle layers considerable trade off between the parameters describing these layers can occur and different combinations can give rise to comparable predictions of sea level change in particular the trade off between lithospheric thickness and upper mantle viscosity can be important and for any reasonable value for the lithospheric thickness a corresponding mantle viscosity structure can be found that gives a plausible comparison of sealevel predictions with observations in particular thin lithosphere models will lead to low estimates for the upper mantle viscosity while thick lithosphere models lead to high viscosity values however either solution may represent only a local minimum in the model parameter space and may not correspond to the optimum solution it becomes important therefore that in the inversion of observational data a comprehensive search is conducted throughout the entire model parameter space to ensure that the solution identified does indeed correspond to the optimum solution the sea level data for the british isles lend themselves well to such an inversion because of the relatively high quality of the data the good geographic distribution of the data relative to the former ice sheet and reasonable observational constraints on the dimensions of the former ice sheet and on its retreat furthermore because of the contribution to the sea level signal from the distant ice sheets as well as from the melt water load the observational data base for the region also has some resolving power for the viscosity of the deeper mantle the parameter space explored is defined by up to five mantle layers the lithosphere of effective elastic thickness d and a series of upper mantle layers i 2 4 extending down to depths of 200 400 and 670 km respectively each of viscosity qi and a lower mantle layer of viscosity qlm extending down to the coremantle boundary the range of parameters explored is 30 d i 120 km 3 x loi9 iqi

shoreline displacements in southern central sweden and the evolution of the baltic sea since the last maximum glaciation during late and post glacial times the baltic basin has been periodically isolated from the atlantic and freshwater and saline conditions have alternated this is a consequence of the interactions between the spatially variable glacial rebound of the region and the simultaneous eustatic sea level rise in the adjacent atlantic observations of the timing of these isolations and of the location of the barriers therefore provide constraints on the rebound models high resolution numerical models of rebound of southern sweden the danish straits and the baltic have been developed and tested against observations of lake level change as well as against the observed elevations of the last baltic ice lake shoreline which formed before about 10 3 ka bp predictions of sea and lake levels are used to test two alternative hypotheses about the ice thickness over scandinavia and to estimate parameters that describe the earth s response optimum values for the latter are lithospheric thickness of 60 20 km upper mantle viscosity of 3 3 10 20 pa s and lower mantle viscosity of 10 22 pa s the rapid lake level fall at the end of the baltic ice lake stage is estimated to be 30 5 m the optimum ice model for scandinavia is one in which the ice thickness over southeastern and southern scandinavia was relatively thin compared with the ice thickness over sweden and norway the ice thickness in the southeast and south changes slowly with distance inwards of the ice margin whereas over sweden and norway the ice thickness profiles are considerably steeper the earth and ice models have been combined with high resolution digital terrain data to develop a comprehensive model for the evolution of the baltic basin since the time the area last became ice free the reconstructions predict the occurrence of barriers at certain times which impede free flow between the atlantic and baltic and confirm that the baltic lake levels are controlled by rebound at four localities degerfors in the narke region of southern central sweden the vanern outlet through the gota alv oresund and the darss langelands store baelts in denmark

genesis and evolution of a beach ridge plain reflecting relative sea level rise a case study from trab el makhadha gulf of gabes southeastern tunisia abstract the trab el makhadha beach ridge plain presents a progradational shoreline feature on the gulf of gabes tunisia diachronic analysis coupled with a morpho sedimentary approach was applied to elucidate the genesis mode of the beach ridge plain its sedimentary sources and the climatic conditions responsible for the prograding trends in the gulf of gabes shapes dimensions sedimentologic compositions and other textural parameters of the sandy ridges have been analyzed therein we found that the trab el makhdha coast is made up of two distinctive categories of eolian beach ridge complex progradational sequences implying a significant change in climatic and hydrological conditions during the deposition of each ridge in the holocene sequence about 5600 14c years old the predominance of detrital material suggests an important contribution to sediment supply from continental input the preservation of the eolian beach ridge and its adjacent marine sediment has been favored by the postglacial hydro isostatic rebound today the paucity of rainfall is reflected by the decrease in input of terrigenous material therefore the modern sequence which has been emerging since 1987 is made mainly of bioclastic sand supplied by subaqueous shoals due to a rapid rise in sea level the observed decrease of sea level around 2100 14c yr b p largely contributed to the formation of the swale the formation of the beach ridge plain shows that since the middle holocene highstand the coastal segment of trab el makhadha has been governed by equilibrium of sediment abundance

holocene glacial rebound and sea level change in nw europe summary observations of late pleistocene and holocene sea level change relative to the crust exhibit very considerable variations across nw europe in consequence of the response of the earth s crust to the deglaciation of fennoscandia and of the water added to the oceans from the melting of all late pleistocene ice sheets inversion of sea level observations from a site near the centre of the fennoscandian ice sheet and from three sites located beyond the margin of the ice sheet at the time of maximum glaciation yield a range of plausible models for the earth s response and for the ice models further constraints on this range of models is placed by a comparison of observed sea levels with predicted values at other sites near the former ice sheet margins the resulting mantle parameters are upper mantle viscosity 3 5 x 10 pa s lower mantle viscosity 2 7 x loz1 pa s lithospheric thickness 100150 km these values represent effective parameters that describe the response of the earth to surface loading of short to intermediate wavelengths on a time scale of 104yr the lower mantle viscosity is poorly constrained but the marked increase from upper to lower mantle is a characteristic of all plausible solutions the inversion places a constraint on the total volume of ice in the fennoscandian ice sheet such that the equivalent sea level rise from this contribution is about 13 14 m a less well determined constraint of about 10 m equivalent sea level rise is suggested for the barents kara ice sheet the inversion also indicates that a small amount of melt water from ice sheets far away from europe continued to be added into the oceans during late holocene time so as to raise the equivalent sea level by about 3 m during the past 6000 yr consistent with similar inversions of data from sites in the australian and pacific regions

postglacial sea level change on a rotating earth first results from a gravitationally self consistent sea level equation we present and solve a gravitationally self consistent sea level equation which governs postglacial sea level variations on a spherically symmetric self gravitating viscoelastic and rotating earth we find that the inclusion of a glacio isostatically induced rotational excitation can significantly affect previous predictions of both present day sea level rates and postglacial sea level histories which were based on a theory that assumed a non rotating earth model to illustrate we consider present day sea level rates and tide gauge corrections along the us east coast and relative sea level curves in the far field of the late pleistocene ice sheets

on the choice of timescale in glacial rebound modelling mantle viscosity estimates and the radiocarbon timescale summary most glacial rebound studies have been carried out with respect to the radiocarbon timescale whose departures from the calendar timescale are becoming increasingly well established in consequence it has sometimes been argued that the choice of the radiocarbon timescale may invalidate some of the conclusions drawn from rebound and sea level analyses the purpose of this note is to compare rebound model results based on both timescales using the british isles data for the test the results indicate that the choice of timescale is unimportant provided that the time dimension of viscosity is appropriately defined the results confirm that the radiocarbon viscosities are about 15 per cent less than the corresponding calendar time viscosities also provided that consistency of timescales is maintained in the analysis and that the timeaccuracy estimates of the radiocarbon data reflect the departures from a linear timescale the use of the radiocarbon timescale does not impinge on inferences drawn about the timing of melting of ice sheets or eustatic sea level change

reconciliation of late quaternary sea levels derived from coral terraces at huon peninsula with deep sea oxygen isotope records a major discrepancy between the late quaternary sea level changes derived from raised coral reef terraces at the huon peninsula in papua new guinea and from oxygen isotopes in deep sea cores is resolved the two methods agree closely from 120 ka to 80 ka and from 20 ka to 0 ka ka 1000 yr before present but between 70 and 30 ka the isotopic sea levels are 20 40 m lower than the huon peninsula sea levels derived in earlier studies new high precision u series age measurements and revised stratigraphic data for huon peninsula terraces aged between 30 and 70 ka now give similar sea levels to those based on deep sea oxygen isotope data planktonic and benthic 18o data using the sea level and deep sea isotopic data oxygen isotope ratios are calculated for the northern continental ice sheets through the last glacial cycle and are consistent with results from greenland ice cores the record of ice volume changes through the last glacial cycle now appears to be reasonably complete