an updated holocene sea level curve for the delaware coast abstract we present an updated holocene sea level curve for the delaware coast based on new calibrations of 16 previously published radiocarbon dates kraft 1976 belknap and kraft 1977 and 22 new radiocarbon dates of basal peat deposits a review of published and unpublished 137 cs and 210 pb analyses and tide gauge data provide the basis for evaluating shorter term 10 2 yr sea level trends paleosea level elevations for the new basal peat samples were determined from the present vertical zonation of marsh plants relative to mean high water along the delaware coast and the composition of plant fossils and foraminifera current trends in tidal range along the delaware coast were used to reduce elevations from different locations to a common vertical datum of mean high water at breakwater harbor delaware the updated curve is similar to belknap and kraft s j sediment petrol 47 1977 610 629 original sea level curve from 12 000 to about 2000 yr bp the updated curve documents a rate of sea level rise of 0 9 mm yr from 1250 yr bp to present based on 11 dates in good agreement with other recent sea level curves from the northern and central u s atlantic coast while the previous curve documents rates of about 1 3 mm yr based on 4 dates the precision of both estimates however is very low so the significance of these differences is uncertain a review of 210 pb and 137 cs analyses from salt marshes of delaware indicates average marsh accretion rates of 3 mm yr for the last 100 yr in good agreement with shorter term estimates of sea level rise from tide gauge records

holocene sea level and climate change in the black sea multiple marine incursions related to freshwater discharge events abstract repeated marine invasions of the black sea during the holocene have been inferred by many eastern scientists as resulting from episodes of marine inflow from the mediterranean beneath a brackish outflow from the black sea we support this scenario but a fundamental question remains what caused the repeated marine invasions we offer an hypothesis for the repeated marine invasions of the black sea based on 1 the overall similarity of sea level curves from both tectonically quiescent and active margins of the black sea and their similarity to a sequence stratigraphic record from the us mid atlantic coast the similarity of the records from two widely separated regions suggests their common response to documented holocene climate ocean atmosphere reorganizations coolings 2 the fact that in the modern black sea freshwater runoff from surrounding rivers dominates over evaporation so that excess runoff might have temporarily raised black sea level although the black sea would have remained brackish following the initial invasion of the black sea by marine mediterranean waters through the marmara sea in the early holocene repeated marine incursions were modulated or perhaps even caused by freshwater discharge to the black sea climatic amelioration warming following each documented ocean atmosphere reorganization during the holocene likely shifted precipitation patterns in the surrounding region and caused mountain glaciers to retreat increasing freshwater runoff above modern values and temporarily contributing to an increase of black sea level freshwater to brackish water discharges into the black sea initially slowed marine inflow but upon mixing of runoff with more marine waters beneath them and their eventual exit through the bosphorus marine inflow increased again accounting for the repeated marine invasions the magnitude of the hydrologic and sea level fluctuations became increasingly attenuated through the holocene as reflected by black sea level curves

a high resolution record of climate variability and landscape response from kettle lake northern great plains north america abstract a decadal scale multiproxy record of minerals pollen and charcoal from kettle lake north dakota provides a high resolution record of climate and vegetation change spanning the entire holocene from the northern great plains ngp in north america the chronology is established by over 50 ams radiocarbon dates this record exhibits millennial scale trends evident in other lower resolution studies but with much more detail on short term climate variability and on the rapidity and timing of major climatic shifts as a proxy for precipitation we utilize the rate of endogenic carbonate sedimentation which depends on groundwater inflow which in turn depends on precipitation independent cluster analyses of mineral and pollen data reveal major holocene mode shifts at 10 73 ka ka cal yr bp 9 25 ka and 4 44 ka the early holocene 11 7 9 25 ka was generally wet with perhaps a trend to higher evaporation associated with warming temperatures a switch from calcite to aragonite deposition associated with a severe but brief drought occurred at 10 73 ka from 10 73 ka to 9 25 ka climate was generally humid but punctuated at 100 300 yr intervals by brief droughts including the most severe drought of the entire holocene at 9 25 ka this event was coeval with the 9 3 9 2 ka event in the greenland ice cores and observed at a number of sites worldwide in contrast the prominent 8 2 ka event in greenland is not remarkable at kettle lake the prominence of the 9 25 event locally in the ngp may be due to a major drawdown and northward retreat of lake agassiz at this time reducing its mesoclimatic effect on the ngp and thrusting the region into an insolation controlled regime the mid holocene 9 25 4 44 ka was characterized by great variability in moisture on a multi decadal scale with severe droughts alternating with more humid periods the high abundance of the weedy but drought intolerant ambrosia generally during the mid holocene and specifically during the multi decadal drought periods is seemingly paradoxical but can be explained by high interannual variability of moisture overlaid on the multi decadal variability the late holocene 4 44 ka present was also characterized by multi decadal variability in moisture but was generally wetter than the mid holocene and the magnitude of variability was less the trends in wet dry mineral pollen and charcoal proxies were similar to the mid holocene but late holocene mineral pollen assemblages are distinct from mid holocene the shift to wetter climate in the late holocene was more gradual than the abrupt shift to arid conditions 9 25 ka which may explain the asymmetric retreat and readvance of forest along the eastern margin of the ngp precipitation variations in the ngp have been linked with pacific and atlantic sea surface temperatures and mid holocene drought in the ngp has been linked with sustained la nina like conditions in the pacific these linkages may explain the decadal and millennial scale variations seen in the ngp but cause of the prominent century scale variations remains elusive

40ar 39ar ages from the botwood mount peyton region newfoundland possible paleomagnetic implications hornblende and biotite from the freshest available sample of the gabbroic early phase of the mount peyton batholith have both yielded 40ar 39ar apparent age plateaus an age of 420 8 ma is sugg

holocene sea level history and neotectonics of the united states mid atlantic region applications and corrections published local relative holocene sea level histories derived from various dated materials at positions along the united states east coast fail to agree on the timing and magnitude of sea level change published eustatic curves suffer the same disagreement and have lead to recent declarations in the literature that a true eustatic history is unattainable this has been generally accepted by workers in light of the myriad of complicating factors which have been identified as influencing the position of sea level through time in this study a single local relative sea level curve kraft 1976 has been analyzed for elevation and temporal errors resulting from fine sediment compaction paleotidal range and neotectonic phenomena additionally the cross latitude history of vertical crustal velocity along the united states east coast is suggested as providing a means of correlating adjacent curves which have been corrected in such a manner this enhances the applicability of a local relative curve for purpo

deglaciation induced vertical motion of the north american continent and transient lower mantle rheology the last deglaciation event of the current ice age which began approximately 18 000 years ago and ended about 7000 years ago continues to exert a profound influence on the vertical motion of the solid earth in and surrounding the regions which were once ice covered observations of such vertical motions may be employed to constrain the radial viscoelastic structure of the planet and therefore to contribute in an important way to the understanding of geodynamic processes in general in this paper both present day rates of vertical motion as recorded on tide gauges and long time scale records of vertical motion as recorded in 14c controlled relative sea level histories are employed to refine previously constructed models of the radial viscoelastic structure an interesting sidelight to this analysis is the demonstration that the lower mantle viscosity inferred from the vertical motion data could represent a transient rather than the steady state value a fact which would help considerably to reconcile the small viscosity stratification required by the glacial rebound data with the large stratification which seems to be required by some recent analyses of the geoid height anomalies associated with internal density heterogeneity of the mantle which has been revealed by application of seismic tomographic techniques a further product of these new analyses is obtained by the application of the glacial isostatic adjustment model to filter this signal from the secular trends of relative sea level observed on tide gauges from both the east and west coasts of the north american continent these results may be important in the context of recently proposed scenarios of climatic change

late stage estuary infilling controlled by limited accommodation space in the hudson river high resolution seismic data and sediment cores reveal the late holocene subsurface stratigraphy of the broad tappan zee piermont region of the hudson river estuary we identify a series of distinct extensive horizons beneath the marginal flats channel banks and main channel in this area physical properties and lithology from sediment cores suggest that these horizons are surfaces of erosion or nondeposition radiocarbon dates indicate that they correspond with three distinct time horizons with maximum ages of 3400 2200 and 1600 yr bp we also distinguish two sedimentary facies that occupy the marginal flats and channel banks the deeper facies forms a deposit 2 km wide and 7 km long that accumulated at rates of 2 4 mm yr in the vicinity of the sparkill creek prior to 1700 yr bp overlying and onlapping the 2200 yr bp seismic surface based on its internal geometry morphology and proximity to a tributary we interpret this facies as a delta deposit the shallower facies accumulated more slowly 1 2 mm yr overlying the delta deposit to the south and dominating the marginal flats to the north surface sediment samples and geophysical data reveal that the modern marginal flats are no longer actively depositional but dominated by nondeposition or erosion limited accommodation space in the hudson river estuary may be the critical factor contributing to the observed sedimentary pattern characterized by intervals of deposition punctuated by episodes of erosion an estuarine system that has reached a state of morphological equilibrium will be sensitive to even small fluctuations in sea level and climate conditions which may account for the intervals of deposition and erosion we observe limited accommodation space and intermittent sediment deposition in the hudson river estuary may be due to its evolution from a fjord filled with glacial lake sediments which distinguishes its infilling behavior from the classic drowned river valley estuary

modern saltmarsh diatom distributions of the outer banks north carolina and the development of a transfer function for high resolution reconstructions of sea level we collected modern diatom samples from currituck barrier island oregon inlet and pea island marshes outer banks north carolina usa which have different salinity regimes due to their varying distances from a major barrier island inlet multivariate analyses separate the saltmarsh diatom assemblages into distinct elevational zones dominated by differing abundances of polyhalobous mesohalobous and oligohalobous taxa suggesting that the distribution of saltmarsh diatoms is a direct function of elevation with the most important controlling factors being the duration and frequency of subaerial exposure we developed the first diatom based transfer function for the east coast of north america to reconstruct former sea levels based upon the relationship between diatom assemblage and elevation results imply that this is possible to a precision of 0 08 m superior to most similar studies from temperate mid latitude environments the transfer function is used to construct a relative sea level curve from fossil assemblages from salvo north carolina these results suggest a sea level rise of 0 7 m over the last c 150 years at an average of c 3 7 mm year 1 this is

thermal history of the southwestern meguma zone nova scotia from an 40ar 39ar and fission track dating study of intrusive rocks two geologically distinct regions within the meguma terrane have been studied in detail and are shown to have contrasting thermal histories this conclusion is based on 31 new 40ar 39ar age spectra on micas k feldspars and hornblendes from several of the plutons in southern nova scotia which are satellites to the much larger south mountain batholith smb in addition we report four k feldspar age spectra from a locality in the northeastern part of the smb and seven fission track ages from both the southern and northern areas the complex age spectrum of hornblende from a mafic phase associated with the bamngton passage pluton suggests a minimum intrusive age of 385 ma a result consistent with geologic evidence that this pluton represents an early less evolved magmatic pulse later intrusive activity appears to have been coeval with the intrusion of the smb at ca 370 ma ago in the southern region argon clocks in feldspars were completely reset and mica clocks variably reset by a later thermal event the cumulative geochronologic and geologic evidence constrains this event to 300 320 ma ago in the smb this alleghanianl hercynian thermal disturbance is much less pronounced and appears to be localized to small areas that are often associated with economic mineralization k feldspars from the southern plutons record an episode of argon loss 220 230 ma ago which is less evident in the smb to the north upper triassic dike injection in the southern region associated with the initial rifting phase of the canadian atlantic margin accompanied this milder thermal pulse apatites in the two regions record a mean fission track age of ca 180 ma which we attribute to the final cooling of the terrane below about 100 c the timing of this event coincides with regional uplift recorded in sedimentary sequences along much of the maritime continental shelf deux kgions gtologiques distinctes inttgkes au terrane de meguma ont ctt ctudites en dctai1 et leurs histoires thermales

sea level climate correlation during the past 1400 yr we present a new mean high water curve for hammock river marsh clinton connecticut obtained by improving the age model for an existing record of relative marsh elevation based on foraminiferal analysis of a 1 8 m long peat core unlike the earlier curve the new curve confirms trend changes in mean high water rise during the past 1400 yr as noted for salt marshes 15 km farther west suggesting a regional cause these trend changes and century scale mean high water variations in the clinton record correlate positively with large scale regional variations in sea surface and summer air temperature indicating a link between sea level and the climate ocean system on the basis of the clinton mean high water curve we conclude that real sea level oscillated centimeters to decimeters on a century time scale over the past 1400 yr was 25 25 cm higher ca a d 1050 medieval warm period than ca a d 1650 little ice age and rose at a mean rate of 1 mm yr 1 over the past 350 yr there was little or no rise during the cool 1800s

geologic and human factors in the decline of the tidal salt marsh lithosome the delaware estuary and atlantic coastal zone abstract two to three thousand years ago the fringing tidal salt marsh wetlands including brackish and freshwater marsh of the delaware coastal zone were three to four times wider than at present observed variations in rates of marsh surface aggradation suggest that some areas are undergoing inundation whereas many other areas are undergoing aggradation at rates greater than sea level rise as measured by a local tidal gauge average 33 cm century based on a 70 year record and may be undergoing floral succession accompanying these sedimentary processes are coastal erosion rates up to 6 9 m yr along the delaware estuary up to 2 8 m yr along the delaware atlantic coast and ranging from 0 1 m yr to 0 6 m yr along the delaware atlantic coastal lagoons human development has destroyed nearly 9 of delaware s fringing salt marshes between 1938 and 1975 the rapidly growing trend toward hardening the edge of the adjacent landward uplands leads us to the conclusion that much of the fringing salt marsh of delaware will disappear over the next two to three centuries with only small remnants declining to extinction ca 1500 1700 years into the future impacts on the state of delaware comprised of 13 fringing salt marshes 1 4 century ago will be profound in terms of destruction of a large segment of the atlantic coastal or eastern north american migratory bird flyway and an eventual forced accommodation of the inhabitants of delaware to these naturally ongoing geological processes

field experiments on bioturbation in salt marshes bombay hook national wildlife refuge smyrna de usa implications for sea level studies the suitability of marsh sites for sea level studies was examined based on field experiments along a transect from low to high marsh bead distributions were determined both seasonally and after 7 years seasonal sediment mixing was greatest in the low marsh and in the late spring and early summer when biological activity is greatest however after an initial interval of relatively intense reworking the bead concentrations reached an approximate equilibrium profile characteristic of each marsh environment as reflected by the profiles obtained after 7 years mixed layer thickness is greatest 10 cm in the intermediate and low marsh and burial rates are rapid 3 7 11 1 mm yr 1 moreover burial rates are comparable to or even surpass longer term 30 to 150 yr radiotracer derived sediment accumulation rates and rates of local and regional sea level rise 4 mm yr 1 therefore sediment accumulation rates appear to reflect primarily sediment resuspension redeposition within the system due to bioturbation thus bioturbation may be critical to the ability of marshes to keep pace with sea level while seemingly precluding the use of low marsh for high resolution sea level studies copyright 2008 john wiley sons ltd

quantitative vertical zonation of salt marsh foraminifera for reconstructing former sea level an example from new jersey usa we present a quantitative technique to reconstruct sea level from assemblages of salt marsh foraminifera using partitioning around medoids pam and linear discriminant functions ldf the modern distribution of foraminifera was described from 62 surface samples at three salt marshes in southern new jersey pam objectively estimated the number and composition of assemblages present at each site and showed that foraminifera adhered to the concept of elevation dependent ecological zones making them appropriate sea level indicators application of pam to a combined dataset identified five distinctive biozones occupying defined elevation ranges which were similar to those identified elsewhere on the u s mid atlantic coast biozone a had high abundances of jadammina macrescens and trochammina inflata biozone b was dominated by miliammina fusca biozone c was associated with arenoparrella mexicana biozone d was dominated by tiphotrocha comprimata and biozone e was dominated by haplophragmoides manilaensis foraminiferal assemblages from transitional and high salt marsh environments occupied the narrowest elevational range and are the most precise sea level indicators recognition of biozones in sequences of salt marsh sediment using ldfs provides a probabilistic means to reconstruct sea level we collected a core to investigate the practical application of this approach ldfs indicated the faunal origin of 38 core samples and in cross validation tests were accurate in 54 of 56 cases we compared reconstructions from ldfs and a transfer function the transfer function provides smaller error terms and can reconstruct smaller rsl changes but ldfs are well suited to rsl reconstructions focused on larger changes and using varied assemblages agreement between these techniques suggests that the approach we describe can be used as an independent means to reconstruct sea level or importantly to check the ecological plausibility of results from other techniques

a sea level rise curve from guilford connecticut usa abstract high resolution stratigraphic studies based on sediment chemistry lithology macroflora and benthic foraminiferal assemblages in three peat cores from coastal salt marshes at guilford connecticut show that coastal marshes are ephemeral environments marsh wide environmental variations were common and century long episodes of relative submergence alternated with emergence despite about 2 m of relative sea level rise rslr in connecticut over the last 1500 years the marshes have expanded both landwards and seawards and marsh accretion has been outpaced only marginally by rslr we used radiocarbon dating and the level of anthropogenic markers metal pollution as dated with 210 pb in the cores for age control for most of the last 1000 years the rate of rslr was between 1 3 and 1 8 mm yr but over the last 300 400 years it increased to 2 9 3 3 mm yr and has been faster than the accretion rate especially in the middle marsh the net submergence rate or submergence index ratio of the rate of rslr and marsh accretion rate averaged about 1 15 over the last 1000 years and increased to about 1 5 over the last 200 years the rate of rslr was very sluggish during the early part of the little ice age but we found a slightly higher rate during the little climate optimum this excursion is close to the noise level however the most significant observation is that rslr increased strongly around a d 1650 the onset of this acceleration falls in the middle to end of the little ice age and thus preceded the period of modern global warming that started late last century and that has been tentatively correlated with anthropogenic emissions of greenhouse gases

the process of sedimentation on the surface of a salt marsh abstract an unditched salt marsh creek drainage basin holland glade marsh lewes delaware has a sedimentation rate of 0 5 cm year 1 during normal storm free conditions the creek carries negligible amounts of sand and coarse silt of the material in the waters flooding the marsh surface over 80 disappears from the floodwaters within 12 m of the creek about one half of the lost material is theoretically too fine to settle even if flow were not turbulent however sediment found on spartina stems can account for the loss the quantity of suspended sediment that does reach the back marsh during these normal tides is inadequate to maintain the marsh surface against local sea level rise this suspended sediment is also much finer than the deposited sediments additionally remote sections of low marsh sections flooded by only the highest spring tides have 15 30 cm of highly inorganic marsh muds this evidence indicates that normal tidal flooding does not produce sedimentation in holland glade study of the effects of two severe storms of a frequency of once per year suggests that such storms can deposit sufficient sediment to maintain the marsh the actual deposition of fine grained sediments fine silt and clay appears to result primarily from biological trapping rather than from settling in addition this study proposes that the total sedimentation on mature marshes results from a balance between tidal and storm sedimentation storms will control sediment supply and movement on micro and meso tidal marshes and will have less influence on macro tidal marshes

early silurian paleolatitude for central newfoundland from paleomagnetism of the wigwam formation redbeds and minor volcanic rocks of the early silurian wigwam formation of the botwood group were sampled in the exploits subzone of the dunnage zone of central newfoundland at 18 sedimentary and 3 volcanic sites thermal demagnetization isolated a shallow northward or southward magnetization d 356 0 i 16 8 k 12 9 95 9 2 n 21 site means after correction for the tilt of bedding a positive fold test demonstrates that this remanence predates regional siluro devonian folding a primary age for the remanence is indicated by positive conglomerate tests on volcanic clasts and reversals correlated with sedimentary stratigraphy antiparallel remanence directions at sites of opposite polarity indicate that the primary remanence is not partially overprinted by a secondary component the exploits subzone of the dunnage zone is interpreted to have been at low paleolatitudes 8 5 s 5 during the early silurian we reached a similar conclusion for the notre dame subzone of the dunnage zone in

late pleistocene upland stratigraphy of the western delmarva peninsula usa abstract new pedological geological archaeological and geochronological data from the miles point site in eastern maryland are compared with similar data from other nearby sites to develop a framework for interpreting the upland stratigraphy in the western delmarva peninsula our results indicate the presence of two different intervals of loess deposition the earlier loess miles point loess was deposited between 41 and 25 ka a paleosol tilghman soil formed in this loess was initially developed in grasslands and boreal environments during a subsequent period of landscape stability between 25 and 18 ka between 18 and 12 8 ka the miles point loess and the tilghman soil were eroded in many areas as evidenced by diagnostic ca 12 8 ka clovis age artifacts lying unconformably on the tilghman soil cores adjacent to the deep channel area of the chesapeake bay confirm this erosional unconformity prior to 12 7 ka a relatively uniform terminal pleistocene loess paw paw deposited prior to the early archaic period buried clovis age lag artifacts and other archaeological remains older than 13 2 ka stratigraphic evidence from the late pleistocene lower susquehanna river valley suggests that the paw paw loess is the result of eolian redeposition and reworking of non glacial eroded upland sediments that filled the valley between 12 7 and 11 5 ka

holocene sea level changes along the north carolina coastline and their implications for glacial isostatic adjustment models abstract we have synthesized new and existing relative sea level rsl data to produce a quality controlled spatially comprehensive database from the north carolina coastline the rsl database consists of 54 sea level index points that are quantitatively related to an appropriate tide level and assigned an error estimate and a further 33 limiting dates that confine the maximum and minimum elevations of rsl the temporal distribution of the index points is very uneven with only five index points older than 4000 cal a bp but the form of the holocene sea level trend is constrained by both terrestrial and marine limiting dates the data illustrate rsl rapidly rising during the early and mid holocene from an observed elevation of 35 7 1 1 m msl at 11062 10576 cal a bp to 4 2 m 0 4 m msl at 4240 3592 cal a bp we restricted comparisons between observations and predictions from the ice 5g vm2 with rotational feedback glacial isostatic adjustment gia model to the late holocene rsl last 4000 cal a bp because of the wealth of sea level data during this time interval the ice 5g vm2 model predicts significant spatial variations in rsl across north carolina thus we subdivided the observations into two regions the model forecasts an increase in the rate of sea level rise in region 1 albemarle currituck roanoke croatan and northern pamlico sounds compared to region 2 southern pamlico core and bogue sounds and farther south to wilmington the observations show late holocene sea level rising at 1 14 0 03 mm year 1 and 0 82 0 02 mm year 1 in regions 1 and 2 respectively the ice 5g vm2 predictions capture the general temporal trend of the observations although there is an apparent misfit for index points older than 2000 cal a bp it is presently unknown whether these misfits are caused by possible tectonic uplift associated with the mid carolina platform high or a flaw in the gia model a comparison of local tide gauge data with the late holocene rsl trends from regions 1 and 2 support the spatial variation in rsl across north carolina and imply an additional increase of mean sea level of greater than 2 mm year 1 during the latter half of the 20th century this is in general agreement with historical tide gauge and satellite altimetry data

recent volumetric changes in salt marsh soils salt marsh sediment volume decreases from organic decomposition compaction of solids and de watering and each of these processes may change with age variability in the vertical accretion rate within the upper 2 m was determined by assembling results from concurrent application of the 137 cs and 210 pb dating techniques used to estimate sediment age since 1963 1964 and 0 to ca 100 years before present ybp respectively the relationship between 210 pb and the 137 cs dated accretion rates sed 210 and sed 137 respectively was linear for 45 salt marsh and mangrove environments sed 210 averaged 75 of sed 137 suggesting that vertical accretion over the last 100 years is driven by soil organic matter accumulation as shown for the pre 137 cs dated horizon the ratio of sed 210 sed 137 declines with increasing mineral content a linear multiple regression equation that includes bulk density and sed 137 to predict sed 210 described 97 of the variance in sed 210 sediments from connecticut delaware and louisiana coastal environments dated with 14 c indicate a relatively constant sediment accretion rate of 0 13 cm year 1 for 1000 7000 ybp which occurs within 2 m of today s marsh surface and equals modern sea level rise rates soil subsidence is not shown to be distinctly different in these vastly different coastal settings the major reason why the sed 137 measurements indicate higher accretion rates than do the sed 210 measurements is because the former apply to younger sediments where the effects of root growth and decomposition are greater than in the latter the most intense rates of change in soil volume in organic rich salt marshes sediments is therefore neither in deep or old sediments 4 m 1000 years but within the first several hundreds of years after accumulation the average changes in organic and inorganic constituents downcore are nearly equal for 58 dated sediment cores from the northern gulf of mexico these parallel changes downcore are best described as resulting from compaction rather than from organic matter decomposition thus most of the volumetric changes in these salt marsh sediments occurs in the upper 2 m and declines quickly with depth extrapolation forwards or backwards using results from the 210 pb and the 137 cs dating technique appear to be warranted for the types of samples from the environments described here

influence of glacial isostatic adjustment on tide gauge measurements of secular sea level change modem tide gage records of secular sea level change are strongly contaminated by the ongoing influence of glacial isostatic adjustment in this paper we employ an accurate high resolution model of the glacial isostatic adjustment process to filter this signal from time series consisting of annual mean heights observed on over 500 tide gages from which records of duration longer than 10 years are available these records are all contained in the archive of the permanent service for mean sea level at bidston in the united kingdom prior to removal of the isostatic adjustment contamination from these records the secular sea level change signal is seen to exhibit both rising and falling levels depending upon geographic location with regions of falling level corresponding to those that were ice covered during the last glaciation event of the present ice age after filtering the geographic heterogeneity in rates is considerably reduced so much so that a globally coherent component consisting of a rise of sea level at a rate of 2 4 0 9 mm yr 1 is revealed this could conceivably be driven by the greenhouse effect although no particular mechanism has been unambiguously identified by our analyses we investigate the impact of a number of different variants of the analysis procedure upon the inferred global signal

sediment transport and trapping in marsh systems implications of tidal flux studies although the concept that marshes act as major sediment sinks may be accurate when viewing them over the last few millennia tidal transport studies suggest considerable variability with most marshes presently exporting material on an annual basis high salinity marshes along the mid atlantic coast of the united states appear to be losing 1 2 kg m 2 yr 1 while submerged upland marshes on the delmarva peninsula are eroding at rates of up to 14 kg m 2 yr 1 by comparison at least one deltaic marsh on the dutch coast along with several estuarine marshes appear to be accumulating sediment in order to assess the trapping ability of marshes in large estuaries we constructed a sediment budget for chesapeake bay which included a variety of wetland types calculations indicate that estuarine marshes trap 5 11 of the annual chesapeake bay sediment input or about one half that previously estimated it appears that most sedimentation in estuaries and perhaps other coastal systems occurs in subtidal flats below the limit of emergent marsh vegetation as mud flats become vegetated and estuarine infilling proceeds there may be a tendency for tidal currents to become ebb dominated which promotes a net export of particulates the extent to which major storm events are capable of returning enough material to balance the long term accretionary budget of tidal marshes and keep them abreast of rising sea level is open to question differences in tidal dynamics seasonal changes in sea levels and higher temperatures may help explain why in the u s southern marshes are more susceptible to export and eventual erosion than northern marshes we hypothesize that another factor the recent reductions of terrigenous sediment inputs from the southern river systems of the u s may also be critical sediment starvation may have led to undernourishment of wetland systems of the coastal zone over the last half century which may be reflected in the net export measured in the tidal marshes in this region furthermore we postulate that changes in sediment inputs are more important than eustatic sea level rise in causing the past losses of marshes which are now undergoing mass erosion thus future wetland survival will depend as much as particulate inputs to the coastal zone as on the prospects of a global rise in sea level and more efforts should be made to quantify the sediment budgets of tidal marshes

integrated high precision analyses of holocene relative sea level changes lessons from the coast of maine a suite of salt marsh peat samples from four sites along the coast of maine wells phippsburg gouldsboro and machiasport has been analyzed using high precision techniques to determine local relative sea level trends and to evaluate proposed along coast warping a spatially variable set of relative sea level records in maine would have important implications for geophysical models that predict the response of the lithosphere during deglaciation and postglacial isostatic relaxation the amplification of m sub 2 tidal range in the gulf of maine and the bay of fundy during the holocene is modeled and applied to the mean high water data yielding best estimate envelopes of mean tide level change for each location average long term thousands of years mean tide level rise did not exceed approx 2 mm yr at any time during the late holocene at wells phippsburg and machiasport between 4 5 and 3 ka calibrated cal the apparent rate of rise at gouldsboro was higher than at any other site studied this along coast variation in the rate of mean tide level rise may reflect time of deglaciation neotectonics or differential isostatic adjustments a slight acceleration of mean tide level rise has occurred during the past millennium in gouldsboro and machiasport if 12 m downwarping inmore easternmost maine occurred as suggested in other publications it must have happened prior to 5 7 ka cal 84 refs 13 figs 8 tabs less

mid holocene sea level change on the eastern shore of virginia abstract the 1965 and 1987 curves of relative sea level rsl change for the eastern shore of virginia differ markedly from similar curves for delaware new jersey and new england the latter show a rapid and continuous rsl rise between 6000 and 3000 or 2000 yrs b p whereas the curves for the eastern shore of virginia suggest a sea level lowering between 5100 and 4400 yrs b p or a marked retardation between 4700 or earlier and 4000 yrs b p new radiocarbon dates on high marsh basal peat samples from the eastern shore of virginia indicate however a mid holocene rate of rsl rise similar to that indicated by the other regional curves

geochemical impacts to prehistoric iron rich siliceous artifacts in the nearshore coastal zone abstract in the middle atlantic region of the united states landscapes drowned by sea level rise contain scores of prehistoric archaeological sites these sites provide archaeologists with a rare opportunity to investigate various geologic processes during the transition from a terrestrial to an offshore setting the materials associated with an archaeological site are exposed to a series of geochemical processes inherent to the formation of tidal marsh the duration of the geochemical exposure to tidal marsh is largely dependent on the rate of marine transgression here we describe the stages associated with the sulfidization and sulfuricization scheme and the impact to iron rich lithic artifacts from naturally drowned archaeological sites sulfidization and sulfuricization should also impact buried archaeological materials as a result of anthropogenic dredge spoil dumping and the creation of man made tidal marshes along modern coastlines our results indicate that the surfaces of an iron rich artifact as well as its interior are visually and geochemically altered by prolonged exposure to the anaerobic conditions of a tidal marsh not only should researchers be cautious about making lithic material identification on artifacts found within coastal tidal marsh areas but museum curators should be aware of the damaging impact of long term aerobic storage the geochemical tidal marsh scheme that has altered or corroded iron rich lithic artifacts in the nearshore zone is an expression of a process that has impacted numerous earlier prehistoric sites currently located on the continental shelf or beneath the coastal estuaries around the world

sea level change and subsidence in the delaware estuary during the last 2200 years abstract we produced eight new sea level index points that reconstruct a 2 5 m relative sea level rsl rise at sea breeze in the delaware bay from 200 bce to 1800 ce the precision of our reconstruction improved upon existing data by using high resolution surveying methods ams radiocarbon dating of in situ plant macrofossils collected immediately above the basal contact between pre holocene sand and salt marsh sediments foraminifera as sea level indicators and by accounting for tidal range changes through time our new data were combined with a database of 65 sea level index points available for the delaware bay to estimate the rate of rsl rise in the upper 1 26 0 33 mm yr and lower bay 1 30 0 36 mm yr using a spatial temporal model correction for changes in tidal range through time removed the disparity in rate between the upper and lower delaware bay that had previously been postulated after paleotidal correction the rates of rsl rise estimated for the delaware bay 1 25 0 27 mm yr correlate with the 1 3 mm yr rate reported for new jersey maryland and virginia and confirm that the maximal ongoing forebulge collapse along the u s atlantic coast is focused on the mid atlantic

micropaleontologic record of late pliocene and quaternary paleoenvironments in the northern albemarle embayment north carolina u s a abstract micropaleontological data provide a strong actualistic basis for detailed interpretations of quaternary paleoenvironmental change the 90 m thick quaternary record of the albemarle embayment in the mid atlantic coastal plain of the usa provides an excellent opportunity to use such an approach in a region where the details of quaternary environmental change are poorly known the foraminiferal record in nine cores from the northern outer banks east of albemarle sound north carolina indicates the deposition of subhorizontal mostly open marine early to late pleistocene units unconformably upon a basement of late pliocene reduced oxygen fine grained shelf basin deposits pollen data record several warm cool fluctuations within the early to mid pleistocene deposits diatom data indicate that some fresh and brackish water units occur within the generally open marine pleistocene succession a channel cut by the paleo roanoke river during the last glacial sea level lowstand occurs in the northern part of the study area pollen indicates that the basal fluvial valley fill accumulated in cooler than modern climate conditions in the latest pleistocene overlying silts and muds accumulated under cool climatic estuarine conditions according to diatom and pollen data radiocarbon ages from the estuarine deposits indicate that the bulk of these sediments accumulated during the latest pleistocene the estuarine channel fill deposits are overlain by holocene open marine sands deposited as the rising sea transgressed into the estuary approximately 8 5 to 9 0 kyr bp within the barrier island drill cores of this study fully marine sedimentation occurred throughout the holocene however immediately west of the present barrier island mid to late holocene estuarine deposits underlie the modern albemarle sound the islands that currently form a continuous barrier across the mouth of albemarle sound have a complex history of holocene construction and destruction and large portions of them may be less than 3 kyr old the barrier island sands overlie open marine sands of colington shoal in the north and to the south overlie fluvial and marine sand filling paleo roanoke tributary valleys the pleistocene sediments underlying the northern outer banks study area are mainly of open inner to mid shelf origin if as is likely sea level continues to rise a return to such environmental conditions is likely in the near future

holocene environmental and parasequence development of the st jones estuary delaware usa foraminiferal proxies of natural climatic and anthropogenic change abstract the benthic foraminiferal record of marshes located along western delaware bay st jones estuary usa reflects the response of estuaries to sea level and paleoclimate change during the holocene system tracts are recognized and within them parasequences based on sedimentological and foraminiferal assemblages identification the parasequences defined by foraminiferal assemblages appear correlative with rapid holocene climate changes that are of worldwide significance 6000 5000 4200 3800 3500 2500 1200 1000 and 600 cal years bp following postglacial sea level rise modern subestuaries and marshes in the region began to develop between 6000 and 4000 years bp depending on their proximity to the mouth of delaware bay and coastal geomorphology initial sediments were fluvial in origin with freshwater marshes established around 4000 years bp the subsequent sea level transgression occurred sufficiently slowly that freshwater marshes alternated with salt marshes at the same sites to around 3000 years bp locally another two transgressions are identified at 1800 and 1000 years bp respectively marine influence increased in the estuaries until 600 years bp little ice age when regression occurred sea level began to rise again during the mid 19th century at the end of the little ice age when marshes became established the presence of a sand lens in the upper and middle estuary and the reduction in the number of tests in the top samples in cores from the same area also suggest an anthropogenic influence the estuary infill resulted in a sharp transgressive sequence represented by salt marsh foraminiferal assemblages in the upper part of the cores the increase in marsh foraminifera in both areas suggests an increase in marine influence that might be due to the transgression beginning at the end of the little ice age about 150 180 years ago coupled with anthropogenic straightening of the channel in 1913