debris fan constrictions and flood hydraulics in river canyons some implications from two dimensional flow modelling rapids in river canyons are frequently found at sites where debris fans constrict flow along the channel whereas some fans may have persisted in the same location with unchanging geometry for centuries to millennia others have changed in response to flow conditions imposed by successive floods such a change in boundary conditions may alter local flow hydraulics this paper utilizes two dimensional flow modelling to compare flood hydraulics along two alternative versions of an idealized reach of a river canyon one with uniform width gradient and cross section and a second perturbed by a prominent debris fan along the valley wall the flow pattern along the reach with the fan is far more complex than the pattern along the uniform reach maximum velocity along the debris fan reach is up to 50 per cent higher than along the uniform reach maximum bed shear stress is up to three or four times higher and an area of supercritical flow is predicted extending from the nose of the fan into the zone of flow expansion immediately downstream comparison of model output along longitudinal profiles of the two reaches indicates that the backwater effect of the fan extends several valley widths upstream predicted flows based on the same stage are as much as 190 to 230 per cent greater along the uniform reach than along the debris fan reach reconstruction of palaeoflood discharge based on remnant flood marks in the vicinity of the fan would be sensitive to assumptions about boundary conditions that existed in the past this effect relaxes over a longitudinal distance of several hundred metres furthermore there are significant cross stream gradients that change slope and direction several times in the vicinity of the fan calling into question the utility of one dimensional step backwater hydraulic models for predicting high water marks in areas of complex valley morphology

sea level change along the italian coast during the holocene and projections for the future published and new sea level data are used to provide projections of sea level change in italy for the year 2100 by adding new isostatic and tectonic component to the ipcc and rahmstorf projections comparison of the observations from more than 130 sites with different geomorphological and archaeological sea level markers with the predicted sea level curves provides estimates of the vertical tectonic contribution to the relative sea level change the results are based on the most recent anu model for the ice sheets of both hemispheres including an alpine deglaciation model on the basis of the eustatic tectonic and isostatic components to the sea level change projections are provided for marine inundation scenarios for the italian coastal plains for the year 2100 that today are at elevations close to current sea level

interhemispheric air temperature phase relationships in the nonlinear dansgaard oeschger oscillation it has previously been suggested that the southern ocean might act as a thermal reservoir in mediating the relationship between the northern and southern hemisphere air temperature signals during a dansgaard oeschger cycle on the basis of a climate model based analysis we demonstrate on the contrary that it is equatorial and subtropical north atlantic thermocline waters that act so as to integrate and damp the northern hemisphere signal to fix the amplitude and phase of the southern hemisphere counterpart to the more intense north atlantic component of the oscillation the dynamics of the southern ocean component of the atlantic meridional overturning circulation are critical in explaining the evolution of the interhemispheric temperature phase relationships european project for ice coring in antarctica dronning maud land inferred air temperature variations are in phase with sea surface temperatures north of the antarctic sea ice edge suggesting that it is via a fast atmospheric pathway that this temperature signal is transmitted into the antarctic ice core record

space geodetic and water level gauge constraints on continental uplift and tilting over north america regional convergence of the ice 6g_c vm5a vm6 models

thermohaline instability and the formation of glacial north atlantic super polynyas at the onset of dansgaard oeschger warming events late quaternary rapid warming events inferred on the basis of oxygen isotopic data from greenland ice cores are the most prominent characteristic of millennial scale dansgaard oeschger oscillations in a coupled climate model simulation which has accurately reproduced this oscillatory behavior for the first time we show that formation of a glacial north atlantic super polynya characterizes the initial stage of transition from cold stadial to warm interstadial conditions the winter polynya forms within the otherwise sea ice covered north atlantic as a consequence of the onset of a thermohaline convective instability beneath an extensive stadial sea ice lid early in the stadial period the tendency for thermal convective instability of an extensive warm pool beneath the sea ice lid is strongly inhibited by a stabilizing vertical salinity gradient which gradually diminishes until a thermohaline convective instability occurs that leads to polynya formation and the rapid retreat of north atlantic sea ice cover

elevation of the last interglacial highstand in sicily italy a benchmark of coastal tectonics well preserved mis 5 5 terraces in sicily are identified primarily by the index fossil strombus bubonius and dated by amino acid racemization aar electron spin resonance esr uranium thorium u th and thermo luminescence tl methods this review of published data and new results for the island of sicily and neighbouring small islands of egadi ustica and lampedusa identifies areas of rapid uplift in the east up to 175 m elevation above sea level slower uplift in the north 29 m and relative stability in the northwest 2 18 m in contrast about 250 km of the southern coastline of sicily does not appear to contain mis 5 5 outcrops in eastern sicily correlation of mis 5 5 highstands is based on strombus bubonius discovered at 86 m and correlated with the inner margin terrace at 110 m in the taormina area a fossiliferous marine conglomerate on a terrace with an inner margin at 115 m occurs in an area with undated terrace morphology and elevation data based on esr methodology applied to fossils sampled at 105 m in taormina we attribute this terrace to mis 5 probably 5 5 this age allows us to constrain the date of one point along a very long coastline that is otherwise undated a newly discovered fossil beach between 7 and 9 m at cefalu north central sicily attributed to mis 5 1 5 3 using aar analysis permits correlation of mis 5 5 to a 29 m high tidal notch geomorphologically related to a terrace at the same elevation cefalu lies in an important position between the uplifted coastline of northeastern sicily and the more stable coastline of western sicily this compilation of mis 5 5 data for all of sicily reflects the active tectonics of eastern sicily in contrast to the rest of the island

8000 years of coastal changes on a western mediterranean island a multiproxy approach from the posada plain of sardinia abstract a multi proxy palaeoenvironmental investigation was conducted to reconstruct the holocene history of coastal landscape change in the lower posada coastal plain of eastern sardinia in the mediterranean region coastal modifications during the holocene have been driven by a complex interplay between climate geomorphological processes and human activity in this paper millennial scale human sea level environment interactions are investigated near posada one of the largest coastal plains in eastern sardinia biostratigraphic and palynological approaches were used to interpret the chrono stratigraphy exhibited by a series of new cores taken from the coastal plain this new study elucidates the main paleoecological changes phases of shoreline migration and relative sea level change during the last 8000 years these results indicate the major role of sea level stabilization and high sediment supply in driving major landscape changes especially during the neolithic period 6th 4th millennia bc and the long term settlement history of this coastal valley area it is concluded that human occupation of the coastal plain from prehistoric to historical times was most likely constrained by the rapid and constant evolution of this coastal landscape

the efficacy of stream power and flow duration on geomorphic responses to catastrophic flooding abstract geomorphologists have long studied the impacts of extreme floods yet the association between the magnitude of flow parameters discharge velocity shear stress or stream power and resulting geomorphic effectiveness remains vague and non deterministic attempts have been made to include flow duration and total expenditure of stream power in combination with peak unit stream power as important variables but there has been minimal exploration of this hydraulic combination taking advantage of tropical storm irene s rapid track through eastern vermont usa in late summer 2011 this paper presents the array of geomorphic responses to a short duration time to peak of

coarse sediment distribution as evidence of an elevation limit for flash flooding bear creek colorado bear creek is a tributary of the south platte river in central colorado the stream flows east from an elevation of 4348 m at the continental divide to the mountain front at 1670 m it thus encompasses the 2300 m elevation limit for substantial rainfall flooding in the colorado front range proposed by jarrett maximum paleoflood discharges estimated from flood deposits at four sites along bear creek demonstrate a consistent decrease in unit discharge with increasing elevation and support the hypothesis of an upper elevation limit for rainfall floods the unit discharge values were used to explain coarse sediment distribution along bear creek measurements of coarse grained channel sediment at 19 sites along the creek indicate a decrease in particle size in flood deposits with increasing elevation as well as a decrease in the size of clasts introduced to the main channel along tributaries these changes in grain size are hypothesized to reflect changes in the competence of channel transport as a result of snowmelt dominated versus rainfall dominated discharge regimes above and below 2100 m elevation calculations of flow competence versus entrainment thresholds for the deposits may support this interpretation one of the geomorphic implications of the elevation limit on flash flooding is a reversal of the usual downstream fining trend in coarse channel sediments

constraining holocene sea levels using u th ages of phreatic overgrowths on speleothems from coastal caves in mallorca western mediterranean phreatic overgrowths on speleothems pos are carbonate formations deposited at the water table of caves in unique karstic coastal settings having morphologies that can be directly related to sea level at the time of formation the u th ages of calcite and aragonite overgrowths collected from the modern water table in coastal caves on mallorca cova de cala varques a and cova des pas de vallgornera were determined using high precision mc icpms techniques u th ages indicate that phreatic carbonate deposition occurred between ca 2 8 and at least 0 6 ka bp and are in accord with an archeologically estimated age of 3 7 3 0 ka bp for a drowned prehistoric construction at a depth of 1 m below current sea level in a cave from the same area speleothem 13c and 18o and chemical composition of cave pools provide supportive evidence that pos reflect mixing between seawater and brackish water table copyright 2010 john wiley sons ltd

tidal notches in mediterranean sea a comprehensive analysis abstract recent works evelpidou et al 2012 suggest that the modern tidal notch is disappearing worldwide due sea level rise over the last century in order to assess this hypothesis we measured modern tidal notches in several of sites along the mediterranean coasts we report observations on tidal notches cut along carbonate coasts from 73 sites from italy france croatia montenegro greece malta and spain plus additional observations carried outside the mediterranean at each site we measured notch width and depth and we described the characteristics of the biological rim at the base of the notch we correlated these parameters with wave energy tide gauge datasets and rock lithology our results suggest that considering the development of tidal notches the consequence of midlittoral bioerosion as done in evelpidou et al 2012 is a simplification that can lead to misleading results such as stating that notches are disappearing important roles in notch formation can be also played by wave action rate of karst dissolution salt weathering and wetting and drying cycles of course notch formation can be augmented and favoured also by bioerosion which can in particular cases be the main process of notch formation and development our dataset shows that notches are carved by an ensemble rather than by a single process both today and in the past and that it is difficult if not impossible to disentangle them and establish which one is prevailing we therefore show that tidal notches are still forming challenging the hypothesis that sea level rise has drowned them

side valley tributary fans in high energy river floodplain environments sediment sources and depositional processes navarro river basin california side valley tributary fans within the main axial valley river floodplain system are integral components of the sediment assemblage characterizing floodplains in the high energy navarro river basin california laboratory analyses of subsurface core and auger samples from four study sites reveal that sediment size distributions within the floodplain are controlled by spatial and temporal variation in sediment sources and depositional processes over 75 of sediment within individual lower fan strata are poorly sorted and include gravel clasts inferred to be contributions from the side valley tributary whereas remaining strata are composed of fine sediment less than 2 mm without gravel high water marks indicate that portions of the side valley tributary fans are episodically inundated by axial valley overbank flow a factor that influences fan relief and profile thus two dominant sources supply sediment to this transitional environment side valley tributaries and the axial valley river the transport and depositional processes that supply sediment to the fans operate under three conditions 1 tributary debris or fluvial flows and selective entrainment of fines by fan surface flows deposit sediment when there is no overbank flow from the axial channel 2 overbank flow deposits sediment derived from the axial valley river when there is no tributary input and 3 tributary flows deposit sediment while the floodplain is inundated by floods from the axial valley river the mixing and interlayering of sediment from these disparate sources within the active floodplain illustrate the significance of both hillslope floodplain and channel flood plain interactions in high energy fluvial systems with floodplains

mantle dynamics in the mediterranean the mediterranean offers a unique opportunity to study the driving forces of tectonic deformation within a complex mobile belt lithospheric dynamics are affected by slab rollback and collision of two large slowly moving plates forcing fragments of continental and oceanic lithosphere to interact this paper reviews the rich and growing set of constraints from geological reconstructions geodetic data and crustal and upper mantle heterogeneity imaged by structural seismology we proceed to discuss a conceptual and quantitative framework for the causes of surface deformation exploring existing and newly developed tectonic and numerical geodynamic models we illustrate the role of mantle convection on surface geology a coherent picture emerges which can be outlined by two almost symmetric upper mantle convection cells the downwellings are found in the center of the mediterranean and are associated with the descent of the tyrrhenian and the hellenic slabs during plate convergence these slabs migrated backward with respect to the eurasian upper plate inducing a return flow of the asthenosphere from the backarc regions towards the subduction zones this flow can be found at large distance from the subduction zones and is at present expressed in two upwellings beneath anatolia and eastern iberia this convection system provides an explanation for the general pattern of seismic anisotropy in the mediterranean first order anatolia and adria microplate kinematics and may contribute to the high elevation of scarcely deformed areas such as anatolia and eastern iberia more generally the mediterranean is an illustration of how upper mantle small scale convection leads to intraplate deformation and complex plate boundary reconfiguration at the westernmost terminus of the tethyan collision

driving mechanisms of holocene coastal evolution in the bonifacio strait western mediterranean abstract we produced a new suite of sea level data which allowed assessing the holocene evolution of the bonifacio strait a key coastal sector of the mediterranean sea which experienced significant morphological changes since the last glacial maximum squeezed between corsica and sardinia islands this strait connects the two major basins of the western mediterranean due to its peculiar geographic and morphological setting the bonifacio strait is affected by extreme meteomarine conditions characterized by severe winds waves and currents the millennial sea level changes were reconstructed through multiproxy investigations made of sediment coring and underwater beachrock sampling carried out on both sides of the strait these data provided fresh insights into the timing of the progressive opening of the bonifacio strait which followed the last glacial maximum when corsica and sardinia were connected forming the largest mediterranean island major palaeogeographic changes occurred before 7 ka bp since that period the significant decrease of the northern ice sheet melting triggered a significant sea level stabilization which induced only minor modifications in the palaeogeography of the strait in the late holocene the isostatic related subsidence became the dominant factor controlling the sea level changes which rose with rates 0 35 mm a 1 in the last four millennia our data have also an important archaeological implication because they indicate that the bonifacio strait has not represented a significant geographical barrier along the early neolithic migration path which connected mainland italy to northern corsica and finally to sardinia this further confirms the ability of early neolithic communities to navigate not also across large sea stretches but also maritime areas characterized by extremely complex meteomarine conditions

multiproxy assessment of holocene relative sea level changes in the western mediterranean sea level variability and improvements in the definition of the isostatic signal abstract a review of 917 relative sea level rsl data points has resulted in the first quality controlled database constraining the holocene sea level histories of the western mediterranean sea spain france italy slovenia croatia malta and tunisia we reviewed and standardized the geological rsl data points using a new multi proxy methodology based on 1 modern taxa assemblages in mediterranean lagoons and marshes 2 beachrock characteristics cement fabric and chemistry sedimentary structures and 3 the modern distribution of mediterranean fixed biological indicators these rsl data points were coupled with the large number of archaeological rsl indicators available for the western mediterranean we assessed the spatial variability of rsl histories for 22 regions and compared these with the ice 5g vm2 gia model in the western mediterranean rsl rose continuously for the whole holocene with a sudden slowdown at 7 5 ka bp and a further deceleration during the last 4 0 ka bp after which time observed rsl changes are mainly related to variability in isostatic adjustment the sole exception is southern tunisia where data show evidence of a mid holocene high stand compatible with the isostatic impacts of the melting history of the remote antarctic ice sheet our results indicate that late holocene sea level rise was significantly slower than the current one first estimates of gia contribution indicate that at least in the northwestern sector it accounts at least for the 25 30 of the ongoing sea level rise recorded by mediterranean tidal gauges such contribution is less constrained at lower latitudes due to the lower quality of the late holocene index points future applications of spatio temporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of 20th century acceleration of mediterranean sea level rise

relative sea level in the western mediterranean basin a regional test of the ice 7g_na vm7 model and a constraint on late holocene antarctic deglaciation abstract the mediterranean basin is a region of special interest in the study of past and present relative sea level evolution given its location south of the ice sheets that covered large fractions of northern europe during the last glaciation the large number of biological geological and archaeological sea level indicators that have been retrieved from its coastal regions as well as its high density of modern coastal infrastructure models of the glacial isostatic adjustment gia process provide reconstructions of past relative sea level evolution and can be tested for validity against past sea level indicators from the region it is demonstrated herein that the latest ice 7g na vm7 model of the gia process the north american component of which was refined using a full suite of geophysical observables is able to reconcile the vast majority of uniformly analyzed relative sea level constraints available for the western part of the mediterranean basin a region to which it was not tuned we also revisit herein the previously published interpretations of relative sea level information obtained from roman era coastal mediterranean fish tanks analyze the far field influence of the rate of late holocene antarctic ice sheet melting history on the exceptionally detailed relative sea level history available from southern tunisia and extend the analysis to complementary constraints on the history of antarctic ice sheet melting available from islands in the equatorial pacific ocean the analyses reported herein provide strong support for the global exportability of the ice 7g na vm7 model a result that speaks directly to the ability of spherically symmetric models of the internal viscoelastic structure to explain globally distributed observations while also identifying isolated regions of remaining misfit which will benefit from further study

glacio isostatic adjustment in the po plain and in the northern adriatic region vertical movements in the po plain northern italy are controlled by natural and anthropogenic effects since italy is located in the far field of the former late pleistocene ice sheets isostatic deformations are primarily driven by melt water loading and represent a major component of long term natural movements across the entire mediterranean in addition to far field sources here we consider the isostatic effects of melting of the nearby wurm alpine ice sheet suggesting that it is possible to put bounds on its maximum thickness extent and chronology by holocene relative sea level observations from the northern adriatic using various plausible ice models and adopting a viscosity profile that matches holocene relative sea level observations in the mediterranean we find that melting of the alpine ice sheet is always responsible for upward movements in the po plain currently at rates of 0 5 mm yr when both far and near field sources are considered the rate of sea level change in the venetian lagoon for the most reasonable mantle rheology and melting chronology is negative i e opposite to that attributed to human activity and recent climatic variations however its amplitude fractions of mm yr is small compared to the secular signal observed by tide gauges 2 mm yr which makes glacial isostasy a second order mechanism of sea level variation in this region

vertical gps ground motion rates in the euro mediterranean region new evidence of velocity gradients at different spatial scales along the nubia eurasia plate boundary we use 2 5 to 14 years long position time series from 800 continuous global positioning system gps stations to study vertical deformation rates in the euro mediterranean region we estimate and remove common mode errors in position time series using a principal component analysis obtaining a significant gain in the signal to noise ratio of the displacements data following the results of a maximum likelihood estimation analysis which gives a mean spectral index 0 7 we adopt a power law white noise stochastic model in estimating the final vertical rates and find 95 of the velocities within 2 mm yr with uncertainties from filtered time series 40 smaller than from the unfiltered ones we highlight the presence of statistically significant velocity gradients where the stations density is higher we find undulations of the vertical velocity field at different spatial scales both in tectonically active regions like eastern alps apennines and eastern mediterranean and in regions characterized by a low or negligible tectonic activity like central iberia and western alps a correlation between smooth vertical velocities and topographic features is apparent in many sectors of the study area glacial isostatic adjustment and weathering processes do not completely explain the measured rates and a combination of active tectonics and deep seated geodynamic processes must be invoked excluding areas where localized processes are likely or where subduction processes may be active mantle dynamics is the most likely process but regional mantle modeling is required for a better understanding

dansgaard oeschger oscillations predicted in a comprehensive model of glacial climate a kicked salt oscillator in the atlantic during the period from 60 000 to 35 000 years ago summit greenland ice core records of the oxygen isotopic ratio 18o 16o exhibit intense millennium time scale oscillations these dansgaard oeschger oscillations have been interpreted to represent the variations in north atlantic air temperature caused by correlative changes in the strength of north atlantic deep water production we apply a comprehensive model of glacial climate to unambiguously identify the mechanism responsible for this phenomenon this is shown to involve a salt oscillation of relaxation oscillator form this nonlinear oscillation does not require the existence of feedback due to freshwater release from grounded ice on the continents during the warm phase of the cycle

tyrrhenian holocene palaeoclimate trends from spelean serpulids abstract in tropical regions changes in sea level and sea surface temperature sst can be obtained from coral reefs in temperate seas such as the mediterranean where there are neither fossil nor actively growing coral reefs palaeoclimatic trends and associated sea level rise can be reconstructed through radiocarbon ages and the geochemical properties of serpulid calcite tubes from colonies that dwell in submerged caves in the present work we reconstructed holocene palaeoclimate trends for the tyrrhenian sea through the oxygen isotopic composition of marine polychaete serpulids that colonised continental speleothems when the sea invaded the caves which open along the italian coast the long term 18 o trend extracted from multiple serpulid skeletons of 0 7 per mil increase over the last 8 kyr can be interpreted in terms of temperature change but could also be due to long term changes in the salinity balance of the mediterranean if the 18 o trends recorded by serpulid calcite reflected changes in mediterranean sst starting at 8200 cal yr bp it would coincide with the cooling trend recorded in the tropics and in greenland ice cores spelean serpulids radiocarbon ages allowed us to reconstruct a tyrrhenian sea level curve comparable to that recorded along the french mediterranean coast spelean serpulid calcite therefore can be used as a useful tool to reconstruct paleoclimate and sea level changes in temperate coastal karst regions

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

geomorphic complexity and sensitivity in channels to fire and floods in mountain catchments abstract fires and floods are important drivers of geomorphic change while the hydrologic and geomorphic effects of fires have been studied at the hillslope scale we have much more limited data on post fire runoff channel changes and inferred or measured sediment storage and delivery at larger scales in this study we intensively documented channel changes over four years in two very similar 15 km2 catchments in the northern colorado front range skin gulch and hill gulch that were burned primarily at high and moderate severity in june 2012 ten and 11 cross sections and longitudinal profiles along the lower channel network were repeatedly surveyed in skin gulch and hill gulch respectively summer thunderstorms generally caused deposition in the valley bottoms while incision resulted from the intervening baseflows and spring snowmelt but a very high intensity summer thunderstorm in skin gulch just one week after burning caused much more deposition than in hill gulch fifteen months after burning both watersheds experienced an exceptional long duration flood resulting from a multi day rainstorm with a several hundred year recurrence interval this removed nearly all of the deposited post fire sediment along with some of the older valley bottom deposits the expansion and coarsening of the channel has greatly decreased the geomorphic sensitivity of both watersheds to future floods and eliminated the more typical and persistent post fire depositional signature the channel changes in skin gulch after the fire and long duration flood were much greater than in hill gulch and this can be attributed to the much greater sediment deposition in skin gulch shortly after the fire reduced geomorphic sensitivity in hill gulch resulting from a large erosional flood in 1976 and the spatial distribution of burn severity and storm rainfalls leading to lower peak flows in hill gulch these results suggest that fires in the rocky mountains can trigger significant and dynamic hillslope and channel changes over sub decadal timescales but unusually long or intense rainstorms can cause larger and more persistent changes regardless of whether a catchment has recently burned

palaeoenvironmental reconstruction of the ancient harbors of rome claudius and trajan s marine harbors on the tiber delta during the first and second centuries ad emperor claudius and then emperor trajan successively ordered the construction of two large harbors on the tyrrhenian coast research resulted in advances in understanding the palaeoenvironments of the portus from a bathymetric point of view the drillings indicate a 7 8 m depth for the main basins different sedimentary behaviors were observed claudius basin shows sand accretion whereas the access channel to trajan s basin shows mud accumulation trajan built the second hexagonal basin because claudius harbor did not protect the ships from the wind and swell and not because it was prone to rapid silting in terms of chronology the channel between both basins worked between the end of the 2nd century and the beginning of the 5th century when it became completely clogged this means that after the beginning of the 5th century only the junction channel canale traverso remained to provide an access to the tiber and to the sea

the antarctica component of postglacial rebound model ice 6g_c vm5a based on gps positioning exposure age dating of ice thicknesses and relative sea level histories

space geodesy constrains ice age terminal deglaciation the global ice 6g_c vm5a model a new model of the last deglaciation event of the late quaternary ice age is here described and denoted as ice 6g c vm5a it differs from previously published models in this sequence in that it has been explicitly refined by applying all of the available global positioning system gps measurements of vertical motion of the crust that may be brought to bear to constrain the thickness of local ice cover as well as the timing of its removal additional space geodetic constraints have also been applied to specify the reference frame within which the gps data are described the focus of the paper is upon the three main regions of last glacial maximum ice cover namely north america northwestern europe eurasia and antarctica although greenland and the british isles will also be included if peripherally in the discussion in each of the three major regions the model predictions of the time rate of change of the gravitational field are also compared to that being measured by the gravity recovery and climate experiment satellites as an independent means of verifying the improvement of the model achieved by applying the gps constraints several aspects of the global characteristics of this new model are also discussed including the nature of relative sea level history predictions at far field locations in particular the caribbean island of barbados from which especially high quality records of postglacial sea level change are available but which records were not employed in the development of the model although ice 6g c vm5a is a significant improvement insofar as the most recently available gps observations are concerned comparison of model predictions with such far field relative sea level histories enables us to identify a series of additional improvements that should follow from a further stage of model iteration

john m hayes 1940 2017 father of isotopes in modern and ancient biogeochemical processes biosynthetic carbon and hydrogen isotope fractionation and compound specific isotope analytical techniques john michael hayes professor of chemistry and geology for 26 years at indiana university bloomington until 1996 then director of the national ocean sciences accelerator mass spectrometry facility at woods hole oceanographic institution and adjunct professor at harvard university until 2007 died peacefully at his home in berkeley california on february 3rd 2017

on eustatic sea level history last glacial maximum to holocene abstract this paper addresses the question of the magnitude and time dependence of the globally averaged eustatic rise of sea level that occurred subsequent to the time of last glacial maximum lgm at approximately 21 000 calendar years before present through the analysis of relative sea level rsl histories predicted by a realistic mass conserving and gravitationally self consistent theory of postglacial sea level change it is demonstrated that there are preferred oceanic locations at which this eustatic function is well approximated by local sea level history one such location is the island of barbados in the caribbean sea a site from which a coral based record exists that extends from mid holocene to lgm because of the sea level ambiguity that is inherent to coral based records however it is important that the global ice equivalent eustatic sea level curve inferred on the basis of the barbados data be tested against observations at other locations from which similarly extensive records are also available but which are derived on the basis of sea level indicators which are not subject to the ambiguities inherent to corals it is shown that when the eustatic function employed in the global theoretical model is tuned so as to enable the model to fit the barbados observations where the maximum relative sea level rsl depression is assumed to be near 120 m then the theory misfits the record from the sunda shelf in the indonesian archipelago as well as the record from j bonaparte gulf in northern australia both of these recently published records appear to constrain the lgm low stand of rsl to a value above 120 m the implications of these results for interpretation of the long coral derived records from the huon peninsula of papua new guinea and the island of tahiti are also discussed

archaeological remains as sea level change markers a review abstract the mediterranean sea constitutes a unique basin from an historical and archaeological point of view as it has been a privileged way of communication for thousands of years for the people that dwelled on its shores their passage has left many traces on the seabeds in the areas where the ancient commercial routes passed and remains of structures where moorings havens or dwellings existed some of these structures nowadays submerged offer interesting indications aiding the reconstruction of the ancient coastlines this contribution aims to examine recent work in coastal geo archaeology targeting both 1 gathering and discussion of the data particularly those pertaining to the italian coasts and 2 commentary on the methodological debate and verification of the possibility of a protocol that may contain unequivocal referring elements to investigate the archaeological evidence currently underwater because of the relative sea level variations harbour infrastructures fishponds villae maritimae caves nymphaei private or public buildings or town quarters pre and protohistorical villages quarries caves etc a clear and more coherent methodological assumption may be needed the archaeological interpretation must initially establish the maritime and or harbour nature and vocation of the site determine its typology and specific usage analyze the elements of its building techniques that reveal themselves as meaningful markers of height or depth at the time of building and its functional elements the measure of the emerged part with respect to the average sea level and point out the time of construction its chronological range of usage frequentation the dynamics of its abandonment destruction obliteration the evaluation of both the height and functional depth to the mean sea level depends on the typology of the archaeological evidence its use and the local tide amplitudes the surface of a pier surely has a functional elevation different from that of a haulage area or a platea or a pavement

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

beachrock a tool for reconstructing relative sea level in the far field abstract today s understanding of sea level change developed through a combination of process based physical modelling and observational data observational data of sea level change derives from coral reefs in the far field of the former ice sheets where a geographically variable relative sea level signal is expected as a response of the earth to ocean loading given this variability and the limited geographical distribution of coral reefs there is a need to explore other non coral based sea level markers to further understand sea level change and for example to fingerprint melt water here we present beachrock as a coastal deposit suitable for relative sea level rsl observations in the far field beachrock is an intertidal deposit forming in the zone where carbonate saturated meteoric and marine water mix and p co 2 decreases we provide the conceptual framework for beachrock analysis and describe techniques suitable for analysing and dating the deposit the approach is standardised by outlining the sediment characteristics in terms of rsl indicative meaning and indicative range and is tested against published data a study conducted on coasts of the mediterranean sea exemplifies the utility of beachrock for rsl reconstruction it is shown that the precision of the reconstruction is derived from the combined uncertainty of age and tidal amplitude or tidal range the uncertainty can be reduced to half the tidal amplitude when a deposit can be ascribed to the upper or lower intertidal zone beachrock based data benefit from the lack of non quantifiable error terms such as post depositional compaction due to the instantaneous formation and high preservation potential of the deposit this underlines the high precision of beachrock based rsl reconstruction which is a prime requirement for testing and extending coral based records

sea level change during the holocene in sardinia and in the northeastern adriatic central mediterranean sea from archaeological and geomorphological data abstract we provide new data on relative sea level change from the late holocene for two locations in the central mediterranean sardinia and ne adriatico they are based on precise measures of submerged archaeological and tide notch markers that are good indicators of past sea level elevation twelve submerged archaeological sites were studied six aged between 2 5 and 1 6 ka bp located along the sardinia coast and a further six dated 2 0 ka bp located along the ne adriatic coast italy slovenia and croatia for sardinia we also use beach rock and core data that can be related to holocene sea level the elevations of selected significant archaeological markers were measured with respect to the present sea level applying corrections for tide and atmospheric pressure values at the time of surveys the interpretation of the functional heights related to sea level at the time of their construction provides data on the relative changes between land and sea these data are compared with predictions derived from a new glacio hydro isostatic model associated with the last glacial cycle sardinia is tectonically relatively stable and we use the sea level data from this island to calibrate our models for eustatic and glacio hydro isostatic change the results are consistent with those from another tectonically stable site the versilia plain of italy the northeast adriatic italy slovenia and croatia is an area of subsidence and we use the calibrated model results to separate out the isostatic from the tectonic contributions this indicates that the adriatic coast from the gulf of trieste to the southern end of istria has tectonically subsided by 1 5 m since roman times

a two dimensional tidal model for the mediterranean sea the tidal propagation in the mediterranean sea is described through a high resolution two dimensional hydrodynamic model forced by the equilibrium tide and the incoming tide at the strait of gibraltar the four most significant constituents m2 s2 k1 and o1 are included in the model good agreement with a set of 63 coastal gauges is achieved the significance of the equilibrium tide and the forcing at the open boundary is investigated the incoming wave from the strait of gibraltar is important in tuning the tides in the whole of the mediterranean for the north aegean sea the solution without the forcing at gibraltar results in a doubling of the amplitudes of the semidiurnal tides the estimated energy dissipation due to bottom friction is 8 8 108 w the major area of dissipation is the gulf of gabes energy fluxes through the major straits are calculated

the late pleistocene to holocene palaeogeographic evolution of the porto conte area clues for a better understanding of human colonization of sardinia and faunal dynamics during the last 30 ka the timing of the colonization of sardinia by mammalian fauna and anatomically modern humans amh is currently under debate the understanding of the geological and palaeoclimatological conditions that characterized the late pleistocene and the holocene is essential to investigate colonization processes and requires an integrated multidisciplinary approach in this research we combine for the first time new radiometric dating field evidence of relative sea level changes rsl sea level and glacial isostatic adjustment modelling stratigraphical palaeontological palaeoecological and isotope analyses that were performed on sites and finds from the porto conte and capo caccia area alghero nw sardinia the most important late pleistocene fossiliferous deposits in sardinia have been discovered in this part of the island modelled palaeogeographical reconstructions of the porto conte area combined with the inferred environmental context and chronology of late pleistocene faunal assemblages from medusa dragonara cave suggest that homo sapiens did not inhabit this area before the holocene our results support the hypothesis that human presence in sardinia during the last glacial maximum was at best sporadic

bounds on the time history and holocene mass budget of antarctica from sea level records in se tunisia solving the sea level equation for a maxwell earth we analyze the sensitivity of holocene sea level records in se tunisia to the time history of remote ice sheets assuming that mantle viscosity increases moderately with depth we find that in this region the sea level variations driven by the northern hemisphere ice sheets cancel so that the late holocene sea level high stand suggested by the geological record merely reflects the melting history of antarctica new insight into the history of this ice sheet is obtained analyzing the information contained in a revised set of relative sea level observations for sites across the mediterranean covering the last 8 kyrs from a trial and error misfit analysis it holds true that in this region the match between model predictions and observations improves when the volume of water released from antarctica is well below the value imposed by the ice3g chronology and when a sudden meltwater pulse is allowed between 8 and 7 kyrs before present corresponding to the epoch of the catastrophic rise event known as cre3

an updated database of holocene relative sea level changes in ne aegean sea abstract the reconstruction of holocene relative sea levels has several implications ranging from the investigation of coastal vertical movements to the calibration of earth rheology models and ice sheet reconstructions the north eastern aegean sea is among the tectonically complex sectors of the eastern mediterranean mainly influenced by the activity of the north anatolian fault in this paper we created a relative sea level rsl database by expanding upon the previous compilation with recently published geological and archaeological data we reconstruct the rsl history in those aegean coastal sectors located within the south marmara microplate a broad shear zone located between western anatolia and central greece and affected by dominant strike slip faulting at times combined with a normal component then we compared it with the rsl histories obtained for the surrounding coastal sectors the analysis of the database indicated that it is not possible to define a common holocene rsl curve for the entire ne aegean as rsl history here is majorly influenced by changes in deformation patterns in addition data in our database are consistent with a continuous rsl rise in the last 6 0 ka bp in the whole ne aegean sea and cannot support the hypothesis of a mid holocene rsl highstand in the area finally we present our best estimates of late holocene rates of rsl prior to any possible acceleration during the twentieth century in the broad area of ne aegean here we identified the fastest rising rate 0 9 mm a 1 in that sector whose active tectonic deformation is mainly controlled by the north anatolian fault activity

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

far field test of the ice 4g model of global isostatic response to deglaciation using empirical and theoretical holocene sea level reconstructions for the fiji islands southwestern pacific holocene paleosea level data for fiji represented by 77 dates and emergence magnitudes are presented screened and adjusted most data are from coral microatolls potentially the most precise paleosea level indicators in this region holocene sea level changes are reconstructed for five areas within fiji known to have had different late quaternary tectonic histories resulting analysis suggests that postglacial sea level in fiji reached its present level more than 6900 14c yr b p it also suggests either that a single maximum 5650 3200 14c yr b p perhaps 2 19 m but more likely 1 35 1 50 m occurred or that two maxima occurred 6100 4550 14c yr b p 0 75 1 85 m and 3590 2800 14c yr b p 0 90 2 46 m broad agreement exists between these empirical sea level reconstructions and those derived theoretically using the ice 4g model predicted maximum 4000 14c yr b p 2 1 m this suggests that both methods of reconstructing holocene sea level changes are valid as are the assumptions underpinning the ice 4g model the most important of these that eustatic sea level had effectively stopped rising by late middle holocene time 5000 4000 yr b p is confirmed by observations from fiji

fluvial response to debris associated with mass wasting during extreme floods evolution of channels and bottomlands in mountain valleys of the central appalachians is strongly influenced by debris supplied to stream channels from mass wasting during extreme storms the type of change observed varies with basin scale and storm characteristics along channels receiving coarse sediment from debris avalanches or debris flows during hurricane camille in 1969 pure scour occurred in drainage areas less than 1 km 2 and gradients steeper than 0 1 in hurricane camille and in the june 1949 storm mixed erosion and deposition with continuous reworking of the valley floor was observed along streams with drainage areas up to 65 km 2 in basins larger than 100 km 2 valley floor reworking associated with influx of debris during both storms was localized and discontinuous in the south branch potomac river basin in west virginia intense precipitation within a small contributing area generated scores of debris slides and avalanches in june 1949 debris transported by tributaries to main valleys exceeded the competence of the larger channels and formed new bottomland long duration moderate intensity precipitation in november 1985 generated fewer debris avalanches flood peaks associated with a larger contributing area along the main valleys were 80 to 190 larger than in 1949 and caused extensive channel and flood plain erosion including truncation and removal of 1949 deposits at some locations relict debris deposits may have influenced hydraulic conditions and affected patterns of erosion and deposition during the 1985 storm sequential occurrence of extreme storms with different hydrologic characteristics creates a bottomland mosaic of surfaces with varying elevations and textures

last glacial maximum ice sheet impacts on north atlantic climate variability the importance of the sea ice lid 1 last glacial maximum lgm ice 5g vm2 ice 6g vm5a and paleoclimate modelling intercomparison project phase 3 ice sheet reconstructions are employed in high resolution coupled climate model simulations to investigate the changes they induce in north atlantic climate variability an initial ice 5g vm2 experiment develops a rapid increase of sea ice extent once a thermal threshold is exceeded in this multimillennial simulation subpolar sea ice concentration and thickness are found to be strongly impacted by topographically induced downstream thermal effects from the laurentide ice sheet in each of the reconstructions however in the two additional lgm perturbation experiments the modeled changes in sea ice area are sufficiently similar to the lgm ice 5g vm2 experiment to lead to an equilibrium atlantic meridional overturning circulation strength that is also reduced by the same 40 from preindustrial even though we find significant variation among the models in the deep convection regions of the subpolar glacial north atlantic model predicted sea ice concentrations in this critical region exceed those based upon multiproxy reconstructions and we trace these significant differences to the intensity of the interannual variability of sea ice cover predictions

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

spatial variability of late holocene and 20th century sea level rise along the atlantic coast of the united states accurate estimates of global sea level rise in the pre satellite era provide a context for 21 st century sea level predictions but the use of tide gauge records is complicated by the contributions from changes in land level due to glacial isostatic adjustment gia we have constructed a rigorous quality controlled database of late holocene sea level indices from the u s atlantic coast exhibiting subsidence rates of 0 8 mm a 1 in maine increasing to rates of 1 7 mm a 1 in delaware and a return to rates 0 9 mm a 1 in the carolinas this pattern can be attributed to ongoing gia due to the demise of the laurentide ice sheet our data allow us to defi ne the geometry of the associated collapsing proglacial forebulge with a level of resolution unmatched by any other currently available method the corresponding rates of relative sea level rise serve as background rates on which future sea level rise must be superimposed we further employ the geological data to remove the gia component from tide gauge records to estimate a mean 20 th century sea level rise rate for the u s atlantic coast of 1 8 0 2 mm a 1 similar to the global average however we fia distinct spatial trend in the rate of 20 th century sea level rise increasing from maine to south carolina this is the fi rst evidence of this phenomenon from observational data alone we suggest this may be related to the melting of the greenland ice sheet and or ocean steric effects

episodic uplift deduced from holocene shorelines in the perachora peninsula corinth area greece four raised shorelines between 1 1 m and 3 5 m have been identified at two localities on the perachora peninsula and were dated by ams 14c to between 6400 and 1500 calibrated years ago uplift movements seem to have occurred in increments of 0 8 0 3 m with a return period of about 1600 years the last uplift coincided with a regional tectonic paroxysm which has already been documented in several areas of the eastern mediterranean the average uplift rate was probably faster during the holocene than the average since the last interglacial period no important vertical displacement occurred in this area at the time of or after the 1981 earthquake but a new episode of coseismic uplift may be in preparation

influence of glacial isostatic adjustment upon current sea level variations in the mediterranean abstract present day sea level variations in the mediterranean depend on various factors including recent climatic forcing tectonic activity anthropogenic effects and glacio isostatic adjustment the latter is governed by mantle rheology and the spatio temporal distribution of the late pleistocene ice sheets and it is expected to produce a long wavelength pattern of sea level variations across the mediterranean mostly determined by the response of the solid earth and of the geoid to loading effects of melt water since the end of deglaciation modeling glacio isostatic effects in this region is necessary for a correct interpretation of tide gauge and gps time series and thereby to constrain both the present day climate related sea level rise and regional or local geological tectonic and human driven displacements by an exhaustive exploration of the parameter space of mantle rheology and ice sheet chronologies in this work we outline upper and lower bounds on the current rate of sea level variation associated with glacial isostatic adjustment in the mediterranean this may contribute to a full assessment of coastal vulnerability by sea level rise on a regional and local scale

controls on sedimentation in distal margin palaeovalleys in the early tertiary alpine foreland basin south eastern france the influence of palaeodrainage characteristics palaeogeography and tectonic setting are rarely considered as controls on stratigraphic organization in palaeovalley or incised valley systems this study is an examination of the influence of source region vs downstream base level controls on the sedimentary architecture of a set of bedrock confined palaeovalleys developed along the distal margin of the alpine foreland basin in south eastern france three distinct facies associations are observed within the palaeovalley fills fluvial facies association a is mainly dominated by poorly sorted highly disorganized clast to matrix supported cobble to boulder conglomerates that are interpreted as streamflood deposits facies association b comprises mainly yellow siltstones and is interpreted as recording deposition in an estuarine basin environment estuarine marine facies association c comprises interstratified estuarine siltstones and clean well sorted washover sandstones the sedimentary characteristics of the valley fill successions are related to the proximity of depositional sites to sediment source areas palaeovalleys located proximal to structurally controlled basement palaeohighs are entirely dominated by coarse fluvial streamflood deposits in contrast distal palaeovalley segments which are located several kilometres downstream contain successions showing upward transition from coarse fluvial facies into estuarine central basin fines and finally into estuarine marginal marine facies facies distributions suggest that the fluvial deposits form wedge shaped downstream thinning sediment bodies whereas the estuarine deposits form an upstream thinning wedge the vertical stacking of fluvial to estuarine to marginal marine depositional environments records the fluvial aggradation and subsequent transgression of relatively small bedrock confined river valleys which drained a rugged upland terrain facies geometries suggest that a fluvial sediment wedge initially prograded downvalley in response to high bed load sediment yields subsequently palaeovalleys became drowned during the passage of a marine transgression with the establishment of estuarine conditions initial fluvial aggradation and subsequent marine flooding of the palaeovalleys is a consequence of the interaction of high local rates of sediment supply and relative sea level rise driven by flexural subsidence of the basin

holocene sea level database for the atlantic coast of the united states we have constructed a database of holocene relative sea level rsl observations for the atlantic coast of the united states the database contains 492 index points which locate the position of rsl in time and space and 344 limiting dates which constrain the minimum or maximum limit of former sea level the majority of the index points in the database are from 6 ka bp to present with only 7 older than 6 ka bp spatially index points are distributed between maine and south carolina but there is an absence of data from georgia and the atlantic coast of florida the database is sub divided into 16 regions based on the distance from the former laurentide ice sheet and are classified depending upon their susceptibility to compaction the index points and limiting data demonstrate that rsl did not exceed present 0 m during the holocene except potentially in regions 1 and 2 eastern maine and southern maine rates of rsl change were highest during the early holocene and have decreased over time due to the diminishing response of the earth s mantle to glacial isostatic adjustment and reduction of ice equivalent meltwater input along the atlantic coast of the united states the linear rate of rsl rise prior to 4 ka bp ranged from 0 5 to 4 5 mm a 1 compared to 0 6 1 8 mm a 1 from 4 ka bp to ad 1900 the database suggests minimal 0 3 mm yr changes in these rates of rsl rise during the late holocene deglaciation of the laurentide ice sheet caused the spatial variability captured by the database the maximum rate of late holocene and ongoing rsl rise occurred in mid atlantic regions new jersey and inner delaware because of collapse of the peripheral forebulge

new relative sea level insights into the isostatic history of the western mediterranean abstract a recent suite of relative sea level rsl data for the past 12 ka bp has provided new insights into the sea level histories of the western mediterranean region our analysis of the chronostratigraphic context of sea level indicators from spain catalonia the balearic islands and the gulf of valencia france corsica island and italy sardinia island has yielded 162 new sea level index and limiting points these data have considerably enhanced previous rsl compilations in addition to improving the quality of spatio temporal sea level reconstructions and our capacity to estimate isostatic related vertical motions in the western mediterranean basin the glacial and hydro isostatic adjustment gia pattern elucidated by the new database shows discrepancy with respect to those predicted by the available gia models in particular the new results underscore a non coherent isostatic response of the central portion of the western mediterranean with the balearic islands manifesting significant departures from the sea level histories of corsica sardinia and more generally along most of the western mediterranean coast our results are a crucial contribution to defining both the pattern and the magnitude of the isostatic signal along the western mediterranean coast in fact vertical isostatic motions represent a key to better assess any possible post industrial acceleration in sea level rise and to define future scenarios of coastal inundation in the context of global change

holocene relative sea level changes and glacial isostatic adjustment of the u s atlantic coast the first quality controlled holocene sea level database for the u s atlantic coast has been constructed from 686 sea level indicators the database documents a decreasing rate of relative sea level rsl rise through time with no evidence of sea level being above present in the middle to late holocene the highest rates of rsl rise are found in the mid atlantic region we employ the database to constrain an ensemble of glacial isostatic adjustment models using two ice ice 5g ice 6g global ice sheet reconstructions and two mantle viscosity models vm5a vm5b vm radial variation of viscosity in the sublithospheric mantle variations to assess whether the spherically symmetric viscoelastic models are able to survive intercomparison with a more refined database of postglacial rsl history we identify significant misfits between observations and predictions using ice 5g with the vm5a viscosity profile ice 6g provides some improvement for the northern atlantic region but misfits remain elsewhere decreasing the upper mantle and transition zone viscosity by a factor of 2 to 0 25 10 21 pa s vm5b removes significant discrepancies between observations and predictions along the mid atlantic coastline although misfits remain in the southern atlantic region these may be an indication of the importance of laterally heterogeneous viscosity in the upper mantle

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

holocene sea level change in sicily and its implications for tectonic models new data from the taormina area northeast sicily the northeast coast of sicily shows emergent marine features that have been uplifting during the holocene along the footwalls of two major regional fault systems the malta escarpment and messina fault system previously uplift rates were interpreted as up to about 1 8 mm mm a 1 new dates on shelly remains collected close to sea level from the taormina area north of mount etna and amended sea level curves are used to show that uplift over the past 6000 years has been proceeding at a slower rate of about 1 4 mm a 1 however over a longer time period from the tyrrhenian oxygen isotope stage 5 5 about 125 ka to the present day the uplift rate has been yet slower at about 1 mm a 1 northeast sicily lies in a complex plate boundary region whereas in contrast the rest of sicily appears to have been stable throughout the later quaternary further comparisons show that the french mediterranean coast lambeck bard 2000 earth planet sci lett 175 202 222 is a region of crustal stability where movement is dominated by subsidence of the outer portion of the proglacial forebulge of the last glaciation there the coastline has been progressively submerged during the holocene and sea level has never been higher than at present northeastern sicily uplift is therefore more likely controlled by plate processes that mask most of the effects of glacio hydro isostatic adjustment

effects of forest cover topography and sampling extent on the measured density of shallow translational landslides 1 we use regionally available digital elevation models and land cover data calibrated with ground and photo based landslide inventories to produce spatially distributed estimates of shallow translational landslide density number unit area to discern effects of land use we focus on resolving landslide density relationships with forest cover we account for topographic variability between sites and landslide detection bias in air photo mapping even so for sites in the oregon coast range we find great variability in the ratios of landslide density in forest classes among sites we present strategies for subsampling available data to quantify this variability for these data we find that older forests when sampled over tens of square kilometers commonly exhibited the highest landslide densities but over hundreds of square kilometers always exhibited the lowest densities averaging 30 of that in recently harvested areas and 79 of that in younger managed forests