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Holocene data from the Caribbean and the Atlantic coast of South America have been critically assessed and a subset of the best quality data are presented. These data cover a large north–south geographic extent and display a distinct spatial variation. We make the first comparisons of this data set to predictions based on a realistic model of glaciation-induced sea-level change with the main aims of understanding the cause of the observed spatial trend and estimating a eustatic signal for the Holocene. The spatial variation is dominated by the influence of the ice and ocean mass redistribution on sea-level change, with the ice-induced effect dominating the observed north–south trend. A best-fitting model is applied to estimate a Holocene eustatic signal from the observations. We find that the model-corrected data are consistent with a relatively rapid rise of 7–8 mm/yr in the early Holocene with a marked reduction in this rate around 7 cal. kyr BP. From this time until present, the model-corrected data suggest that the volume of mass transfer between ice sheets and oceans was no more than ∼ ± 1 m (eustatic sea-level equivalent).

Relative sea level (RSL) data derived from isolation basins at Innaarsuit, a site on the south shores of the large marine embayment of Disko Bugt, West Greenland, record rapid RSL fall from the marine limit (ca. 108 m) at 10,300–9900 cal yr B.P. to reach the present sea level at 3500 cal yr B.P. Since 2000 cal yr B.P., RSL rose ca. 3 m to the present. When compared with data from elsewhere in Disko Bugt, our results suggest that the embayment was deglaciated later and more quickly than previously thought, at or slightly before 10,300 cal yr B.P. The northern part of Disko Bugt experienced less rebound (ca. 10 m at 6000 cal yr B.P.) compared with areas to the south. Submergence during the late Holocene supports a model of crustal down-warping as a result of renewed ice-sheet growth during the neoglacial. There is little evidence for west to east differences in crustal rebound across the southern shores of Disko Bugt.

New relative sea-level (RSL) data from Disko Bugt, a large marine embayment in West Greenland, are used to examine the deglacial history of the Jakobshavns Isbrae ice stream. RSL data show rapid deglaciation after 10.3rka cal. yr BP. Once deglaciation began, a bedrock high in the west of the bay exerted no discernible influence on the deglacial chronology. Following initial rapid retreat, ice stream recession slowed as it approached the eastern shores of the bay. Seabed elevations increase here and the ice stream terminus lingered for several thousand years before retreating into the narrow bedrock-confined Jakobshavns Isfjord. The seabed topography of Disko Bugt includes several deep channels which probably record the former course of the ice stream. Using a simple water depth/calving velocity relationship it is estimated that the maximum calving velocity on deglaciation was c. 4.8rkm am1. This is less than the present rate (6-7rkmram1), although ice discharge was two to four times that observed today. Initiation of rapid ice stream retreat was probably caused by ice stream thinning and increased surface melting. A critical point in time was the retreat of the ice stream from shallow continental shelf waters (c. 400rm) into the deep bedrock trough (>800rm) which marks the entrance to Disko Bugt.

Data collected recently from select areas within the eastern, central and western English Channel are used to reconstruct the Holocene evolution and sea-level history of the southern coast of England. Rapid sea-level rise in the early Holocene produced a ubiquitous vertical and lateral expansion in the marine influence. From ca. 6800 cal. (calendar) yr BP the rate of sea-level rise declined and a shift from minerogenic to organogenic sedimentation is also widely recorded. A further decline in the rate of sea-level rise occurred in the late Holocene, during which time the eastern and central English Channel experienced coastal inundation and a return to minerogenic sedimentation. Explanations for this apparent contradiction include the effects of this decline on the accumulation of minerotrophic peat and changes in sediment supply. Sea-level index points from the eastern Channel generally plot below those from the central and western Channel, indicating differential crustal movement, although sediment compaction and tidal range also may be responsible for apparent altitudinal variation between these areas. Despite an increase in the quantity and quality of the data available from this region over the past 20 yr these, and a number of other important issues, require further clarification. Copyright © 2003 John Wiley & Sons, Ltd.

This paper examines the evolution of Pagham Harbour, southern England following storm-induced breaching of a protective barrier in AD 1910. Stratigraphic studies of sediments collected from intertidal areas show the presence of a distinct stratigraphic horizon in the northeast of Pagham Harbour at ca. 0 to +1.0 m ordnance datum (OD). Radiometric data indicate that this horizon is a ‘reclamation surface’ formed after land claim in AD 1846. Following marine flooding in AD 1910, sediment has accreted relatively rapidly (at a broadly constant rate of between 4 and 8 mm a−1), wave and/or tidal energy have decreased and extensive marshes have developed. An asymptotic reduction in sediment accretion rate through time, as predicted in various theoretical models of salt marsh accretion, is not observed. Over the entire Pagham Harbour area, the period between AD 1948 and AD 1986 has seen an average marsh loss of 0.0087 km2 a−1, which is relatively small in comparison with other more exposed sites in the local area. Historically breached sites such as Pagham Harbour are common around European coasts, and these provide important natural laboratories within which the medium-term (decadal to centennial) coastal response to barrier breaching, and to managed-realignment coastal protection schemes, can be assessed.

Research campaigns over the last decade have yielded a growing stream of data that highlight the dynamic nature of Arctic cryosphere and climate change over a range of time scales. As a consequence, rather than seeing the Arctic as a near static environment in which large scale changes occur slowly, we now view the Arctic as a system that is typified by frequent, large and abrupt changes. The traditional focus on end members in the system – glacial versus interglacial periods – has been replaced by a new interest in understanding the patterns and causes of such dynamic change. Instead of interpreting changes almost exclusively as near linear responses to external forcing (e.g. orbitally-forced climate change), research is now concentrated on the importance of strong feedback mechanisms that in our palaeo-archives often border on chaotic behaviour. The last decade of research has revealed the importance of on-off switching of ice streams, strong feedbacks between sea level and ice sheets, spatial and temporal changes in ice shelves and perennial sea ice, as well as alterations in ice sheet dynamics caused by shifting centres of mass in multi-dome ice sheets. Recent advances in dating techniques and modelling have improved our understanding of leads and lags that exist in different Arctic systems, on their interactions and the driving mechanisms of change. Future Arctic research challenges include further emphases on rapid transitions and untangling the feedback mechanisms as well as the time scales they operate on.

This proposal, by a Working Group of Integration of ice-core, marine, and terrestrial records (INTIMATE) and the Subcommission on Quaternary Stratigraphy (SQS) of the International Commission on Stratigraphy (ICS), is for a formal subdivision of the Holocene Series/Epoch. Although previous attempts to subdivide the Holocene have proved inconclusive, recent developments in Quaternary stratigraphy, notably the definition of the Pleistocene–Holocene boundary and the emergence of formal subdivisions of the Pleistocene Series/Epoch, mean that it may be timely to revisit this matter. The Quaternary literature reveals a widespread but variable informal usage of a tripartite division of the Holocene (“early”, “middle” or “mid-”, and “late”), and we propose that this de facto subdivision should now be formalised to ensure consistency in stratigraphic terminology. We advocate a formal Early–Middle Holocene boundary at 8200 a BP and a formal Middle–Late Holocene boundary at 4200 a BP, each of which is linked to a Global Stratotype Section and Point (GSSP).

Mid-Holocene coasts were radically different to those of the early or late Holocene, different in both form and process. To begin to understand this distinctiveness this report reviews recent research concerning relative sea-level (RSL) change and coastal evolution during the period between c. 7800 and 4400 cal. yr BP (c. 7000 to 4000 14 C yr BP). RSL changed rapidly during this time because of a fall in meltwater discharge from the dwindling ice sheets of the northern hemisphere, coupled with a reduced Antarctic contribution. This review begins by addressing the problem of eustatic changes during the mid-Holocene before turning to consider age/altitude evidence and then patterns of coastal evolution.

The evolution of tidal channels and, in particular, the sedimentological and biostratigraphic evidence for channel infilling, are areas of palaeoenvironmental research that have received relatively limited attention in stratigraphic studies aimed at landscape reconstruction. This paper details the results of a multidisciplinary investigation into the late Holocene evolution of the Wainway, a large tidal channel in Walland Marsh, East Sussex. Lithostratigraphic, microfossil and sedimentological data, as well as geomorphological and historical evidence detail the rapid infill of this channel between the tenth and sixteenth centuries. This infilling was associated with localized changes in coastal configuration caused by storm events. Our analyses suggest that the channel sediments provide a detailed insight into the dynamics of this important watercourse during the closure of the New Romney tidal inlet and the opening of a tidal inlet at Rye during this period. The final stages of sedimentation within the Wainway Channel record its progressive infilling and final inning at c . ad 1600. This is reflected in the sedimentological and micropalaeontological data by a progressive upward fining of the sediment sequence and the development of low energy mudflat and saltmarsh conditions. In this study we find significant differences in the usefulness of different microfossil groups for palaeoenvironmental interpretation. In particular, the foraminiferal data provide a more continuous and sensitive record of changing intertidal conditions compared with the diatom record.

Although records of late Holocene relative sea-level (RSL) change have been reported from high-energy coastal environments, such as the raised beaches of Alaska (Jordon and Mason, 1999) and Antarctica (Zwartz et al., 1998), some of the most detailed records are preserved in the saltmarsh deposits which have accumulated on the passive margins of the Atlantic Ocean under a predominantly upward trend in RSL. This situation contrasts with that found in much of the Pacific Ocean or the Mediterranean, where tectonic processes control patterns of RSL and coastal evolution, often overprinting any sea level - climate link (e.g., Long and Shennan, 1998; Nelson et al., 1998; Pirazzoli, 1998; Benson et al., 1999; Goff and Chague-Goff, 1999; Hindson and Andrade, 1999; Hindson et al., 1999; Shennan et al., 1998; 1999; Stanley, 1999). Recently published research into late Holocene sea-level change and climate in North America and Canada, northwest Europe and the Pacific is now considered, before some general issues emerging from this work are explored.

The mid- and late-Holocene vegetation of Walland Marsh (situated on the south coast of England) is reconstructed through multi-proxy (pollen, plant macrofossil and diatom analyses and radiocarbon dating) investigations of an extensive peat layer at five locations. These data, combined with previous work from southern England and regions bordering the southern North Sea, are used to assess the processes controlling the development of, and successional trends in, coastal mire vegetation. On Walland Marsh fen carr vegetation, with Alnus glutinosa , was sustained at sites influenced by the flow of base-rich groundwater from the uplands and more widely promoted by rising relative sea level (RSL). Acidophilous vegetation, including ombrotrophic bog (with Sphagnum imbricatum ssp. austinii present), developed at sites isolated from base-rich water. Spatial isolation was enhanced by the accumulation of peat, while vertical isolation was induced by a decline in the rate of RSL rise and, at ca. 2600 cal. yr BP, by climate change. Similar patterns of mire development can be identified in the other areas reviewed. Vegetation development in coastal lowlands reflects a unique interplay between regional and local processes. These processes can only be disentangled by multi-site investigations.

This paper presents the results of an investigation into Holocene relative sea-level (RSL) change, isostatic rebound and ice sheet dynamics in Disko Bugt, West Greenland. Data collected from nine isolation basins on Arveprinsen Ejland, east Disko Bugt, show that mean sea level fell continuously from ca. 70 m at 9.9 ka cal. yr BP (8.9 ka 14C yr BP) to reach a minimum of ca. −5 m at 2.8 ka cal. yr BP (2.5 ka 14C yr BP), before rising to the present day. A west–east gradient in isostatic uplift across Disko Bugt is confirmed, with reduced rebound observed in east Disko Bugt. However, RSL differences (up to 20 m at 7.8 ka to 6.8 ka cal. yr BP (7 ka to 6 ka 14C yr BP)) also exist within east Disko Bugt, suggesting a significant north–south component to the area’s isostatic history. The observed magnitude and timing of late Holocene RSL rise is not compatible with regional forebulge collapse. Instead, RSL rise began first in the eastern part of the bay, as might be expected under a scenario of crustal subsidence caused by neoglacial ice sheet readvance. The results of this study demonstrate the potential of isolation basin data for local and regional RSL studies in Greenland, and the importance of avoiding data compilations from areas where the isobase orientation is uncertain. Copyright © 1999 John Wiley & Sons, Ltd.

The record of late-Holocene sea-level change and coastal evolution in the Romney Marsh region is either absent or made complex by the range of environmental variables which influence sedimentation in both drift-aligned barrier and barrier estuary settings. A multidisciplinary approach (stratigraphy, diatoms and mineral magnetism) was employed in the study of sediments from the area of Denge Marsh with the aim of establishing the record of sea-level change for the last 2000 years, and to distinguish sedimentary records which are the result of sea-level change or storms. A grid-based stratigraphic framework was used to identify the morphology of the buried gravel ridges and the marsh stratigraphy. A tripartite fining-upward sequence was identified and investigated to determine the nature of sediment processing, deposition and provenance. An early phase of tidal flat sedimentation was dominated by a high terrigenous sediment influx. This was followed by intertidal mudflat deposition in a barrier estuary as the gravel foreland prograded eastward. It is likely that this phase of marsh accretion came to an end in the 8th century AD. The final phase of barrier estuary deposition would appear to be the result of storm surges which inundated the marsh during the 13th century AD. Comparison of stratigraphic contact altitudes, as approximate indicators of past MHWS level, with the present day MHWS provides only equivocal data on late-Holocene sea-level change.

A common problem facing sea-level researchers lies in determining the cause of rapid changes observed in coastal stratigraphic sequences. Such changes are commonly ascribed to the interaction of processes that operate over differing temporal and spatial scales, i.e. rapid local and regional sea-level trends and storm magnitude/frequency. At least some of the difficulty in distinguishing between these processes lies in the often limited stratigraphic database upon which palaeoenvironmental reconstruction is based. Here, we present the results of detailed morphostratigraphic and micropalaeontological investigations from a series of sites located at the interface between the protective gravel barrier complex of Dungeness and the barrier estuary sediments of Romney Marsh, England. A period of rapid coastal regression is identified between c. 4500 and 3000 cal. yrs BP, during which time the sea level continued to rise but was outpaced by sediment accretion and peat accumulation. A subsequent acceleration in the rate of rise led to a reversal of this excess of sediment supply over sea-level rise, and to rapid inundation of the entire barrier estuary between c. 2800 and 1900 cal. yrs BP. At the local level, coastal development reflects an interdependence between storms and long-term relative sea-level (RSL) rise; processes which lie at opposite ends of the magnitude/frequency spectrum. However, when viewed from a holistic perspective encompassing the Holocene development of Romney Marsh as a whole, storms are of secondary importance in controlling coastal evolution. Rather, our study suggests that at this macro-scale coastal evolution responds primarily to the combined effects of RSL rise and sediment supply

Much geological evidence points to repeated plate-boundary earthquakes on the Cas-cadia subduction zone, Pacific Northwest USA. Current land motions, calculated. using shortterm (-1 100 krn’. High precision microfossil and RSL data from Johns River (Washington) and Netarts Bay (Oregon) register repeated episodes of late-Holocene coseismic submergence. This is contrary to the coseismic uplift expected, based on differences in uplift rates calculated using late-Quaternary marine terrace data from the region. Moreover, the magnitudes of coseismic submergence inferred from these RSL data are typically half the modelled predictions based on current deformation rates. Lastly, we identify evidence from Netarts Bay for pre-seismic RSL rise of up to 0.4 mm yr’ in the decades immediately preceding each episode of marsh burial. Together, our findings shine new light on models of rapid relative sea-level rise in the Pacific Northwest, and highlight the need to strengthen further the dialogue between long-term geological and short-term geodetic studies in this region.

New stratigraphic data collected from six sites in the Humber estuary establish a record of Holocene relative sea-level (RSL) change, and enable testing of four possible causes of rapid coastal change: sea-level rise, changes in sedimentation, storm-surge history, and human impact. Mean high water of spring tides (MHWST) in the Humber rose from c. 9 m OD at 7500 cal. yrs BP to 0 m OD by 4000 cal. yrs BP, at an average long-term rate of c. 3.9 mm yr-1. After this, the rate of rise gradually decreased to c. 1 mm yr’. Discrete episodes of rapid RSL rise are not identified although their absence may reflect limited data availability. However, we do observe two episodes of rapid coastal change in the Humber estuary. The first occurs between c. 3200 and 1900 cal. yrs BP, as marine conditions expand to their Holocene maximum and then contract. This pattern of coastal development differs from that in the East Anglian Fenlands, suggesting local processes control sedimentation at one or both of these sites. The second period of rapid change relates to a well-documented episode of increased storm surge activity in the Humber estuary and elsewhere in the UK and the North Sea region between c. 700 and 500 cal. yrs BP. Coastal development during this period varies considerably with erosion, accretion and flooding in different parts of the estuary system. Finally, we examine evidence for accelerated sediment delivery to the Humber estuary due to woodland clearance and prehistoric agriculture from 5700 cal. yrs BP onwards. Maximum sediment input is likely at c. 3200 to 1900 cal. yrs BP; a period which tentatively correlates with an episode of estuary infilling and shoreline advance.

This is the second investigation where we apply the methods and scientific framework common to sea-level investigations in northwest Europe to test a model of coseismic land subsidence followed by land uplift during interseismic strain accumulation, used to explain alternating peat–mud couplets of late Holocene age found in many of the estuaries of the Pacific Northwest of the USA and Canada. Recent studies in this region interpret such couplets as the product of repeated large (magnitude 8 or 9) earthquakes on the Cascadia subduction zone. Stratigraphic investigations of the intertidal sediments at Netarts Bay, Oregon, using lithological, pollen and diatom analyses reveal different types of submergence associated with peat–mud couplets during the last 3500 yr. Three peat-mud couplets record gradual sedimentation changes within an infilling body of water. Four other couplets record rapid submergence, burial of tidal marshes and their replacement by low marsh environments. In three of the events rapid submergence is small, 0–0.5 m. The most recent marsh submergence event, around AD 1700, was 0.4±0.3 m. Most of the buried peats contain microfossil evidence for a gradual increase in marine influence before the rapid change from organic to minerogenic sedimentation. Similar gradual changes are common in comparable palaeoenvironments on non-seismic coasts and are strong evidence against a simple interseismic strain accumulation-coseismic subsidence model. One hypothesis is that the gradual increase in marine influence before each submergence represents pre-seismic relative sea-level rise caused by a reduction in the rate of land uplift. The microfossil analyses provide evidence of three stages within an earthquake deformation cycle: coseismic subsidence; interseismic land uplift; and pre-seismic reduction in the rate of land uplift. At present the microfossil data do not differentiate between rapid post-seismic land uplift and rapid sedimentation.

Global-mean sea-level rise will drive impacts and adaptation needs around the world’s coasts over the 21st century and beyond. A key element in assessing these issues is the development of scenarios (or plausible futures) of local relative sea-level rise to support impact assessment and adaptation planning. This requires combining a number of different but uncertain components of sea level which can be linked to climatic and non-climatic (i.e., uplift/subsidence of coastal land) factors. A major concern remains about the possibility of significant contributions from the major Greenland and Antarctic ice sheets and this must be factored into the assessments, despite the uncertainty. This paper reviews the different mechanisms which contribute to sea-level change and considers a methodology for combining the available data to create relative (or local) sea-level rise scenarios suitable for impact and adaptation assessments across a range of sophistication of analysis. The methods that are developed are pragmatic and consider the different needs of impact assessment, adaptation planning, and long-term decision making. This includes the requirements of strategic decision makers who rightly focus on low probability but high consequence changes and their consequences. Hence plausible high end sea-level rise scenarios beyond the conventional Intergovernmental Panel on Climate Change (IPCC) range and which take into account evidence beyond that from the current generation of climate models are developed and their application discussed. Continued review and development of sea-level scenarios is recommended, starting with assimilating the insights of the forthcoming IPCC AR5 assessment. © 2013 John Wiley & Sons, Ltd.

Multiproxy analysis (grain size, mineral magnetics, pollen, diatoms and radiocarbon dates) of deep (20 m+) cores collected from the Rye area of the Romney Marsh region are used to reconstruct coastal evolution between ca. 7000 and 2000 yr “conventional radiocarbon” B.P. A rapid phase of sea-level rise and tidal flat sedimentation occurred between ca. 7000 and 6000 “conventional radiocarbon” yr B.P., after which peat accumulation took place as a coastal barrier of sand and gravel extended eastward across Rye Bay and the rate of sea-level rise fell. Marine conditions returned to these areas at ca. 3000-2000 yr B.P. Erosion and landward migration of the barrier accompanied this return, heralding a change in the stability of the barrier and its ability to afford protection to back-barrier areas of the Romney Marsh region. Comparison with other sites in the central and eastern English Channel and the Thames estuary suggests that the prolonged removal of marine conditions from the study site accompanying barrier establishment reflects an ample sediment supply and the large volume of material within the barrier, which would have provided considerable scope for internal re-organisation when faced with changing coastal processes.

Tidal-wetland stratigraphy reveals that great plate boundary earthquakes have caused hundreds of kilometers of coast to subside at the Cascadia subduction zone. However, determining earthquake recurrence intervals and mapping the coastal extent of past great earthquake ruptures in this region are complicated by the effects of many sedimentologic, hydrographic, and oceanographic processes that occur on the coasts of tectonically passive as well as active continental margins. Tidal-wetland stratigraphy at many Cascadia estuaries differs little from that at similar sites on passive-margin coasts where stratigraphic sequences form through nonseismic processes unrelated to coseismic land level changes. Methods developed through study of similar stratigraphic sequences in Europe provide a framework for investigating the Cascadia estuarine record. Five kinds of criteria must be evaluated when inferring regional coastal subsidence due to great plate boundary earthquakes: the suddenness and amount of submergence, the lateral extent of submerged tidal-wetland soils, the coincidence of submergence with tsunami deposits, and the degree of synchroneity of submergence events at widely spaced sites. Evaluation of such criteria at the Cascadia subduction zone indicates regional coastal subsidence during at least two great earthquakes. Evidence for a coseismic origin remains equivocal, however, for the many peat-mud contacts in Cascadia stratigraphic sequences that lack (1) contrasts in lithology or fossils indicative of more than half a meter of submergence, (2) well-studied tsunami deposits, or (3) precise ages needed for regional correlation. Paleoecologic studies of fossil assemblages are particularly important in estimating the size of sudden sea level changes recorded by abrupt peat-mud contacts and in helping to distinguish erosional and gradually formed contacts from coseismic contacts. Reconstruction of a history of great earthquakes for the Cascadia subduction zone will require rigorous application of the above criteria and many detailed investigations.

Many of the estuaries of the Pacific Northwest of the U.S.A. and Canada contain stratigraphic sequences typified by alternating peat-mud couplets. Recent studies in this region interpret such couplets as the product of repeated large (magnitude S or 9) earthquakes on the Cascadia subduction zone. The resultant pattern of land-level movements is described by a model, the ‘earthquake deformation cycle’, of coseismic land subsidence followed by land uplift during interseismic strain accumulation. However, peat-mud couplets similar to those recorded in the Pacific Northwest are found on other less tectonically active temperate-latitude coasts, such as northwest Europe and the Atlantic coast of the U.S.A., where they have been interpreted as the product of non-seismic coastal processes. In this paper we apply the methods and scientific framework common to sea-level investigations in northwest Europe to a sequence of peat-mud couplets recorded in the lower Johns River, an estuary in southern Washington, to provide a test of the ‘earthquake deformation cycle’. Stratigraphic investigations of the intertidal sediments along the lower Johns River, using lithological, pollen, diatom and foraminiferal data, show evidence for eight coastal submergence events during the last 5000 years. To evaluate the ‘earthquake deformation cycle’ we assess the lateral extent of peat-mud couplets, the synchroneity of submergence, the presence of tsunami deposits accompanying submergence, and the suddenness and amount of submergence. Each submergence is shown to be accompanied by changes in coastal sedimentation broadly commensurate with those predicted by the ‘earthquake deformation cycle’, demonstrating the continued intermittent seismic activity of the Cascadia subduction zone throughout the mid and late-Holocene. Quantitative analyses of contemporary and fossil biostratigraphic data, using TWINSPAN and Detrended Correspondence Analysis, enable us to estimate the magnitude of submergence accompanying each peat-mud couplet. One event was accompanied by submergence of about 1.5 m or more, four events by intermediate submergence of about 1±0.5 m, and a further three events by submergence of

Previous stratigraphical investigations of Romney Marsh have tended to be local in scale, and this has hindered efforts to establish a unifying stratigraphical framework for this area. This paper addresses this problem, by describing the results of a 12-km transect across Romney Marsh, linking previously studied back- and fore-marsh sites (Horsemarsh Sewer and Broomhill respectively), and presenting additional pollen, diatom and radiocarbon data from an intermediate, mid-marsh site (Brookland). One main organic unit is recorded across much of Romney Marsh, although its age, altitude and composition varies. Microfossil and radiocarbon data from Brookland and elsewhere on Romney Marsh show that this organic unit accumulated under a general removal and return of marine conditions that took place between ca. 5100 and 2000 yr BP. A recently proposed model of barrier development is used to investigate the history of back-barrier sedimentation in Romney and Walland Marshes. This model suggests a three-phase life-history for gravel barriers, which consists of initiation, stability and breakdown. Although there are problems in relating back-barrier deposits directly to barrier dynamics, nevertheless the Romney Marsh data do, for the most part, agree with the expected number and sequence of sea-level tendencies predicted by this model. The back-barrier stratigraphical data suggest that initiation, stability and breakdown of the Dungeness foreland occurred between ca. 6000 and 5000 yr BP, 5000 and 2000 yr BP and 2000 yr BP and present, respectively.

A late-Holocene fall in relative sea level in northwest Scotland, from ca. 1.3mm yr−1 to ca. 1.0 mm yr−1, is interpreted from lithostratigraphic, biostratigraphic, chronostratigraphic and numerical analyses of fossil tidal marsh and acidic peat bog communities elevated by isostatic uplift. Pollen, diatom and stratigraphic data from contemporary depositional environments are used to define the indicative range (±0.2 m) and reference water level (mean high water of spring tides or highest astronomical tide) of thirteen dated sea-level index points. No Holocene intertidal sediments are recorded above + 7.7 m OD and all sea-level index points are younger than ca. 4 kyr B.P. In parts of Kentra Moss, beyond the limit of Holocene intertidal clastic sedimentation, raised bog communities were established by at least 8.3 kyr B.P. These age and altitude parameters differ from those interpolated for the “Main Postglacial Shoreline”, but support a regional model in which isostatic uplift continues at present in the Kentra Moss area.

The Dungeness foreland is located in the eastern part of the English Channel, and consists of over 500 gravel beaches which have accumulated since the mid-Holocene. The south coast of the foreland, between Jury's Gut and Galloway's Lookout, is characterised by alternating areas of marsh sediments and gravel which have previously been interpreted as evidence for several oscillations in sea level. Stratigraphic and diatom data from the marsh sediments in this area indicate that they accumulated under marine/ brackish and brackish tidal channel conditions, while pollen data from a peat bed recorded in the base of Wickmaryholm Pit show a removal and return of the marine influence at ca. 2038 ± 97 yrs B.P. and ca. 1000-700 yrs B.P., respectively. An established age/altitude graph of sea-level changes for the region shows that sea level changed little during the period of gravel deposition in the study area (ca. 4000-2000 yrs B.P.). It is therefore argued that the alternating gravel and marsh sediments of the study area probably accumulated as a result of changes in storm incidence and gravel supply, and not oscillations in long-term sea level. Under periods of high storm incidence, increased northward distal extension of the beach ridges in the study area has occurred, while under calmer conditions reduced distal extension has taken place. No clear relationship is apparent between long-term time/altitude changes in sea level and episodes of foreland development during the last ca. 4000 years. However, evidence for a regional episode of increased storm incidence at ca. 700–800 yrs B.P. may be recorded by the return of marine conditions to Wickmaryholm Pit, breaching of the Dungeness foreland at Rye, and a sudden increase in the altitude of the gravel beaches in Denge Beach. Identifying the importance of local and regional controls on foreland evolution is difficult, though, as the sensitivity of the foreland to processes operating at different spatial scales may well have changed through time.

Pollen, diatom, lithostratigraphic and radiocarbon data from five sites in northwestern Scotland provide new data from an area previously devoid of reliable and precise information on Late Devensian and Holocene sea-level changes. The sites cover a range of palaeoenvironments, indicative of diversity in coastal evolution since deglaciation. For each site and palaeoenvironment the reference water (tide) level, indicative range, age and tendency of sea-level movement of all sea-level index points are quantified to enable correlation of the diverse coastal environments. The data record patterns of relative sea-level change and tendencies of sea-level movement from 12 ka BP to 1 ka BP. This is the longest and most comprehensive published record of relative sea-level change from the area. The information is used to test the accuracy of existing models of relative sea-level change. The results are only broadly consistent with a quantitative rebound model, and there is significant disagreement with empirical models during the Late Devensian and the early Holocene.

Integration of geological data and glacio-isostatic adjustment (GIA) modelling shows that it is possible to decouple complex mechanisms of relative sea-level (RSL) change in a tectonically active glacial environment. We model a simplest solution in which RSL changes in upper Cook Inlet, Alaska, are a combination of the interplay of tectonic and isostatic processes driven by the unique rheology of this tectonically active location. We calculate interseismic uplift during latter part of the penultimate earthquake cycle to vary from 0.3 to 0.7 mm/yr. Diatom based reconstructions of RSL from tidal marsh sediment sequences coupled with detailed age models, from AD 1400 to the AD 1964 great earthquake, show deviations from a purely tectonically driven model of regional RSL. Glacial isostatic modelling, constrained by GPS data, predicts up to 70 cm sea-level change due to mountain glacier mass balance changes during the Little Ice Age. Misfits between the GIA model predictions and RSL reconstructions in the 19th and 20th century highlight that the tidal marshes of upper Cook Inlet potentially record a hemispheric-wide acceleration in sea level and that other more complex Earth process combinations may contribute to regional RSL change.

Isolation basins are natural topographic depressions that at various times in their history may be connected to or isolated from the sea by changes in relative sea-level (RSL). They provide a valuable source of data for tracking large scale (tens of meters) changes in RSL over millennia, as well as quiet-water depositional environments where abrupt changes caused by tsunami, iceberg roll or storms may be recorded. In this paper we review isolation basins as sources of RSL data with a particular focus on their use in Greenland to constrain the Holocene history of the ice sheet. A new RSL curve from Disko Fjord, West Greenland is presented, which shows that local ice free conditions were established at c. 11 k cal yr BP, after which RSL fell rapidly from a marine limit at c. 80 m to reach close to present sea level by c. 4 k cal yr BP. We compare this record with other isolation basin RSL data from six other sites in Disko Bugt and note a strong northwest/southeast differential rebound across the area during the early and mid-Holocene that reflects variations in ice load history. We compare the Disko Bugt data with other previously published isolation basin RSL records from Sisimiut (central West Greenland), Nanortalik (south Greenland) and Ammassalik (southeast Greenland). RSL fell below present during the early-Holocene at Nanortalik (c. 10 k cal yr BP) and during the mid to late Holocene elsewhere before rising to present. These differences reflect variations in the timing and amount of Greenland ice load change since the last glacial maximum, as well as non-Greenland processes, notably the collapse of the Laurentide forebulge and also changes in ice equivalent sea-level. Isolation basin data have relatively small age and height uncertainties compared with other RSL indicators, enabling them to resolve between different earth and ice sheet models, especially during periods of large ice load and RSL change.

Existing geotechnical approaches that describe volumetric changes in intertidal sediments in response to applied vertical effective stresses are limited by a lack of empirical research into their one-dimensional compression behaviour. In this paper we address this deficiency by presenting the results of an investigation into the compression behaviour of minerogenic low marsh and tidal flat sediments. We have tested samples of these sediment types obtained from Greatham Creek (Cowpen Marsh, Tees Estuary, UK). Analysis of physical properties and oedometer compression tests demonstrates that, contrary to the implicit assumptions of existing models, the surface sediments studied are overconsolidated. Structural variability between samples arises due to sedimentological factors, notably variations in organic content. We attribute overconsolidation to tidal exposure and falls in groundwater level that permit desiccation and cause capillary suction stresses. Greater rates of compression with respect to effective stress occur in sediments with higher initial voids ratios and more open, unstable initial structures. Variability in structure decreases with application of higher effective stresses due to the destructuration of the sediments, which also creates increased homogeneity of compression behaviour under higher effective stresses. We subsequently develop a new conceptual framework to describe compression behaviour in minerogenic intertidal sediments that incorporates overconsolidation. We advocate a statistical approach that accounts for structural variability and variations in compression behaviour at effective stresses less than and greater than the yield stress. We argue that our conceptual framework is broadly applicable to minerogenic intertidal sediments at different locations and burial depths within Holocene stratigraphic sequences providing site-specific compression data are collected. Inter-site transfer and application of measured material properties should not be undertaken due to local variations in compression behaviour resulting from varying ecological, sedimentological, geochemical, climatic, geomorphic and hydrographic conditions. The individual characteristics of different field locations should be carefully considered before the suggested framework is routinely applied.

Fields of glacioisostatically uplifted beach ridges on the eastern Varanger Peninsula coast in northern Norway record the occurrence of major storms since deglaciation. More than 70 radiocarbon dates of palaeoshoreline indicators establish the Late Weichselian and Holocene history of beach-ridge building and relative sea-level change. Optimal ridge-building in the region requires sustained, strong easterlies driving high waves across the Barents Sea. Such winds occur when low pressure systems are forced across the North Sea and the Baltic landmass to the region of the Gulf of Bothnia and the Kola Peninsula. This situation probably frequently occurs during transition periods from milder to cooler climate in the region. The beach-ridge morphology reveals a fall of local sea level following the stormy episodes. Over the short term, this is related to the end of storm-induced set-up and the termination of mild-phase-related warm coastal currents. Over the long term, local sea-level falls with the onset of sustained calm winter-type conditions and continued glacioisostatic uplift. Pre- and early-Holocene changes in climate regime occurred with a frequency of several decades to several centuries. The mid- to late-Holocene records show increased climatic stability, transitions occurring with less frequency, and mild phases frequently lasting many hundreds of years.

This paper describes the results of a litho-, bio- and chronostratigraphic survey of the Midley Church bank, Romney Marsh. These results are then combined with other previously published sea-level data from Romney Marsh to study the relationship between Holocene coastal sedimentation and (i) barrier development; (ii) time/altitude changes in sea-level in Romney Marsh and southeast England. Pollen data show that a peat bed which underlies the Midley Church bank accumulated under a gradual decrease and then increase in the proximity of marine conditions. Four 14 C dates indicate that peat accumulation at this site took place between c . 3700−2200 bp (4050−2200 calibrated years bp ). Peat accumulation was encouraged by a slow rate of regional sea-level change during this period, and by the probable existence of a shingle barrier to the southwest and southeast of the study site. The time/altitude distribution of sea-level index points from Romney Marsh is comparable with those from other sites in East Sussex, suggesting that the altitudes of these index points are the product of regional and not local processes. However, the age of peat formation in Romney Marsh is variable, and with the current dataset there is no support for synchronous local sea-level tendencies during the last 7000 calibrated years bp. It is argued that the nature of Holocene coastal sedimentation and the chronology of sea-level tendencies in Romney Marsh have been strongly influenced by local factors. These local factors appear to have operated during periods of both high and low rates of sea-level rise. The stratigraphie record of Romney Marsh therefore records evidence of both local and regional coastal processes.

Terrestrial and marine geological archives in the Arctic contain information on environmental change through Quaternary interglacial–glacial cycles. The Arctic Palaeoclimate and its Extremes (APEX) scientific network aims to better understand the magnitude and frequency of past Arctic climate variability, with focus on the “extreme” versus the “normal” conditions of the climate system. One important motivation for studying the amplitude of past natural environmental changes in the Arctic is to better understand the role of this region in a global perspective and provide base-line conditions against which to explore potential future changes in Arctic climate under scenarios of global warming. In this review we identify several areas that are distinct to the present programme and highlight some recent advances presented in this special issue concerning Arctic palaeo-records and natural variability, including spatial and temporal variability of the Greenland Ice Sheet, Arctic Ocean sediment stratigraphy, past ice shelves and marginal marine ice sheets, and the Cenozoic history of Arctic Ocean sea ice in general and Holocene oscillations in sea ice concentrations in particular. The combined sea ice data suggest that the seasonal Arctic sea ice cover was strongly reduced during most of the early Holocene and there appear to have been periods of ice free summers in the central Arctic Ocean. This has important consequences for our understanding of the recent trend of declining sea ice, and calls for further research on causal links between Arctic climate and sea ice.

In a study of the Holocene sediments in the Hacklinge-Deal area of the East Kent Fens, Southeastern England, hand-coring data has shown that the pre-Holocene surface in this area is incised by one or more valley features, now infilled with unconsolidated Holocene sediments. A shear-wave seismic refraction survey was carried out along profiles where hand-coring had failed to penetrate to bedrock in an attempt to define the detailed form of the pre-Holocene surface. The seismic refraction work was successful because of the large velocity contrast for seismic shear-waves between the Holocene sediments and the Cretaceous chalk bedrock. The seismic data showed that the maximum depth to chalk in the area was almost 20 m, and the results obtained from one profile were subsequently confirmed by hand-coring to a depth of 9 m. Hand-coring, seismic, and Ordnance Survey spot height data have been combined to produce a first estimation of the three-dimensional form of the pre-Holocene surface in the study area.

The record of Holocene coastal sedimentation and sea-level change recorded in the East Kent Fens is compared with those from other areas in southeast England, UK. Chronologies of sea-level tendencies are proposed for the East Kent Fens, Essex, the Thames Estuary, and East Sussex and West Kent. These chronologies are highly variable, and similar sea-level tendencies are recorded in all areas during only 1000 of the last 7500 years. This is in contrast to the altitude/time record of relative sea-level for this region. Relative sea-level is seen to rise from c . −15 m OD at 7500 cal. years bp to between −3 and −4 m OD by 2000 cal. years bp. Altitude/time data from all areas within southeast England show general agreement. It is argued here that the altitude of past sea-level indicators reflect the operation of a regional driving mechanism (changes in the altitude of the sea), but that the nature of coastal sedimentation and the chronology of sea-level tendencies reflect the operation of more local processes.

The recent mass loss of the Greenland ice sheet (Chen et al. 2006), the observed increases in the velocity of its fast-flowing outlets (Luthcke et al. 2006) and the melting of the permafrost demonstrate the profound changes occurring in the Arctic region as a result of global warming (ACIA 2005). This is corroborated by systematic satellite monitoring that shows there has been a progressive decrease in the extent of sea ice over the last 30 years, with a record low in 2007 (Comiso et al. 2008). Forward modelling predicts accelerated rates of sea-ice disintegration and the almost complete disappearance of Arctic Ocean summer sea-ice cover within this century. It is clear that the environment in the Arctic is changing at a pace not previously monitored by humankind. It is equally clear, however, that to place the current changes in a millennial time perspective, we need to know more about the Pleistocene natural variability and amplitude of, for example, the Greenland ice sheet, Arctic Ocean sea ice and permafrost. Such a longer time perspective can only be established through international collaborative and multidisciplinary studies of nature’s own archives, such as marine and terrestrial stratigraphic records, sediment distribution and landforms.

Dungeness Foreland is a large sand and gravel barrier located in the eastern English Channel that during the last 5000 years has demonstrated remarkable geomorphological resilience in accommodating changes in relative sea-level, storm magnitude and frequency, variations in sediment supply as well as significant changes in back-barrier sedimentation. In this paper we develop a new palaeogeographic model for this depositional complex using a large dataset of recently acquired litho-, bio- and chrono-stratigraphic data. Our analysis shows how, over the last 2000 years, three large tidal inlets have influenced the pattern of back-barrier inundation and sedimentation, and controlled the stability and evolution of the barrier by determining the location of cross-shore sediment and water exchange, thereby moderating sediment supply and its distribution. The sheer size of the foreland has contributed in part to its resilience, with an abundant supply of sediment always available for ready redistribution. A second reason for the landform's resilience is the repeated ability of the tidal inlets to narrow and then close, effectively healing successive breaches by back-barrier sedimentation and ebb- and/or flood-tidal delta development. Humans emerge as key agents of change, especially through the process of reclamation which from the Saxon period onwards has modified the back-barrier tidal prism and promoted repeated episodes of fine-grained sedimentation and channel/inlet infill and closure. Our palaeogeographic reconstructions show that large barriers such as Dungeness Foreland can survive repeated “catastrophic” breaches, especially where tidal inlets are able to assist the recovery process by raising the elevation of the back-barrier area by intertidal sedimentation. This research leads us to reflect on the concept of “coastal resilience” which, we conclude, means little without a clearly defined spatial and temporal framework. At a macro-scale, the structure as a whole entered a phase of recycling and rapid progradation in response to changing sediment budget and coastal dynamics about 2000 years ago. However, at smaller spatial and temporal scales, barrier inlet dynamics have been associated with the initiation, stabilisation and breakdown of individual beaches and complexes of beaches. We therefore envisage multiple scales of “resilience” operating simultaneously across the complex, responding to different forcing agents with particular magnitudes and frequencies.

The margin of the Greenland Ice Sheet retreated rapidly during the first few thousand years of the Holocene. During this period of relative warmth, known as the Holocene thermal maximum, ice core records identify a significant short-lived cooling event at approximately 8.4–8.0 ka cal. yr BP (the ‘GH-8.2 event’) associated with a 5–7 °C fall in mean annual air temperature over the centre of the ice sheet. In this paper we constrain the history of the ice sheet margin in Disko Bugt (west Greenland) and that of a major ice stream, Jakobshavns Isbrae, during the early Holocene, which incorporates the interval of the GH-8.2 event. Our work is based on a new relative sea-level curve and minimum age estimates for the timing of deglaciation from two field sites, combined with a review of previously published research from the study area. We identify important differences in the chronology of ice margin recession during the early Holocene, most noticeably, the margin of Jakobshavns Isbrae retreated well inland of the adjacent ice sheet at this time. We conclude that the early Holocene ‘Fjord Stade’ moraines in Disko Bugt do not record a uniform ice sheet margin response to the GH-8.2 event. Rather, these moraines are diachronous and formed between c. 10–8 ka cal. yr BP, their age varying as a function of the interplay between topography and ice sheet/ice stream dynamics. We hypothesise that one cause for the lack of an identifiable response to the GH-8.2 event is because topographic controls dominated ice sheet behaviour at this time. In lowland areas, any increase in ice sheet mass balance was probably associated with an increase in calving rather than any major advance of a grounded ice sheet margin.

This paper examines the role of peat compaction as a driving mechanism behind the widespread inundation of a late Holocene coastal wetland in southeast England, UK. Detailed stratigraphic and dating evidence (lithology, grain size, foraminifera, pollen and radiocarbon dates) from a sample site in Romney Marsh documents the gradual inundation of a coastal wetland after 1263–1085 cal. yr BP (c. 700–850 AD) and the establishment of a saltmarsh. Shortly thereafter there was a rapid increase in water depth that was associated with the deposition of nearly 4 m of laminated intertidal mudflat and tidal channel sediments, prior to site reclamation from the sea by AD 1460. Grain-size data and statistical analysis of sand and mud laminae thicknesses suggest the laminated sediments accumulated rapidly (c. 0.2 m per year) as heterolithic tidal rhythmites. Rapid compaction of the thick peat bed that underlies the study site provided the accommodation space for their deposition. This process began with the gradual tidal inundation of the site, but accelerated following the widening of a breach in a coastal barrier in the 13th century. Compaction lowered the peat surface by at least 3 m and was associated with widespread landscape change. The study demonstrates the powerful influence that compaction had on the evolution of the late Holocene landscape at this site and, we believe, at many other coastal lowlands in northwest Europe. This process is likely to have been a key driving mechanism behind rapid late Holocene coastal change, far exceeding the longer-term effects of either eustatic change or crustal uplift/subsidence.

Although cliffs form approximately 75% of the world's coastline, the understanding of the processes through which they evolve remains limited because of a lack of quantitative data on the morphological changes they undergo. In this paper the combination of terrestrial time-of-flight laser scanning with high-resolution digital photogrammetry is examined to generate high-quality data-sets pertaining to the geomorphic processes governing cliff development. The study was undertaken on a section of hard rock cliffs in North Yorkshire, UK, which has been monitored over a 12-month period. High-density, laser-scanned point clouds have been used to produce an accurate representation of these complex surfaces, free from the optical variations that degrade photographic data. These data-sets have been combined with high-resolution photographic monitoring, resampled with the fixed accuracies of the terrestrial laser survey, to generate a new approach to recording the volumetric changes in complex coastal cliffs. This has led to significant improvements in the understanding of the activity patterns of coastal cliffs.

The prediction of subsidence rates and magnitudes is a challenging problem due to the range of complex variables that combine to determine the displacement of the surface. Many subsidence prediction models utilise an approach that involves detailed modelling of mechanical behaviour of strata transferring strain from the underground void to the surface. Such approaches are typically calibrated using subsidence records. Even after this calibration they generally struggle to predict accurately and reliably actual subsidence in virgin terrain. In this paper a model is presented based on an alternative data-driven approach using statistical techniques. This approach utilises past patterns of monitored subsidence to predict future movements at any point in space and time as a consequence of mining activities. Testing of the model proved that 89% of the estimations are between -1.65 mm/year and +1.40 mm/year of the actual subsidence value and 51% of the estimations are between -0.6 mm/year and 0.4 mm/year of the actual subsidence value.

Marked differences exist between long- and short-term estimates of sea-level rise in southern England. Crucial to resolving these differences is the development of dating techniques capable of bridging the gap between the late-Holocene radiocarbon chronology and the more recent 210 Pb and observational records of sediment accretion and sea-level change. In this paper we identify an increase in Pinus pollen in a sediment core collected from a saltmarsh in Poole Harbour, Dorset. This has been dated to ca. 1750 AD and reflects the historically documented spread of coniferous plantations across the region. This biostratigraphic age horizon, together with other pollen and radiocarbon data, is used to analyse long- and short-term rates of sediment accretion and sea-level change. A basal radiocarbon date indicates a rise in relative sea-level since 1510–1260 cal. yr BC (3130±60 14 C yr BP) of 1.99 m, at a rate of approximately 0.59 mm a -1 . Between ca. 1750 AD and ca. 1890 AD sediment accretion rates rose from 0.29 mm a -1 to 1.14 mm a -1 , perhaps reflecting an acceleration in relative sea-level rise. These rates increased further to 7.17 mm a -1 after ca. 1890 AD, following the development of a Spartina anglica dominated saltmarsh in Poole Harbour. These data demonstrate that caution should be exercised when using sediment accretion rates from saltmarshes recently colonised by S. anglica as proxy data for sea-level rise.