Late Holocene Relative Sea-level Changes Research Articles

Correction: Late Holocene relative sea-level changes and coastal landscape readings in the island group of Mykonos, Delos, and Rheneia (Cyclades, Greece)

Correction: Late Holocene relative sea-level changes and coastal landscape readings in the island group of Mykonos, Delos, and Rheneia (Cyclades, Greece)

Late Holocene relative sea-level changes and coastal landscape readings in the island group of Mykonos, Delos, and Rheneia (Cyclades, Greece)

Late Holocene relative sea-level changes and coastal landscape readings in the island group of Mykonos, Delos, and Rheneia (Cyclades, Greece)

Within-region replication of late Holocene relative sea-level change: An example from southern New England, United States

Tide-gauge measurements in the western North Atlantic Ocean show coherent, multi-decadal relative sea-level (RSL) trends across multiple spatial scales. Proxy reconstructions developed from salt-marsh sediment can extend this instrumental record. However, the degree of coherence in proxy reconstructions is underexamined through within-region replication. To explore within-region replication, we developed a new RSL reconstruction from Fox Hill Marsh, Rhode Island to complement similar records at nearby sites. We established the elevation of former sea level from assemblages of foraminifera and bulk-sediment δ13C values using a Bayesian transfer function. We employed radiocarbon dating and recognition of pollution horizons to construct a core chronology. Since ∼1200 BCE, RSL rose by ∼3.7 m at Fox Hill Marsh. After correction for glacial isostatic adjustment, application of a statistical model intended to quantify (multi-) century-scale trends showed that the fastest rate of rise in at least the past 3000 years was 1.71 ± 0.84 mm/yr (95% credible interval) in 2020 CE. This result replicates regional tide-gauge measurements and other proxy reconstructions. Using an alternative statistical model constructed to identify sub-centennial sea-level changes, we examined if there was a hotspot of 18th century rise in the northeastern United States and found no spatially-coherent trend (i.e., occurring at all or most sites). This lack of replication indicates that accelerated rise during the 18th century is likely local (site-specific) in scale, or an artifact of individual reconstructions. Continued efforts to replicate RSL reconstructions will increase confidence in the accuracy of records and their subsequent interpretation.

Late-Holocene relative sea-level changes and palaeoenvironment of the Pre-Viking Age ship burials in Salme, Saaremaa Island, eastern Baltic Sea

Two unique Pre-Viking Age ship burials were found from Salme village, Saaremaa Island, eastern Baltic Sea, containing remains of seven men in the smaller and 34 men in the larger ship. According to the archaeological interpretations, these ships belonged to a viking crew possibly from the Stockholm-Mälaren region, eastern Sweden. Geoarchaeological research was conducted in the area to reconstruct Late-Holocene relative sea-level (RSL) changes and shoreline displacement to provide environmental context to these burials. In this paper we present a Late-Holocene shore displacement curve for the Saaremaa Island and GIS-based palaeogeographic reconstructions for the Salme area. The curve shows an almost linear RSL fall from 5.5 to 0.8 m a.s.l. between 1000 BC and 1300 AD with an average rate of 2 mm/year. A slowdown in regression may be attributed to accelerated sea-level rise after the Little Ice Age and during the industrial period, being consistent with the tide-gauge measurements from the 20th century. Palaeogeographic reconstructions indicate the existence of a strait in the Salme area during the burial of the ships. The eastern part of the strait with water depth up to 2.8 m was about 80–100 m wide. The relatively steep and wind-protected shores in that part of the strait were probably the best places in the area for landing the viking ships. According to sedimentological evidence and diatom data, the narrowing of Salme palaeostrait occurred between 1270 and 1300 AD. Salme I and II ships were buried at 650–770 AD into the sandy-gravelly coastal deposits which had accumulated there in the open coastal zone about 710–450 years earlier. Reconstructions show that the ships were located about 2–2.5 m above coeval sea level and more than 100 m from the coastline. Thus, both ships were probably moved from the shore to the higher ground for burial.

Causes and implications of Mid- to Late Holocene relative sea-level change in the Gulf of Kachchh, western India

AbstractThe relict intertidal deposits from the Kharod River Estuary, Gulf of Kachchh, and the distal end of Kori Creek are used to infer the Mid- to Late Holocene relative sea-level (RSL) change in western India. Employing sedimentology, geochemistry, palynology, ichnology, and optical and radiocarbon dating, the study suggests the dominance of fluvial activity between 16.5 ± 1.6 and 9.9 ± 0.7 ka. After ~7 ka (7.3 ± 0.4, 6.8 ± 0.5 ka), the sea level showed a positive tendency until 4.7 ± 0.2 ka. The tectonically corrected Mid-Holocene RSL change is estimated as 1.45 ± 0.33 m between ~7 and ~5 ka. The study suggests that the Mid-Holocene RSL high was due to the meltwater contribution from the Himalayan cryosphere, with subordinate contribution from glacio-isostatic adjustment and crustal subsidence. The Late Holocene tectonically corrected RSL change at ~1 ka (1.1 ± 0.1 ka and 1045 ± 175 cal yr BP) is estimated as 0.53 ± 0.43 m. This is ascribed to monsoon wind-driven tidal ingression that might have affected the tidal amplitude positively. The study suggests that the Mid-Holocene RSL change did not play a deterministic role in the abandonment of the Harappan coastal settlements.

Cliff evolution and late Holocene relative sea level change along the Otranto coast (Salento peninsula, southern Apulia, Italy)

The geomorphological analysis of cliff coast stretching to the north of Otranto (southern Apulia, Italy) was integrated by penetrometer tests and geophysical survey aiming to reconstruct its late Holocene evolution. In particular, the study focuses on the inactive cliff of Torre dell'Orso inlet which hosts a 150m - wide beach and a high dune belt. The survey detected the cliff/wave-cut platform junction at about 3.8m below m.s.l. The platform is covered by a dune/beach sedimentary cover about 7m thick.The collated data along with the available local sea level curves allow to reconstruct Otranto's cliff evolution as the result of late Holocene relative sea-level change due to eustasy and land motions. Cliff development was promoted by a sea still-stand level at about 3.5m below present mean sea level occurred between 3400 and 2400 years BP. A rapid sea level rise followed so that several tracts of cliffs were partly drowned becoming plunging cliffs. Cliff recession followed fast sea level rise only along preferential groundwater flow lines where hyperkarst process, due to fresh/salt water mixing, produced deep notches in the calcarenite bedrock inducing rock falls and cliff recession. This process is responsible for the indentation of present shoreline. Finally, during the last four centuries a wide beach and a high dune belt formed at Torre dell'Orso inlet as a result of the increased carry load of Ofanto River, so that the plunging cliff has been separated by shoreline becoming an inactive cliff.Finally, comparing the reconstructed local sea level history during the late Holocene with the available sea level curves produced by glacio-hydro-isostastic models, a yo-yoing land motion with a period of about 4500 years and amplitude of about 2 m can be inferred for the eastern coast of Salento peninsula.

Late Holocene sea-level fall and turn-off of reef flat carbonate production: Rethinking bucket fill and coral reef growth models

Relative sea-level rise has been a major factor driving the evolution of reef systems during the Holocene. Most models of reef evolution suggest that reefs preferentially grow vertically during rising sea level then laterally from windward to leeward, once the reef flat reaches sea level. Continuous lagoonal sedimentation (bucket fill) and sand apron progradation eventually lead to reef systems with totally filled lagoons. Lagoonal infilling of One Tree Reef (southern Great Barrier Reef) through sand apron accretion was examined in the context of late Holocene relative sea-level change. This analysis was conducted using sedimentological and digital terrain data supported by 50 radiocarbon ages from fossil microatolls, buried patch reefs, foraminifera and shells in sediment cores, and recalibrated previously published radiocarbon ages. This data set challenges the conceptual model of geologically continuous sediment infill during the Holocene through sand apron accretion. Rapid sand apron accretion occurred between 6000 and 3000 calibrated yr before present B.P. (cal. yr B.P.); followed by only small amounts of sedimentation between 3000 cal. yr B.P. and present, with no significant sand apron accretion in the past 2 k.y. This hiatus in sediment infill coincides with a sea-level fall of ~1-1.3 m during the late Holocene (ca. 2000 cal. yr B.P.), which would have caused the turn-off of highly productive live coral growth on the reef flats currently dominated by less productive rubble and algal flats, resulting in a reduced sediment input to backreef environments and the cessation in sand apron accretion. Given that relative sea-level variations of ~1 m were common throughout the Holocene, we suggest that this mode of sand apron development and carbonate production is applicable to most reef systems.

Quantifying the contribution of sediment compaction to late Holocene salt-marsh sea-level reconstructions, North Carolina, USA

Salt-marsh sediments provide accurate and precise reconstructions of late Holocene relative sea-level changes. However, compaction of salt-marsh stratigraphies can cause post-depositional lowering (PDL) of the samples used to reconstruct sea level, creating an estimation of former sea level that is too low and a rate of rise that is too great. We estimated the contribution of compaction to late Holocene sea-level trends reconstructed at Tump Point, North Carolina, USA. We used a geotechnical model that was empirically calibrated by performing tests on surface sediments from modern depositional environments analogous to those encountered in the sediment core. The model generated depth-specific estimates of PDL, allowing samples to be returned to their depositional altitudes. After removing an estimate of land-level change, error-in-variables changepoint analysis of the decompacted and original sea-level reconstructions identified three trends. Compaction did not generate artificial sea-level trends and cannot be invoked as a causal mechanism for the features in the Tump Point record. The maximum relative contribution of compaction to reconstructed sea-level change was 12%. The decompacted sea-level record shows 1.71mmyr−1 of rise since AD 1845.

Using Holocene relative sea-level data to inform future sea-level predictions: An example from southwest England

Holocene relative sea-level data contain information on vertical land movements along coasts and, hence, can provide vital input for predictions of future sea-level change. At Thurlestone, in southwest England, late Holocene coastal sediments were cored and sampled in coastal back-barrier marshes. The presence of a basal sedimentary unit containing salt-marsh microfossils made it possible to obtain precise estimates of late Holocene relative sea-level change from the sediments. This is important because previous studies have suggested that the southwest of England is experiencing the fastest rates of land subsidence in the British Isles. Ten new late Holocene basal sea-level index points fill an important gap in the palaeosea-level data set for southwest England. Another 15 early and middle Holocene sea-level index points are available from previous work. The data show that relative sea level rose by about 10 m between 9000 and 7000 cal. yr BP and a further 8 m in the last 7000 yr. In the last 2000 yr, relative sea level rose on average by 0.9 mm/yr. The coast is currently subsiding by 1.1 mm/yr due to ongoing glacial isostatic adjustment (GIA). The Bradley et al. (2009) GIA model, which is used in the United Kingdom to determine land-motion rates for input into future sea-level predictions, underestimates the rate of coastal subsidence by about 0.16 mm/yr, but performs better than other models. Our data validate the land-motion rates currently used in regional sea-level projections.

Millstones as indicators of relative sea-level changes in northern Sicily and southern Calabria coastlines, Italy

New data are presented for late Holocene relative sea-level changes in two coastal sites of Sicily and Calabria, southern Italy. Reconstructions are based on precise measurements of submerged archaeological remains that are valuable indicators of past sea-level position. The archaeological remains are millstone quarries carved on sandstone coastal rocks and nowadays partially submerged which, to the authors’ knowledge, are used for the first time as sea-level markers. Millstones of similar typology are located on the coast of Capo d’Orlando (northern Sicily) and Capo dell’Armi (southern Calabria). When the archeologically-based sea-level position is compared with the shoreline elevation provided by geological markers (Holocene beachrock, Late Pleistocene marine terraces), a refined understanding of relative sea-level changes and rates of vertical tectonic movements for these coastline locations is gained.

Late Holocene land- and sea-level changes in the British Isles: implications for future sea-level predictions

Four decades of palaeosea-level research in the British Isles have produced a large dataset of age–altitude curves of postglacial sea-level changes. Patterns of late Holocene relative sea-level change reveal the persistent influence of the British/Irish Ice Sheet and the larger Scandinavian Ice Sheet on contemporary rates of vertical land movements. The Shennan and Horton (2002) map of late Holocene relative land movements has been used in future sea-level rise predictions by the United Kingdom Climate Impact Programme in their 2002 assessment (UKCIP02), but has been mistaken for a map of absolute land movements. In this paper, land-motion data for Britain are extracted from the Shennan and Horton (2002) relative sea-level data, and a new map of crustal land movements is presented which also includes Ireland. This procedure takes into account the regional 20th century sea-level rise (∼0.14 m) and the process of ocean syphoning ( i.e. a global fall in sea level of ∼0.3 mm/yr due to GIA induced ocean-floor lowering and re-distribution of ocean mass). The calculated land-motion rates also depend on the global late Holocene ice-equivalent sea-level change, given by the Intergovernmental Panel on Climate Change as 0.0–0.2 mm/yr. Accounting for these processes reduces the misfit between geological observations of vertical land motion and those independently derived from gravity-aligned Global Positioning System (AG GPS) measurements and shows that UKCIP02 has underestimated land subsidence in southern Britain and over-estimated land uplift in Scotland, both by 0.1–0.2 mm/yr. A best fit between GPS and geological estimates of land movements in Britain is achieved for a global long-term eustatic sea-level fall of ca 0.2 mm/yr, suggesting some global ice expansion in the late Holocene, rather than melt. If this is correct, uplift rates in Scotland would be lower and subsidence rates in southern Britain would be faster (by 0.4–0.5 mm/yr) than estimated by UKCIP02. More high-quality late Holocene relative sea-level data are required to quantify vertical land motion as accurately as possible, especially near large coastal population centres, for input into regional scenarios of future sea-level rise.

Compaction of Holocene strata and the implications for relative sealevel change on the east coast of England

The contribution of compaction of Holocene strata to sea-level rise, shoreline erosion, and wetland loss is difficult to decipher because of a lack of long-term empirical data. We analyzed more than 360 radiocarbon-dated index points to constrain relative sea levels along the east coast of England during the Holocene and to provide estimates of sediment compaction. The isostatic effect of glacial rebound explains regional-scale differences in relative sea levels. Northeast England, the most northern study area, reveals a middle to late Holocene highstand, <1 m above present, ca. 3–4 kyr B.P., whereas the Tees Estuary, Humber Estuary, Lincolnshire Marshes, Fenlands, and North Norfolk each reveal sea-level histories of an upward trend during the Holocene. Within each area, sediment compaction explains the variation in elevation between sealevel reconstructions derived from index points taken from basal peat and those from peat intercalated within thick sequences of Holocene sediments. We find average compaction rates of 0.4 ± 0.3 mm yr−1 with higher values for the large estuaries. Rates of late Holocene relative sea-level changes, calculated from basal peats, range from −0.2 ± 0.1 mm yr−1 (i.e., sea-level fall) in northeast England to 0.8 ± 0.1 mm yr−1 in North Norfolk. Inclusion of intercalated index points overestimates late Holocene rates by 0.1–0.4 mm yr−1 because of the effects of sediment compaction.

Sedimentary record of late-Holocene relative sea-level change and tectonic deformation from the Guerrero Seismic Gap, Mexican Pacific Coast

Studies of the coastal sedimentary record have allowed both the reconstruction of relative sea-level changes and the determination of local rates and magnitudes of tectonic deformation, particularly in tectonically active areas. Despite their successful use elsewhere, studies of this type are much less common for the Mexican Pacific coast, which parallels the Cocos-North America subduction plate boundary. Stratigraphic, geochemical and microfossil data from sediments in Laguna Mitla, the Pacific coast of Guerrero, Mexico, document late-Holocene sea-level changes induced by tectonic activity in the Mexican subduction zone. Three major events are identified. First, the formation of the lagoon by c. 4630 yr BP, as indicated by a freshwater to brackish peat. Second, a relative sea-level rise, or land subsidence, as indicated by a shift from a freshwater marginal lagoon environment to a marine setting, preceded by a marine inundation represented by a sand unit (possibly a tsunami deposit), by c. 3400 yr BP. And finally, a return to lagoonal conditions indicating a drop in relative sea level or coastal uplift by c. 2300 yr BP. The Laguna Mitla stratigraphy indicates general coastal subsidence or relative sea level rise of c. 1 mm/yr. We argue that these relative sea-level (land-level) changes have been induced by tectonic activity associated with the Mexican megathrust. A plausible explanation for the 3400 yr BP marine inundation is probably a tsunami produced by a large seismic event accompanied by coastal subsidence. Discrete fining upward, fine to coarse, sand units with an erosional basal contact, medium to poor sorting, and clay/mud rip-up clasts; an increase in Na and Sr elemental concentrations, indicative of a marine origin; and the landward extent of the sands support a tsunamigenic source for these deposits. However, these apparent tsunami deposits require further study to determine their lateral extent and to assess whether they can be correlated from one site to another. This study demonstrates the applicability of a multiproxy sedimentary approach in interpreting relative sea-level (land-level) changes and to derive data on related earthquake and tsunami events in tropical coastal lagoons.

Late Holocene sea-level changes along the southern coast of Finland, Baltic Sea

Lake isolation studies provide a reliable method for reconstructing the sea-level history of areas affected by the glacio-isostatic land uplift. In this study, Late Holocene relative sea-level changes were investigated along the southern coast of Finland, Gulf of Finland in the Baltic Sea, by studying 11 isolation basins in four areas (Kirkkonummi, Orslandet, Tenhola and Prästkulla), which extend across 120 km of Finnish coastline that is characterised by a narrow archipelago. The methods employed were lithostratigraphic interpretation, diatom analyses and radiocarbon dating. Also used in this work are the results from three previously studied isolation basins with four 14C dates. The sea-level history varies within the study area. The 3000 yr old Baltic Sea shoreline is located about 11 m above present sea-level (a.s.l.) in Prästkulla, and about 8 m a.s.l. in Kirkkonummi. These differences are due to the differences in isostatic uplift rates, which have been slower in the east. The main trend in relative sea-level along the southern coast of Finland is one characterised by a generally decreasing uplift rate during the Late Holocene. However, we identify the uplift anomalies in two areas where our data show phases of relative sea-level lowering. They are the first verified Late Holocene land uplift anomalies detected in Finnish sea-level data.

Late Holocene relative sea-level changes in Lebanon, Eastern Mediterranean

Twenty-nine 14C dates of precise biological sea-level indicators from the Lebanese coast show evidence for two significant regional crustal uplift episodes during the past 6000 years. We elucidate: (1) an upper shoreline at ca. + 120 to + 140 cm, which lasted from ca. 6000 to 3000 BP; and (2) a lower shoreline at + 80 ± 40 cm, developed between the fifth century BC and the sixth century AD. These movements are associated with: (1) two major seismic crises along the Yammuneh fault and the Roum-Tripoli Thrust (RTT); and (2) subsequent seismic events on a series of second-order ENE trending dextral transpressive faults. Vertical movements affected north Lebanon, whilst the coasts of south Lebanon generally underwent crustal downlift. This is in contrast with relative stability in northern Israel, suggesting an area of stationary tectonic conditions west of the Dead Sea–Rosh Hanikra/Ras Nakoura fault. The main 14C age cluster, corresponding to the second uplift event, may have resulted from fault movements during the “Early Byzantine Tectonic Paroxysm” (EBTP), between ca. 1750 and 2000 BP. Relative sea level stabilised to present level around 1000 BP.

Mid-to late-Holocene relative sea-level change in southwest Britain and the influence of sediment compaction

Relative sea-level changes in southwest Britain are poorly constrained because of limitations in the quality and quantity of existing geological data. As a consequence, in contrast to most other regions in the UK, it is not possible to reliably infer rates of land and sea-level change during the last few thousand years. Furthermore, geologically based sea-level reconstructions from this area display significant misfits with relative sea-level predictions based on a recent global model of the glacio-isostatic adjustment process. This paper presents a new record of relative sea-level change for the last 4000 years derived from radiocarbon-dated sea-level index points. In addition to providing information concerning the pattern and rates of late Holocene sea-level change, these data are used to evaluate the suggestion that the apparent misfits between model predictions and geological reconstructions can be satisfactorily explained as a consequence of the lowering of sea-level index points by sediment compaction. The results indicate that a simple, first-order method of decompaction based on the stratigraphic position of sea-level index points, can eliminate much of the misfit between reconstructions and predictions, and substantially reduce vertical scatter in geological data. They also suggest that the influence of compaction on sea-level data from this region may be larger than previously thought. The simple addition of reliable stratigraphic data, in combination with targeted sampling, has the potential to improve our understanding of the compaction process, and increase the utility of existing data. This is increasingly important as the partnership between geophysical modelling and geological investigation becomes more commonplace in sea-level studies around the world.

Late Holocene relative sea-level changes and the earthquake deformation cycle around upper Cook Inlet, Alaska

Multiple peat-silt couplets preserved in tidal marsh sediment sequences suggest that numerous great plate boundary earthquakes caused the coast around Cook Inlet, Alaska, to subside over the past 3500 years. Field and laboratory analyses of the two youngest couplets record the well-documented earthquake of AD 1964 and the penultimate one, approximately 850 cal yr BP. Diatom assemblages from a range of modern day estuarine environments from tidal flat through salt marsh to acidic bog produce quantitative diatom transfer function models for elevation reconstructions based on fossil samples. Only nine out of 124 fossil assemblages analysed, including previously published data for the AD 1964 earthquake, have a poor modern analogue. Calibration of fossil samples indicate co-seismic subsidence of 1.50±0.32 m for AD 1964, similar to measurements taken after the earthquake, and 1.45±0.34 m for the ∼850 cal yr BP earthquake. Elevation standard errors for individual fossil samples range from ∼0.08 m in peat layers to ∼0.35 m in silt units. Lack of a chronology within fossil silt units prevents identification of changes in the rate of recovery and land uplift between the post-seismic and inter-seismic periods. However, preservation of multiple peat-silt couplets indicates no net emergence over multiple earthquake cycles. Glacio-isostatic movements from Little Ice Age glacier advance and retreat explains a ∼0.15 m relative sea-level oscillation recorded within the peat layer subsequently submerged as a result of the AD 1964 earthquake. Before both this and the ∼850 cal yr BP earthquake, diatom assemblages suggest pre-seismic relative sea-level rise of ∼0.12±0.13 m, representing possible precursors to great earthquakes.

Mid‐ to late Holocene relative sea‐level change in Poole Harbour, southern England

AbstractA foraminiferal transfer function for mean tide level (MTL) is used in combination with AMS radiocarbon dated material to construct a record of relative sea‐level (RSL) change from Poole Harbour, southern Britain. These new data, based on multiple cores from duplicate sites, indicate four phases of change during the last 5000 cal. (calendar) yr: (i) rising RSL between ca. 4700 cal. yr BP and ca. 2400 cal. yr BP; (ii) stable to falling RSL from ca. 2400 cal. yr BP until ca. 1200 cal. yr BP; (iii) a brief rise in RSL from ca. 1200 cal. yr BP to ca. 900 cal. yr BP, followed by a period of stability; (iv) a recent increase in the rate of RSL rise from ca. 400–200 cal. yr BP until the present day. In addition, they suggest that the region has experienced long‐term crustal subsidence at a rate of 0.5 mm C14 yr−1. Although this can account for the overall rise in MTL observed during the past 2500 yr, it fails to explain the changes in the rate of rise during this period. This implies that the phases of RSL change recorded in the marshes of Poole Harbour reflect tidal range variations or ‘eustatic’ fluctuations in sea‐level. Copyright © 2001 John Wiley &amp; Sons, Ltd.

Evaluating late-Holocene relative sea-level change in the Somerset Levels, southwest Britain

Holocene relative sea-level (RSL) change is investigated at Nyland Hill (Somerset Levels). The lithostratigraphy comprises turfa peat underlying marine clay, both onlapping a sloping Upper Palaeozoic basement. The altitude of the peat-clay contact ranges from 2.42 to 4.52 m OD, becoming lower down basement slope, yet 14C dates of three samples taken laterally along the contact at different altitudes yield similar ages (3640-3330, 3715-3460, 3725-3465 cal. yrs BP), suggesting either very rapid (‘instantaneous’) RSL rise or sediment compaction. Biostratigraphic data indicate a gradual transition to marine conditions across the peat-clay contact. Therefore, the height difference is interpreted as evidence for significant compaction. We consider 4.64 m OD the minimum pre-compaction altitude, indicating maximum observed compaction of 2.22 m. The clay surface, reclaimed during Roman occupation, represents an anthropogenically induced negative tendency and is dated chemostratigraphically to 1776 ± 46, using a datum related to the onset of local Roman lead mining AD 43-49. Sedimentation rates of the marine clay are established: 1.58-1.92 mm yr-1 and 0.8-0.96 mm yr-1 at sites of maximum and less severe compaction respectively. RSL continued to rise throughout the deposition of the clay unit at a rate of 0.41-0.82 mm yr-1, a view that disagrees with previous models that imply stabilised RSL by 3000 BP. These earlier studies underestimate compaction with implications for subsequent studies employing these sea-level data, particularly in crustal studies where the apparent trend of subsidence is overestimated/increased.

Geomorphology and Sedimentary Record of Three Cuspate Forelands as Indicators of Late Holocene Relative Sea-level Changes, Disko, West Greenland

Geografisk Tidsskrift, Danish Journal of Geography 97: 33–46, 1997. The coastal geomorphology of three cuspate forelands at Saqqarliit Ilorliit, western Disko, West Greenland is described, sediment core data from salt marshes and lagoons are presented, an emergence curve is constructed, and data are discussed in relation to late Holocene relative sea-level (RSL) changes. On western Disko, falling RSL in early-middle Holocene was followed by rising RSL in late Holocene. Emergence continued until c. 2.5 ka BP. The coastal geomorphology at Saqqarliit Ilorliit suggest transgression early in the interval 2.5—1.0 ka BP and between 0.7 ka BP and the present. The first transgression resulted in formation of an intertidal platform and coastal cliffs. Washover ridges and lagoons developed during the transgression after 0.7 ka BP. Based on the core data it is suggested that the transgression after 0.7 ka BP might have consisted of three transgression phases separated by periods with stable or slightly regressive conditions.