Temporal changes of accretion rates on an estuarine salt marsh during the late Holocene — Reflection of local sea level changes? The Wadden Sea, Denmark

AbstractCores and exposed cliff sections in salt marshes around Ho Bugt, a tidal embayment in the northernmost part of the Danish Wadden Sea, were subjected to 14C dating and litho- and biostratigraphical analyses to reconstruct paleoenvironmental changes and to establish a late Holocene relative sea-level history. Four stages in the late Holocene development of Ho Bugt can be identified: (1) groundwater-table rise and growth of basal peat (from at least 2300 BC to AD 0); (2) salt-marsh formation (0 to AD 250); (3) a freshening phase (AD 250 to AD 1600?), culminating in the drying out of the marshes and producing a distinct black horizon followed by an aeolian phase with sand deposition; and (4) renewed salt-marsh deposition (AD 1600? to present). From 16 calibrated AMS radiocarbon ages on fossil plant fragments and 4 calibrated conventional radiocarbon ages on peat, we reconstructed a local relative sea-level history that shows a steady sea-level rise of 4 m since 4000 cal yr BP. Contrary to suggestions made in the literature, the relative sea-level record of Ho Bugt does not contain a late Holocene highstand. Relative sea-level changes at Ho Bugt are controlled by glacio-isostatic subsidence and can be duplicated by a glacial isostatic adjustment model in which no water is added to the world's oceans after ca. 5000 cal yr BP.

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Quantifying the Contribution of Sediment Compaction to late Holocene Salt-Marsh Sea-Level Reconstructions, North Carolina, USA

Quaternary Research ◽

10.1016/j.yqres.2014.08.003 ◽

2015 ◽

Vol 83 (1) ◽

pp. 41-51 ◽

Cited By ~ 26

Author(s):

Matthew J. Brain ◽

Andrew C. Kemp ◽

Benjamin P. Horton ◽

Stephen J. Culver ◽

Andrew C. Parnell ◽

...

Keyword(s):

North Carolina ◽

Salt Marsh ◽

Sea Level ◽

Late Holocene ◽

Depositional Environments ◽

Causal Mechanism ◽

Sea Level Changes ◽

Level Change ◽

Relative Contribution ◽

Changepoint Analysis

AbstractSalt-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 1.71 mm yr− 1 of rise since AD 1845.

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Middle to Late Holocene relative sea-level changes recorded on the coast of Apulia (Italy) / Variations relatives du niveau marin pendant l'Holocène moyen et supérieur le long des côtes méridionales des Pouilles (Italie)

Géomorphologie relief processus environnement ◽

10.3406/morfo.2004.1196 ◽

2004 ◽

Vol 10 (1) ◽

pp. 19-33 ◽

Cited By ~ 16

Author(s):

Rita Auriemma ◽

Giuseppe Mastronuzzi ◽

Paolo Sansò

Keyword(s):

Sea Level ◽

Late Holocene ◽

Sea Level Changes ◽

Relative Sea Level

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GROUNDWORK: Late Holocene relative land- and sea-level changes: Providing information for stakeholders

GSA Today ◽

10.1130/gsatg50gw.1 ◽

2009 ◽

pp. 52-53 ◽

Cited By ~ 28

Author(s):

Ian Shennan

Keyword(s):

Sea Level ◽

Late Holocene ◽

Sea Level Changes ◽

And Sea Level

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BIOINDICATORS OF SEA-LEVEL FLUCTUATIONS IN SOUTHEASTERN BRAZIL: NEW DATA AND METHODOLOGICAL REVIEW

Radiocarbon ◽

10.1017/rdc.2021.50 ◽

2021 ◽

pp. 1-15

Author(s):

Julia Caon Araujo ◽

Kita Chaves Damasio Macario ◽

Vinícius Nunes Moreira ◽

Anderson dos Santos Passos ◽

Perla Baptista de Jesus ◽

...

Keyword(s):

Sea Level ◽

Late Holocene ◽

Data Interpretation ◽

Progressive Increase ◽

Southeastern Brazil ◽

Recrystallization Process ◽

Sea Level Changes ◽

Sea Level Fluctuations ◽

Data Gap ◽

Current Zero

ABSTRACT The vermetidae fossils of Petaloconchus varians, formed by calcium carbonate, associated with their radiocarbon ages, are the most accurate indicators of paleo sea level due to their restricted occupation in the intertidal zone in the rocky shore. However, the recrystallization of minerals can affect these age calculations and, consequently, the interpretation of the data. The aim of this study is to present new indicators of paleo sea-level changes in Southeast Brazil for the last 6000 years contributing to fill the data gap for the late Holocene. The influence of the recrystallization process was successfully resolved using the CarDS protocol, enabling the separation of the original aragonite fraction by density, prior to radiocarbon dating. This avoids the rejuvenation of ages and ensures greater efficiency for data interpretation. Paleo sea-level indicators were able to show a progressive increase in sea level up to the transgressive maximum of 4.15 m in 3700 BP years, followed by a regression to the current zero. This regression seems to have in addition, here we reinforce the reliability of the use of fossil vermetids as indicators of sea-level fluctuations.

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Late Holocene relative sea level changes in SW Crete: evidence of an unusual earthquake cycle

Annals of Geophysics ◽

10.4401/ag-3999 ◽

1996 ◽

Vol 39 (3) ◽

Author(s):

S. C. Stiros

Keyword(s):

Sea Level ◽

Late Holocene ◽

Hanging Wall ◽

Earthquake Cycle ◽

Sea Level Changes ◽

Land Uplift ◽

Unusual Pattern ◽

Wide Range ◽

Coastal Changes ◽

Seismic Deformation

Coastal challenges ill West Crete ill the last 4000 years can be described as a series of 11 relatively small (25 cm on the average) land subsidences alternating with short (150-250 year long) relatively still stands of the sea level. At 1500 B.P. an up to 9 m episodic relative land uplift and tilting of this part of the island occurred, but since then no significant coastal changes have been identified. There is strong evidence that these Late Holocene coastal changes are not a product of fluctuations of sea level, but reflect palaeoseismic events. The sequence of the latter is at variance with models of seismic deformation deduced from a wide range of observations in different tectonic environments, including coastal uplifts near major trenches: according to these models, strain buildup and release through earthquakes is described as a cyclic and rather uniform process, the earthquake cycle. In this process, the permanent seismic deformation accumulates after each earthquake to produce geological features, while the long-term deformation rate is approximately equal to the short term one. Obviously this is not the case with West Crete. The unusual pattern of seismic deformation in this island has been observed in other cases as well, but its explanation is not easy. The juxtaposition of different earthquake cycles, variations in the source and rate of stress or internal deformation of the uplifted hanging wall of a thrust in the pre-seismic period are some possible explanations for this unusual pattern of earthquake cycle in Greece.

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Historical rates of salt marsh accretion on the outer Bay of Fundy

Canadian Journal of Earth Sciences ◽

10.1139/e01-002 ◽

2001 ◽

Vol 38 (7) ◽

pp. 1081-1092 ◽

Cited By ~ 23

Author(s):

Gail L Chmura ◽

Laurie L Helmer ◽

C Beth Beecher ◽

Elsie M Sunderland

Keyword(s):

Salt Marsh ◽

Sea Level ◽

Sea Level Change ◽

Bay Of Fundy ◽

Relative Sea Level ◽

Early 19Th Century ◽

Level Change ◽

Pollen Stratigraphy ◽

Accretion Rates ◽

Marsh Accretion

We examine rates of salt marsh accumulation in three marshes of the outer Bay of Fundy. At each marsh we selected a site in the high marsh with similar vegetation, and thus similar elevation. Accretion rates were estimated by 137Cs, 210Pb, and pollen stratigraphy to estimate rates of change over periods of 30, 100, and ~170 years, respectively. These rates are compared with records from the two closest tide gauges (Saint John, New Brunswick, and Eastport, Maine) to assess the balance of recent marsh accretion and sea-level change. Averaged marsh accretion rates have ranged from 1.3 ± 0.4 to 4.4 ± 1.6 mm·year1 over the last two centuries. Recent rates are similar to the rate of sea-level change recorded at Eastport, Maine, suggesting that they are in step with recent sea-level change but very sensitive to short-term variation in relative sea level. Based on the pollen stratigraphy in the marsh sediments, the marsh accretion rate was higher during the late 18th to early 19th century. Higher rates probably were due to local increases in relative sea level as a result of neotectonic activity and may have been enhanced by increased sediment deposition through ice rafting.

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Late Holocene sea-level change around Newfoundland

Canadian Journal of Earth Sciences ◽

10.1139/e07-036 ◽

2007 ◽

Vol 44 (10) ◽

pp. 1453-1465 ◽

Cited By ~ 11

Author(s):

Julia F Daly ◽

Daniel F Belknap ◽

Joseph T Kelley ◽

Trevor Bell

Keyword(s):

Salt Marsh ◽

Sea Level Rise ◽

Sea Level ◽

Late Holocene ◽

Sea Level Change ◽

Laurentide Ice Sheet ◽

Change Analysis ◽

Level Change ◽

Rising Sea Level ◽

Holocene Sea Level

Differential sea-level change in formerly glaciated areas is predicted owing to variability in extent and timing of glacial coverage. Newfoundland is situated close to the margin of the former Laurentide ice sheet, and the orientation of the shoreline affords the opportunity to investigate variable rates and magnitudes of sea-level change. Analysis of salt-marsh records at four sites around the island yields late Holocene sea-level trends. These trends indicate differential sea-level change in recent millennia. A north–south geographic trend reflects submergence in the south, very slow sea-level rise in the northeast, and a recent transition from falling to rising sea-level at the base of the Northern Peninsula. This variability is best explained as a continued isostatic response to deglaciation.

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