Accurate Holocene relative sea-level curves are vital for modelling future sea-level changes, particularly in regions where relative sea-level changes are dominated by isostatically induced vertical land movements. In North Wales, various glacial isostatic adjustment (GIA) models predict a mid-Holocene relative sea-level highstand between 4 and 6 ka, which is unsubstantiated by any geological sea-level data but affects the ability of geophysical models to model accurately past and future sea levels. Here, we use a newly developed foraminifera-based sea-level transfer function to produce a 3300-year-long late-Holocene relative sea-level reconstruction from a salt marsh in the Malltraeth estuary on the south Anglesey coast in North Wales. This is the longest continuous late-Holocene relative sea-level reconstruction in Northwest Europe. We combine this record with two new late-Holocene sea-level index points (SLIPs) obtained from a freshwater marsh at Rhoscolyn, Anglesey, and with previously published regional SLIPs, to produce a relative sea-level record for North Wales that spans from ca. 13,000 BP to the present. This record leaves no room for a mid-Holocene relative sea-level highstand in the region. We conclude that GIA models that include a mid-Holocene sea-level highstand for North Wales need revision before they are used in the modelling of past and future relative sea-level changes around the British Isles.
ApplebyPG (2001) Chronostratigraphic techniques in recent sediments. In: LastWMSmolJP (eds) Tracking Environmental Change Using Lake Sediments: Physical and Geochemical Methods, Volume 1. Dordrecht: Springer, pp. 171–203.
2.
ArgusDFPeltierWRDrummondR, et al. (2014) The Antarctica component of postglacial rebound model ICE-6G_C (VM5a) based on GPS positioning, exposure age dating of ice thicknesses, and relative sea level histories. Geophysical Journal International198: 537–563.
3.
BarlowNLLongAJSaherMH, et al. (2014) Salt-marsh reconstructions of relative sea-level change in the north Atlantic during the last 2000 years. Quaternary Science Reviews99: 1–16.
4.
BarlowNLShennanILongAJ, et al. (2013) Salt marshes as late Holocene tide gauges. Global and Planetary Change106: 90–110.
5.
BedlingtonDJ (1994) Holocene sea-level changes and crustal movements in North Wales and Wirral. PhD Thesis, Durham, University of Durham.
6.
BlaauwMChristenJA (2011) Flexible paleoclimate age-depth models using an autoregressive gamma process. Bayesian Analysis64: 57–474.
7.
BradleySLMilneGAHortonBP, et al. (2016) Modelling sea level data from China and Malay-Thailand to estimate Holocene ice-volume equivalent sea level change. Quaternary Science Reviews137: 54–68.
8.
BradleySLMilneGAShennanI, et al. (2011) An improved glacial isostatic adjustment model for the British Isles. Journal of Quaternary Science26: 541–552.
9.
BradleySLMilneGATeferleFN, et al. (2009) Glacial isostatic adjustment of the British Isles: New constraints from GPS measurements of crustal motion. Geophysical Journal International178: 14–22.
10.
BrainMJLongAJWoodroffeSA, et al. (2012) Modelling the effects of sediment compaction on salt marsh reconstructions of recent sea-level rise. Earth and Planetary Science Letters345–348: 180–193.
11.
BrooksAJBradleySLEdwardsRJ, et al. (2008) Postglacial relative sea-level observations from Ireland and their role in glacial rebound modelling. Journal of Quaternary Science23: 175–192.
12.
BruunP (1962) Sea-level rise as a cause of shore erosion. Journal of the Waterways and Harbors Division88: 117–132.
13.
ClarkCDElyJCGreenwoodSL, et al. (2018) BRITICE glacial map, version 2: A map and GIS database of glacial landforms of the last British–Irish ice sheet. Boreas: An International Journal of Quaternary Research47: 11–27.
14.
CloutHD (2007) Contemporary Rural Geographies – Land, Property, and Resources in Britain: Essays in Honour of Richard Munton. London: Routledge.
15.
CollinsABuchanC (2004) Provenance and age constraints of the South Stack Group, Anglesey, UK: U-Pb SIMS detrital zircon data. Journal of the Geological Society161: 743–746.
16.
De RijkS (1995) Agglutinated Foraminifera as Indicators of Salt Marsh Development in Relation to Late-Holocene Sea Level Rise (Great Marshes at Barnstable, Massachusetts). Utrecht: Febo.
17.
EdwardsRJHortonBP (2000) Reconstructing relative sea-level change using UK salt-marsh foraminifera. Marine Geology169: 41–56.
18.
EdwardsRJWrightAJvan de PlasscheO (2004) Surface distributions of salt-marsh foraminifera from Connecticut, USA: Modern analogues for high-resolution sea level studies. Marine Micropaleontology51: 1–21.
19.
FarrellWEClarkJA (1976) On postglacial sea level. Geophysical Journal of the Royal Astronomical Society46: 647–667.
20.
FosterIMighallTProffittH, et al. (2006) Post-depositional 137Cs mobility in the sediments of three shallow coastal lagoons, SW England. Journal of Paleolimnology35: 881–895.
21.
GaleSJHoarePG (1991) Chemical composition and analysis. In: GaleSJHoarePG (eds) Quaternary Sediments: Petrographic Methods for the Study of Unlithified Rocks. Chichester; New York: Wiley, pp. 262–265.
22.
GehrelsWR (1994) Determining relative sea-level change from salt-marsh foraminifera and plant zones on the Coast of Maine, U.S.A. Journal of Coastal Research10: 990–1009.
23.
GehrelsWR (2000) Using foraminiferal transfer functions to produce high-resolution sea-level records from salt-marsh deposits, Maine, USA. The Holocene10: 367–376.
24.
GehrelsWR (2010) Late Holocene land- and sea-level changes in the British Isles: Implications for future sea-level predictions. Quaternary Science Reviews29(13): 1648–1660.
25.
GehrelsWRAndersonWP (2014) Reconstructing Holocene sea-level change from coastal freshwater peat: A combined empirical and model-based approach. Marine Geology353: 140–152.
26.
GehrelsWRDawsonDAShawJ, et al. (2011) Using Holocene relative sea-level data to inform future sea-level predictions: An example from southwest England. Global and Planetary Change78(3–4): 116–126.
27.
GrinstedAMooreJCJevrejevaS (2004) Application of the cross wavelet transform and wavelet coherence to geophysical time series. Nonlinear Processes in Geophysics11: 561–566.
28.
HassaniHCovey-CrumpSJRutterEH (2004) On the structural age of the Rhoscolyn antiform. Geological Journal39: 141–156.
29.
HeyworthAKidsonC (1982) Sea-level changes in southwest England and Wales. Proceedings of the Geologists’ Association93: 91–111.
30.
HorakJMEvansJA (2011) Early Neoproterozoic limestones from the Gwna Group, Anglesey. Geological Magazine148(1): 78–88.
31.
JugginsS (2003) User Guide C2, Software for Ecological and Palaeoecological Data Analysis and Visualisation (User Guide Version 1.3). Newcastle: Department of Geography.
32.
KempACHortonBPVaneCH, et al. (2013) Sea-level change during the last 2500 years in New Jersey, USA. Quaternary Science Reviews81: 90–104.
33.
KraftJCChrzastowskiMJ (1985) Coastal stratigraphic sequences. In: DavisRA (ed.) Coastal Sedimentary Environments. New York: Springer, pp. 625–663.
34.
LambeckK (1996) Glaciation and sea-level change for Ireland and the Irish sea since late Devensian/Midlandian time. Journal of the Geological Society153: 853–872.
35.
LisleRJ (1988) Anomalous vergence patterns on the Rhoscolyn Anticline, Anglesey: Implications for structural analysis of refolded regions. Geological Journal23: 211–220.
36.
LloydJMZongYFishP, et al. (2013) Holocene and late-glacial relative sea-level change in north-west England: Implications for glacial isostatic adjustment models. Journal of Quaternary Science28: 59–70.
37.
MarshallWAGehrelsWRGarnettMH, et al. (2007) The use of ‘bomb spike’ calibration and high-precision AMS 14C analyses to date salt-marsh sediments deposited during the past three centuries. Quaternary Research68: 325–337.
38.
MilneGAShennanIYoungsBAR, et al. (2006) Modelling the glacial isostatic adjustment of the UK region. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences364: 931–948.
39.
PackhamJRLiddleMJ (1970) The Cefni salt marsh Anglesey, and its recent development. Field Studies3: 331–356.
40.
PattersonRTRoland GehrelsWBelknapDF, et al. (2004) The distribution of salt marsh foraminifera at Little Dipper Harbour New Brunswick, Canada: Implications for development of widely applicable transfer functions in sea-level research. Quaternary International120: 185–194.
41.
PeltierWR (1994) Ice age paleotopography. Science265: 195–201.
42.
PeltierWR (2002) Global glacial isostatic adjustment: Palaeogeodetic and space-geodetic tests of the ICE-4G (VM2) model. Journal of Quaternary Science17: 491–510.
43.
PeltierWR (2004) Global glacial isostasy and the surface of the ice-age earth: The ICE-5G (VM2) model and grace. Annual Review of Earth and Planetary Sciences32: 111–149.
44.
PrinceHE (1988) Late-glacial and post-glacial sea-level movements in North Wales with particular reference to the techniques for the analysis and interpretation of unconsolidated estuarine sediments. PhD Thesis, Aberystwyth, University of Wales.
45.
ReimerPJBrownTAReimerRW (2004) Discussion: Reporting and calibration of post-bomb 14C data. Radiocarbon46(1): 1299–1304.
46.
RhindPMBlackstockTHHardyHS, et al. (2001) The evolution of Newborough Warren dune system with particular reference to the past four decades. In: JAHoustonSEEdmondsonPJRooney (eds) Coastal Dune Management: Shared Experience of European Conservation Practice: Proceedings of the European Symposium Coastal Dunes of the Atlantic Biogeographical Region Southport, Northwest England, September 1998. Liverpool: Liverpool University Press, pp. 345–380.
47.
RobertsMJScourseJDBennellJD, et al. (2011) Late Devensian and Holocene relative sea-level change in North Wales, UK. Journal of Quaternary Science26: 141–155.
48.
RoeHMDohertyCTPattersonRT, et al. (2009) Contemporary distributions of saltmarsh diatoms in the Seymour–Belize Inlet Complex, British Columbia, Canada: Implications for studies of sea-level change. Marine Micropaleontology70: 134–150.
49.
ScottDSMedioliFS (1978) Vertical zonations of marsh foraminifera as accurate indicators of former sea-levels. Nature272: 528–531.
50.
ScottDBMedioliFS (1980) Quantitative Studies of Marsh Foraminiferal Distributions in Nova Scotia: Implications for Sea Level Studies. Washington, DC: Cushman Foundation for Foraminiferal Research.
51.
ShennanIBradleySMilneG, et al. (2006) Relative sea-level changes, glacial isostatic modelling and ice-sheet reconstructions from the British Isles since the last glacial maximum. Journal of Quaternary Science21: 585–599.
52.
ShennanIBradleySLEdwardsR (2018) Relative sea-level changes and crustal movements in Britain and Ireland since the Last Glacial Maximum. Quaternary Science Reviews188: 143–159.
53.
ShennanIMilneGBradleyS (2012) Late Holocene vertical land motion and relative sea-level changes: Lessons from the British Isles. Journal of Quaternary Science27(1): 64–70.
54.
SimonKMRivaREMKleinherenbrinkM, et al. (2018) The glacial isostatic adjustment signal at present day in northern Europe and the British Isles estimated from geodetic observations and geophysical models. Solid Earth9: 777–795.
55.
SmallDClarkCDChiverrellRC, et al. (2017) Devising quality assurance procedures for assessment of legacy geochronological data relating to deglaciation of the last British-Irish ice sheet. Earth-Science Reviews164: 232–250.
56.
StockampJBishopPLiZ, et al. (2016) State-of-the-art in studies of glacial isostatic adjustment for the British Isles: A literature review. Earth and Environmental Science Transactions of the Royal Society of Edinburgh106: 145–170.
57.
StuiverMReimerPJReimerRW (2018) CALIB 7.1 [WWW program]. Available at: http://calib.org
58.
Troels-SmithJ (1955) Characterization of unconsolidated sediments, Volume 4. Copenhagen: Danmarks Geologiske Undersøgelse.
59.
UeharaKScourseJDHorsburghKJ, et al. (2006) Tidal evolution of the northwest European shelf seas from the last glacial maximum to the present. Journal of Geophysical Research: Oceans111: C09025.
60.
WatchamEPShennanIBarlowNLM (2013) Scale considerations in using diatoms as indicators of sea-level change: Lessons from Alaska. Journal of Quaternary Science28(2): 165–179.
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