Diatoms, vascular vegetation, sediment data and water salinity from contemporary intertidal environ ments in Roudsea Marsh, northwest England, are used to define altitudinal relationships between diatom assem blages and reference water levels. Comparison of these data with the high-resolution diatom biostratigraphy of a fossil marsh sequence allows identification of fluctuations of relative sea level in the mid- and late Holo cene. Two oscillations in relative sea level are recorded. A rise in sea level (> 0.6 m) led to the inundation of the site after 6000 BP and was followed by a fall in sea level (c. 1 m) around 4700 BP. A second rise in sea level (> 0.5 m) occurred before 2420 BP and was followed by a relatively stable or smaller rise of sea level during the last millennium. The use of diatom groups based on marsh altitude was successful.
Admiraal, W., Peletier, H. and Zomer, H.1982: Observations and experiments on the population dynamics of epipelic diatoms from an estuarine mudflat. Estuarine, Coastal and Shelf Science14, 471-87.
2.
Aleem, A.A.1950: The diatom community inhabiting the mud-flats at Whitstable . New Phytologists49, 174-88.
3.
— 1969: Zonal distribution of littoral diatoms at Cullercoats, Northumberland (England) and their relation to the plankton. Pubbl. Staz. Zool. Napoli37, 332-68.
4.
Allen, J.R.L.1990: Constraints on measurement of sea-level movements from salt-marsh accretion rates. Journal ofGeological SocietyLondon147, 5-7.
5.
— 1995: Salt-marsh growth and fluctuating sea level: implications of a simulation model for Flandrian coastal stratigraphy and peat-based sea-level curves. Sedimentary Geology100, 21-45.
6.
Birks, H.J.B.1982: Mid-Flandrian forest history of Roudsea Wood National Nature Research, Cumbria. New Phytologist90, 339-54.
7.
Carter, N.1932-33: A comparative study of the alga flora of two salt marshes . Journal of Ecology20, 341-70; 21, 128-208, 385-403.
8.
Colquhoum, D.J. and Brooks, M.J.1986: New evidence from the Southeastern US for eustatic components in the late Holocene sea levels. Geo-archaeology1, 275-91.
9.
Denys, L.1991/2 : A check-list of the diatoms in the Holocene deposits of the western Belgian coastal plain with a survey of their apparent ecological requirements . Professional Paper 1991/2 No. 246, De Lescluzestraat, 68, B-2600 Berchem, Belgium.
10.
— 1994: Diatom assemblages along a former intertidal gradient: a palaeoecological study of a subboreal clay layer, western coastal plain , Belgium. Netherlands Journal of Aquatic Ecology28, 85-96.
11.
Denys, L. and Baeteman, C.1995: Holocene evolution of relative sea level and local mean high water spring tides in Belgium - a first assessment. Marine Geology124, 1-19.
12.
Denys, L. and Verbruggen, C.1989: A case of drowning - the end of subatlantic peat growth and related palaeoenvironmental changes in the lower Scheldt basin (Belgium) based on diatom and pollen analysis. Review of Palaeobotany and Palynology59, 7-36.
13.
Devoy, R.J.N.1979: Flandrian sea-level changes and vegetational history of the lower Thames Estuary. Phil. Trans. R. Soc. Lond. B 285, 355-407.
14.
Gehrels, R.W.1994: Determining relative sea-level change from salt-marsh foraminifera and plant zones on the coast of Maine, USA. Journal of Coastal Research10, 990-1009.
15.
Godwin, H.1975: The History of the BritishFlora (2nd edition). Cambridge : Cambridge University Press.
16.
Grimm, E.1993: TILIA: a pollen program for analysis and display . Illinois State Museum, Springfield .
17.
Hartley, B.1986: A check-list of the freshwater, brackish and marine diatoms of the British Isles and adjoining coastal waters. Journal of Marine Biological Association66, 531-610.
18.
Hemphill-Haley, E.1995a: Intertidal diatoms from Willapa Bay, Washington: Application to studies of small-scale sea-level changes. Northwest Science69, 29-45.
19.
— 1995b: Diatom evidence for earthquake-induced subsidence and tsunami 300 yr ago in southern coastal Washington. GSA Bulletin107, 367-78.
20.
Hendey, N.I.1964: An introductory account of the smaller algae of British coastal waters. Bacillariophyceae (diatoms). Fishery Investigation Series N, London: HMSO.
21.
Hewlett, R. and Birnie, J.1996: Holocene environmental change in the inner Severn estuary, UK: an example of the response of estuarine sedimentation to relative sea-level change. The Holocene6, 49-61.
22.
Houghton, J.T., Meira Filho, L.G., Callander, B.A., Harris, N., Kattenberg, A. and Maskell, K., editors, 1996: Climate change 1995: the science of climate change . Cambridge: Cambridge University Press.
23.
Hustedt, F. and Aleem, A.A.1951: Littoral diatoms from the salstone, near Plymouth . Journal of Marine Biological AssociationXXX, 177-96.
24.
Karentz, D. and McIntire, C.D.1977: Distribution of diatoms in the plankton of Yaquina estuary, Oregon (USA). Journal of Phycology13, 379-88.
25.
Kelley, J.T., Gehrels, W.R. and Belknap, D.F.1995: Late Holocene relative sea-level rise and the geological development of tidal marshes at Wells, Maine, USA. Journal of Coastal Research11, 136-153.
26.
Lamb, H.H.1977: Climate: present, past and future (Volume 2). London: Methuen .
27.
Long, A.J. and Innes, J.B.1995: The back-barrier and barrier depositional history of Romney Marsh, Walland Marsh and Dungeness, Kent, England. Journal of QuaternaryScience10, 267-83.
28.
Long, A.J. and Tooley, M.J.1995: Holocene sea-level and crustal movements in Hampshire and Southeast England, United Kingdom. Journal of Coastal Research Special Issue No. 17, 299-310.
29.
Main, S.P. and McIntire, S.D.1974: The distribution of epiphytic diatoms in Yaquina estuary, Oregon (USA). Botanica MarinaXVII, 88-99. McIntire, C.D.1973: Diatom association in Yaquina estuary, Oregon: a multivariate analysis. Journal of Phycology9, 254-59.
30.
Miller, K.R. and Livingstone, D.A.1993: Late-Holocene changes in sea level and environment on eastern Cape Breton Island, Nova Scotia, Canada . The Holocene3, 211-19.
31.
Moore, W.W. and McIntire, C.D.1977: Spatial and seasonal distribution of littoral diatoms in Yaquina estuary, Oregon (USA). Botanica MarinaXX, 99-109.
32.
Nelson, A.R. and Kashima, K.1993: Diatom zonation in southern Oregon tidal marshes relative to vascular plants, foraminifera, and sea level. Journal of Coastal Research9, 673-97.
33.
Palmer, A.J.M. and Abbott, W.H.1986: Diatoms as indicators of sea-level change. In van de Plassche, O., editor, Sea-level research: a manual for the collection and evaluation of data, Norwich : Geo Books, 457-88.
34.
Pirazzoli, P.A.1991: World atlas of Holocene sea-level changes. Amsterdam: Elsevier.
35.
Plater, A.J. and Shennan, I.1992: Evidence of Holocene sea-level change from the Northumberland coast, eastern England. Proceedings of the Geologists' Association103, 201-16.
36.
Riznyk, R.Z.1973: Interstitial diatoms from two tidal flats in Yaquina estuary, Oregon (USA). Botanica MarinaXVI, 113-38.
37.
Round, F.E.1960: The diatom flora of a salt marsh on the River Dee . New Phytologists'59, 332-48.
38.
Shaw, J. and Carter, R.W.C.1994: Coastal peats from northwest Ireland: implications for late-Holocene relative sea-level change and shoreline evolution. Boreas23, 74-91.
39.
Shennan, I.1986: Flandrian sea-level changes in the Fenland. II: tendencies of sea-level movement, altitudinal changes, and local and regional factors. Journal of QuaternaryScience1, 155-79.
40.
— 1987: Impacts on the Wash of sea-level rise. Reprinted in Tooley, M.J. and Jelgersma, S., editors, 1992, Impacts of sea-level rise on European coastal lowlands, Oxford: Basil Blackwell, 72-93.
41.
— 1989: Holocene crustal movements and sea-level changes in Great Britain. Journal of Quaternary Science4, 77-89.
42.
Shennan, I., Innes, J.B., Long, A.J. and Zong, Y.1994: Late Devensian and Holocene relative sea-level changes at Loch nan Eala, near Arisaig, northwest Scotland. Journal of QuaternaryScience9, 261-83.
43.
— 1995a: Late Devensian and Holocene relative sea-level changes in northwest Scotland: new data to test existing models. Quaternary International26, 97-123.
44.
— 1995b: Holocene relative sea-level changes and coastal vegetation history at Kentra Moss, Argyll, northwest Scotland. Marine Geology124, 43-59.
45.
Shennan, I., Long, A.J., Rutherford, M.M., Green, F.M., Innes, J.B., Lloyd, J.M., Zong, Y. and Walker, K.J.1996: Tidal marsh stratigraphy, sea-level change and large earthquakes, I: a 5000 year record in Washington, USA. Quaternary Science Reviews, 15, 1023-59.
46.
Shennan, I., Tooley, M.J., Davis, M.J. and Haggart, B.A.1983: Analysis and interpretation of Holocene sea-level data . Nature302, 404-406. Sullivan, M.J.1975: Diatom communities from a Delaware salt marsh. Journal of Phycology11, 384-90.
47.
— 1978: Diatom communities structure: taxonomic and statistical analyses of a Mississippi salt marsh. Journal of Phycology14, 468-75.
48.
— 1982: Distribution of edaphic diatoms in a Mississippi salt marsh: A canonical correlation analysis. Journal of Phycology18, 130-33.
49.
Tooley, M.J.1978: Sea-level changes in northwest England during the Flandrian Stage. Oxford: Clarendon Press.
50.
— 1982: Sea-level changes in northern England. Proceedings of the Geologists' Association93, 43-51.
51.
— 1993: Long term changes in eustatic sea level. In R.A. Warrick, E.M. Barrow and T.M.L. Wigley, editors, Climate and sea level change: observations, projections, and implications , Cambridge: Cambridge University Press, 120-29.
52.
Troels-Smith, J.1955: Karakterisaring af løse jordater (Characterisation of Unconsolidated Sediments). Geological Survey of DenmarkIV (3), 1-73.
53.
Underwood, G.J.C.1994: Seasonal and spatial variation in epipelic diatom assemblages in the Severn Estuary. Diatom Research9, 451-72.
54.
Vos, P.C. and de Wolf, H.1993a: Diatoms as a tool for reconstructing sedimentary environments in coastal wetlands; methodological aspects. Hydrobiologia269/270, 285-96.
55.
— 1993b: Reconstruction of sedimentary environments in Holocene coastal deposits of the southwest Netherlands; the Poortvliet boring, a case study of palaeoenvironmental diatom research. Hydrobiologia269/270, 297-306.
56.
van de Werff, H. and Huls, H.1958-66: Diatomeeënflora van Nederland (8 parts) . Published privately by van de Werff, De Hoef (U), The Netherlands.
57.
Whiting, M.C. and McIntire, C.D.1985: An investigation of distributional patterns in the diatom flora of Netarts Bay, Oregon, by correspondence analysis. Journal of Phycology21, 655-61.
58.
Zong, Y.1992: Postglacial stratigraphy and sea-level changes in the Han River Delta, China. Journal of Coastal Research8, 1-28.
59.
Zong, Y. and Tooley, M.J.1995: The incursion of marine sediment inland during severe storms. An unpublished research report for theNational Radiological Protection Board, Chilton, UK.
60.
— 1996: Holocene sea-level changes and crustal movements in Morecambe Bay, northwest England. Journal of Quaternary Science11, 43-58.
