Vertical saltmarsh accretion and its relationship to sea-level in the Severn Estuary, UK: an investigation using Foraminifera as tidal indicators

Haslett, S.K, Strawbridge, F, Martin, N.A and Davies, C.F.C (2001) 'Vertical saltmarsh accretion and its relationship to sea-level in the Severn Estuary, UK: an investigation using Foraminifera as tidal indicators.' Estuarine, Coastal and Shelf Science, 52 (1). pp. 143-153. ISSN 0272-7714

Abstract

Saltmarsh vertical accretion has been used as a proxy for sea-level rise in previous studies on the assumption that accretion is in quasi-equilibrium with sea-level rise. This assumption requires verification in each case, as accretion may lag or exceed sea-level rise, leading to under- or over-estimates of sea-level rise, respectively. Verification may be provided by biostratigraphic analysis, where biological remains in saltmarsh sediments may be related to former tide levels. Foraminifera are well-suited, as studies of modern saltmarshes have demonstrated distinct tidal relationships which may be used to calibrate downcore/temporal foraminifera sequences. It is hypothesized that, depending on the relationship between sea-level rise and accretion, quasi-equilibrium, submergence, and emergence foraminifera sequences may be recognized. These are explored here in a Severn Estuary (U.K.) saltmarsh, where an emergence foraminifera sequence is identified, suggesting that previous sea-level rise rates for the Severn Estuary, based on saltmarsh accretion rates, may be over-estimates. Wider consequences of this may include over-estimation of regional crustal subsidence rates, required to accommodate artificially high sea-level rise rates. Saltmarsh accretion rates are clearly not a suitable proxy for sea-level rise in all cases, and as such each saltmarsh requires biostratigraphic evaluation to establish sea-level rise/accretion relationships. Preferably, independent Sea-Level Index Points (SLIPs) should be used over saltmarsh accretion rates in constructing sea-level histories.

Item Type:	Article
Keywords:	saltmarshes, sediment accretion, tidal indicators, sea-level foraminifera, Holocene, Severn Estuary
Divisions:	School of Sciences Chancelry and Research Management
Identification Number:	https://doi.org/10.1006/ecss.2000.0740
Date Deposited:	18 Nov 2012 04:45
Last Modified:	28 Nov 2023 17:58
URI / Page ID:	https://researchspace.bathspa.ac.uk/id/eprint/331

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