Academic Journal

A multi-proxy modern training set for reconstructing Holocene relative sea level using salt-marsh sediment (Prince Edward Island, Canada).

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Τίτλος: A multi-proxy modern training set for reconstructing Holocene relative sea level using salt-marsh sediment (Prince Edward Island, Canada).
Συγγραφείς: Kemp, Andrew C., Edwards, Robin J., Alvarez-Agoues, Fermin, Bustamante, Emmanuel, Roseby, Zoë A., Hawkes, Andrea D., Woodworth, Philip L.
Πηγή: Canadian Journal of Earth Sciences; 2025, Vol. 62 Issue 6, p1172-1190, 19p
Θεματικοί όροι: Sea level, Plant communities, Sediment sampling, Salt marshes, Holocene Epoch, Foraminifera
Περίληψη: Reconstructing Holocene relative sea-level change from salt-marsh sediment requires a modern training set that captures the observable relationship between proxies and local tidal elevation. We collected 143 surface sediment samples from four salt marshes in Prince Edward Island (PEI, Canada) to develop a modern training set of foraminifera and bulk-sediment δ13C and δ15N values. Two sites have semi-diurnal tidal regimes, one has a mixed regime, and one has a diurnal regime. Combining and standardizing datasets from different tidal regimes fails to adequately characterize the relationship between elevation and inundation. Our principal results are from the semi-diurnal sites. Salt-marsh foraminifera in PEI form low-diversity, elevation-dependent zones that are replicated within sites, among sites, and between two studies conducted 44 years apart. Botanical zonation of PEI salt marshes often includes a platform with C4 plants and an adjacent, higher transitional community of C3 plants. Bulk-sediment δ13C values mirror the dominant vegetation. Isotopic results from PEI are combined with datasets from Delaware to Massachusetts to explore how elevation thresholds and δ13C cut-off values can recognize environments of deposition. We propose that δ13C values more negative than –20.0‰ indicate formation above an elevation threshold placed slightly below mean higher high water, while δ13C values less negative than –17.0‰ characterize environments lower than an elevation threshold slightly above mean higher high water. Bulk-sediment δ15N values display a correlation with tidal elevation and botanical zone, but may be subject to anthropogenic and post-depositional modification limiting their utility as a sea-level proxy. The dataset of modern foraminifera is suitable for reconstructing relative sea level and could be combined with informative δ13C values in a multi-proxy approach. [ABSTRACT FROM AUTHOR]
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Βάση Δεδομένων: Complementary Index
Περιγραφή
ISSN:00084077
DOI:10.1139/cjes-2024-0166