Relative sea-level change in Newfoundland, Canada during the past ~3000 years

PUBLISHED Several processes contributing to coastal relative sea-level (RSL) change in the North Atlantic Ocean are observed and/or predicted to have distinctive spatial expressions that vary by latitude. To expand the latitudinal range of RSL records spanning the past ~3000 years and the likelihood...

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Bibliographic Details
Published in:Quaternary Science Reviews
Main Authors: Kemp, Andrew, Wright, Alexander, Edwards, Robin, Barnett, Robert, Brain, Matthew, Kopp, Robert, Cahill, Niamh, Horton, Benjamin, Charman, Dan, Hawkes, Andrea, Hill, Troy, van de Plassche, Orson
Format: Article in Journal/Newspaper
Language:English
Published: 2018
Subjects:
sea level change
Smart & Sustainable Planet
BENTHIC FORAMINIFERA
SALT-MARSH
SALTMARSH
relative sea-level change
Big River
Canada
Newfoundland
North Atlantic
Online Access:http://hdl.handle.net/2262/85902
http://people.tcd.ie/edwardsr
https://doi.org/10.1016/j.quascirev.2018.10.012
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Summary:PUBLISHED Several processes contributing to coastal relative sea-level (RSL) change in the North Atlantic Ocean are observed and/or predicted to have distinctive spatial expressions that vary by latitude. To expand the latitudinal range of RSL records spanning the past ~3000 years and the likelihood of recognizing the characteristic fingerprints of these processes, we reconstructed RSL at two sites (Big River and Placentia) in Newfoundland from salt-marsh sediment. Bayesian transfer functions established the height of former sea level from preserved assemblages of foraminifera and testate amoebae. Age-depth models constrained by radiocarbon dates and chronohorizons estimated the timing of sediment deposition. During the past ~3000 years, RSL rose by ~3.0mat Big River and by ~1.5mat Placentia. A locally calibrated geotechnical model showed that post-depositional lowering through sediment compaction was minimal. To isolate and quantify contributions to RSL from global, regional linear, regional non-linear, and localscale processes, we decomposed the new reconstructions (and those in an expanded, global database) using a spatio-temporal statistical model. The global component confirms that 20th century sea-level rise occurred at the fastest, century-scale rate in over 3000 years (P > 0.999). Distinguishing the contributions from local and regional non-linear processes is made challenging by a sparse network of reconstructions. However, only a small contribution from local-scale processes is necessary to reconcile RSL reconstructions and modeled RSL trends. We identified three latitudinally-organized groups of sites that share coherent regional non-linear trends and indicate that dynamic redistribution of ocean mass by currents and/or winds was likely an important driver of sea-level change in the North Atlantic Ocean during the past ~3000 years.

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