Within-region replication of late Holocene relative sea-level change: An example from southern New England, United States. (15th January 2023)

• Record Type: Journal Article
• Authors: Stearns, Rachel B.; Engelhart, Simon E.; Kemp, Andrew C.; Hill, Troy D.; Brain, Matthew J.; Corbett, D. Reide
• Is Part Of: Quaternary science reviews. Volume 300(2023)
• Publication Date: 2023-01-15
• Subjects: Holocene -- Bayesian -- Sea level changes -- North Atlantic -- Micropaleontology -- Foraminifers -- Hotspot -- Organic geochemistry -- Salt marsh -- Data treatment -- Data analysis -- Geomorphology -- Coastal; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2022.107868
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: Tide-gauge measurements in the western North Atlantic Ocean show coherent, multi-decadal relative sea-level (RSL) trends across multiple spatial scales. Proxy reconstructions developed from salt-marsh sediment can extend this instrumental record. However, the degree of coherence in proxy reconstructions is underexamined through within-region replication. To explore within-region replication, we developed a new RSL reconstruction from Fox Hill Marsh, Rhode Island to complement similar records at nearby sites. We established the elevation of former sea level from assemblages of foraminifera and bulk-sediment δ 13 C values using a Bayesian transfer function. We employed radiocarbon dating and recognition of pollution horizons to construct a core chronology. Since ∼1200 BCE, RSL rose by ∼3.7 m at Fox Hill Marsh. After correction for glacial isostatic adjustment, application of a statistical model intended to quantify (multi-) century-scale trends showed that the fastest rate of rise in at least the past 3000 years was 1.71 ± 0.84 mm/yr (95% credible interval) in 2020 CE. This result replicates regional tide-gauge measurements and other proxy reconstructions. Using an alternative statistical model constructed to identify sub-centennial sea-level changes, we examined if there was a hotspot of 18th century rise in the northeastern United States and found no spatially-coherent trend (i.e., occurring at all or most sites). This lack of replication indicates that accelerated rise during the 18th century is likely local (site-specific) in scale, or an artifact of individual reconstructions. Continued efforts to replicate RSL reconstructions will increase confidence in the accuracy of records and their subsequent interpretation. Highlights: Proxy reconstructions are used to investigate late Holocene relative sea-level changes in southern New England. A new relative sea-level record from Fox Hill Marsh, Rhode Island, documents ∼3.7 m of rise since ∼1200 BCE. The fastest century-scale rate of sea-level rise in at least the past 3000 years was 1.71 ± 0.84 mm/yr in 2020 CE We find no spatially-coherent trend supportive of an 18th century hotspot of sea-level rise in the northeastern United States. Accelerated 18th century sea-level rise at some sites is likely local in scale, or an artifact of individual reconstructions.