Reassessing transfer-function performance in sea-level reconstruction based on benthic salt-marsh foraminifera from the Atlantic Coast of NE North America

• Published in: Marine Micropaleontology
• Main Author: EDWARDS, ROBIN JAMES
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2011
• Subjects: Geology; Transfer functions; sea level; Newfoundland
• Online Access: http://hdl.handle.net/2262/59851; http://people.tcd.ie/edwardsr; https://doi.org/10.1016/j.marmicro.2011.07.003

PUBLISHED The need to increase the number and distribution of sea-level records spanning the last few hundred years has led to particular interest in developing high-precision, geologically based sea-level reconstructions that capture decimetre and multi-decadal scale changes. Transfer functions for tide level are statistical tools that quantify the vertical relationship between inter-tidal microfossils and elevation within the tidal frame and their use in sea-level reconstruction is growing in popularity. Whilst a range of sampling strategies, dataset qualities and underlying statistical models have been used in transfer-function development, all variants share the common requirement of accurately extracting precise species-elevation relationships from surface data, and reliably applying these to fossil assemblages to infer past conditions. We present surface foraminiferal data from six transects sampled at three sites spanning a large latitudinal range extending from Newfoundland (Canada) to North Carolina (USA). These data demonstrate that significant spatial differences exist within the high-marsh foraminiferal assemblages commonly used to reconstruct past relative sea-level (RSL). We standardise these data to account for inter-site differences in tidal range using several variants of the standardised water level index (SWLI) of Horton et al. (1999b) and show that the best performance is achieved by using the highest occurrence of foraminifera as the upper tidal datum level. The standardised surface foraminiferal data are used to develop a suite of foraminiferal transfer functions for tide level which are then applied to fossil assemblages from two sediment cores to reconstruct palaeomarsh-surface elevation. We highlight the manner in which species-elevation relationships are extracted and modified during transfer-function development, and the impacts that choices in dataset composition and transfer-function type have on the resulting reconstructions. Our results graphically illustrate the importance of ...