Reconstructing recent relative sea-level changes in West Greenland: Local diatom-based transfer functions are superior to regional models

摘要

We present the results of an investigation into the potential of salt marshes in the Aasiaat area, West Greenland, for recent relative sea-level (RSL) reconstruction. We use 64 modern diatom samples to develop a transfer function that has a RMSEP of 0.16 m and an r~2 of 0.84. We combine these with a similar data set from Sisimiut, 250 km south of Aasiaat, standardising the data to account for tidal range differences. An Aasiaat, Sisimiut and a combined model is used to reconstruct RSL change from two recently deposited sediment sections. All three models predict similar RSL change for sediment deposited in low marsh settings, but for sediment deposited in high marsh environments the models differ. Our preferred Aasiaat model reconstructs RSL rise from c. -0.6 m at c. 570 calyr BP to stabilise within ～ ±0.20 m of present after 400 cal yr BP. Model differences are related to variations in the high marsh/ upland vegetation zones, diatom assemblages and organic content between sites that are likely related to differences in tidal range. We conclude that a local transfer-function model is superior to a combined site model for RSL reconstruction in West Greenland.