Holocene sea-level database from the Atlantic coast of Europe

Abstract

High-quality relative sea-level (RSL) data reveal spatial and temporal variations in crustal movements during the Holocene, which are used for many applications, ranging from calibrating models of earth rheology and ice sheet reconstructions to the development of coastal lowlands and human occupation. Here, we present a Holocene RSL database for the Atlantic coast of Europe (ACE) and estimate rates of RSL change from the ACE database using a spatio-temporal empirical hierarchical model. The database contains 214 index points, which locate the RSL position in space and time, and 126 limiting dates, which constrain RSL to above or below a certain elevation at a specific point in time. The temporal distribution extends from present to ~11.5 ka, with only 42 index points older than 7 ka. The spatial distribution spans 1700 km from French Flanders (France) to Algarve (Portugal), with more than half of the index points concentrated along the French coast. The ACE database shows RSL was below present during the Holocene. Rates of RSL change were highest during the early Holocene, ranging between 6.8 ± 0.5 mm yr-1 in middle Portugal and 6.3 ± 0.8 mm yr-1 in southern France from 10 to 7 ka. Mid-to late-Holocene rates decreased over time with rates ranging between 0.9 ± 0.4 mm yr-1 in middle France and 0.1 ± 0.5 mm yr-1 in middle Portugal from 4 ka to present. Comparison of the RSL data to output from a glacial-isostatic adjustment model suggests that deglaciation of the British-Irish and Fennoscandian Ice Sheets dominates the large-scale variability captured by the ACE database, which reflects a decreasing influence of the collapsing British-Irish and Fennoscandian peripheral forebulge that migrated from the northeast to the northwest after ~4 ka. (c) 2018 Elsevier Ltd