A new Holocene relative sea-level curve for western Brittany (France): Insights on isostatic dynamics along the Atlantic coasts of north-western Europe

QUATERNARY SCIENCE REVIEWS

卷:129

Article

Goslin, Jerome¹  Lanoe, Brigitte Van Vliet²  Spada, Giorgio³  Bradley, Sarah⁴  Tarasov, Lev⁵  Neill, Simon⁶  Suanez, Serge¹ 

[1] European Inst Marine Studies, Geomer Lab, CNRS, UMR 6554,LETG, F-29280 Plouzane, France

[2] European Inst Marine Studies, Domaines Ocean Lab, CNRS, UMR 6538, F-29280 Plouzane, France

[3] Univ Urbino Carlo Bo, Dipartimento Sci Base & Fondamenti, I-61029 Urbino, PU, Italy

[4] Univ Utrecht, Inst Marine & Atmospher Res Utrecht IMAU, NL-3584 CC Utrecht, Netherlands

[5] Mem Univ Newfoundland, Dept Phys & Phys Oceanog, St John, NF A1C 5S7, Canada

[6] Bangor Univ, Sch Ocean Sci, Isle Of Anglesey LL59 5AB, Wales

关键词: Relative sea-level;    Holocene;    Isostasy;    GIA models;    Tidal-range modelling;    Earth structure;    Brittany;   

DOI  :  10.1016/j.quascirev.2015.10.029

来源: Elsevier

【 摘 要 】

This study presents new Relative Sea Level (RSL) data that were obtained in the Finistere region (Western tip of Brittany, France) and the implications those data have for the understanding of the isostatic dynamics across north-western Europe, and more specifically along the Atlantic and Channel coasts. New stratigraphic sequences were obtained and analyzed to derive 24 new Sea-level Index Points, in which 6 are basal. These new data considerably increase the knowledge we have of the RSL evolution along the coasts of Western Brittany since the last 8 kyr B.P. From this new dataset, RSL was estimated to rise continuously over the last 8 kyr with a major inflection at ca. 6 kyr cal. BP. Our results show large vertical discrepancies between the RSL records of Brittany and South-Western UK, with the latter plotting several meters below the new data. From this comparison we suggest that the two regions underwent a very different pattern and/or amplitude of subsidence during the last 8 kyr which has implications for the spatial and temporal pattern of the peripheral bulge of the European ice sheets. We compared our data against predictions from Glacio-Isostatic Adjustment models (GIA models). There are large misfits between RSL observations and the predictions of the global (ICE-5G (VM2a) - Peltier, 2004, GLAC1-b - Tarasov and Peltier, 2002; Tarasov et al., 2012, Briggs et al., 2014) and regional UK models (BIIS - Bradley et al., 2009; Bradley et al., 2011; Kuchar- Kuchar et al., 2012), which can't be resolved through significant changes to the deglaciation history and size of the British Irish Ice sheet. Paleo-tidal modelling corrections indicate regional changes in the tidal ranges played a negligible role in the data-model misfits. Hence, we propose that the misfits are due to some combination of: (i) unaccounted mass-loss of far-field ice-sheets (Antarctic ice-Sheet or Laurentide Ice-Sheet), (ii) unresolved differences in the deglaciation history and size of the Fennoscandian Ice sheet or, more likely, (iii) significant lateral variations in the Earth's structure across the English Channel. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

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