New constraints on late Holocene eustatic sea-level changes from Mahé, Seychelles

Abstract

Citation for published item:oodro'eD F eF nd vongD eF tF nd wilneD qF eF nd fryntD gF vF nd homsD eF @PHISA 9xew onstrints on lte roloene eustti seElevel hnges from wh¡ eD eyhellesF9D uternry siene reviewsFD IIS F ppF IEITF Further information on publisher's website: httpXGGdxFdoiForgGIHFIHITGjFqusirevFPHISFHPFHII Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Quaternary Science Reviews. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Quaternary Science Reviews, 115, 1 May 2015, 10.1016/j.quascirev.2015.02.011. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThis study provides new estimates of globally integrated ice sheet melt during the late Holocene (since 4 ka BP) from Seychelles in the western Indian Ocean, a tectonically stable, far field location where the necessary Glacial-Isostatic Adjustment (GIA) correction is small and is relatively insensitive to predictions using different Earth viscosity profiles. We compare sea-level data from Seychelles to estimates of eustasy from two GIA models, ICE-5G and EUST3, which represent end-members in the quantity of global melt during the late Holocene. We use data from a range of coastal environments including fringing reef, present day beaches, fossil plateau and mangrove deposits on the largest island of the Seychelles archipelago, Mahé to reconstruct relative sea-level changes. Our data suggest that extensive coastal deposits of carbonate-rich sands that fringe the west coast formed in the last 2 ka and the horizontal nature of their surface topography suggests RSL stability during this period. Mangrove sediments preserved behind these deposits and in river mouths date to c. 2-1.5 ka and indicate that RSL was between -2 m and present during this interval. Correcting the reconstructed sea level data using a suite of optimal GIA models based on the two ice models mentioned above and a large number (c. 350) of Earth viscosity models gives a result that is consistent with the sedimentological constraints. When uncertainties in both model results and data are considered, it is possible to rule out eustatic sea levels below c. 2 m and more than a few decimetres above present during the past two millennia. This uncert...

Modelling sea level data from China and Malay-Thailand to estimate Holocene ice-volume equivalent sea level change

“…It is useful to also compare the timing and chronology of Holocene ESL in the final 643 model to estimates made from other global far-field sites. In a recent study 644 (Woodroffe et al, 2015) where RSL predictions from the final model and ICE5G 645 were compared to sea level data from the Seychelles, it was concluded that the ESL 646 rise over the last 2 kyr was less than 2 m and that the observed RSL signal was more 647 compatible with the results of our final model. Milne and Peros (2013) that would not contribute to a sea-level rise (Fig.…”

“…9). 504 (We note that this model has been referred to in previous publications as EUST3 505 (Milne and Peros, 2013;Woodroffe et al, 2015). As Fig.…”

Holocene Relative Sea-Level Changes from Near-, Intermediate-, and Far-Field Locations

“…Stable islands off the coast of southern Africa (Mauritius, Reunion and Mayotte) record no highstand (with RSL stabilizing at present level by 3 ka) because these small atoll islands subside with the ocean floor from hydro-isostatic loading [44,146,147]. A recent study of late Holocene RSL in the Seychelles [148], a location demonstrated to closely measure eustatic sea level [39], showed RSL rising <2 m in the last 2 ka.…”

Holocene vegetation dynamics in response to climate change and hydrological processes in the Bohai region

“…Presently, the relationship of sea-level change and coastal vegetation (especially mangrove) evolution has been studied by many researchers (e.g. Engelhart et al, 2007;Gonzaĺez and Dupont, 2009;Franç a et al, 2012;Woodroffe et al, 2015;Hendy et al, 2016). However, studies on the long-term dynamics of coastal vegetation, coupled with climate change and river evolution, are sparse.…”