Abrupt intrinsic and extrinsic responses of southwestern Iberian vegetation to millennial‐scale variability over the past 28 ka

Type Article
Date 2022-04
Language English
Author(s) Cutmore AnnaORCID1, 2, Ausín Blanca3, 4, Maslin Mark1, Eglinton Timothy4, Hodell David5, Muschitiello Francesco6, 7, Menviel Laurie8, Haghipour Negar4, 9, Martrat Belen10, Margari Vasiliki1, Tzedakis Polychronis C.1
Affiliation(s) 1 : Department of Geography University College London London, United Kingdom
2 : Department of Marine Microbiology and Biogeochemistry NIOZ Royal Institute for Sea Research ,Netherlands
3 : Geography Department University of Salamanca Salamanca, Spain
4 : Geological Institute ETH Zürich Zürich ,Switzerland
5 : Department of Earth Sciences University of Cambridge Cambridge ,United Kingdom
6 : Department of Geography University of Cambridge Cambridge ,United Kingdom
7 : NORCE Norwegian Research Centre Bergen ,Norway
8 : Climate Change Research Centre University of New South Wales Sydney ,Australia
9 : Laboratory for Ion Beam Physics, ETH Zürich Zürich ,Switzerland
10 : Department of Environmental Chemistry Spanish Council for Scientific Research (CSIC), Institute of Environmental Assessment and Water Research (IDAEA) Barcelona, Spain
Source Journal Of Quaternary Science (0267-8179) (Wiley), 2022-04 , Vol. 37 , N. 3 , P. 420-440
DOI 10.1002/jqs.3392
WOS© Times Cited 4
Keyword(s) abrupt climate change, Holocene, Marine Isotope Stage 2, pollen, southwest Iberia
Abstract

We present new high-resolution pollen records combined with palaeoceanographic proxies from the same samples in deep-sea cores SHAK06-5K and MD01-2444 on the southwestern Iberian Margin, documenting regional vegetation responses to orbital and millennial-scale climate changes over the last 28 ka. The chronology of these records is based on high-resolution radiocarbon dates of monospecific samples of the planktonic foraminifera Globigerina bulloides, measured from SHAK06-5K and MD01-2444 and aligned using an automated stratigraphical alignment method. Changes in temperate and steppe vegetation during Marine Isotope Stage 2 are closely coupled with sea surface temperature (SST) and global ice-volume changes. The peak expansion of thermophilous woodland between ~10.1 and 8.4 cal ka bp lags behind the boreal summer insolation maximum by ~2 ka, possibly arising from residual high-latitude ice-sheets into the Holocene. Rapid changes in pollen percentages are coeval with abrupt transitions in SSTs, precipitation and winter temperature at the onset and end of Heinrich Stadial 2, the ice-rafted debris event and end of Heinrich Stadial 1, and the onset of the Younger Dryas, suggesting extrinsically forced southwestern Iberian ecosystem changes by abrupt North Atlantic climate events. In contrast, the abrupt decline in thermophilous elements at ~7.8 cal ka bp indicates an intrinsically mediated abrupt vegetation response to the gradually declining boreal insolation, potentially resulting from the crossing of a seasonality of precipitation threshold.

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Cutmore Anna, Ausín Blanca, Maslin Mark, Eglinton Timothy, Hodell David, Muschitiello Francesco, Menviel Laurie, Haghipour Negar, Martrat Belen, Margari Vasiliki, Tzedakis Polychronis C. (2022). Abrupt intrinsic and extrinsic responses of southwestern Iberian vegetation to millennial‐scale variability over the past 28 ka. Journal Of Quaternary Science, 37(3), 420-440. Publisher's official version : https://doi.org/10.1002/jqs.3392 , Open Access version : https://archimer.ifremer.fr/doc/00734/84593/