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The impact of abrupt deglacial climate variability on productivity and upwelling on the southwestern Iberian margin

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Ausín Blanca, Hodell David A., Cutmore Anna, Eglinton Timothy I.,
Project TEMPORAL RELATIONSHIPS AMONG PROXY SIGNALS IN MARINE SEDIMENTS (TRAMPOLINE)
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Original article (peer-reviewed)

Journal Quaternary Science Reviews
Volume (Issue) 230
Page(s) 106139 - 106139
Title of proceedings Quaternary Science Reviews
DOI 10.1016/j.quascirev.2019.106139

Open Access

URL http://doi.org/10.1016/j.quascirev.2019.106139
Type of Open Access Publisher (Gold Open Access)

Abstract

This study combines high-resolution records of nannofossil abundances, oxygen and carbon stable isotopes, core scanning X-ray fluorescence (XRF), and ice rafted debris (IRD) to assess the paleoceanographic changes that occurred during the last deglaciation on the SW Iberian Margin. Our results reveal parallel centennial-scale oscillations in coccolithophore productivity, nutricline depth and upwelling phenomena not previously observed, explained by means of arrival of iceberg-melting waters, iceberg-induced turbulent conditions, SST changes and riverine discharges. On millennial time-scales, higher primary productivity (PP), shallower nutricline, and upwelling occurrence/invigoration are observed for the Last Glacial Maximum (LGM) and Bølling-Allerød (B/A). The opposite scenario (i.e., lower productivity, deeper nutricline and upwelling weakening/absence) is linked to cold spells such as Heinrich Stadials 2 and 1 (HS2 and HS1) and the Younger Dryas (YD). Such paleoproductivity variations are attributed to latitudinal migrations of the thermal fronts associated with oceanic gyres in the North Atlantic, in parallel to oscillations in the strength of the Atlantic Meridional Overturning Circulation (AMOC). Moderate-to-high PP during the Holocene is ascribed to the development of the modern seasonal surface hydrography, with a more persistent Iberian Poleward Current (IPC) and seasonal wind-induced upwelling.
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