Late Holocene current patterns in the northern Patagonian fjords recorded by sediment drifts in Aysén Fjord

Type Article
Date 2021-11
Language English
Author(s) Wils Katleen1, Wermersche Marlies1, Van Rooij David1, Lastras Galderic2, Lamy Frank3, Arz Helge W.4, Siani Giuseppe5, Bertrand Sebastien1, Van Daele Maarten1
Affiliation(s) 1 : Renard Centre of Marine Geology (RCMG), Department of Geology, Ghent University, Ghent, Belgium
2 : GRC Geociències Marines, Universitat de Barcelona, Barcelona, Spain
3 : Alfred Wegener Institut für Polar- und Meeresforschung, Bremerhaven, Germany
4 : Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock-Warnemünde, Germany
5 : GEOPS, UMR 8148 Université de Paris-Saclay, Orsay, France
Source Marine Geology (0025-3227) (Elsevier BV), 2021-11 , Vol. 441 , P. 106604 (16p.)
DOI 10.1016/j.margeo.2021.106604
WOS© Times Cited 1
Keyword(s) Patagonia, Sediment drift, Bottom current circulation, Climatic variability, Tectonic control
Abstract

Present-day circulation patterns in the southeastern Pacific Ocean are driven by the Antarctic Circumpolar Current, directing subantarctic surface water into the Patagonian fjords since at least the early Holocene. In this way, bottom current patterns in the area are regulated by the regional climate, although the complex bathymetry of the fjords has a significant impact as well. To understand the potential interplay of climate, seafloor topography-and circulation patterns, we study the sedimentary infill of Aysén Fjord (~45°S) and reveal the first active sediment drifts in the region. These allow constraining the present-day circulation patterns in northern Patagonia and show an incoming (southward) as well as returning (northward) flow direction. While the general sedimentary evolution of the fjord (and thus also the sediment drifts) is climate-driven (i.e., it reflects variability in southern westerly wind strength), the onset of drift formation at ~3.7 ka does not seem to have originated from an abrupt change in regional climate. Instead, we propose that a megathrust earthquake described in paleoseismic records in the area could have resulted in subsidence of one (or more) of the many bathymetric highs in the Patagonian fjords, thus contributing to enhanced spilling of subantarctic water into the fjord. This study underscores the importance of multidisciplinary research to understand past and present bottom current circulation patterns and disentangle different possible feedback mechanisms.

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Wils Katleen, Wermersche Marlies, Van Rooij David, Lastras Galderic, Lamy Frank, Arz Helge W., Siani Giuseppe, Bertrand Sebastien, Van Daele Maarten (2021). Late Holocene current patterns in the northern Patagonian fjords recorded by sediment drifts in Aysén Fjord. Marine Geology, 441, 106604 (16p.). Publisher's official version : https://doi.org/10.1016/j.margeo.2021.106604 , Open Access version : https://archimer.ifremer.fr/doc/00718/82990/