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

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 climat...

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Bibliographic Details
Published in:Marine Geology
Main Authors: Wils, Katleen, Wermersche, Marlies, Van Rooij, David, Lastras, Galderic, Lamy, Frank, Arz, Helge W., Siani, Giuseppe, Bertrand, Sebastien, Van Daele, Maarten
Format: Article in Journal/Newspaper
Language:English
Published: 2021
Subjects:
Earth and Environmental Sciences
Patagonia
Sediment drift
Bottom current circulation
Climatic variability
Tectonic control
SEA-SURFACE TEMPERATURE
LAST GLACIAL MAXIMUM
CHILEAN PATAGONIA
SOUTHERN WESTERLIES
HUDSON VOLCANO
SEISMIC STRATIGRAPHY
CONTOURITE DRIFTS
CONTINENTAL RISE
LAKE-SEDIMENTS
VARIABILITY
Antarctic
The Antarctic
Pacific
Hudson
Antarc*
Online Access:https://biblio.ugent.be/publication/8723033
http://hdl.handle.net/1854/LU-8723033
https://doi.org/10.1016/j.margeo.2021.106604
https://biblio.ugent.be/publication/8723033/file/8723034
Description
Summary: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 Aysen Fjord (similar to 45 degrees 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 similar to 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 paleo-seismic 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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