Late Holocene current patterns in the northern Patagonian fjords recorded by sediment drifts in Aysén Fjord
| Autor: | Helge W Arz, Maarten Van Daele, Frank Lamy, Giuseppe Siani, Galderic Lastras, Marlies Wermersche, Sebastien Bertrand, Katleen Wils, David Van Rooij |
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| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Fjord 010502 geochemistry & geophysics Oceanography Megathrust earthquake 01 natural sciences Geochemistry and Petrology Patagonia Bottom current circulation Bathymetry 14. Life underwater Holocene 0105 earth and related environmental sciences geography geography.geographical_feature_category Climatic variability Tectonic control Subsidence (atmosphere) Geology Last Glacial Maximum Seafloor spreading Sediment drift Sea surface temperature 13. Climate action |
| Zdroj: | Marine Geology (0025-3227) (Elsevier BV), 2021-11, Vol. 441, P. 106604 (16p.) |
| ISSN: | 0025-3227 |
| Popis: | 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 (~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. |
| Databáze: | OpenAIRE |
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