Hydroclimate variability of northern Chilean Patagonia during the last 20 kyr inferred from the bulk organic geochemistry of Lago Castor sediments (45°S)

Fiers, Géraldine; Bertrand, Sébastien; Daele, Maarten Van; Granon, Emma; Reid, Brian; Vandoorne, Willem

doi:10.1016/j.quascirev.2018.11.015

Cited by 11 publications

(6 citation statements)

References 46 publications

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“…These conditions are ultimately compatible with an intensification of ENSO activity, as indicated by marked variation in wind and precipitation, in Lago Fagnano driving changes in water column stratification. These results are in agreement with studies that indicate a major climate change in these southern latitudes during the past two millennia, interpreted as a co-intensification of ENSO events in the Western Antarctic Peninsula (Etourneau et al 2013) and other regions in South America (Conroy et al 2008;Makou et al 2010;Fiers et al 2019;Cai et al 2020), as well as SHWW intensification and increased aridity in the northern Tierra del Fuego steppe (Laprida et al 2021).…”

Section: Palaeoclimate Reconstructionsupporting

confidence: 90%

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Southern Hemisphere Westerly Winds have modulated the formation of laminations in sediments in Lago Fagnano (Tierra del Fuego, Argentina) over the past 6.3 ka

Vizcaino

Jiménez‐Espejo

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et al. 2022

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Section: Palaeoclimate Reconstructionsupporting

confidence: 90%

“…2010; Fiers et al . 2019; Cai et al . 2020), as well as SHWW intensification and increased aridity in the northern Tierra del Fuego steppe (Laprida et al .…”

Section: Discussionmentioning

confidence: 99%

Southern Hemisphere Westerly Winds have modulated the formation of laminations in sediments in Lago Fagnano (Tierra del Fuego, Argentina) over the past 6.3 ka

Vizcaino

Jiménez‐Espejo

Dunbar

et al. 2022

Boreas

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“…During the last 4.4 ka, the influence of climate variability on the available turbidite record is assumed to be limited. Precipitation and westerly strength in the region increased significantly around 8 ka and remained high since then (Fiers et al, 2019). Deglaciation in the Aysén Fjord area itself is assumed to have been completed at 15 ka, and glaciers in its catchment probably reached its current state between 10 and 5 ka (Davies et al, 2020).…”

Section: 1029/2020jb019405mentioning

confidence: 99%

Seismo‐Turbidites in Aysén Fjord (Southern Chile) Reveal a Complex Pattern of Rupture Modes Along the 1960 Megathrust Earthquake Segment

et al. 2020

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Grainsize analysis and end-member modeling of a long sediment core from Aysén Fjord (southern Chile) allows to identify over 25 seismo-turbidites in the last 9,000 years. Considering the shaking intensities required to trigger these turbidites (V½-VI½), the majority can be related to megathrust earthquakes. Multiple studies in south-central Chile have aimed at finding traces of giant, tsunamigenic megathrust earthquakes leading to the current 5,500-year-long paleoseismological record of the Valdivia segment. However, none of these cover the southern third of the segment. Aysén Fjord allows to fill this data gap and presents the first, crucial paleoseismic data to demonstrate that the 1960 event was not unique for the Valdivia segment, yielding a recurrence rate of 321 ± 116 years in the last two millennia. Moreover, the oldest identified events in Aysén Fjord date back to 9,000 cal years BP and, thus, also extend the regional paleoseismological record in time. We infer a large temporal variability in rupture modes, with successions of full-segment ruptures alternating with partial and cascading ruptures. The latter seems to significantly postpone the occurrence of another full rupture when consecutively occurring in different parts of the segment. Additionally, one outstanding period of seismic quiescence-during which no megathrust earthquake evidence has been found at any paleoseismic site-occurred after a full rupture in AD~745 that presents an unusual uplift/subsidence pattern. Such variability makes it highly speculative to anticipate the rupture mode of the next megathrust earthquake along the Valdivia segment.

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“…In the austral winter, the SWW are more diffuse, with the core SWW belt driven slightly northwards as the jet stream moves into subtropical latitudes of about 30 °S. This equatorward shift broadens and weakens, the core wind belt, particularly north of ~50 °S (Garreaud et al, 2013;Bertrand et al, 2014;Fiers et al, 2019). As a result, winter precipitation is more intense further north of ~35 °S (Figure 4D).…”

Section: 24mentioning

confidence: 99%

Late Glacial and Holocene Palaeolake History of the Última Esperanza Region of Southern Patagonia

et al. 2022

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We undertook multi-proxy analyses on two sediment cores from Lago Pato, a small lake basin at 51°S topographically separated from Lago del Toro in Torres del Paine (TdP), to provide insights into glacier dynamics and lake-level change in the TdP and Última Esperanza region over the last ∼30,000 cal a BP (30 ka). Lago Pato is situated in a region overridden by the Southern Patagonian Ice Field during the Last Glacial and in a transitional climatic zone of Southern Patagonia sensitive to seasonal- to millennial-scale changes in the Southern Hemisphere Westerly Winds (SWW). Results show that a deep ice-dammed and enlarged palaeolake encompassed Lago del Toro and Lago Pato c. 30–20 ka after the ice had retreated from local-Last Glacial Maximum (l-LGM) limits at c. 48–34 ka and during the build-up to the global-Last Glacial Maximum (g-LGM), c. 26–19 ka. Gaps in both sediment records between c. 20–13.4 ka and c. 20–10 ka suggest hiatuses in sediment accumulation during the g-LGM and Antarctic Cold Reversal (ACR) readvances and/or removal by lake lowering or flushing during the Late Glacial–early Holocene. The palaeolake level dropped from >100 m a.s.l. to ∼40–50 m a.s.l. towards the end of the ACR c. 13.4–13.0 ka, creating a shallower glaciolacustrine environment dammed by an ice tongue in the Estancia Puerto Consuelo–Última Esperanza fjord. Further lowering of the enlarged palaeolake level occurred when the ice thinned to <40 m a.s.l., eventually isolating Lago Pato from Lago del Toro and glaciogenic sediment input at c. 11.7 ka. After isolation, the ecology and water levels in Lago Pato became sensitive to regional climate shifts. The shallow, stable, and highly anoxic environment that developed after c. 11.7 ka is associated with weaker (or poleward shifted) SWW at 51°S and was replaced at c. 10 ka by an increasingly productive shallow-littoral lake with a variable lake-level and periodic shifts in anoxic-oxic bottom water conditions and ratios of benthic-planktonic diatoms. A more open Nothofagus forest, established at c. 8.6–7.5 ka, and more arid conditions c. 7.5–5.7 cal ka BP are linked to another phase of weaker (or poleward shifted) SWW at 51°S. More persistently wet conditions from c. 5.7 ka, with extensive closed Nothofagus forests and planktonic diatoms dominant, are associated with stronger (or equatorward shifted) SWW over 51°S. The abrupt return of benthic-to-tychoplanktonic diatoms after c. 3 ka reflects enhanced SWW at 51°S. Increasingly stable lacustrine and littoral wetland conditions established in the last ∼500 years reflect weaker SWW and lasted until recent decades.

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Hydroclimate variability of northern Chilean Patagonia during the last 20 kyr inferred from the bulk organic geochemistry of Lago Castor sediments (45°S)

Cited by 11 publications

References 46 publications

Southern Hemisphere Westerly Winds have modulated the formation of laminations in sediments in Lago Fagnano (Tierra del Fuego, Argentina) over the past 6.3 ka

Southern Hemisphere Westerly Winds have modulated the formation of laminations in sediments in Lago Fagnano (Tierra del Fuego, Argentina) over the past 6.3 ka

Seismo‐Turbidites in Aysén Fjord (Southern Chile) Reveal a Complex Pattern of Rupture Modes Along the 1960 Megathrust Earthquake Segment

Late Glacial and Holocene Palaeolake History of the Última Esperanza Region of Southern Patagonia

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