The largest rock avalanches in Patagonia: Timing and relation to Patagonian Ice Sheet retreat

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61988987%3A17310%2F23%3AA2402M79" target="_blank" >RIV/61988987:17310/23:A2402M79 - isvavai.cz</a>

Výsledek na webu

<a href="https://pdf.sciencedirectassets.com/271861/1-s2.0-S0277379123X0002X/1-s2.0-S0277379123000100/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKD%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLWVhc3QtMSJHMEUCIH4YYo0s2lXbU92hgPp3Rgp12ARilDwkSV1Fcrln7%2B%2BTAiEAowthJaN" target="_blank" >https://pdf.sciencedirectassets.com/271861/1-s2.0-S0277379123X0002X/1-s2.0-S0277379123000100/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKD%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLWVhc3QtMSJHMEUCIH4YYo0s2lXbU92hgPp3Rgp12ARilDwkSV1Fcrln7%2B%2BTAiEAowthJaN</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.quascirev.2023.107962" target="_blank" >10.1016/j.quascirev.2023.107962</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The largest rock avalanches in Patagonia: Timing and relation to Patagonian Ice Sheet retreat

Popis výsledku v původním jazyce

One of the largest concentrations of giant landslides (≥108 m3) in Patagonia is in the eastern part of Lago Cochrane/Pueyrredón (LP) valley in Argentina. In addition to minor earthflows and rock slides, this landslide cluster is dominated by rock and debris avalanches that affect the northern slope of Meseta Belgrano, the largest of which have volumes >1 km3 and a runout of >10 km. To determine the chronology of these large landslides and their relationship to the geological setting and the glacial history related to the Last Glacial Maximum (LGM) ∼20–18 ka ago, we combined geomorphological mapping with absolute dating (luminescence and radiocarbon dating) and numerical modelling of slope stability. Dating and cross-cutting relationships with glaciolacustrine deposits suggest that some of the largest rock avalanches collapsed directly into a glacial lake between ∼17 and ∼12 ka, soon after deglaciation, but some were pre-glacial and landslide activity continued until today, posing a potential hazard to the area. In agreement with these data, numerical modelling suggests that slope stability was only marginally affected by ice retreat and glacial lake drainage, and landslides were most likely favoured by relatively low rock strength, related glacially-conditioned topography, and, possibly, seismic activity. A newly identified active fault at the base of the Meseta Belgrano, whose activity was likely enhanced by postglacial rebound, was probably the key factor that concentrated postglacial rock avalanches into the LP valley. We conclude that exceptionally large (km-scale) landslides can occur on slopes made of relatively weak rocks in a glacially-conditioned topographic setting even without a strong direct triggering effect of deglaciation, while fatigue due to long-term seismicity may promote collapse.

Název v anglickém jazyce

The largest rock avalanches in Patagonia: Timing and relation to Patagonian Ice Sheet retreat

Popis výsledku anglicky

One of the largest concentrations of giant landslides (≥108 m3) in Patagonia is in the eastern part of Lago Cochrane/Pueyrredón (LP) valley in Argentina. In addition to minor earthflows and rock slides, this landslide cluster is dominated by rock and debris avalanches that affect the northern slope of Meseta Belgrano, the largest of which have volumes >1 km3 and a runout of >10 km. To determine the chronology of these large landslides and their relationship to the geological setting and the glacial history related to the Last Glacial Maximum (LGM) ∼20–18 ka ago, we combined geomorphological mapping with absolute dating (luminescence and radiocarbon dating) and numerical modelling of slope stability. Dating and cross-cutting relationships with glaciolacustrine deposits suggest that some of the largest rock avalanches collapsed directly into a glacial lake between ∼17 and ∼12 ka, soon after deglaciation, but some were pre-glacial and landslide activity continued until today, posing a potential hazard to the area. In agreement with these data, numerical modelling suggests that slope stability was only marginally affected by ice retreat and glacial lake drainage, and landslides were most likely favoured by relatively low rock strength, related glacially-conditioned topography, and, possibly, seismic activity. A newly identified active fault at the base of the Meseta Belgrano, whose activity was likely enhanced by postglacial rebound, was probably the key factor that concentrated postglacial rock avalanches into the LP valley. We conclude that exceptionally large (km-scale) landslides can occur on slopes made of relatively weak rocks in a glacially-conditioned topographic setting even without a strong direct triggering effect of deglaciation, while fatigue due to long-term seismicity may promote collapse.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10508 - Physical geography

Projekt

<a href="/cs/project/GA19-16013S" target="_blank" >GA19-16013S: Obří sesuvy na předpolí ledovců: chybějící část příběhu vývoje Patagonského ledovcového štítu a přilehlých ledovcových jezer</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Quaternary Science Reviews

ISSN

0277-3791

e-ISSN

—

Svazek periodika

—

Číslo periodika v rámci svazku

February

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

18

Strana od-do

1-18

Kód UT WoS článku

000963236100001

EID výsledku v databázi Scopus

2-s2.0-85146613176