Large landslide of the hyperarid Central Western Andes triggered during a humid period of the Late Pleistocene (ca. 19°S; northern Chile)

Abstract

The western flank of the Central Andes offers a unique geomorphological record of large paleolandslides that are well preserved on long time‐scales (i.e. ≥Pleistocene) due to the long‐lasting aridity of this region. However, the lack of chronological constraints on those landslides limits our understanding of the respective role of tectonics and climate on their triggering. Here, we report new 10Be surface exposure dating obtained on one of those giant slope‐failures: the Limaxina landslide (northern Chile, 19°S). Five tightly grouped exposure‐ages (one outlier discarded) point to a single landslide failure at 80 ± 4 ka. This timing being consistent with others local records of a wet episode in the Atacama Desert, it suggests a primary role of climate‐forcing on landslide activity in this region, calling to further slope failures dating in the arid Central western Andes to explore landscapes responses to Quaternary climate oscillations and extreme events.

A 121‐ka record of Western Andean fluvial response to suborbital climate cycles recorded by rhythmic grain size variations of the Lima fluvial fan

“…The Lima fan registered a moderate increase in sedimentation rates during 87 ± 1 to ka, reaching 0.25 m a −1 around 77 ka, possibly as a delayed response to pluvial period C21a. For this time period, rainfall‐induced landslides have been recognised at 19° lat (Zerathe et al, 2023; see Figure 10b).…”

“…We speculate that the punctual excursions towards less negative δ 18 O values, indicative for less precipitation, were of too short a duration to regulate the volume of sediment that entered the fluvial system and as such they were not perceivable in the total sediment budget reaching the Lima fluvial fan. Similar to the Lima fan, during the Ouki wet phase (pluvial periods C26 to C24), very large volumes of alluvial fan, braided river, and landslide sediments were deposited throughout the Andes (Figures 9 and 10a,b) that were generally attributed to a single pluvial event (Margirier et al, 2015;Steffen et al, 2010;Viveen et al, 2020Viveen et al, , 2022Zerathe et al, 2023). Our data demonstrate here a more probable control of 1-to-5-ka-long, suborbital pluvial periods superimposed on the precession cycle as drivers for fluvial deposition during the Ouki phase.…”

Characterization of Southern Peru hydrothermal systems: New perspectives for geothermal exploration along the Andean forearc

“…In addition, sparse markers of glacial erosion in higher part of the High Cordillera above 4000 m asl can be observed (Rivera et al, 2020;Mariño et al, 2021). Massive landslide deposits also indicate fluctuating paleoclimatic conditions during the Quaternary (e.g., Caquilluco, Laguna Aricota; Zerathe et al (2017Zerathe et al ( , 2023; Delgado et al (2020Delgado et al ( , 2022, Fig. 1a and b).…”

Characterization of Southern Peru Hydrothermal Systems: New Perspectives for Geothermal Exploration Along the Andean Forearc

“…In addition, sparse markers of glacial erosion in higher part of the High Cordillera above 4,000 m asl can be observed (Mariño et al, 2021;Rivera et al, 2020). Massive landslide deposits also indicate fluctuating paleoclimatic conditions during the Quaternary (e.g., Caquilluco, Laguna Aricota; Zerathe et al (2017); Zerathe et al (2023); Delgado et al (2020Delgado et al ( , 2022, Figures 1a and 1b).…”