Timing and extent of late pleistocene glaciation in the arid Central Andes of Argentina and Chile (22°-41°S)

Zech, Jana; Terrizzano, Carla; Veit, Heinz; Zech, Roland

doi:10.18172/cig.3235

Cited by 41 publications

(62 citation statements)

References 51 publications

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“…5). Glaciers advanced in nearby parts of the southern Central Andes around this time, for example the Nevado de Chañi (24°S; Martini et al, 2017) and the Sierra de Quilmes (26°S; Zech et al, 2017), as well as farther north at the Chajnantor plateau (23°S; Ward et al, 2015;, Uturuncu volcano (22°S; Blard et al, 2014;Ward et al, 2017), and the Cordillera Huayhuash in Peru (10°S; Hall et al, 2009). We therefore infer that the M1 advance at the Sierra de Aconquija occurred within a more widespread wet period in the Central Andes, corresponding to the summer insolation maximum around 40-45 ka, during which the SASM was intensified.…”

Section: Moraine Unit M1mentioning

confidence: 99%

“…Prior works identified anomalously old outliers on the grounds that they (i) sit far away from age clusters (e.g., Martini et al, 2017); (ii) violate the local stratigraphic order (e.g., Bromley et al, 2016;Ward et al, 2017;Zech et al, 2017); (iii) can be identified by statistical testing (e.g., Smith et al, 2005a,b;Jomelli et al, 2011);or (iv) by field observations that suggest a particular boulder is significantly older or was derived from hillslope debris (e.g., Martin et al, 2018).…”

Section: Nuclide Inheritancementioning

confidence: 99%

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Timing of past glaciation at the Sierra de Aconquija, northwestern Argentina, and throughout the Central Andes

D’Arcy

Schildgen

Strecker

et al. 2019

Quaternary Science Reviews

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Advances in cosmogenic nuclide exposure dating have made moraines valuable terrestrial recorders of palaeoclimate. A growing number of moraine chronologies reported from the Central Andes show that tropical glaciers responded sensitively to past changes in precipitation and temperature over timescales ranging from 10 3 to 10 5 years. However, the causes of past glaciation in the Central Andes remain uncertain. Explanations have invoked insolation-modulated variability in the strength of the South American Summer Monsoon, teleconnections with the North Atlantic Ocean, and/or cooling in the Southern Hemisphere.The driver for these past climate changes is difficult to identify, partly due to a lack of dated moraine records, especially in climatically sensitive areas of the southern Central Andes.Moreover, new constraints are needed on precisely where and when glaciers advanced. We use cosmogenic 10 Be produced in situ to determine exposure ages for three generations of moraines at the Sierra de Aconquija, situated at 27°S on the eastern flank of the southern Central Andes. These moraines record glacier advances at approximately 22 ka and 40 ka, coincident with summer insolation maxima in the sub-tropics of the Southern Hemisphere, as well as at 12.5 ka and 13.5 ka during the Younger Dryas and the Antarctic Cold Reversal, respectively. We also identify minor glaciation during Bond Event 5, also known as the 8.2 ka event. These moraines register past climate changes with high fidelity, and currently constitute the southernmost dated record of glaciation on the eastern flank of the Central Andes. To contextualise these results, we compile 10 Be data reported from 144 moraines in the eastern Central Andes that represent past glacier advances. We re-calculate exposure ages from these data using an updated reference production rate, and we re-interpret the moraine ages by taking the oldest clustered boulder age (after the exclusion of outliers attributed to nuclide inheritance) as closest to the timing of glacier advance-an approach for which we provide empirical justification. This compilation reveals that Central Andean glaciers have responded to changes in temperature and precipitation. We identify cross-latitude advances in phase with insolation cycles, the last global glacial maximum, and episodes of strengthened monsoonal moisture transport including the Younger Dryas and Heinrich Stadials 1 and 2. Our results from the Sierra de Aconquija allow us to constrain the southerly limit of enhanced precipitation associated with Heinrich Stadials at ~25°S. More broadly, our findings demonstrate at both local and regional scales that moraines record past climate variability with a fine spatial and temporal resolution.3

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Section: Moraine Unit M1mentioning

confidence: 99%

Section: Nuclide Inheritancementioning

confidence: 99%

Timing of past glaciation at the Sierra de Aconquija, northwestern Argentina, and throughout the Central Andes

D’Arcy

Schildgen

Strecker

et al. 2019

Quaternary Science Reviews

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“…La evolución de éstos glaciares se corresponde con otros estudios para los Andes Centrales (Espizua 1999(Espizua , 2002(Espizua y 2004Moreiras et al, 2016) y en general en la cordillera de los Andes (Ackert, et al 2008;Glasser, et al 2008;Martinez et al, 2011;Martini et al, 2017;Rabassa et al, 2011;Ward et al, 2017;Zech et al, 2017;Vargo et al, 2018), habiéndose identificado en diversos depósitos morrénicos de los Andes Áridos los eventos del Último Máximo Glacial y el Tardiglaciar (Moreiras et al, 2016y Martini et al, 2017.…”

Section: Discussionunclassified

“…Las glaciaciones ocurridas durante el periodo Cuaternario, han modelado intensamente el relieve actual de la cordillera de los Andes (Ackert, et al 2008;Glasser, et al 2008;Martinez et al, 2011;Martini et al, 2017;Ward et al, 2017;Zech et al, 2017;Vargo et al, 2018). Durante el Pleistoceno (2,58 a 0,0117 Ma) y Holoceno (desde hace 11,700 ka antes del presente, BP) han ocurrido diversos eventos de descenso de temperatura y avances de los frentes de hielo glacial.…”

Section: Introductionunclassified

Reconstrucción geomorfológica del último máximo glaciar en la cuenca del río San Juan, Argentina

Forte

Villarroel

2019

CyG

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“…The local last glacial maximum ice extension is thought to have occurred prior to the global Last Glacial Maximum (LGM, ca . 35–40 kyr); however, no LGM glacial reconstruction is yet available for the study area. The headwaters of the Santa Cruz, Mondaca and Pachón valleys were covered by Pleistocene valley glaciers, based on the observed presence of erosive forms and glacial deposits over all the main valleys and subordinated creeks (Figure ).…”

Section: Study Areamentioning

confidence: 99%

Rockslides and rock avalanches in the Central Andes of Argentina and their possible association with permafrost degradation

Baldis¹,

Liaudat²

2019

Permafrost & Periglacial

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The identification of hazardous slopes with degrading permafrost is a key task in the mountain periglacial environment. If rockslides have previously been preconditioned by rock wall permafrost, similar events may be triggered from present unstable rock walls. An inventory of rockslides and rock avalanches in the austral part of the Santa Cruz river basin (31°40′–31°50′S, 70°30′–70°10’W), San Juan, Argentina, was made. The study area comprises a surface of approximately 432 km2 (50% above 3,500 m asl); 15 rockslides, 12 complex rockslides evolving to rock avalanches and 19 rock avalanches were identified. The deposits were analyzed with remote sensory imagery and during fieldwork in order to study processes under permafrost degradation caused by global warming. Rock sampling procedures and laboratory rock‐resistivity testing were also carried out. We characterized the detachment scars and deposits for two rockslides. Two different mechanisms were identified. In one rockslide, shallow active layer detachment was favored by shear‐displacement along pre‐existing joints, as a result of short‐term periods of climate warming. In the other, long‐term permafrost degradation favored a deeper failure process. The studied landslide processes could not be explained by permafrost degradation alone. Faults, the geometric arrangement of their structural elements and seismic activity may contribute to trigger these phenomena. It is expected that the magnitude and frequency of rockslide hazards will increase during the 21st century.

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Timing and extent of late pleistocene glaciation in the arid Central Andes of Argentina and Chile (22°-41°S)

Cited by 41 publications

References 51 publications

Timing of past glaciation at the Sierra de Aconquija, northwestern Argentina, and throughout the Central Andes

Timing of past glaciation at the Sierra de Aconquija, northwestern Argentina, and throughout the Central Andes

Reconstrucción geomorfológica del último máximo glaciar en la cuenca del río San Juan, Argentina

Rockslides and rock avalanches in the Central Andes of Argentina and their possible association with permafrost degradation

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