Across the Arid Diagonal: deglaciation of the western Andean Cordillera in southwest Bolivia and northern Chile

Abstract

ABSTRACT. Here we review published cosmogenic records of glaciation and deglaciation from the western cordillera of the arid subtropical Andes of northern

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

“…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.…”

“…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).…”

“…Much of the Central Andes are currently unglaciated due to the relatively warm and dry climate in this region. However, during the past several tens of thousands of years, the Central Andes experienced glacial advances during cooler and wetter episodes associated with orbital cycles and millennial-scale climate events (Smith et al, 2005a,b;Jomelli et al, 2014;Bromley et al, 2016;Martini et al, 2017;Ward et al, 2017). These climate changes have been reconstructed using archives and proxies including lake cores and shorelines (Sylvestre et al, 1999;Baker et al, 2001;Placzek et al, 2006Placzek et al, , 2013Baker and Fritz, 2015), plant fossils and pollen (Chepstow-Lusty et al, 2005;Maldonado et al, 2005;Torres et al, 2016), stable isotopes (Cruz et al, 2005;Wang et al, 2007;Kanner et al, 2012), ice cores (Thompson et al, 1995(Thompson et al, , 1998Ramirez et al, 2003), biomarkers (Fornace et al, 2016), and basin sediments (Nester et al, 2007;Steffen et al, 2009Steffen et al, , 2010Bekaddour et al, 2014;Schildgen et al, 2016;Tofelde et al, 2017).…”

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

“…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.…”

“…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.…”