Antarctic-like temperature variations in the Tropical Andes recorded by glaciers and lakes during the last deglaciation

Abstract

Highlights-Cosmic ray exposure ages and paleo-ELAs determined for Bolivian Andes late-glacial moraines -New 14 C shoreline ages constrain the depth of paleolake Coipasa (12.5 cal kyr BP) -Temperature and precipitation reconstructed from coupled glacier-lake modeling -Lake-induced precipitation recycling effect accounted in reconstruction -Precipitation modulated by Northern Hemisphere, temperatures by Antarctic during 19-11 ka BP

Cosmogenic 3He paleothermometry on post-LGM glacial bedrock within the central European Alps

“…Alternative approaches using artificial targets (e.g., Vermeesch et al, 2009) or scaling P3 He measured in retentive minerals (i.e., olivine; e.g., Cerling and Craig, 1994;Goehring et al, 2010) have hence been used. While we adopted the Stone (2000)-scaled P3 He from Vermeesch et al (2009;i.e., 116 at g −1 yr −1 ) in this study, a ∼ 10 % higher 3 He production rate has also been proposed from olivine 3 He measurements scaled to quartz (e.g., Masarik and Reedy, 1995;Ackert et al, 2011). Applying an increased P3 He (Stone-scaled P3 He = 128 at g −1 yr −1 ) in general leads to smaller EDTs in order to match the measured 3 He concentrations, as well as to an older range of possible times for the EDT change.…”

“…Because glaciers are sensitive to both temperature and precipitation, obtaining information about in situ temperature conditions from an independent proxy is critical to disentangling the role of either variable in recorded glacier fluctuations and to adequately use these records for paleoclimate reconstructions. In particular, paleoglacier records can be used as direct, site-specific paleo-precipitation indicators (e.g., Kerschner N. He paleothermometry in the Alps et al, 2000;Kerschner and Ivy-Ochs, 2008;Martin et al, 2020) to trace changes in regional atmospheric circulation systems (Kuhlemann et al, 2008;Becker et al, 2016;Gribenski et al, 2021). More detailed information about paleoclimate conditions would moreover improve both our understanding of glacier responses to current climate change as well as our ability to anticipate glacier evolutions for proposed future climate scenarios (Zemp et al, 2006;Haeberli et al, 2022).…”

Palaeoglaciation in the Low Latitude, Low Elevation Tropical Andes, Northern Peru

“…The ELA is the theoretical line where accumulation and ablation are equal (Benn et al, 2005) and has been frequently used as a proxy of the surrounding climate conditions of temperature and precipitation for the reconstruction of tropical Andean glaciers and climate (Porter, 2001;Bromley et al, 2011a;Martin et al, 2020). Although the ELA would not have been static for long periods of time due to the varying climate conditions, the reconstructed palaeo-ELA inferred in this study is assumed to be at its lowest potential elevation and thus represents the time the glaciers were at their most extensive (i.e., LLGM).…”

Cosmogenic <sup>3</sup>He paleothermometry on post-LGM glacial bedrock within the central European Alps

“…Because glaciers are sensitive to both temperature and precipitation, obtaining information about in situ temperature conditions from an independent proxy is critical to disentangling the role of either variable in recorded glaciers fluctuations and to adequately use these records for paleoclimate reconstructions. In particular, paleoglacier records can then be used as direct site-specific paleo-precipitation indicators (e.g., Kerschner et al, 2000;Kerschner and Ivy-Ochs, 2008;Martin et al, 2020) to trace changes in regional atmospheric circulation systems (Kuhlemann et al, 2008;Becker et al, 2016;Gribenski et al, 2021). More detailed information about paleoclimate conditions would moreover improve our understanding of glacier response(s) to current climate change as well as our ability to anticipate glacier evolutions for proposed future climate scenarios (Zemp et al, 2006;Haeberli et al, 2020).…”