Abstract
The sensitivity of tropical glaciers to paleoclimatic conditions that prevailed during the Antarctic cold reversal (ACR, ca. 14.5-12.9 ka) has been the subject of a wide debate. In 2014 a paper suggested that tropical glaciers responded very sensitively to the changing climate during the ACR (Jomelli et al., 2014). In this study, we reexamine the conclusions from this study by recalculating previous chronologies based on 226 10Be and 14 3He ages respectively, and using the most up-to date production rates for these cosmogenic nuclides in the Tropical Andes. 53 moraines from 25 glaciers were selected from the previous analysis provided by Jomelli et al. (2014) located in Colombia, Peru and Bolivia. We then focused on two distinct calculations. First we considered the oldest moraine and its uncertainty for every glacier representing the preserved evidence of the maximum glacier extents during the last deglaciation period, and binned the results into 5 distinct periods encompassing the Antarctic cold reversal and Younger Dryas (YD) chronozones: pre-ACR, ACR, ACR-YD, YD and post-YD respectively. Results revealed a predominance of pre-ACR and ACR ages, accounting for 60% of the glaciers. Second we counted the number of moraines per glacier according to the different groups. 21 moraines (40%) of the selected glaciers belong to the pre-ACR-ACR chronozones while 3 moraines only (5%) were dated to the YD and YD-Holocene groups. The rest was assigned to the ACR-YD. These results suggest that moraine records are a very good proxy to document the ACR signal in the Tropical Andes.
Highlights
Climatic-induced glacier fluctuations during the last deglaciation (18.0-11.5 ka) have been recognized at several localities in the southern hemisphere (Thompson et al, 2000; 2006; Rodbell et al, 2009)
We investigate if tropical glaciers experienced an advance during the ACR and/or during Younger Dryas (YD) periods and determine when the maximum glacial extent occurred between 14.5 and 11.6 ka ago, and whether it was synchronous between the northern and southern tropical Andes
To determine the behavior of tropical glaciers, we focused on two different calculations
Summary
Climatic-induced glacier fluctuations during the last deglaciation (18.0-11.5 ka) have been recognized at several localities in the southern hemisphere (Thompson et al, 2000; 2006; Rodbell et al, 2009). This ACR cold event provoked glacier advances in different regions of the southern mid latitudes. Glaciers of the Lago Argentino basin, Southern Patagonian Icefield experienced a major glacial stillstand or re-advance at ca. After the ACR period the large ice lobes that filled the eastern reaches of Lago Argentino retreated and separated into individual outlet glaciers. This recession was interrupted only by a stillstand or minor re-advance during the YD at 12.2 ka. The impacts of the ACR cooling event on glaciers located at lower latitudes of the southern hemisphere remained unclear in particular in the tropics. Jomelli et al (2014) established the chronology of Ritacuba Negro glacier located in the northern tropics of Colombia
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
