Younger Dryas glacier advances in the tropical Andes driven by increased precipitation.

ABSTRACT: There is currently a debate about the timing and drivers of former glacier behaviour and climate change in the tropical Andes. Using 10Be dating we determined the ages of 21 boulders on moraines in the Santa Cruz Valley, Peru (∼10°S, altitudes ~ 4100 to ~ 4300 m a.s.l.). Former glacier extent is marked by a suite of nested outer lateral and terminal moraines. These moraines are dated to 11.1 ka, 11.6 ka, 11.8 ka and 12.0 ka, falling within the Younger Dryas Chronozone (YDC; ∼12.9-11.6 ka). Nine 10Be samples from the Lake Arhuaycocha catchment document a period of glacier thinning and lateral contraction between 12.0 ka and 11.8 ka. Reconstructed glacier Equilibrium Line Altitudes (ELA) at 11.0 to 12.0 ka with an area-altitude balance ratio (AABR) of 1.00-2.50 are between 4675 and 4835 m a.

SUBMITTER: Glasser NF 

PROVIDER: S-EPMC12370917 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature