Evaluating Pacific and Atlantic Ocean-driven Late Glacial and Holocene climate fluctuations in the tropical Peruvian Andes using high resolution geochemical profiles of lake sediments and surface exposure ages of moraines

Discerning the timing and pattern of Late Glacial and Holocene glacial variability in the tropical Andes is important for our general understanding of global climate changes. Cosmogenic ages on moraines, and radiocarbon-dated clastic sediment and geochemical profiles from a suite of alpine lakes document the waxing and waning of alpine glaciers in the Eastern and Western Cordilleras of the Peruvian Andes during the last ca. 15 ka. There are notable similarities and differences in the glacial chronologies and other paleoclimate records when comparing archives along an east-west transect through the Andes. For example, the pattern of glacier variability at Nevado Huaguruncho during the Late Glacial and Holocene suggests that sea-surface temperatures (SSTs) in the tropical Atlantic Ocean drove much of the observed climatic variability along the Eastern Cordillera. Glaciers in the Western Cordillera appear to have been sensitive to both tropical Atlantic Ocean and Pacific Ocean influences, with notable phases of glacial retreat occurring during periods of the Holocene with more frequent El Niño events. Although the acquisition of recent proxy records has improved our understanding of the timing of glacial variability in the tropical Andes during the Late Glacial and Holocene, more work is needed in order to understand the relative contributions of temperature and precipitation changes to glacier fluctuations.