Proxies of Amazon Climate in a Peruvian Ice Core

The Amazon rainforest, the largest in the world, is a big producer of aerosols. They can be of either natural or anthropic origin. The forest is also responsible for controlling much of the weather in South America. Approximately 70 km distant, in the Cordillera Vilcanota, in the Peruvian Altiplano, lies the biggest tropical ice cap in the world at an altitude of about 5674 meters above sea level. In 2022, an ice core was drilled at the Summit Dome, by the Climate Change Institute (University of Maine) as part of a joint US-Brazil-Italy collaboration, recovering the entirety of the ice cap thickness at that point in an ice core 128.3 meters-long recording possibly the last 2 thousand years of South American tropical climate. The ice core is being analyzed for levoglucosan, organic acids and major ions to understand if it could be a reliable site for studying Amazon changes in the past. The first 35 meters of which 18 meters represent the superficial firn pack have already been analyzed. The preliminary results indicate that much of the ionic signal is preserved within the most superficial sections of the ice cap both for the inorganic ionic species (such as Na⁺, Ca²⁺, NH₄⁺, Mg²⁺, Cl^-, SO₄^2-, NO₃^-) and the organic species (MSA, C1-formic, C2-acetic, C2-glycolic and C2:C7 diacids). Further analyzes are still being made and should bring progress on the state of the ice core geochemistry, revealing other processes and enhancing the knowledge whether Amazon signal is recorded in such an isolated environment.