Temperate glaciers are often considered poor climate archives because of ice fusion and water percolation in the warmest months of the year; these phenomena cause partial to total loss of the chemical signal in ice. However, thanks to their grain size, insoluble particles are often well preserved and can be used for palaeoclimate reconstructions. The Adamello Glacier (46° 09’ N, 10° 32’ E) is located on the southern slopes of the European Alps (Italy), at an altitude between 2560 and 3420 m a.s.l.; it is considered a temperate glacier. In 2021, a 224 m long ice core was drilled in the Pian di Neve, the summit plateau of the Adamello Glacier. In this sector of the glacier, the ice has an accumulation rate of ca 0.9 m/year. The annual signal is constituted of ca 2-10% in ice thickness by dark spring/summer layers rich in insoluble particles, while the remnant of the yearly signal is composed of autumn-winter clear ice, almost devoid of particles. The spring/summer layers are very rich in biotic proxies. For this study, eight different types of particles are investigated contemporaneously: pollen, diatoms, fern and fungi spores, charcoal fragments, phytoliths, sponge spicules, and green algae. So far, 143 samples have been examined, for a total of ca 60,000 objects identified and subdivided in the various proxy classes. Each proxy presents its own pattern, but it is from the combination of all the proxies that two different sources of paleoenvironmental signals can be identified: a medium-distance extralocal component, mainly constituted by pollen and spores from the woodlands downhill from the glacier, and a long-distance component represented by Saharan Dust events. The combination of these components creates unique features for each year so that events like wildfires or deposition of Sahara Desert dust can be traced and used both to reconstruct environmental and climate changes, and to refine the ice core chronology.
A multi-proxy approach to unravel palaeoenvironmental variations at subannual scale: the ADA270 ice core (Adamello Massif, N Italy).
MANGILI C.Primo
;FIORINI D.;MANARA V.;MAUGERI M.;PINI R.Membro del Collaboration Group
;MAGGI V.
2025
Abstract
Temperate glaciers are often considered poor climate archives because of ice fusion and water percolation in the warmest months of the year; these phenomena cause partial to total loss of the chemical signal in ice. However, thanks to their grain size, insoluble particles are often well preserved and can be used for palaeoclimate reconstructions. The Adamello Glacier (46° 09’ N, 10° 32’ E) is located on the southern slopes of the European Alps (Italy), at an altitude between 2560 and 3420 m a.s.l.; it is considered a temperate glacier. In 2021, a 224 m long ice core was drilled in the Pian di Neve, the summit plateau of the Adamello Glacier. In this sector of the glacier, the ice has an accumulation rate of ca 0.9 m/year. The annual signal is constituted of ca 2-10% in ice thickness by dark spring/summer layers rich in insoluble particles, while the remnant of the yearly signal is composed of autumn-winter clear ice, almost devoid of particles. The spring/summer layers are very rich in biotic proxies. For this study, eight different types of particles are investigated contemporaneously: pollen, diatoms, fern and fungi spores, charcoal fragments, phytoliths, sponge spicules, and green algae. So far, 143 samples have been examined, for a total of ca 60,000 objects identified and subdivided in the various proxy classes. Each proxy presents its own pattern, but it is from the combination of all the proxies that two different sources of paleoenvironmental signals can be identified: a medium-distance extralocal component, mainly constituted by pollen and spores from the woodlands downhill from the glacier, and a long-distance component represented by Saharan Dust events. The combination of these components creates unique features for each year so that events like wildfires or deposition of Sahara Desert dust can be traced and used both to reconstruct environmental and climate changes, and to refine the ice core chronology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
