In the heart of the Calderon glacier there are traces of plants and insects

The drilling campaign has ended at Calderon on the Gran Sasso River, the last example of the glacial retreat of the Apennine Range. Scientists have available for the first time a deep-ice sample of glacial ice, the chemical analysis of which will allow to reconstruct the climatic and ecological past of the massif and its surroundings. The mission, as part of the International Ice Memory Project, was organized by the Polar Institute of the National Research Council (Cnr-Isp) and Ca’ Foscari University of Venice, in collaboration with the National Institute of Geophysics and Volcanology (Ingv), the University of Padua and the companies Georicerche srl and Engeoneering srls .

The flight, initially due to bad weather, took 12 days and was made possible by the National Fire Brigade (VVF), which made vehicles and personnel from the Pescara and Rome Ciampino flight departments available to reach the glacier basin. The foot of Corno Grande, at an altitude of 2,673 meters above sea level. While personnel and lighter materials were transported in a modernized AW-139 helicopter, the core drilling machine, weighing 4,500 kg, was moved to the boiler by an Erickson Air Crane S-64, the “flying crane” Heavy loads up to 9000 kg. Operations were facilitated by the extraordinary opening of the Franchetti Sanctuary, owned by the Italian Alpine Club (Cai) in Rome, by the operational support of Abruzzo Alpine Rescue and the municipality of Pietracamela.

The core barrel touched the bedrock of the Gran Sasso glacier field at a depth of 27.2 meters, updating the 26-meter estimate made by the same team in recent weeks, thanks to geophysical surveys that made it possible to identify the most promising points for perforation. “The drilling was very difficult,” says Jacopo Gabrielli, a CNR-ISP researcher and field coordinator, “because of the often harsh weather conditions, and because the ice was plastic, very hot and soaked in water, and the tip of the core tended to knead, not Capable of engraving the surface.

“The management immediately recognized the scientific significance of the Ice Memory project, ensuring maximum cooperation with Cnr, with highly trained personnel and the use of helicopters capable of carrying out complex and risky operations at high altitudes,” asserts Governor Laura Lega, chief of the fire department. “Even with such activities, the role of the National Authority is further strengthened, it is always ready to deal with new challenges and technological innovations that can, as in this case, contribute to environmental protection, handing over part of the “climate memory” of our country to the future and with it professionalism The extremely high and selfless Italian fire brigade.

Sample after sample, the researchers explored the depth of the boiler. “Under a blanket of debris, we gradually encountered ice that became increasingly ‘clean’ but differs from alpine glaciers due to the special thermal conditions of the different layers,” continues Gabrielli. “Through targeted laboratory studies, we will try to characterize them and obtain stored chemical and isotopic information, if available. In the central part of the profile we have checked for plant and insect remains, the dating of which will help in understanding when the surrounding ice accumulated.”

“This trip was a gamble, we didn’t know what we would find in the depths of the cauldron, which every year loses almost one meter in thickness,” comments Carlo Barbant, CNR-Isp Director, Professor at Ca’ Foscari University in Venice. He was a co-creator of the international Ice Memory programme. “The extracted carrot seems to have all the credentials to be able to obtain important information about the climatic and ecological history of central Italy and the entire Mediterranean basin. A truly unique ecological archive that really presents at first glance very interesting glacial properties.”

Once the initial stage of sample analysis has been completed and the stratigraphic conservation, climatic and environmental signals verified, the core will be made available to the International Ice Memory Program and then transported to a storage site at the DomeC site, in Antarctica.

Activities at the Coral are part of a series of Italian glacier expeditions funded by the Ministry of University and Research (with the Integrative Special Fund for Research, Fisr) and supported by AKU and KARPOS.

Information about the boiler
The Calderon represents the most recent example of the Apennine glaciation, as well as the southernmost ice body in Europe. Split into two units in 2000, Calderone is an iconic and now unique image of Mediterranean ice. The classification of the two parts has been reduced from glaciers to glaciers, snow and ice formations without any kind of downstream movement, a typical feature of still dynamic and dynamic glacial ecosystems.

The boiler is a great example of how micro-local conditions can make the difference between maintaining or disappearing layers of ice. The northern exposure and geomorphology of the steep rock walls surrounding the ice circle still ensure good winds and avalanche contributions during the winter.

However, the high summer temperatures cause nearly all of the seasonal snow to melt and some of the ice below. However, the deeper layers of ice are still easier to maintain through a layer of surface debris that protects the ice from high temperatures and intense summer radiation. Despite this exceptional thermal insulation, the thickness of Calderon glaciers decreases year by year.

The main objective of the geophysical survey campaign, which was carried out in March 2022, was to determine the current residual thickness of the ice body, at a maximum depth of 26 meters, as well as to determine the layers of the ice mass and the cover of debris. These high melt rates require rapid preservation of the young ice that is still present before the climate information stored in it is lost forever.

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