A landscape shaped by ice
High on the Pollino Massif, which forms the border between Calabria and Basilicata, the landscape holds secrets from the last ice age. Here, features known as rock glaciers mark the southernmost evidence of glacial activity in Italy. These are not true glaciers of pure ice, but rather a frozen slurry of limestone debris and interstitial ice that once crept downslope. The most distinct example, the Pollino rock glacier, is found at an altitude of around 1,750 meters.
These formations are remnants from the Last Glacial Maximum (LGM), a period that peaked around 20,000 years ago when mean annual temperatures were 4–6 °C lower than today. During the LGM, the equilibrium line for glaciers on Monte Pollino—the altitude where snow accumulation equaled melt—was about 1,800 meters. The rock glaciers formed below this line, likely deforming moraine ridges left by retreating true glaciers. Their lobate shapes and surface ridges are classic indicators of this slow, frozen flow, a process that has long since ceased. The features seen today are considered relict, meaning they are no longer active.
The hunt for buried permafrost
While the rock glaciers are inactive, scientists suspect they may conceal pockets of ancient, frozen ground. The thick layer of rock debris acts as an insulator, potentially shielding ice deep within the structure from modern, warmer temperatures. This has led to ongoing research to determine if relict permafrost still exists here, far south of its typical range.
Ground temperature monitoring on the highest peaks of the Pollino massif provides intriguing clues. Data shows that in some locations, the mean annual ground surface temperature is close to 0°C. These conditions are conducive to the preservation of permafrost at depth. Scientists use geophysical methods like electrical resistivity tomography (ERT) to probe beneath the surface. This technique measures how easily an electrical current passes through the ground; ice-rich permafrost is highly resistive compared to unfrozen rock and soil. The presence of permafrost this far south would record past climatic conditions and how landscapes respond to warming. The entire Pollino area is recognized as a UNESCO Global Geopark due to its geological heritage.