Pietra Alta, Glacial erratic in Caselette, Piedmont, Italy.
Pietra Alta is a massive serpentinite boulder that rises approximately 10 meters above ground with a circumference of roughly 50 meters. The rock sits at an elevation of 368 meters near Lake Caselette and forms a striking feature in the local landscape.
During the Riss glaciation, a massive serpentinite block was transported by glacier ice from the Susa Valley to its current location. This movement across frozen terrain during that ancient ice age shaped the geological history of the region.
The name Pietra Alta means High Stone, reflecting how local people have recognized this boulder as a key landmark in the landscape for centuries. Residents call it Pera Aota in the Piedmontese dialect and use it as a traditional navigation reference point.
The route follows Via Pietra Alta, an asphalt lane that connects to a walking path leading toward Lake Caselette's shore. The terrain is relatively easy to reach on foot and provides good views of the boulder from several vantage points.
The boulder's surface displays geological rinds resembling desert varnishes, indicating past semi-arid climate conditions in the region. These surface patterns are visible to visitors and reveal clues about environmental changes that occurred over long periods.
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