Ranco (VA)
Via Quassa 27
CIN: IT012116B1DVMX5E8U CIR O IDENTIFICATIVO UNICO REGIONALE: 012116-CAM-00001
21020
Italia
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The "Sass Cavalàsc" is a colossal erratic boulder located on the shore of Lake Verbano, in the municipality of Ranco, near the border with Ispra. It, like many other erratic boulders scattered throughout our area, testifies to a significant geological phenomenon that began about 60,000 years ago and ended 15,000 to 20,000 years ago. Since then, no geological event of such importance and grandeur has occurred on the Earth's surface. The Alpine chain, which was much higher than it is today, was covered by a massive blanket of snow and ice that, due to gravitational force on the inclined plane it rested on and aided by the heat of the Earth, began to descend and spread, transporting a vast amount of stones. This era was called the "glacial" period and was marked by a succession of glacial phases and interglacial phases with a milder climate, and perhaps at times even warmer than today.
In our area, there were four phases, with the greatest expansion during the second glaciation not surpassing Gallarate. The subsequent floods, which occurred due to the melting of the ice, carried much of the fine material (pebbles, gravel, sand, and silt) into the Pliocene Sea, giving rise to the Po Valley. Before the current building development, which has altered construction techniques, boulders that had suitable characteristics for use in masonry were utilized as they were discovered; however, those that have reached a certain volume have been protected by landscape law for several decades and should not be destroyed for any reason. The volume of the boulders varies depending on the glaciations they belong to: those from the first glaciation are smaller than those from subsequent ones, reaching volumes of several hundred cubic meters in the last glaciation.
Regarding erratic boulders, popular imagination, sensing that they were blocks that came from afar, speculated that their transport was aided by fabulous giants or even the devil himself. In our area, these colossi abound in the region between Ranco, Angera, Sesto Calende, Lentate, Barza, and Ispra. At the head of these boulders stands the famous "Sass Cavalàsc," well-known even to foreign geologists, first described by Antonio Stoppani, a writer and naturalist from the last century. It is protected by regional law no. 86 of 1983.
It has a parallelepiped shape, measuring 5 x 8 meters, but it is impossible to calculate its volume even approximately, as it is embedded in the ground and the invisible part seems significant, considering it resists gravitational force despite being strongly inclined. It is made of serpentinite, as are many others in the area. They were part of a colossal landslide that, halted on the surface of the glacier in the Alps, perhaps in the Gotthard area, later spread out in the described region. At the base of the side facing the lake, there is a small mill or pot hole, a roughly cylindrical cavity formed by a rather curious geological phenomenon, due to the action of a vortex of water and pebbles on the rock; it was discovered by Professor Don Luigi Ragazzoni from the Barza Seminary. For most of the year, the base of the boulder with the mill is submerged in the lake.
CIN: IT012116B1DVMX5E8U CIR O IDENTIFICATIVO UNICO REGIONALE: 012116-CAM-00001
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