The Apennine Mountains of Reggio Emilia are very interesting from a geologist's point of view, some of the main areas of interest are also found elsewhere along the mountain ridges; other, rarer elements are only found in this specific section of the Apennines. The high concentration of geological phenomena in this relatively limited area is rather unusual.
The most interesting phenomena include the volcanic salses, the ravines, the miocenic rocks, the rocks in the Upper Secchia Valley, and the ophiolites.
The backbone of almost all the main peaks in the Apennine Mountains of Reggio Emilia is made of sandstone
, a sedimentary rock that can consist of different formations. The most common type of sandstone on the ridge is hard, solid "siliceous sandstone" that is not subject to rapid erosion. Layers of limestone are also common and may be stratified with other types of rock (called calcareous-marly flysch
). The rock is worn away at some points, near rivers for example, leaving layers of flysch on view and easy to spot. You can see how different thicknesses and different materials were gradually deposited on the seabed over thousands of years, and have now been transformed into a mountainous landscape because of shifts in the earth’s movement. At times, when the stratification shifted vertically, the softer layers were washed away leaving only the harder rock standing and lending it the look of gigantic walls (like the so called Devil's Wall
between Vezzano and Casina).
The points of interest also include the Pietra di Bismantova
with its massive, rocky cliff face soaring 1047 metres above sea level. A large expanse of fields stretches over the top of this flat mountain, covering an area of 12 hectares, and are surrounded by hornbeams and hazelnut trees. The Pietra di Bismantova and its surroundings is part of the Tuscan-Emilian Apennine National Park and is a very interesting site for both archaeologists and naturists.
The highest reaches of the Apennine Mountains of Reggio Emilia also bear traces of ancient glaciers
, now extinct. During the ice age of the Quaternary period of the Ice Age (the last one was 10,000 years ago), several glaciers formed in the mountains above Reggio Emilia. As they slowly made their way downhill, the debris they took along with them eroded the terrain below. Traces of their passage can be seen in the form of huge amphitheatres, hewn out of the mountain sides in the Ozola valley at Lama di Mezzo or at the source of the river Secchia on Mount Casarola, in mounds of morainic debris and natural lakes in the mountains, including Cerreto Lake
and Calamone Lake
nestling under the summit of Mount Ventasso.