Paesaggio Naturale e Seminaturale Protetto Collina Reggiana - Terre di Matilde

It is the largest and most well-known "salsa" of the Reggiano (once a subject of study by famous scholars such as Antonio Vallisneri and Lazzaro Spallanzani) and is located in the upper part of a slope that, inclined to the east, drains the mud in that direction. As is known, the phenomenon originates from a considerable depth (a few hundred meters) along a complex of faults, mixed waters with gas (especially methane, but also hydrogen sulphide) and other hydrocarbons (traces are frequent of bitumen and oil). The clay from one of the many Eocene "melanges" surfacing in the area and once included in the so-called "scaly clays" come to the day, in the form of muds: the presence of salts, mostly sodium and potassium chlorides, derives from the once these clays were laid in the marine environment.