The soils of the morainic hills of the Bardolino zone are characterized by extreme variability (the zoning programme has identified 66 different types), due to the deposits left by the glaciers that formed the basin of Lake Garda and, in part, by those that came down the valley of the River Adige.
Even if there does not seem to be total agreement among researchers regarding the attribution of the various morainic ridges, it is believed that the morainic deposits of the Lake Garda area were formed during the Günz, Mindel, Riss and Würm glaciations:
to the two oldest ice ages, Günz and Mindel, limited morainic deposits have been attributed, whereas generally the outermost ridges are attributed to the Riss glaciation and the inner ones to the Würm glaciation.
The various glaciers left behind enormous accumulations of materials, deposited in the large amphitheatre of Lake Garda or in the inland one of Rivoli Veronese: these are huge piles of pebbles, accumulations of gravel, glacial erratics, hard strata of loess and clays. In the Upper Garda zone, in the territory of Brenzone, there are deposits of dolomite, which were once used for the production of Dolomina (magnesium).
The land reclamation operations that have been carried out over the course of the centuries have given rise to the dry stone walls, constructed using the so-called “seregni” removed from the fields: in other words, limestone or porphyry stones whose edges were made rounded as they were dragged down by the glaciers. Each single plot of land surrounded by walls of “seregni” is referred to locally as a “brol”. Even Goethe, in his “Italian Journey”, mentions these stones that “are piled up in strata alongside the road and serve to form very massive walls”.
The origin of the subzones