The landscape of the Adamello Brenta Geopark derives from the interaction between the glacial, fluvial, gravitational and karst processes (the latter in the Brenta Dolomites).
The glaciers of the Park have seen different phases of expansion and withdrawal. During the Last Maximum Glacial (UMG), which reached the maximum around 18,000 years ago, some tongues descending from the Adamello and the Brenta converged to the east in the Atesino Glacier. Then they continued south to the area of Lake Garda. Others converged south into the Chiese and Oglio glaciers reaching the current Po Valley.
Subsequently, the glaciers abandoned the large valleys with subsequent modest advancements. The last obvious expansion of the Alpine glaciers occurred during the so-called Little Ice Age (PEG) between 1600 and 1800.
The glacial modeling, called “exaration”, smoothed reliefs and rocks (roches moutonnées). Thus giving the valleys the characteristic parabolic profile (U-shaped). The Val di Fumo is a majestic example. In some points the erosive strength of the glacier was stronger, giving rise to steps in the valleys or hollows deepened by over-excavation in glacial cirques. Today in these basins numerous lakes have formed, some of them in very recent times (Lago Nuovo del Mandrone and Lago Nuovo di Lares).
The deposits originating from materials eroded by glaciers are also evident. Numerous cords and morainic banks are visible along all the valleys of the Geopark. As well as the large erratic boulders torn from the slopes and transported by ice for kilometers. The PEG moraines in Val d’Amola, Valagola and Val Nardis are spectacular. In fact, they perfectly draw the limits of the glacial tongues that originated them. Other forms related to the periglacial (near the glacier) environment are the rock glaciers. That is, detritus tongues whose movement takes place thanks to the ice inside them.
The Brenta Dolomites are also characterized by forms linked to glaciocarsism. In fact, there are numerous basins within which the karst, the chemical action of water and carbon dioxide on the limestone, was added to the glacial modeling, creating crevasses and sinkholes, as well as grooves. For example, Pozza Tramontana, Conca dei XII Apostoli and Pian della Nana.
There are also numerous caves and cavities linked to hypogean karst (in depth). Among them the Bus della Spia, near Castel Sporo di Sporminore, the Grotta di Aladino (southern Adamello), the Grotta dello Specchio and the Castelletto di Mezzo. The latter contain hypogean ice deposits. Karst generates an intense water circulation network in the depths of the Brenta Dolomites. For example, the springs of the Rio Bianco and the Vallesinella waterfalls.
Gravity also shapes the landscape. For example, the debris at the base of slopes, such as the screes at the base of the pinnacles of the Dolomites, or the gullies full of detritus that descend from the slopes of the Val Genova. They are due to mass transport phenomena called debris flow mixed with water. Very numerous and easily recognizable both in the Adamello and in the Dolomitic area of the Park. Furthermore there are landslide deposits. Spectacular those of landslide blocks at the base of Cima Grostè and at the head of Vallesinella.
The action of the rivers has engraved the valleys of the Geopark giving them the typical V-shape. For example, the Val Nambrone where the deposit of the rivers prevails over erosion. There are alluvial plains along the banks, as in Val Rendena where the Sarca flows slowly depositing debris.