The land surrounding the park is steeped in geological history, dating back to the formation of the embedded walls and ancient bed and the formation of Castro. Such rock, deposited back about 190 MA in a marine platform environment, looks chaotic and shows almost no sign of stratification. In more recent times, this same rock formation has been altered, as evidenced by the many traces of overlapping events, formative at first and then shaping due to the flow of rivers, karst development, and glacial actions. The gorge rock has undergone a long erosion process that has resulted in a narrow and stunning opening where traces of the progressive lowering of the river bottom and the heady swirl of waters are very visible. On more than one level, one can see circular shapes called potholes, which are caused by erosion as the fast flowing water swirls, carrying fragments of stones and pebbles which grind down the rock to form the pothole structures.
The limestone rocks show signs of karst especially along fractures and faults, while the chemical deposition of calcium carbonate had created wide and interesting travertine formations along the walls.
Important water circuits end their flow near two sources located within the park limits. Over a period of time between 2 million and 10 thousand years ago, the glacial action worked on this portion of the territory. Outstanding ice thicknesses have occupied the gorge over time.
Finally, through the canyon of the Tinazzo, water carried the debris that deposited in the basin of the Borlezza when the water reached the lake, forming the delta on which the metallurgical factory was built .