Aspetti geologici del Gran Sasso d'Italia

The Gran Sasso is the highest mountain group of the Central Apennines; from a geological point of view the rocks that now constitute it were formed in an area located very far from where they outcrop today: a broad carbonate platform developed on the margin of a lost ocean called Tethys . The tectonic structure of the Gran Sasso Massif are due to powerful compressive/tangential strain which resulted in the overthrust of the structure toward the Adriatic realm, during the Apennine orogenesis (Upper Miocene – Pliocene). This massif is commonly considered as the most important hydrogeological unit of the Central Italy regarding to its extension and its dynamics: mainly composed of intensely fractured carbonate rocks the complex presents a significant effective infiltration rate (about 800 mm / year for an average rainfall of about 1,200 mm / year). Due to its structural complexity, the aquifer is formed by a several interconnected reservoirs , laterally bounding by impermeable rock formations and feeds a large number of springs located on the northern and southern slope. The cold climatic phases occurred during the Pleistocene greatly influenced the morphology of the central Apennines where it is possible to recognize well-preserved erosional and depositional features of glacial origin. The most impressive example of this morphologies, both for its size and for the state of preservation, is Campo Imperatore: a glacial/karst – alluvial valley , measuring over 13 km long and 4 wide, located close to the Giardino Alpino.