Dinaric Alps - Geology

Geology

The Mesozoic limestone forms a very distinctive region of the Balkans, notable for features such as the Karst, which has given its name to all such terrains of limestone eroded by groundwater. The Quaternary ice ages had relatively little direct geologic influence on the Balkans. No permanent ice caps existed, and there is little evidence of extensive glaciation. Only the highest summits of Durmitor, Orjen and Prenj have glacial valleys and moraines as low as 600 m (1,969 ft). However, in the Prokletije, a range on the northern Albanian border that runs east to west (thus breaking the general geographic trend of the Dinaric system), there is evidence of major glaciation.

One geological feature of great importance to the present-day landscape of the Dinarides must be considered in more detail: that of the limestone mountains, often with their attendant faulting. They are hard and slow to erode, and often persist as steep jagged escarpments, through which steep-sided gorges and canyons are cleft by the rivers draining the higher slopes.

The most extensive example of limestone mountains in Europe are those of the Karst of the Dinaric Alps. Here, all the characteristic features are encountered again and again as one travels through this wild and underpopulated country. Limestone is a very porous rock, yet very hard and resistant to erosion. Water is the most important corrosive force, dissolving the limestone by chemical action of its natural acidity. As it percolates down through cracks in the limestone it opens up fissures and channels, often of considerable depth, so that whole systems of underground drainage develop. During subsequent millennia these work deeper, leaving in their wake enormous waterless caverns, sinkholes and grottoes and forming underground labyrinths of channels and shafts. The roofs of some of these caverns may eventually fall in, to produce great perpendicular-sided gorges, exposing the water to the surface once more. The magnificent gorges of many of the Dinaric rivers, for example those of the Vrbas, Neretva, Tara and Lim, are justly famous. The partially submerged western Dinaric Alps form the numerous islands and harbours along the Croatian coast.

Only along the Dinaric gorges is communication possible across the Karst, and roads and railways tunnel through precipitous cliffs and traverse narrow ledges above roaring torrents. A number of springs and rivers rise in the Dinaric range, including Jadro Spring noted for having been the source of water for Diocletian's Palace at Split. At the same time, the purity of these rocks is such that the rivers are crystal clear, and there is little soil-making residue. Water quality testing of the Jadro River, for example, indicates the low pollutant levels present. Rock faces are often bare of vegetation and glaring white, but what little soil there is may collect in the hollows and support lush lime-tolerant vegetation, or yield narrow strips of cultivation.