Questions of Dry Valleys in Karst: Case Study of Mali Dol, Kras (Slovenia)

Abstract

In the article the geomorphology of the Mali dol dry valley is presented. It is one of at least two dry valleys that cross about 45 km long and up to 15 km wide Kras plateau. Mali dol is a 10 kilometers long, 50 to 75 meters deep dry valley. It meanders on the leveled surface across the Kras plateau in direction NE-SW, perpendicularly to all structures. Because of the sediment and thicker soil cover deep and large solution dolines inside the basic valley-like shape were formed. These dolines are larger and deeper than the dolines formed on the nearby surface of the plateau. Local tectonically crushed zones, limestones with cherts and thick sediment cover allow some overland flow into the valley. In such places some smaller but deep and steep erosion gullies were formed. From the morphology, the position of the dry valley and the sediments we can infer the polygenetic origin of the valley. It was formed during the planation of Kras in the height of the piezometric level.