Surface Karst Morphology
Disposition of karst relief
The karst relief of Serbia exhibits all characteristic landforms of surface karst morphology that occur in the classic Dinaric karst regions. However, because limestone terrains in Serbia are for the most part covered by vegetation and soil, certain landforms are rarer and morphologically more weakly expressed. This applies especially to karren, whose development is possible mainly on naked and exposed limestone surfaces.
In contrast to karren, dolines are morphologically very well expressed. They are most numerous on leveled parts of limestones, especially on karst plains, where they appear both individually and in groups or series along fault lines or on the bottom of dry karst valleys. Dolines are formed that have varying shape and size, depending on the conditions under which they arise. Their sides are mainly rocky, while the bottoms are in most cases covered by soil. In certain karst terrains, they are almost completely covered by a loose soil layer and overgrown with vegetation.
Also developed on karst plains are numerous uvalas, which in most cases exhibit polygenetic features. Encountered very frequently in the karst of Eastern Serbia, karst-selective uvalas are landforms whose formation is governed by geological composition of the terrain, that is by the distribution and thickness of carbonate rocks. They occur mainly in terrains where the thickness of limestones is insignificant, several tens of meters, as well as in places of contact between carbonate and noncarbonate rocks. Uvalas in regions of contact essentially are transformed blind valleys.
Due to the limited distribution of limestones, karst poljes in Serbia are rare and of small dimensions. They are formed in regions of contact between carbonate and noncarbonate terrains. With respect to their origin, they are polygenetic, tectono-erosional landforms.
Of special significance in limestone terrains of Serbia are dry and blind valleys, on whose basis it is possible to establish morphological evolution of the karst relief as a whole. They indicate for certain that a normal surface hydrographic network was developed on limestones prior to the karst process. With the advance of karstification, however, surface run-off of river currents ceased. They flowed off through stream-sinks and expanded joints into the karstic underground and left behind valleys that today are hydrographically inactive. For this reason, karst terrains are almost completely without water on the surface. However, strong karst springs in places of contact with impermeable underlying rocks, at the foot of carbonate massifs around their rim, indisputably indicate the existence of underground river currents.