Dolines, their Morphology and Origin. Case Study: Dolines from the Kras, West Slovenia (The Škocjan Karst)

Abstract

The doline forms from the levelled karst surface in the SE part of the  Kras plateau, between the cave system, Škocjanske jame, and the village  of Divača, W Slovenia are described. There are 776 dolines in the area.  Most of them are small, up to 50 m in diameter and up to 5-8 m deep.  Fifteen per cent of the dolines are medium-sized, having diameters  of 100-200 m and depths of up to 30 m. The largest dolines are believed  to be of collapse origin. These have a total volume of about 38 x 10⁶ m³,  comprising 15 large depressions which are 200-400 m in diameter and  30-80 m deep. The largest collapse doline, the 122 m deep Dol Sokolak,  has a volume of 8.5x10⁶ m³. Within the same territory there are 662 smaller  dolines with a volume about 6-10x10⁶ m³. In small areas, doline density  reaches up to 240 per km². The density depends on several factors,  particularly on the properties of rocks, the dip of slopes and the size of  the dolines.  The dolines vary greatly in their morphology and origins there are solution  dolines, «inherited dolines» which were formed by exposure of underground  caverns by surface erosion, and two types of collapse dolines.