The Zrenj Plateau is a karst plateau in northern Istria, Croatia, with extensive areas of contact karst of the ponor type on its northern and southern margins. Watercourses flow from Eocene clastic rocks and submerge into karstified carbonate rocks that are predominantly Cretaceous in age. Morphographic, morphostructural, and morphometric analyses were conducted in the area, followed by morphogenetic and morphodynamic interpretations. We concluded that the development of the contact karst occurred in at least three distinct phases. First, it acted as a corrosion plain in a shallow karst, followed by tectonic uplift and antecedent incision of watercourses into the corrosion plain. Only within the last phase did surface streams flow into the subsurface and form the contact karst.
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