Geology

In the Miocene era, the area where Szigliget now lies was covered by sea, and later formed part of the so-called Pannonian (Turáni) Lake. Rivers flowing into the lake gradually transformed its waters into freshwater, while also depositing large amounts of sediment, slowly filling up the basin.

At the end of the Tertiary period, during the Pliocene epoch, intense basaltic volcanic activity took place in this region, which had by then become dry land. This geological process created the basalt cones of the Tapolca Basin, including those of Szigliget. During eruptions, lava, volcanic ash, and debris were brought to the surface, forming layers of basalt tuff. In the later stages of volcanic activity, flowing lava emerged through craters, and the vast masses of solidified lava formed the striking basalt hills of the Tapolca Basin. In the case of the Szigliget cones, volcanic activity consisted mainly of the ejection of debris. However, in the formation of Castle Hill, lava flows also played a role: a basalt dyke cut through the tuff ridge of the hill, which can still be clearly seen beneath the castle walls, especially below the Old Tower.
Wind also played a significant role in shaping the landscape, carrying away sediment between the basalt hills and deepening the Tapolca Basin. After the formation of the Balaton Basin, the cones of Szigliget still rose as islands. Later, as the waters gradually receded, they became part of the mainland, resulting in the landscape’s present-day form.