Goričko’s surface is primarily made from sedimentary rocks, which have been deposited by rivers and streams for many millennia. The sedimentary rocks are mostly made from gravel, sand, and clay, among which quartz sands and gravels are economically interesting for building industry. Among the terrain’s special features is sedimentary rock volcanic tuff with olivine nodules, which are of magmatic origin and are one of the kind in Slovenia.

The oldest rocks in the area of Goričko Nature Park can be found in the northwestern part of the Goričko, where they form Sotina Hill and Serdica Hill. These are more than 500 million years old. They are phyllitoid schist shales and are metamorphic rocks, formed from sedimentary rocks deep within the Earth’s crust at very high temperatures and pressures by altering (transforming) their structural, mineral, or chemical composition. There is an active quarry in the area of Sotina Hill (sl. Sotinski Breg), where shale is used as a source of stone useable in construction. In these shales, it is possible to find mineral pyrite with its gold-coloured crystals and other interesting minerals.