Vis belongs to the group of Central Dalmatian islands that lie on the Adriatic carbonate platform – a massive slab of limestone and dolomite that today forms the backbone of most Dalmatian islands and karst terrain in general.
During the Mesozoic era, this was a shallow marine environment above which shells, corals, and other organisms deposited for millions of years, creating thick layers of limestone and dolomite.
Later, during the collision of the Adriatic microplate with Eurasia and the formation of the Dinarides (in the Late Cretaceous and Paleogene), these sediments were folded and thrust over one another, causing them to rise above sea level. This created the outer belt of the Dinarides and the present-day arrangement of the coast and islands. One of the uplifted folded parts of the former platform is today’s island of Vis.
The distinctive feature of the Vis archipelago compared to other Adriatic islands is that it contains some of the oldest rocks in the entire Adriatic – part of the rocks is approximately 220 million years old. The core of the island of Vis consists of volcanogenic rocks, evaporites, sediments, and dolomites, which are also characteristic of the nearby islands of Biševo and Jabuka. In the later Mesozoic, prolonged carbonate deposition continued on these old substrates, namely limestone and dolomite, often with fossils.
After the rocks were raised above sea level, a long process of karst relief formation began. The key features on the island of Vis and its associated islets are karst fields, of which the most extensive are Dračevo polje and Velo polje, bays among which those at the locations of the towns of Vis and Komiža stand out, and caves and caverns (Blue Cave, Medvidina Cave, Green Cave). Red soil deposits, Pleistocene sands, and aeolian dunes are well represented, resulting from phases when the island was part of the Adriatic plain.
During the last glacial maximum (20,000 years ago), the sea level in the Adriatic was 100-120 m lower than today, so Vis was an elevation of that same landmass. With climate change, the ice retreated, and the sea gradually flooded the plain in the Holocene (12,000 years ago), turning the elevations into islands. Vis is thus a relatively “young” island in the geographical sense, but the rocks from which it is built are many times older.
