Geo 1The Earth is not standing still! The magma in the interior is constantly moving... both horizontally and vertically... and the movement is reflected on the Earth's surface: the Earth's crust is rising and falling, surfaces and dives, breaks into tectonic plates, vulcans erupt, earthquakes occur, the continents "travel", crash into each other and separate, slide under each other... (Picture 1 - Cross-section of the Earth)


geo 2For the Kornati area, two tectonic plates are important: African and Eurasian. The boundary zone between them is under the Mediterranean, while the Kornati are on the southern edge of the Eurasian plate. Looking at the geological history, Africa has been travelling to northeast and north for millions of years, and crashes into and moves and slides under Eurasia. That's why the southern edge of the Eurasian plate constantly suffers consequences: earthquakes are frequent, lithosphere wrinkles and faults, rises and falls, comes out of the sea and dives into it again... (Picture 2 - Boundary zone of Africa and Europe)

Geo 3The oldest rocks we find today in Kornati are dolomites and limestones deposited about a hundred million years ago (during the late Mesozoic = Upper Cretaceous). The African plate was much further towards the south than today, and between Africa and Eurasia there was a huge sea called Tethys Ocean (today's Mediterranean Sea is just a remnant of the ocean). The Kornati area was completely submerged in the warm and life-rich sea. When the sea organisms living in the area died and got deposited on the bottom, the dolomites and limestones prevailing in Kornati today were created (the limestones are full of shell fossils). (Picture 3 - Layout of land and sea 65 million years ago)

geo 4Because of the constant movement of Africa and its sliding under Eurasia, the southern edge of Eurasia wrinkled and faulted continuously. At the end of Cretaceous (70-80 million years ago) a part of that edge, together with the Kornati area, surfaced from Tethys. The evidence of the faulting as well as the evidence of rising and lowering of neighbouring rock blocks at fault lines may best be illustrated by the famous Kornati "crowns" (crags or cliffs) that can be found on the majority of the Kornati islands. The "crowns" are parts of a huge fault plane which falls steeply more than 90 metres deep into the sea (Piškera) in some places while in others rises more than 80 metres above sea level (Klobučar). (Picture 4 - Kornati "crowns" (fault plane))

During the "dry land phase", the Kornati area passed through intensive processes of turning into karst: in the limestones and dolomites exposed to the atmospheric influences, there occurred numerous caves, holes, sinkholes and other karst formations. Approximately at the same time, 65 million years ago, a huge asteroid hit the Earth in the area of today's Mexico. The consequences of the impact were catastrophic: almost a half of biological species was wiped from the face of the Earth. Among them were the shells from the rudist group whose fossils can easily be found today in the Kornati limestones. (Picture 5 - A rudist, Picture 6 - Rudist limestone, Picture 7 - Traces of organism movement)


The dry land phase lasted for about 30 million years... but Africa didn't stand still. It travelled further towards northeast and north, and crashed into Euroasia. The edge of Euroasia lowered a bit and the sea surged again into what was dry land – this time in the form of basins and pools, both large and small, more open and closed ones. The pools had a significant influx of fresh water from the surrounding land and the sea became "fresher", that is, brackish. Among the organisms that lived there, predominant were brackish foraminifera – single-celled organisms, milimetre or so in size, with a limestone shell. The foraminifera gave practically all the "building material" for the limestones from that age. The evidence of this geological age can be found on several locations in the Kornati area: Lavsa, Gustac, Ravni Žakan, Kurba Vela, and Kornat (foraminiferal limestones). Further tectonically influenced deepening of the sedimentary basin led to the deposit of the so-called flysch sediments, which can be found only in the Gujak Bay on the island of Kornat, and only in a very small area at that.At the end of Eocene, some 35 million years ago, the Kornati area – because of Africa, again – surfaced again. Since then, the area has been going through intensive processes of turning into karst (the creation of caves, holes, sinkholes).



 (Photo - Foraminiferal limestone)

It's not only the internal forces of the Earth that left interesting traces in Kornati. The change in global climate left its, maybe even more interesting mark. During the last great ice age about 15 thousand years ago, and due to the immense amount of water trapped at the poles, the level of the sea was more than 130 metres lower than today. If we check the depth of the Adriatic, it's not difficult to conclude that Kornati were a part of the mainland at the time, while the sea reached into the Adriatic Depression only to what today is the Jabuka Pit. Due to the global warming and comparatively fast melting of the great ice caps at the poles, the level of the sea suddenly rose. That led to what was hilly dry land becoming fragmented islands (only the tops of the hills remained dry). Numerous karst formations (caves, holes and so on) suddenly ended below the sea, providing habitat and sanctuary to different newly arrived sea organisms. There are theories that the island of Kornat was connected to the mainland 9-10 thousand years ago, and to Long Island up to 2100-2400 years ago (at the time of Hippocrates, Aristotle, Julius Caesar and so on).