The geological history of Cyprus began 92 million years ago when the Troodos ophiolite formed at the bottom of the Neotythean Ocean, which at the time extended from the Pyrenees (through the Alps) to the Himalayas. It is regarded as the most completed and studied ophiolite in the world. It is a fragment of a fully developed oceanic crust, with its stratigraphic completeness making it unique. It consists of a group of basic and ultrabasic rocks, consisting from the lower to the upper stratigraphic units of harzburgite and serpentinite of the upper mantle sequence, dunite, wehrlite, pyrixenite, gabbro and plagiogranite of the cumulate rocks, diabase of the Sheeted Dyke Complex, lava flows of the volcanic horizons and umbers which at the upper statigraphic levels alternate with deep sedimentary rocks such as radiolarites and mudstones (Perapedi Formation).
The Troodos ophiolite complex was formed during the complex processes of oceanic spreading and the formation of new oceanic crust. It was placed and uplifted to its present position through complicated tectonic processes relating to the collision of the African and Arabian Plate with the Eurasian Plate.
The collision of the edges of the Arabian Plate with the Eurasian Plate in the subduction zone, over which Troodos was formed, ended the formation of new oceanic crust, detached the Troodos microplate and rotated it 90o anti-clockwise by the end of the sedimentation of the Kannaviou Formation (75-70 million years ago). What followed was the juxtaposition over and adjacent to the Troodos ophiolite, of older rocks belonging to the Mamonia Complex. This active tectonic period, of about 70 million years ago (Middle Maastrichtian), is observed in the bentonitic clays of the Kannaviou Formation which are strongly faulted and mixed with rocks of the Mamonia Complex and the Troodos ophiolites, particularly in southern, southwestern and southeastern Cyprus. This tectonic event didn’t affect the overlying sediments of the Upper Maastrichtian (67 million years).
After the collision of the Troodos ophiolite with the Mamonia Complex, a period of relative tectonic inactivity followed, characterized by pelagic sedimentation of chalks, cherts and marls of the Lefkara Formation. Some 22 million years ago, the marine basins around the Troodos ophiolite gradually became shallower, depositing chalks and marls of the Pachna Formation, while at the edges of the basins reefal limestones were deposited. At the upper stratigraphic units of the Pachna Formation, we observe a gradual increase in the clastic material content, which resulted to the deposition of calcarenites and conglomerates. The Troodos ophiolite emerged above sea level 10 million years ago.
Some 10 million years ago, the calcareous rocks of the Pentadaktylos Range moved southern, causing folding to all younger autochthonous formations. Later, due to Troodos continued uplift, the sea around Troodos became more and more shallow, favouring the localized development of coral patch reefs and the deposition of the reefal limestones of the Koronia Member, which are very rich in fossils such as bivalves, gastropods, echinoids and corals.
In the Upper Miocene, in small marine basins around the Troodos ophiolite, gypsum and gypsiferous marls of the Kalavasos Formation were deposited. This represents a significant event in the geological evolution of the Mediterranean, known as the “Messinian Salinity Crisis”. During that time, the relative movements of the African and Eurasian Plates provoked the closure of the Gibraltar straits and the isolation of the Mediterranean Sea from the Atlantic Ocean. Evaporation exceeded the inflow of fresh river water into the Mediterranean basin, leading to a drop in sea level by several hundred meters below that of the Atlantic Ocean, and the creation of extensive salt lakes, in which gypsum and salt were deposited.
The reconnection of the Mediterranean Sea with the Atlantic Ocean, with the opening of the Gibraltar Straits (5 million years ago), due to the relative motion between African and Eurasia Plate, resulted in the introduction of a new sedimentary cycle, which today is represented by marls, sandy marls and calcarenites of the Nicosia Formation.
In the Troodos Mountain the ophiolite rocks show an apparent topographic inversion, with the stratigraphically lower suites of rocks outcropping in the highest points of the range, while the stratigraphically upper rocks appear on the periphery of the ophiolite. This apparent stratigraphic inversion is related to the way the ophiolite was uplifted (diapirically) and subsequently exposed by differential erosion. The diapiric uplift of its core took place mainly with episodes of abrupt uplift up until the Pleistocene.
The uplift of Cyprus, combined with heavy rainfall during the Pleistocene period, resulted in extensive erosion of the mountain ranges, particularly that of Troodos but also of Pentadaktylos range, with the transport of large quantities of erosional material (gravels, sands and silts), which in turn were deposited in large river valleys and in the Mesaoria region, forming the Pleistocene sediments (Fanglomerate).
The geological environment of Cyprus is made distinct by the presence of the Troodos ophiolite. It constitutes a world-wide example of old oceanic crust rocks. This fact has attracted the interest of many international research and academic institutions. As a result, many important scientific findings have been published that support theories for the genesis and structure of the earth’s oceanic crust. The Troodos ophiolite, together with other autochthonous and allochthonous rocks in Cyprus, offers a setting for a field laboratory in understanding the geological evolution of the eastern Mediterranean.
Τhe Troodos area makes up a unique geological heritage site which, in addition to geology, offers archaeological, ecological, historical and cultural wealth and fulfils all the special characteristics to be established as the first geopark of Cyprus and become a member of the European Geopark Network. This geopark is expected to contribute to the economic development of the mountainous area enhancing the local tourism product.
Detailed geological mapping and published geological and thematic maps have been completed for a large part of the island. These maps record the geological characteristics and geological history of Cyprus. This knowledge forms the base for all geological research and applications relating to the land and sea territories.