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Gavdos Island, a Lifted and Tilted Aegean Crustal Block

Text, photography: Annemieke van Roekel, geoscience journalist
More articles: www.vuurberg.nl

This article about Gavdos' geology was first published in Gea Magazine (March 2020) and has been (so far partly) translated in English. Many thanks to Kellin Defiel for her corrections.

To seekers of rest, beach visitors, archaeologists and geologists, the island of Gavdos, the most southern point of the European continent, is a rewarding destination. Visible from the coast of Crete, this tiny island is a pearl in the Libyan Sea. Under the Roman name of Claudia, it is already mentioned in the Bible (Acts 27) by Apostle Paul. Right at this spot in the Eastern Mediterranean, an ancient sea floor has risen above the water, presenting to geologists an undisturbed view of astronomical cycles in the geological era of the Miocene.

Gavdos is a small and relatively unknown island southwest of Crete. On clear days. the high mountains on either side of the famous Samaria gorge in Crete can be clearly seen. The island is especially popular with travellers who want to camp freely under and between juniper trees and tamarisks on the northern beaches. In the last decades, a handful of apartments were built, so those who do not want to camp under the open, starry sky can also find a suitable home. The tourist pressure is limited to the summer months; from October to May there is little to do and there is an overwhelming calm. Around forty people live on the island all year round.

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Venetian pavement

With an area of approximately 30 sq. kilometres, the almost audible silence, the Mediterranean visible from almost every location, trees in the most capricious forms and the possibility of walking virtually everywhere, it is an attractive travel destination (photo above, left). Hiking trails have been well marked; some of them must be very old, such as the path between the centrally located village of Kastri and Ambulous, in the west. This is a breathtaking path through pine woods, with an ancient pavement made of local limestone (photo above, right).

"This pavement might go back to the Venetian period," says Katerina Kopaka, archaeology professor at the University of Crete in Heraklion. Since the early 1990s, Kopaka travelled to Gavdos almost every summer to supervise archaeology students. "After years of systematic mapping of the archaeology of the entire island, we are now digging north-east of Kastri on a site that once housed a large agricultural housing complex, which dates from before the middle of the second millennium BC." Archaeologists have proof that Gavdos was already inhabited in 5000 BC.

The history of this island goes even further back to the Palaeolithic. Kopaka's work has shown that on this southernmost tip of the European continent, many generations and thousands of people must have once lived. Terrace walls between Kastri and Ambulous, overgrown and covered with lichen, suggest that there must have been an "intensive" agricultural culture here.

Shelter behind the steep south coast

On historical maps we come across Gavdos in various forms, under the name of Claudia. Gavdos is mentioned in the Bible (Acts 27). The apostle Paul anchored with his ship to escape the infamous winter storm Eurakylon, when, on his trip to Rome, he was unable to the old port of Phoenix on southwest Crete. Fik Meijer, emeritus professor of Ancient History at the University of Amsterdam, describes the journeys of Paul (Meijer, 2012): "Despite the storm, the skipper had managed to temporarily seek shelter from a high coast. In the manuscripts this islet is called C(l)auda or and K(l)auda. Its south coast rises more than 300 meters high and its slopes head northwards. A suitable place to find some shelter against the harsh north wind."

Horsts and graben

Both Crete and Gavdos consist of a collection of horsts and graben, which are geological structures which indicate tensional forces and crustal stretching. The seabed separating both islands, which has a depth of more than 1 km, also consists of such blocks. Strike-slip and reverse faults, a result of compression, have taken place here even during the Pleistocene. The area is still seismically active as a result of continued subduction.

The tilting of the "Gavdos block", which led to the characteristic shape of the island, must have taken place around 11 million years ago, according to Jan Willem Zachariasse, geologist at the Geoscience Department of Utrecht University in the Netherlands (see the box text 'Gavdos in geological perspective' for a detailed description of this process.). Through this tilt, the older Pindos rock, which form the base of Gavdos, is seen on the entire south side.


Copyright: Annemieke van Roekel
Last update: 4 November 2020