Geomorphological Structures


Lesvos Geopark enclose a large number of important geomorphological sites (geomorphosites). The island has not only several caves but also interesting erosional and coastal features.

Many of the caves were inhabited during Neolithic times and are used until now as worship spaces. Most of the caves are found in the eastern part of the island. One of the most important cave of Lesvos is Spilios, the cave of Antissa, the largest cave in western Lesvos.

Along the 382km long coastline of Lesvos, coastal landscapes are places with strong dynamics. They are unique areas, vulnerable and sensitive to the forces of nature.

Lesvos geological and tectonic structure, the variety of rocks, the climate conditions and changes of the sea level  contributed to the formation of various coastal landscapes and geosites, like tafoni, arches and impressive vertical cliffs, especially in the western coastline of Lesvos,  and in Nissiopi islet.

In the coastal area of Ag. Isidoros – Plomari appear important coastal formations called beach rocks, which show great exposure and create continuous zones several hundreds of meters long. They are considered to be significant traces of past shorelines and are a valuable element for the study of the evolution of the coasts and changes of the sea level.

Antissa Cave (Spilios)

The Spilios Cave is carved out of the limestone of the Grigoreli massif which lies amidst thevolcanic rocks of Antissa.

Called “Chaos” by the locals, the entrance to the cave (10m wide and 12m high) is found in the steep face of the southern slope, near the peak of the limestone formation. Its creation is connected to tectonic and karstic factors.

The interior of the cave consists of a large oval chamber divided in two by a wall of boulders. In the first chamber there are traces of the presence of prehistoric humans, while in the second chamber there are two rough rock structures, partly covered by stalagmite material.

In Spilios operated the famous oracle of Orpheus. According to the legend, in the area of Antissa that is now called Orphikia, Orpheus’ head and lyre where washed out, after he was killed and dismembered by the Maenads, who threw his body in the Thracian Sea. Orpheus’ head was placed in the oracle, where it could tell the future, making the oracle famous throughout the ancient world. According to oral tradition associated with the sweet song of Orpheus, the nightingales in this area are chirping much more melodically and sweet than in other areas of the island.


Sea Caves of Kavalouros islet

There are many sea caves half below or completely below sea level on the islet. They serve as refuges for the significant population of the protected species of Mediterranean seals Monachus monachus.


The coastline of Nissiopi island

Impressive arches, small caves, columnar landforms, abrasion platforms and canyons can be observed around the island of Nissiopi. The weathering creates caves on the steep coastline. When weathering continues for long time, stone is eroded and cave openings turn into open arches. Α beautiful big arch called “Colossae” appears on the western coast although on the  eastern coast a characteristic hole is the first stage of the creation of an arch. The southern-western coast characterized by an abrasion platform just above sea level, which is the result of the erosive action of the waves undermining the volcanic material and shaping the resulting platform.



Honeycomb weathering formations also known as “tafoni” are impressive sculptures of nature that appear extensively all along the coastline of Nissiopi and Plaka peninsular. This type of geomorphosites is characterized by spherical cavities of many dimensions, from 50cm to some meters, with smooth concave walls and created by intense wind on the volcanic rocks.


Plomari Beach - Rock Formations

Coastal sediment formations (beach rocks) have developed along the Agios Isidoros – Plomari coastline. These formations are slabs of rock which lie parallel to the shoreline, slightly sloping towards the sea. These beach rocks develop in the inter-tidal zone, when the sea level enters a phase of stabilization.

In the coastal region of Agios Isidoros – Plomari, there are many zones of these beach rocks and they show very strong growth as more zones several hundred meters in length and great width are continuously being created. In the first zone (towards the beach) the upper surface of the beach rock formations are 40m above sea level while the base is 80cm below the present sea level. In the second zone, the upper surface is at 1 m to 1.8m below sea level, while the third zone sits at 2m (continuous slab) and the fourth zone is 3m below sea level.

These beach rock formations consist of sand and coarse materials which are welded together by adhesive calcite material (fragments of gastropods, lamellibranch and ostracods, echinoderm spines and foraminifera shells). The size of rock fragments varies in the different rock slabs from medium grained sandstone to pebbles. The horizons found at lower depths are well compacted while those found at sea level landwards are much less compacted.

The difference in the geometry of the beach rock formation zones reflects the conditions and location of the shoreline at the time of their formation. They are considered important traces of past shorelines and are a valuable asset for the study of the evolution of coastlines and changes in sea levels.


Coastal dunes

Where favorable conditions permit, the formation of coastal dunes is also observed.

Along the coast of Lesbos, dunes are observed on a limited scale but form areas of aesthetic and great environmental value as they host rare and protected species of flora and fauna. The main dune growth occurs in the beaches of the northern part of the island as well as the west and southwest, which lie within the protected area of the Lesvos Petrified Forest.

In the northeastern coast, dunes can be observed in the areas of Lagada (Mandamados area), in the northwest coast can be observed in the beaches of Kampos and Gavathas. In the western coast, in Faneromeni beach, North of Sigri and in the southwest coast along the beaches of Eresos, Podaras and Chrousos. The dunes occur in the form of coastal piles of sand with different characteristics and development and occupy a zone of different width on each coast. Larger dune growth is observed throughout the expanse of Kambos Bay. The dunes reach 5m height and grow in a 500-1000m zone off the coast. In the other places we mentioned, the dunes are smaller in height, 1.5-2m and extend to a width of about 500m from the coast.