Located in the northern region of the Aegean is the Greek island of Lesvos. Since 1985, an area of 150 Km2 around the small fishing village of Sigri (meaning “safe”) on the western side of Lesvos is the site of the state protected Lesvos Island UNESCO Global Geopark and Petrified Forest.
Lesvos is the third largest Greek island, the seventh largest island in the Mediterranean and a popular holiday destination with picturesque villages, Roman aqueducts, Byzantine monasteries and medieval castles.
In 2022 the petrified forest on the Greek Island of Lesvos (39° 12' 32'' N025° 53' 50'' E) was named among the “First 100 Geological Heritage Sites” designated by the International Union of Geological Sciences (IUGS).
The petrified forest of Lesvos is different to the Lake Turkana Petrified Forest in Kenya or the Petrified Forest in Arizona USA because it was covered by volcanic pyroclastic material and the fossilised root systems of the trees indicate that the forest was petrified where it grew. Plus it had some interesting mammals (more later).
The best places to see the petrified forest are at the Natural History Museum of the Lesvos Petrified Forest and the four Petrified Forest Parks of Sigri Park, Plaka Park, Bali-Alonia and Nissiopi Marine Petrified Forest Park.
The first reference to the fossils of Lesvos was recorded by Theophrastus born in Eresos on Lesvos (circa 371 BC). He was a Greek philosopher and the successor to Aristotle in the Peripatetic school who was among the first scientists to consider importance of fossils.
It would not be until the 19th century and the publication of the book Past World (1841-1847) by the Austrian botanist, palaeontologist, and plant physiologist Franz Unger when the Petrified Forest was first mentioned in the scientific journals.
The Miocene Epoch was dated between 23.03 - 5.3 million years ago and forms part of the current Cenozoic Era. The Miocene was the first of the two epochs of the Neogene Period preceded by the Oligocene Epoch and succeeded by the Pliocene Epoch.
The terms Miocene, Palaeozoic and Cenozoic, were first mentioned by Sir Charles Lyell 1st Baronet FRS (1797 –1875) a British lawyer and the foremost geologist when he was examining rocks of the Paris Basin.
The Petrified Forest of Lesvos is a fossilised sub-tropical forest ecosystem of coniferous and fruit-bearing trees dating back to the Lower Miocene Epoch 18.5 million years during the Burdigalian stage (20.44 - 15.97 million years).
The Burdigalian stage was named after the ancient Latin name for the city of Bordeaux and was proposed as a stage name in 1892 by Charles Jean Julien Depéret (1854 – 1929) a French geologist and palaeontologist.
During the Miocene the Aegean was continental rather than marine and was influenced by the subduction of the African tectonic plate under the Eurasian tectonic plate. This created zones of volcanic activity and a series of volcanoes across the region.
Volcanic activity around Lesvos centred on Lepetymnos, Agra, Vatoussa where volcanic ash fell and mudflows allowed for the perfect petrifaction of the forest.
Over the years subsequent volcanic eruptions would cover the forests and their trunks, branches and twigs, fruits and root systems would become fossilised over time.
In addition, to the petrified forest the island of Lesvos has many other volcanic structures such as laccoliths, veins, necks, domes, cones, calderas, lava and pyroclastic flows.
The Petrified Forest has over 46 genera and species of preserved plants including Taxodiaceae (Yews), Protopinaceae, Pinaceae (Pines), Cupressacea (Cypress) and several fossil species are angiosperms such as cinnamon trees, Lauraceae (laurel), poplar , walnut , Fagaceae (beech) , alder, platanus, maple and several kinds of kinds of oak. The fossilised palms are the first recorded of standing petrified palms.
Also found within the Petrified Forest of Lesvos was the oldest known land mammal fossil in Europe. The remains of a lower jawbone and teeth of a Prodeinotherium bavaricum dated at 19 million years old.