A. Talea Ori section: a 250 million years journey in the past
The mountain Kouloukonas (or Talea Ori) is located at the northern part of the Psiloritis Natural Park. It is the only place in Crete where the oldest rocks of the “Plattenkalk” group are exposed, in inverted structures, i.e. the oldest rocks cover the younger ones. It is the result of the intense forces that these rocks suffered several million years ago, which are today presented as innumerable folds and rock fractures.
Following the road which goes from the northern coast inland to the Mylopotamos valley, the visitor makes a virtual trip of approximately 250 million years into the geological past of Crete. On the road cuts, the slopes of the valleys and the narrow ravines, all the rock types of the “Plattenkalk” group are presented together with their faults, impressive folds, fossils and other features of the cultural and natural heritage of the mountains.
Some of the oldest fossils of Crete are located, in a perfect condition, within the metamorphosed dolomites at the road-cuts of the Northern high way of Crete from Heraklion to Hania, near the village of Fodele. These are mainly corals, bryozoans and brachiopods which are approximately 300 million years old. The hosting rock, which was buried more than 30 kms deep inside the earth’s crust some 23 million years ago, suffered high pressure and temperature conditions, which metamorphosed them into marbles. The “Fodele” fossils have retained their features in excellent shape and detail although they have suffered these extreme metamorphic conditions.
The oldest rocks of the “Plattenkalk” group occur around the coastal village of Bali. In several places, within dark schist and dolomite, relicts of Permian fossils (approximately 300 million years old), like trilobites, corals, crinoids and gastropods have been found.
Kouloukonas mountain (Talaia Ori) is built mainly from rocks of the “Plattenkalk” group. It is the only place in Crete where the complete succession of this group, as well as its oldest rocks (Fodele beds), can be seen. The snaking road which leaves from the village of Sisses, passes through the northern slopes of the mountain, and ends up in the Mylopotamos valley, thus offering a virtual trip of 250 million years back into the geological past.
The first outcrops at the road cuts of the Northern Highway of Crete present the dark dolomitic marbles of the “Fodele beds”, which date from approximately 300 million years ago. A few meters away the road crosses the white marbles of the “Sisses beds” with an age of approximately 280 million years, then the stripy and unique stromatolitic dolomite of approximately 200 million years in age, then the white marbles and dark dolomite of approxim
ately 180 million years and finally the typical platy marble of the group (Plattenkalk) in the Mylopotamos valley, with ages ranging between 150 – 50 million years ago.
The peculiarities of this section are based on the fact that these rocks now appear in an upside down position, with the younger rocks being covered by the older ones, due to their intense folding as a result of the strong forces that these rocks suffered some 23 million years ago. Additionally, the stromatolitic dolomite is a very rare and peculiar rock type which has been created by cyanobacteria in environments where oxygen might well be absent. From approximately two billion years ago, and still today on the coasts of Australia, these species have been removing the iron oxides from sea water depositing
them in layers and thus releasing oxygen in the atmosphere in the same way as photosynthesis. In this way a special rock type with reddish curvy beds and gray dolomite has been formed.
Along the road cuts leading from the settlement of Kato Doxaro to the Vossakos Monastery several rocks of the “Plattenkalk” group, such as the platy marble, the yellowish “Gigilos” schist and white marbles occur. It is however within the platy marble where some of the superb folds of the Cretan rocks appear.
The enormous forces that affected these rocks 23 million years ago resulted in a great variety in style and scale, of folds which crop out along a kilometer of road cuts. On a scale in size, in both centimeters and meters, and from a mild distortion to complete duplication, the “Vossakos folds” affect both rocks and landscape. These folds appear even more intense because of the existence of the white silica layers in contrast to the gray marble and they are also often accompanied by impressive faults.
The visitor can look in wonder at the beautiful landscape of the Geropotamos river, with the picturesque old settlement of Doxaro, the mitata with the threshing-floors and the impressive folds, while following the road which heads up the slopes of Kouloukonas ultimately leading to the Vossakos monastery. (see the hiking trail)
The carbonate rocks that dominate in the Psiloritis Mountain can transport water through caves over long distances, sometimes leading directly to the sea.
In such a case, small submarine springs occur in several places in the small bays of the village of Bali, where the water comes out of caves. These springs do however have the special characteristic that they work both ways. During the winter and spring seasons they discharge fresh water and during the rest of the time they suck in seawater. Indeed studies have shown that some of the fresh water comes form the plateaus of the Psiloritis Mountains.