Summary:
Crete has an area of 8,303 square kilometers, its length reaches 260 km while its width ranges from 60 to 12 km, its coasts are diverse and their total length is more than 1,000 km.
Crete is located in the outer part of the Greek arc, in the subduction zone of the Eurasian-African plate. The topography of Crete, due to its position in the geotectonic regime of the Aegean, is characterized mainly by a mountainous relief, which indicates recent and rapid elevation The mountainous terrain includes high mountains such as the White Mountains in the western part, in the central part of Psiloritis and Dikti, while in the east extend the Mountains of Sitia. High mountains frame lower mountain ranges.
In the context of the present study, the caves of the island of Crete were collected. The collection of these caves was made from records of speleological companies, from travel sites and from speleological works.
A database was created which incorporated information regarding the geographical location of each cave, its peripheral unit, its accessibility, its altitude, its length and its depth. The database was imported into a Geographic Information System and the software used is Arc GIS 10.3.
In the context of the present work, the spatial distribution of the caves in Crete was analyzed per regional unit and their density was studied per 100 sq.m. km. The distribution of the caves in relation to their altitude was also investigated. The choice of the study of the specific speleological elements was based on the fact that they contain complete information.
The conclusions of the present study are:
• The total number of caves recorded in the database is 170. The spatial distribution of the caves studied in Crete are 32% of Chania, 30% of Heraklion, 20% Of Lassithi and 18% of the regional unit of Rethymno.
• Statistical analysis of altitudes showed that most caves appear at an altitude of less than 100 meters. The number of caves decreases as the altitude increases. In general, the majority of caves develop at an altitude of less than 700 meters. The smallest number of caves is observed at altitudes greater than 900 meters.
• The density of caves in Chania is equal to 2.3 caves per 100 square meters. km, in Heraklion and Lassithi there are 1.9 caves per 100 sq.m. and in Rethymno 2 caves per 100 sq.m.
• Most caves are located in Jurassic limestones with 51%, in limestones and dolomites with 15%, in phyllites with 4% and marls, sandstones, clays in 13%.
• From the total of the caves it appears that 11 caves are close to faults, in particular one cave near thrust, 8 caves in normal fault and 2 in possible.
• The plan views of the caves of eastern Crete have the same direction as the eastern faults and those of the west the same as the western ones. The conclusion of the above data is that the respective faults have affected the caves and their morphology. This shows us that when the faults were activated then the beginning of the creation of the caves took place. The age of the western caves from which we analyzed the floor plans is Upper Miocene-Lower Pleiocene while respectively of the eastern is Pleiocene.
Keywords:
Spatial distribution of the caves of Crete, G.I.S., faults, floor plans, conclusions
