The mountains of Greece and the
Balkans are part of a mountain chain that runs across Europe
and Asia, as far as south China and is of relative young age.
Some 250 million years ago, when Europe and Asia were separated from
Africa by the shallow
Tethys ocean, thick layers of limestone were formed. Around 60 million
years ago, Africa and
Europe began to move towards each other. Through these movements, mostly
limestone,
mountain chains were formed. Limestone mountains stretch from north
Dalmatia to the
Peloponnese and Crete. They are hard and slow to erode, and often exist
as steep jagged
escarpments through which steep sided gorges and canyons are cut by
rivers.
The absence of permanent ice during the ice ages has helped in the
survival of many tertiary
species of plants, like Ramondas, Haberleas and Jankaea heldreichii.
Contact with the flora of the east was greatly reduced and isolation
resulted in the
disappearance of many species, while at the same time the evolution of
new species began with
the colonisation of new environments. Also the contact with the west
increased through
similarities of climate and terrain.
Not all the new formed mountains are jagged. Like the Pindos high land
areas, where slopes are
moderate and summits rounded. This region also has isolated serpentinite
mountains like
Mt Smolikas, or metamorphic rocks like on Mt Kajmaktcalan.
In Greece winter temperatures in the interior are low. Frost and snow
occur frequently in
Northern Greece. By contrast the coasts are mostly frost free.
The western coast of Greece has a warmer winter climate, rainfall is
between 500 and 900mm
which is more evenly spread throughout the year. The eastern coast and
the Aegean islands have
a more drier climate, there is little or no summer rainfall. Winters are
correspondingly cooler.
Enclosed basins inland may become much colder in winter, and built up
heat in summer.
The Aegean islands and Crete have the same kind of climate but are more
equable, being
tempered by the surrounding seas.