Supervisors info:
Καθηγητής κ. Παπανικολάου Δημήτριος (επιβλέπων), Επίκουρος Καθηγητής κ. Λόζιος Στυλιανός, Επίκουρος Καθηγητής κ. Κωστόπουλος Δημήτριος
Summary:
This postgraduate diploma thesis presents the structural analysis of the
metamorphic units in South Evia. Almyropotamos unit was recognized along with
the metamorphic carbonate platform which is below meta-flysch. Marble lenses
found within the flysch and schists found within the marbles suggest isoclinals
folds. Styra unit has been thrusted with movement top to the east. Styra is
composed of marbles, mica – chlorite schists, quartzites, orthogneisses. The
thrust is consisted of mylonites and cataclasites. Under the Styra unit there
are alkaline granites and phengitic-pyroxene schists found firstly there. Both
units, in the early stages of the greenschist metamorphism isoclinals folds
were formed with axial planar foliation, axe’s direction NE-SW, lineation NE-SW
and sheath folds (NE-SW). Then, the low pressure metamorphism has created
another foliation characterized by albite, chlorite, epidote, white mica and
lineation (ENE-WSW). Glaucophane relicts are observed in albite porphyroblasts,
which indicate that blueschist metamorphism had already been existed. The
transition from ductile to brittle deformation is showed firstly from the
existence of mylonitic rocks, secondly from the change of the direction of
lineation (NW – SE), thirdly from the crenulation cleavage and finally kink
folds having the same direction. Joints are the result caused by extensional
mechanism. The geochemical analysis on the alkaline meta-granites indicates
that the geotectonic environment is VAG and post-COLG. The use of geobarometers
was important because the results have showed 11.5-13.5 kbar and 8 kbar
respectively, based on temperature 370oC.
Keywords:
Cyclades, Isoclinals folds, Kink folds, Alkaline granite, Aegirine
