Supervisors info:
Λόζιος Στυλιανός Επικ. Καθηγητής (επιβλέπων), Μαγκανάς Ανδρέας Καθηγητής, Παπανικολάου Δημήτριος Καθηγητής
Summary:
The study area is situated at the NW part of the Attico-Cycladic Massif and
includes the south part of the island of Evia and more specific, the mountain
of Ochi.
Three tectonic units can be distinguished in the area. Styra Unit is composed
of marbles and schists, while Ochi Unit displays a variety in lithologies, with
marbles, schists and metabasic bodies. The area surrounding the peak of Mt Ochi
is dominated by lithologies of the third tectonic unit, which is a
metamorphosed ophiolitic melange with metabasic, meta-ultrabasic rocks and
metasediments.
The aim of this study is to unravel the tectonic history of these units. To
accomplish this, the following tasks had to be achieved: petrological study of
the lithologies, geochemical analysis of the minerals, microstructural
analysis, geological mapping in 1:5000 scale and geological and structural
mapping in 1:2000 scale.
Five deformation events have been distinguished in the study area. The first
one (Dn) developed under blueschist-facies conditions, the second one (Dn+1)
under MP/LT metamorphism, which represents the transitional face from
blueschist- to greenschist-facies overprint and the third one (Dn+2) under
greenschist-facies metamorphism (LT/LP). Dn+3 deformation event took place
under the brittle-ductile transition regime, with very low-grade metamorphism.
The last Dn+4 phase includes structures of brittle deformation.
Apparently, it appears that Styra Unit, Ochi Unit and the meta-ophiolitic
melange have shared the same deformation and metamorphic path since at least Dn
deformation event. In other words, similar mineral assemblages and common
sequence of tectonic structures suggest a common evolution of the region, from
the depths of blueschist conditions to the greenschist facies retrogression,
until their exhumation.
Keywords:
South Evia, Blueschists, Metaophiolites, Deformation events, Petrology
