Summary:
This PhD thesis,is focusing on the tectonic structure of Mt. Ghiona. Detailed
temporal analysis of the deformation led to the distinction of fourteen (14)
periods / episodes,as evidenced by the successive and progressive
unconformities and the geomorphological, stratigraphic and structural data.
Accordingly, Mt. Ghiona experienced a complex tectonic evolution, first as a
part of a subducting plate (pre-orogenic stage – 9 periods / episodes) and
later as a nappe of the overriding plate (orogenic stage – 5 periods / events).
Calcareous nannofossils were used to identify and date an unconformable
Oligocene to mid-Miocene molassic sequence,which was previously considered part
of the Eocene flysch as well as the younger breccia-conglomerates of Eastern
Ghiona Mt. The distinction of those clastic formations contributed to the
further understanding of the Cenozoic tectonic evolution of Ghiona Mt.
(orogenic stage), which is characterized by five (5) successive episodes of
deformation.The first episode, of Late Eocene (-?Early Oligocene) age, is
associated with thrust faulting; it was followed by Oligocene (-?Early
Miocene)NNW-SSE high angle ?strike-slip fault zones; the third Early Miocene
(-?Middle Miocene) episode, includes large scale E-W open folds
(?extension-parallel-folds) associated with E-W moderate angle thrusts; the
fourth episode, of Middle – Late Miocene age, was related to normal faulting
that to the NNW-SSE Stromi-Galaxidi extensional system. Finally, the fifth
episode of (?Late Miocene) - Plio-Quaternary age was associated with E-W normal
faults that crosscut all the previous structures. Today,Mt. Ghiona is a 1st
order horst in the extensional province of Central Greece bounded by the
Corinth Rift to the south and the North Evia - Sperchios Rift to the north.
The combined study of the age and geometry of the major fault zones and the
Mesozoic and Cenozoic karst features of the carbonate rocks of the mountain,
made possible to understand how the meteoric water circulates through the
Quaternary karst systems and consequently to determine the extent of the
hydrogeological basin of the Itea-Galaxidi brackish coastal and submarine
springs. This multi-approach of karst also elucidates the operational
mechanisms of some “puzzling” karst springs in Northern Ghiona.
Keywords:
Parnassos - Ghiona, Corinth Rift, Molasse, Flysch, Karst forms - karst systems
