S. Gregou et al., THE CARBONATE FLYSCH TRANSITION (LATE MAASTRICHTIAN LATE PALEOCENE) IN THE ARACHOVA SEQUENCE OF THE PARNASSUS-GHIONA ZONE, CENTRAL GREECE, Geological Magazine, 131(6), 1994, pp. 819-836
The transition from the carbonate to the flysch facies in the Arachova
sequence of the Parnassus-Ghiona Zone is represented by argillaceous
limestone beds with flaser structures deposited during latest Maastric
htian-Palaeocene time in a pelagic carbonate environment with a period
ic elastic influx. Deposition was continuous except for a short interr
uption during the K/T boundary interval and the earliest Palaeocene wh
en the area was subaerially exposed. This interruption gave rise to th
e development of a brecciated carbonate horizon through soil-forming p
rocesses. The mineralogical composition of the elastic influx (i.e. qu
artz, feldspars, clay minerals, amorphous iron oxides, amorphous phosp
hatic compounds), in particular the clay mineral assemblages (i.e. ill
ite, chlorite, irregularly interstratified illite-vermiculite), shows
that the elastic supply represents erosional material that originated
from a tectonically active continental setting of both carbonate and e
lastic rocks, presumably the Pelagonian Zone, as for the flysch of the
Beotian and Sub-Pelagonian Zones. The arrival of the first elastic ma
terial in the Arachova area as early as latest Maastrichtian time, its
Pelagonian origin and the persistence of pelagic conditions of sedime
ntation throughout the Palaeocene, indicate that the Arachova area was
situated along the northeastern margin of the Parnassus platform and
that it subsided into the Beotian basin. While the central areas of th
e platform remained tectonically stable during middle Palaeocene times
and there was an extensive development of stromatolites, the northeas
tern marginal areas transitional to the Beotian basin continued to sub
side allowing pelagic carbonate sedimentation with periods of elastic
influx. The total collapse of the platform in the late Palaeocene gave
rise to the deposition of the flysch over the entire zone.