the importance of calcareous nannoplankton in establishing

D.-T. JURAVLE, F. F. FLOREA & L. BOGATU
Fig. 1 – The position of the Suceava – Suceviţa region on the Romanian territory (Gigliuto et al., 2004)
For the present paper, the Tarcău Nappe is
representative. It belongs to the Moldavides
and its structogenesis occurred during the
Styrian tectogenesis (Miocene). From a
lithostratigraphic point of view, the Tarcău
Nappe is characterized by a column made up
of Cretaceous, Paleogene and Miocene
formations.
At the level of the Lower and Middle
Cretaceous, the sedimentation conditions
were uniform, in general, over the area of
Tarcău Domain, giving birth to the deposits of
Audia and Cîrnu-Şiclău formations. Starting
with the Upper Cretaceous, the morphology of
the sedimentation basin has changed
generating conditions for the differentiation of
the sedimentation and the accumulation of the
heteropic facies (sensu Ionesi, 1971, Gigliuto
et al., 2004). Under such conditions, in the
proximal areas as related to the central-
Carpathian source, deposits with a
predominance of arenitic formations are
accumulated, while in the distal areas, the
characteristic feature is given by the close
alternation of the arenitic and silto-lutitic
deposits, with a strong calcareous character.
In the scientific literature, three heteropic
facies have been described for the Eocene
(Tarcău Lithofacies in the west, Doamna
Lithofacies in the east, Tazlău Lithofacies in
the middle). They are partially preserved in
Oligocene-Lower Miocene level (Fusaru
Lithofacies in the west, Kliwa-Petricica
Lithofacies in the east, Moldoviţa Lithofacies in
the middle) (Atanasiu, 1943; Ionesi, 1968;
Mutihac and Ionesi, 1974; Gigliuto et al.,
2004).
When examining the characteristic column
for the three lithofacieses, lithostratigraphic
variations from west to east can be noticed, as
follows:
- in the Lower and Middle Eocene
(Ypresian – Lutetian - Bartonian): Tarcău
Lithofacies is characterized by the
predominance of a sandy flysch, with a
percentage of sandstones exceeding 80% in
the lithologic column. These are arranged
under the form of metric bars, 1-5 m thick
(sometimes even over 10m thick), with
intercalations of red and green clays in the
middle part (Mutihac and Ionesi, 1974; Grasu
et al., 1988); Doamna Lithofacies,
146