THE MEDITERRANEAN LOWER CRETACEOUS

In the Oniurtag and Preslav anticlines the Valanginian is represented by clayey
limestones with intercalations of marls and sandstones (Tica Formation) and of marls
(Kamcija Formation).
In the gorge of Vrana river, to the south of Tàrgoviste, it is difficult to differentiate
the Valanginian from the upper part of the Berriasian. It is represented mainly
by clayey limestones among which there occur intercalations of micrograined
limestones, irregularly distributed, but on the whole rare.
Valanginian sediments in the gorge of Tica river, south of Preslav, are of the
same character, the only difference being the more abundant presence of sandstone
beds in the upper part of the Tica Formation.
To the east of the Preslavska Planina mountain, Valanginian sediments arc
transversed by the boreholes near the villages Zlatar and Veselinovo, and in the Asparuhovo
region.
The following association characteristic of the Valanginian was found at borehole
R-9 Veselinivo at 1502 m: Neocomites sp. indet. and Neocomites platycoslatus
Say n.
The easternmost outcrops of Valanginian sediments are in the core of the Asparuhovo
anticline, to the south and southeast of Asparuhovo village, where they
are represented by alternation of marls and clayey limestones (Tica Formation).
Intercalations of fine-grained sandstones are found in some places.
A definite regularity is observed in the Valanginian section in the Asparuhovo
anticline, expressed as predominance of the clayey limestones in the lower part,
which decrease upwards at the expense of the marls.
The characteristic Valanginian ammonite Kilianella roubaudiana (d'O r b.)
was found in borehole S-l Asparuhovo at 192 m.
Characteristic Valanginian ammonites were also found in the valley of Razkracenica
river, south of Asparuhovo village: Sarasinella walker i (U hi.), S. trezanensis
(Lory) and Neocomites (N.) neocomiensis (d'O г b.).
The characteristic Upper Valanginian ammonite species Neocomites (T.) tesclicnensis
(U h 1.) was found at borehole R-54 Samotino at 3498.50 m.
In borehole R-l Junak (Fig. 12) the Valanginian is well marked by the presence
of Calpionellites darderi (С о 1 о m) at 641.50 m and Lorenziella Imngarica
К nauer, Nagy at 904.50 m.
The thickness of the Valanginian sediments in the Eastern Fore-Balkan is
306-840 m.
The Hauterivian in the Eastern Fore-Balkan is represented by marly sandstone
sediments of the Kamcija Formation, by the mixed rocks of the Hanevci Formation
and by the marls with intercalations of sandstones and siltstones of the Gorna
Orjahovica Formation in the transition to the platform.
The area of Veliko Tàrnovo, Zlatarica, Ljubenci, Omurtag, Preslav, Veselinovo,
Komunari, Asparuhovo, Rudnik, Samotino and Kamcija (R-9) is characterized
by the general development of the Kamcija Formation, which is represented
mainly by thick packets of marls and sandstones. The Formation is characterized
by the lense-like shape of the sandstone packets and beds.
In the southwestern outcrops of the region (Veliko Tarnovo and Elena areas)
the Hauterivian is represented by aleuritic marls, mixed rocks, gritstones and conglomerates,
the latter being known from the areas along the rivers Belica and Veselina.
In the more northern outcrops of Hauterivian sediments around the villages
Kàpinovo, Zlatarica, Dedinci, Rosno and Dlâzka Poljana, the quantity of the sandstones
and siltstones is relatively smaller compared with the southern outcrops.
Psephites do not occur here, and the marls are less aleuritic. This is particularly characteristic
of the more northeastern outcrops from the northern limb of the Bukak
anticline. The thickness of the Hauterivian in these places is around 1200 m.
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