Lithological and biostratigraphical characteristics of the Ruzhintsi, Mirkovo and Zavala Formations in Kula Zone at Ruzhintsi village, Vidin District.

The present study is a contribution to the stratigraphy of the Carpathian type Upper Cretaceous and Paleocene deposits in Kula Zone, NW Bulgaria. It is the result of the development of geosites of scientific value for the purpose of Geopark "Belogradchik rocks". A new formal lithostratigraphic unit Ruzhintsi Formation is characterized to designate a unique facies of the Carpathian type Upper Cretaceous and Paleogene near Beloptichene village, previously related to Kula, Kladorub and Staropatitsa Formations. The new formation is composed of uninterrupted coarse-grained terrigenous sequence of intraclastic marl breccia, conglomerates, gravelites, sandstones, marls and siltstones within the stratigraphic range Upper Campanian--Middle Paleocene. This unit does not meet the definitive features of Kula or Kladorub Formations, and significantly differs from the stratigraphic position of the Staropatitsa Formation. The only surface outcrop near Beloptichene village is pointed as a lectostratotype. In the Upper Cretaceous portion of the section 2 nannofossil zones and 5 subzones are recognized, whereas the Paleocene part belongs to NP 2-NP 5 nannofossil zones (Lower--Middle Paleocene). Besides, exotic outcrops of the Mirkovo Formation and the Krasava Member of Zavala Formation are described in Kurkov Dol, south of Ruzhintsi village, known in the Central and West Srednogorie respectively as "couch-rouge" and "bituminous shale". On the basis of 3 nannofossil zones and 2 subzones recognized in the motley limestone-marl alternation of the Mirkovo Formation, its age is determined as Coniacian--Santonian, while the overlying barren bituminous shale of the Krasava Member of Zavala Formation are related to the Lower Campanian after their stratigraphic position. [ABSTRACT FROM AUTHOR]