Joint biostratigraphy and lithofacies of Berriasian and Valanginian limestones from subsurface sections in NE Bulgaria

The purposes of this study are as follows: 1. To obtain new micropaleontological, palynological, biostratigraphical and lithofacial data from the existing collections of thin-sections in the Geological Institute prepared in the the 80s of 20^th century when Jurassic – Cretaceous well sections in NE Bulgaria were first studied by Сапунов et al. (1986), Рускова, Николов (1984). 2. In addition to the joint calpionellid and calcareous dinocyst successions and zones, to correlate directly dinoflagellate cysts associations and zones. 3. This study is an opportunity to test the bathymetrical range of application of the joint Tithonian to Valangian calpionellid and calcareous dinocyst zonation (Lakova et al., 1999) elaborated for pelagicallimestones, in this case - in a more distal depositional environment where sub-flysch succession was accumulated.