Abstract
The onset of the Jurassic sedimentation in the region of Pernik (southwestern Bulgaria) is at the end of Bajocian with deposition of sandstones (Lyalintsi Member of Gradets Fm.) and continuing during the Bathonian with bioclastic limestones (Polaten Fm.). The section Staro selo is one of the most complete Jurassic sections in Southwest Bulgaria. It is studied from several points of view: lithofacial, depositional processes, biostratigraphic and sequence stratigraphic. In Bajocian-Bathonian interval four 3rd order depositional sequences are individualized: Bj 5, Bat 0, Bat 1 and Bat 2. After a break of sedimentation (Callovian-Oxfordian), the limestones of Gintsi (Lower Kimmeridgian) and Drugan (Middle Kimmeridgian) Formation were deposited in which 3 depositional sequences were recognized (Kim 2-Kim 4). Nineteen depositional sequences of 3rd order are individualized (Kim 5-Ti 1.1-Ti 1.13, Ti 2, Ti 3.1-Ti3.2, Ti 4, Ti 5) in the sediments of Neshkovtsi Formation (Upper Kimmeridgian) and in the Bobovo Member of Kostel Formation (Uppermost Kimmeridgian – Upper Tithonian in the studied area). The recognition of the depositional sequences is based chiefly on the geometry and the superposition of the calcareous and siliciclastic sediments. The divided depositional sequences are compared to those of Western European scheme of Hardenbol et al. (1998). Within the carbonate part of the succession they are of the same number and in the siliciclastic part they are more numerous.
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