VOLUME 19 (6)/December 1989

I. Zagorchev, N. Popov, M. Ruseva. Paleogene stratigraphy in a part of SW Bulgaria. Paleogene sedimentary rocks in the Pijanec graben complex and Padeš Graben (Upper Eocene- Lower Oligocene) have been subdivided into four formations. Suhostrel Formation covers rocks with different composition and age. It begins with the sandstone-conglomeratic Elski Member followed by: coal-bearing Piljovo Member; the flyschoid, shaly-sandstone-conglomeratic alternation of Solaški Member, and the white sandstones of Debočina Member. This formation crops out only in the southernmost part of Padeš Graben, in a part of Vlahina Horst, and in Vetren Graben. The following Komatinica Formation is built up of polymictic variegated conglomerates and breccia-conglomerates. It occurs on a larger territory, and covers Suhoslrel Formation, or rocks of the basement. Logodaš Formation is built up of sandstones interbedded by shales, conglomerates and siltstones, with wedging out bodies of oligomictic breccias. These three formations were formed in mire-lake and river systems during the Late Eocene. At the end of the Late Eocene and during the Early Oligocene, the volcano-sedimentary Padeš Formation was formed in conditions of marine transgression. It was replaced laterally to NE and NW by a transgressive flyschoid alternation (siltstone-sandstone formation). The latter is covered unconformably to the east of Varbovnik Fault by the basal formation of the coal-bearing Bobovdol Basin. The sequence of the latter is of Middle and Upper Oligocene to Lower Miocene age.