The Silurian in the West Balkan Mts. (Svoge Unit, Srednogorie Zone) – 110 years later

Pages: 
pp. 3-15
University of Mining and Geology, Department of Geology and Geo-Information, Studentski Grad,“Prof. Boyan Kamenov” St., Sofia 1700; Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 24, 1113 Sofia, Bulgaria
Abstract: 

Earliest studies on the Silurian System in Bulgaria are associated with the names of Dimitar Allahverdzhiev and Stefan Bonchev. Allahverdzhiev was the first to find Silurian graptolites in this country; his specimens are housed in the Laboratory of Geocollections of the Geological Institute (Bulgarian Academy of Sciences). Bonchev laid the foundations of the lithostratigraphic subdivision of Palaeozoic sediments in the West Balkan Mts. by distinguishing all their lithologic variations. In terms of regional tectonic zonation, the study area is a part of a first-rank Late Alpine unit, the Srednogorie Zone, represented by the Svoge Unit. The lithostratigraphy of the Palaeozoic marine successions in the Svoge Unit consists of nine formal units (Grohoten, Tseretsel, Sirman, Saltar, Mala Reka, Yabukov Dol, Ogradishte, Romcha and Katina formations) and one informal unit (silty-clayey metaformation). Their distribution is illustrated in a geologic map. The biostratigraphic subdivision of the Silurian System in Bulgaria is based on graptolites. Herein, the latest two “standard” zonal schemes are shown: the Generalized graptolite zonation and the Graptolite zonation for the peri-Gondwana (Europe). About 25% of these graptolite zones have not yet been recognized in Bulgaria; the extent of the others is plotted against a generalized section of the Silurian System for the region.

Keywords: 

Silurian, Balkan, Svoge Unit, lithostratigraphy, graptolite biostratigraphy, Bulgaria

VOLUME 44 (1-3)/December 2015

University of Mining and Geology, Department of Geology and Geo-Information, Studentski Grad,“Prof. Boyan Kamenov” St., Sofia 1700; Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 24, 1113 Sofia, Bulgaria
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University of Mining and Geology, Department of Geology and Geo-Information, Sofia; Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 24, 1113 Sofia, Bulgaria
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Westphälische Wilhelms-Universität, Institut für Geologie und Paläontologie, Corrensstr. 24, D-48149 Münster, Germany

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Hungarian Natural History Museum, Department of Botany, 1476 Budapest, P.O. Box 222, Hungary

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl.24, 1113 Sofia; Institute of Geochemistry and Petrology, ETH-Zurich
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Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl.7, 1113 Sofia
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Institute of Geochemistry and Petrology, ETH-Zurich
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Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl.7, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl.24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl.24, 1113 Sofia, Bulgaria