Microfacies, sea-level fluctuations and conodont biostratigraphy of Frasnian–Famennian carbonate sequences from the Preslavtsi-2 well (the Moesian Platform, NE Bulgaria)

Pages: 
pp. 39-54
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
University of Mining and Geology, Studentski Grad, Prof. Boyan Kamenov Str., 1700 Sofia; Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
Abstract: 

The falsiovalis, rhenana, triangularis, marginifera and praesulcata conodont zones have been recognized within the Upper Devonian (Frasnian–Famennian) carbonate succession in the Preslavtsi-2 well from the Moesian Terrane in NE Bulgaria. Five microfacies types (MFT 1–5) are also distinguished and described within the Frasnian carbonate deposits: fenestral peloidal microbial bindstone (MFT 1a); fenestral microbial bindstone with porostromate microstructures (MFT 1b); paleosiphonoclad wackestone and packstone (MFT 2); bioclastic-peloidal packstone and grainstone (MFT 3); bioturbated wackestone to grainstone (MFT 4); and lithoclastic rudstone (MFT 5). They are interpreted as formed in arid peritidal and lagoon environments or deposited in deep-water setting, located below the storm wave base. A sea-level transgression is documented during the late Frasnian (Late rhenana Zone) corresponding to the Lower Kellwasser Event, which was followed by rapid regression. At the beginning of the Famennian, a climate change occurred when the Moesian Terrane was removed from the Subtropical Arid to the Warm Temperate Climatic Zone, when various shallow- and open-marine carbonates were formed under warm temperate climate conditions.

Keywords: 

conodonts, microfacies, sea-level fluctuations, climate changes, Frasnian, Famennian

DOI: 
10.52321/GeolBalc.53.2.39

VOLUME 53 (2)/August 2024

Faculty of Geology and Geography, Department of Geology, Paleontology and Fossil Fuels, Sofia University “St. Kliment Ohridski”, 15 Tsar Osvoboditel Blvd., 1504 Sofia, Bulgaria

Institute of Oceanology, Bulgarian Academy of Sciences, Marine P.O. box 152, 9000 Varna, Bulgaria
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Institute of Oceanology, Bulgarian Academy of Sciences, Marine P.O. box 152, 9000 Varna, Bulgaria
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Geological Institute “Strashimir Dimitrov”, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bl. 24, 1113 Sofia, Bulgaria
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Marmara Research Center, TUBITAK Gebze Campus, Baris Mah. Dr. Zeki Acar Cad. No: 1 P.K. 21, 41470 Gebze Kocaeli, Turkey

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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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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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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University of Mining and Geology, Studentski Grad, Prof. Boyan Kamenov Str., 1700 Sofia; 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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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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National Archaeological Institute with Museum, Bulgarian Academy of Sciences, 2 Saborna Str., 1000 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Faculty of Geology and Geography, Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
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National Archaeological Institute with Museum, Bulgarian Academy of Sciences, 2 Saborna Str., 1000 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 107, 1113 Sofia, Bulgaria
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Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 107, 1113 Sofia, Bulgaria
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Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 107, 1113 Sofia, Bulgaria
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Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 107, 1113 Sofia, Bulgaria
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Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 107, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

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