Event and sequence stratigraphy of the Maastrichtian and Danian in Bulgaria

Pages: 
pp. 55-61
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Sofia University "Sv. Kliment Ohridski", 1504 Sofia, Bulgaria
Abstract: 

The events (physical, geochemical, biological – in the modern sense of the event stratigraphy) in the Maastrichtian and Danian in Bulgaria recently have been a subject of several publications. The main part of them is concentrated on the impact event at the Cretaceous/Tertiary (K/T) boundary and its consequences.
   After the discovery of the K/T boundary clay bed near Bjala (Stoykova, Ivanov, 1992), many authors had explored this locality and represented new data about the iridium anomaly in Bjala sections (Preisinger et aI., 1993a, b; Rogl et aI., 1996). Biological events and biostratigraphy across the K/T boundary in these sections are studied and discussed by Ivanov, Stoykova (1994), Stoykova, Ivanov (1995), Cтoйкoвa, Иванов (1996). The K/T boundary is located in the flysh section near Emona as well (Sinnyovsky, Stoykova, 1995). Later on, Синьовски (1999) reported an iridium anomaly at the K/T boundary in a clay bed, situated in-between shallow-water carbonate sediments in Mezdra region (NW Bulgaria).
   Many articles (or parts of articles) have been devoted to the problem of mass extinction and biological changes among the different fossil groups: calcareous nannoplankton – Preisinger et aI. (1993a, b) Ivanov, Stoykova (1994,1995), Ragl et aI.(1996), Cтoйкoвa, Иванов (1996);  planktonic foraminifera – Ragl et aI. (1996), Adatte ,et aI. (2002); benthic foraminifera – Вълчев (2001); macroinvertebrates – Ivanov Stoykova (1994), Stoykova, Ivanov (1995), Cтoйкoвa, Иванов (1996); Mileva-Ilieva (1998, 2000). There are two comprehensive studies on the K/T boundary in Bulgaria recently published – Стойкова и др. (2000), Adatte et aI. (2002). These papers summarize all data, that had been obtained from the different studies (stratigraphical, sedimentological, paleontological, mineralogical, geochemical, isotope), as well as newly acquired data andinterpretations.
   The value of other types of event-markers in the Maastrichtian – Danian interval is still poorly examined. Until now, Синьовски (1999) documented slumps, tephra-markers (beds containing volcanic ash) and biological events (colonization and immigration of fauna) in Maastrichtian-Danian of Mezdra region. Unfortunately
these event-markers are discerned in a restricted area and it's difficult to estimate their reliability for correlation.
   The first attempts for sequence stratigraphy subdivision of the Maastrichtian-Danian interval are made in the last few years. Синьовски (1999) divided two sequence units in this interval in Mezdra region. Вангелов (2000) separated two units in the Maastrichtian and one in the Maastrichtian-Danian in the East Balkan, Central Balkan-Fore Balkan and East Moesian Platform.
   The formulation of the present study is based of the choice of maximum informative for our purpose objects (sections). Therefore we discarded several well known to the geological community sections. We used only sections, which meet the following requirements: a) to have relatively continuous sedimentation across the  Maastrichtian-Danian, including the K/T border; b) to display different facial and bathymetrical zones in the basin. Three types of sections/environments can be distinguished: shallow-water, hemipelagic and deep-water.
The main goals of the study are: 1) to summarize all available data on the K/T boundary studies in Bulgaria, as well as to reveal some newly obtained data for correlation of the event-markers in the  Maastrichtian-Danian interval; 2) to produce a sequence stratigraphy subdivision and correlation of the third-order units in the interval.

VOLUME 32 (2-4)/December 2002 110th Anniversary of Acad. Prof. Strashimir Dimitrov; XVII Congress of the Carpathian-Balkan Geological Association

Geologica Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 24

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences,Sofia 1113, Bulgaria, Acad. G. Bonchev str, bl. 24
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Geological Institute, Bulgarian Academy of Sciences,Sofia 1113, Bulgaria, Acad. G. Bonchev str, bl. 24
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Earth Science Section of the Uviversity of Geneva, 13, rue des Maraîchers, 1211 Geneva 4, Switzerland
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Earth Science Section of the Uviversity of Geneva, 13, rue des Maraîchers, 1211 Geneva 4, Switzerland

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute BAS, Acad. G. Bonchev Str., Bl. 24 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Sofia University "Sv. Kliment Ohridski", 1504 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Sofia University "Sv. Kliment Ohridski", Tsar Osvobodilel Blvd, 15, 1000 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
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Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
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Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
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University of Mining and Geology "Sv. Ivan Rilski", 1700, Sofia

Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Institute of Geochemistry, Siberian branch of the Russian Academy of Sciences, P.O.B. 4019, 664033 Irkutsk
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
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Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
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Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
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Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
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Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
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Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113

Geological Institute, Bulgarian Academy of Sciences

Geological Institute, BAS, Acad. G. Bonchev Street Bl. 24, 1113 Sofia, Bulgaria

Geological Institute of BAS, 24 Acad. G. Bonchev Sir., BG - 1113 Sofia
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Geological Institute of BAS, 24 Acad. G. Bonchev Sir., BG - 1113 Sofia
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Geological Institute of BAS, 24 Acad. G. Bonchev Sir., BG - 1113 Sofia

Geological Institute at the Bulgarian Academy of Sciences, Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
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Geological Institute at the Bulgarian Academy of Sciences, Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
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Geological Institute at the Bulgarian Academy of Sciences, Acad. G. Bonchev Str., 1113 Sofia, Bulgaria

University of Mining and Geology, Studentski grad, Sofia, 1100, Bulgaria
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Geological Institute of Romania, Caransebes Str. No 1, Bucharest, RO-78344, Romania
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University of Belgrade, Dusina 7, Belgrad, 11000, Yugoslavia
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Geological Institute of Romania, Caransebes Str. No 1, Bucharest, RO-78344, Romania

Geological Institute at Bulgarian Academy of Sciences, Sofia 1113

Sofia University "Sv. Kl. Ohridski", Department of Geology and Palaeontology, 1504 Sofia