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Department of Palaeontology and Stratigraphy, Geological Institute, Bulgarian Academy of Sciences,

Acad. G. Bonchev Bl. 24, 1113 Sofia,  Bulgaria;

(Manuscript received January 9, 1998; accepted in revised form September 1, 1998)

Abstract: Santonian and Campanian dinocyst and Normapolles assemblages are documented from three sections in

Northern Bulgaria. Their successions are considered separately. Two distinct successive dinocyst zones are recognized

within this interval: Dinogymnium denticulatum range zone (Santonian) and Senoniasphaera protrusa range zone (up-

permost Santonian–Lower Campanian). The stratigraphic evaluation of the registered Normapolles taxa was made by

taking into account the age assessment of the already defined dinocyst zones. Two pollen assemblages are recognized.

The lower is defined as an association of Oculopollis zaklinskaiae and Krutzschipollis crassus. The co-occurence of

Krutzschipollis spatiosus and Krutzschipollis crassus is characteristic of the succeeding assemblage.

Key words: Santonian, Campanian, Northern Bulgaria, biozonation, palynology, dinoflagellate cysts, Normapolles.

tions of the Geological Institute, Bulgarian Academy of Sci-

ences, Sofia.

All samples from the upper parts of the sections (the Up-

per Campanian interval) are devoid of palynomorphs. In

general, palynomorphs are well preserved in samples from

the Byalo Burdo Formation, the Dobrindol Formation and

the Venchan Formation. The palynological assemblages are

mainly composed of dinocysts and sporomorphs in fluctuat-

ing relative abundances in the different sections. Their suc-

cessions will be considered separately.


Dinoflagellate cysts

The dinocyst taxa distribution is only qualitatively esti-

mated in the present study. Two successive dinocyst zones

are recognized (Fig. 2).

Dinogymnium denticulatum range zone (Santonian)

Definition: Interval characterized by the complete strati-

graphical range of Dinogymnium denticulatum.

The boundaries of the zone are traced by the FO and LO of

the nominative species. Canningia senonica and Dinogym-

nium microgranulosum are characteristic only for this unit.

Isabelidinium belfastense and Dinogymnium acuminatum

successively appear within the zone.

Age: Santonian.

Localities: Section Dobrinski dol.

Correlations: This zone contains characteristic elements

for correlation. The concurrent range of Dinogymnium den-

ticulatum, D. microgranulosum, Senoniasphaera rotundata

and Canningia senonica characterize the Santonian of the

Isle of Wight, England (Clarke & Verdier 1967). Isabelidini-


Santonian and Campanian dinocyst and pollen successions

have been extensively described from different sections of

the Tethyan and Boreal area. In most cases they have been

reported separately and the age control of the encountered

assemblages is insufficient. This is especially valid for the

existing zonal schemes, based on pollen from the Nor-

mapolles group, although the representatives of this group

are of great importance for Upper Cretaceous stratigraphy.

The aim of this paper is to report Santonian and Campa-

nian dinoflagellate cysts and Normapolles from three sec-

tions in Northern Bulgaria, to evaluate the ranges of their

species and to produce an integrated palynostratigraphic zo-

nation for this time interval. It will contribute to the IGCP

Project 362 “The Tethyan and Boreal Cretaceous” objectives

with new data from this area and with a most precise age as-

sessment of the Normapolles distribution.

Material and methods

In the following, the most important palynological data

from the Novachene, Dobrinski dol and Komounari sections

are summarized. The investigated sediments display consider-

able facies diversity, being represented by glauconitic sand-

stones (Byalo Burdo Formation), glauconitic sandstones and

sandy limestones with glauconite (Dobrindol Formation),

limestones and organogenic limestones (Mourna and Nikopol

Formation), chalk-like and chalk limestones with chart con-

cretions (Venchan Formation) and sandstones (Shoumen For-

mation). Sample position on Fig. 1 are relative to the lithos-

tratigraphic subdivision, proposed by Jolkichev (1988, 1989).

Samples were collected from approximately 1–2 m and

processed according to standard palynological procedures.

The residues and the prepared slides are stored in the collec-

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200                                                                                              PAVLISHINA

Senoniasphaera protrusa range zone (latest Santonian–

Early Campanian)

Definition: Interval from the FO to the LO of Senonias-

phaera protrusa.

The nominative species forms a characteristic constituent

of the zone. Hystrichosphaeropsis ovum, Senoniasphaera

rotundata and Dinogymnium acuminatum are also character-

istic for this unit. The LO of Senoniasphaera rotundata is

well documented near the upper boundary of the zone.

Age: Latest Santonian–Early Campanian.

Localities: The zone is recognized in the Novachene sec-

tion and is indicated in the Dobrinski dol section.

Correlations: The complete stratigraphical range of Se-

noniasphaera protrusa in sections from the Paris Basin and

Central Europe coincides with that registered in the investi-

gated sections. It ranges from Middle and Upper Santonian

to Lower Campanian, according to Foucher (1979, 1980)

and Williams & Bujak (1985). So, the local S. protrusa Zone

corresponds to the same unit in Southern France (Foucher in

Robaszynski et. al. 1980, 1982) and to the lower part of the

Pseudoceratium ceratiosus Zone in Southern England (Clar-

ke & Verdier 1967).


The Santonian and Campanian sediments in the investigat-

ed sections yielded sporomorph assemblages represented

mainly by pollen from the Normapolles group. The strati-

Fig. 1. Geographical sketch of the investigated sections, with li-

thology and sample positions.

Plate I: Figs. 1–2. Senoniasphaera rotundata Clarke & Verdier

1967. Dobrinski dol section, Dobrindol Formation, sample 353, San-



300.  Fig.  3.  Canningia senonica Clarke & Verdier 1967.

Dobrinski dol section, Dobrindol Formation, sample 353, Santonian,


600. Fig. 4. Senoniasphaera protrusa Clarke & Verdier 1967. No-

vachene section, Byalo Burdo Formation, sample 442, Lower Cam-



700. Figs. 5–6. Dinogymnium denticulatum Clarke & Ver-

dier 1967. Dobrinski dol section, Dobrindol Formation, sample 350,

Lower Santonian, 


600. Fig. 7. Dinogymnium microgranulosum

Clarke & Verdier 1967. Dobrinski dol section, Dobrindol Formation,

sample 350, Lower Santonian, 


600. Fig. 8. Isabelidinium belfas-

tense (Cookson & Eisenack 1961) Lentin & Williams 1977. Dobrin-

ski dol section, Dobrindol Formation, sample 349, Lower Santonian,


600.  Fig. 9. Dinogymnium acuminatum  Evitt, Clarke & Verdier

1967. Dobrinski dol section, Dobrindol Formation, sample 353, San-



600.  Fig. 10. Oculopollis zaklinskaiae Goczan 1964. Ko-

mounari section, Dobrindol Formation, sample 326, Lower Santo-



1000.  Fig. 11. Oculopollis parvoculus Goczan 1964.

Komounari section, Dobrindol Formation, sample 326, Lower Santo-



1000. Fig. 12. Suemegipollis triangularis Goczan 1964. No-

vachene section, Byalo Burdo Formation, sample 442, Lower Cam-



1000.  Fig. 13. Oculopollis orbicularis Goczan 1964.

Komounari section, Dobrindol Formation, sample 326, Lower Santo-



1000.  Figs. 14–15. Plicapollis silicatus Pflug 1953. No-

vachene section, Byalo Burdo Formation, sample 442, Lower Cam-



1000.  Fig. 16. Krutzschipollis spatiosus Goczan 1964.

Novachene section, Byalo Burdo Formation, sample 443, Lower



1000. Figs. 17., 18., 19. Krutzschipollis crassus (Goc-

zan 1964) Goczan 1967. Komounari section, Dobrindol Formation,

sample 326, Lower Santonian, 




um belfastense and Dinogymnium acuminatum are a compo-

nent part of Turonian–Santonian assemblages from Met-

aliferi Mountain, Romania (Antonescu 1973). Foucher

(1979, 1980) makes Canningia senonica the characteristic

marker for the Santonian age in the Paris Basin and Central

North Europe. According to the range chart, presented by

Williams & Bujak (1985) the FO of Dinogymnium acumina-

tum in the Middle Santonian is also a biostratigraphic event

with good correlation value.

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PLATE  I                                                                                               201

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202                                                                                               PAVLISHINA

Fig. 2. Integrated stratigraphic range of the palynomorphs.

graphic evaluation of the registered taxa was made by taking

into account the age assessment of the already defined di-

nocyst zones. In general, two pollen assemblages are recog-

nized (Fig. 2).

The samples originating from the Lower Santonian part of

the Dobrinski dol and Komounari sections have yielded

identical palynofloras. The genus Oculopollis predominates

in them and the most profuse species is Oculopollis zaklins-

kaiae. Its FO is registered near the lower Santonian bound-

ary together with the well documented FO of such character-

istic taxa as Trudopollis arector, Oculopollis orbicularis, O.

parvoculus and Krutzschipollis crassus. These FO datums

have also been reported by Pavlishina (1994) when consider-

ing the Turonian–Early Santonian Normapolles succession

in Northeast Bulgaria. The stratigraphic distribution of Ocu-

lopollis zaklinskaiae is restricted to the Lower Santonian

stage in the investigated sections, while the other species

continue into the overlying Upper Santonian and Lower

Campanian sediments. So, this lowermost assemblage might

be defined as an association of Oculopollis zaklinskaiae to-

gether with Krutzschipollis crassus.

The succeeding Late Santonian and Early Campanian pa-

lynofloras could be differentiated from the preceding one by

the presence of Krutzschipollis spatiosus and is denominat-

ed here as an assemblage of Krutzschipollis crassus and

Krutzschipollis spatiosus. Trudopollis arector, Oculopollis

orbicularis and O. parvoculus are also characteristic parts of

this assemblage. Oculopollis maximus, Suemegipollis trian-

gularis and Plicapollis silicatus first occur in the Lower

Campanian strata.

From the point of view of the palynological stratigraphy

all the Normapolles species registered here are component

parts of the existing pollen schemes in the Normapolles

province (Goczan 1964; Krutzsch 1966; Medus 1972; Anto-

nescu 1973; Goczan & Siegl-Farkas 1990). Krutzschipollis

crassus, Kr. spatiosus, Oculopollis zaklinskaiae, Suemegi-

pollis triangularis were first described from the Campanian

Stage in Hungary (Goczan 1964) and were used as zone-

eponymous species in the Hungarian Late Santonian–Late

Maastrichtian palynozonation (Goczan 1964; Goczan &

Siegl-Farkas 1990). The correlation with this zonal scheme

is not easy because of differences in the ranges of these spe-

cies in both areas. Recently, Siegl-Farkas & Wagreich (1996)

refined the chronostratigraphic assessment of this pollen

succession, based on correlation with the nannofossil zona-

tion of the Gosau Group in Austria.


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