GEOLOGICA CARPATHICA, 50, 2, BRATISLAVA, APRIL 1999
TURONIAN AMMONITES FROM THE EASTERN PART
OF THE MOESIAN PLATFORM AND THE FORE-BALKAN
Department of Palaeontology and Stratigraphy, Geological Institute, Bulgarian Academy of Sciences,
Acad. G. Bonchev Bl. 24, 1113 Sofia, Bulgaria; firstname.lastname@example.org
(Manuscript received March 4, 1998; accepted in revised form September 1, 1998)
Abstract: About twenty ammonite species of Turonian age were determined from several sections in North-East Bul-
garia. Six of themSubprionocyclus hitchinensis, Mesopuzosia beloensis, Tongoboryoceras donovani, Tongoboryoceras
rhodanicum, Gaudryceras denseplicatum and Anagaudryceras sacya were found for the first time in Bulgaria. The
three Turonian substages are biostratigraphically proven. Three standard ammonite zones (uppermost Early Turonian
Mammites nodosoides Zone, Middle TuronianCollignoniceras woollgari Zone and Late TuronianSubprionocyclus
neptuni Zone) are established. The lower-middle and middle-upper Turonian boundaries are estimated by ammonites.
Key words: Upper Cretaceous, Turonian, North-East Bulgaria, biostratigraphy, zonation, ammonites.
belongs to three collections stored at the Palaeontological
Museum, Sofia University St. Kliment Ohridski.
The Upper Cretaceous stratigraphy in North-East Bulgaria
was done mainly by Jolkichev (1988; 1989). He recognized
the lithostratigraphic units in this area but did not mention all
the ammonite taxa. Some of the Turonian ammonites obtained
from the investigated region have been published and illus-
trated by Tzankov (1982). The objectives of this study are to
determine and (or) to revise all ammonite species of Turonian
age from this part of the country. It is a part of a larger study
on the Upper Cretaceous ammonite fauna in Bulgaria. This
paper is made in the framework of the project NZ-707
Stratigraphy and paleontological content of the Cenomanian-
Coniacian sediments in parts of the Srednogorie and the Fore-
Balkan, financed by the National Fund for Scientific Re-
search and it represents a contribution to the IGCP Project
362 The Tethyan and Boreal Cretaceous.
Material and methods
The Turonian sequence in the study region is represented by
sandstones and sandy limestones (upper parts of the Madara
Formation) sandy, slightly silty and chalk-like limestones with
extremely abundant carbonate-siliceous and siliceous concre-
tions (Mogila Formation). These sediments are covered by
phosphorite bed and glauconite sandstones (Dobrindol For-
mation), which are laterally replaced by the limestones of the
Venchan Formation (Jolkichev 1989).
More than 150 specimens of Turonian ammonites are doc-
umented from several sections in the region of the towns
Provadiya, Kaspichan and Shoumen, North-East Bulgaria
(Fig. 1). They comprise a relatively high species diversity
and are very well preserved. The largest part of the ammo-
nite taxa obtained is of Late Turonian age. The whole fauna
Fig. 1. Sketch map with location of the sections.
The Early Turonian age is proven by Inoceramus labiatus
Schlotheim (Tzankov et al. 1952, p. 63). Lewesiceras per-
amplum (Mantell) (Pl. IV: Fig. 4) is a characteristic species
for the uppermost Early Turonian ammonite zone (Mam-
mites nodosoides) and the Middle Turonian Collignoniceras
The Middle Turonian ammonites in the investigated sec-
tions are mainly Collignoniceras Breistroffer Collignon-
Plate I: Figs. 16. Collignoniceras woollgari (Mantell) Middle Turonian; 1 2533, 2 Cr
1212, 3 Cr
1211, 4 Cr
BM 242, 6 362. Figs. 79. Collignoniceras carolinum (dOrbigny) Middle Turonian; 7 BM 241, 8 BM 233, 9 Cr
Figs. 1011. Collignoniceras bravaisianum (dOrbigny) Middle-Upper Turonian; 10 379, 11 Cr
1202. Fig. 12. Subprionocyclus
hitchinensis (Billinghurst) Upper Turonian; BM 222. Figs. 1314. Subprionocyclus neptuni (Geinitz) Upper Turonian; 13 Cr
1208, 14 2235
. All figures are natural size with the exception of Figs. 7 and 8
TURONIAN AMMONITES FROM THE EASTERN PART OF THE MOESIAN PLATFORM 195
Plate II: Figs. 15. Romaniceras (Romaniceras) deverianum (dOrbigny) Middle Turonian lower parts of the Upper Turonian; 1
1182, 2 BM 230, 3 BM 231, 4 Cr
1181, 5 3862. Figs. 67. Romaniceras (Yubariceras) ornatissimum (Stoliczka) up-
per parts of the Middle Turonian Upper Turonian; 6 Cr
1184, 7 Cr
1183. All figures are natural size.
Plate III: Figs. 12. Mesopuzosia beloensis Collignon Upper Turonian; 1 BM 229, 2 Cr
1237. Fig. 3. Puzosia curvatisulcata
(Forbes) (? = P. gaudama) Upper Turonian; Cr
1114. Figs. 47. Puzosia hernensis (Schlüter) Upper Turonian; 4 2229, 5 BM
228, 6 BM 219, 7 378. All figures are natural size.
TURONIAN AMMONITES FROM THE EASTERN PART OF THE MOESIAN PLATFORM 197
Plate IV: Fig. 1. Tongoboryoceras rhodanicum (Roman & Mazeran) Upper Turonian; Cr
1139. Fig. 2. Tongoboryoceras donovani
(Collignon) Upper Turonian; 3962. Fig. 3. Lewesiceras mantelli Wright & Wright Middle-Upper Turonian; Cr
1140. Fig. 4.
Lewesiceras peramplum (Mantell) Lower-Middle Turonian; BM 206. Fig. 5. Gaudryceras denseplicatum (Jimbo) uppermost Mid-
dle Turonian Upper Turonian 366. Fig. 6. Anagaudryceras sacya (Forbes) Upper Turonian. All figures are natural size. All pictures
are made in the photo-laboratory of the Geological Institute.
iceras woollgari (Mantell) (Pl. I: Figs. 16), Collignoniceras
carolinum (dOrbigny) (Pl. 1, Figs. 79) and Collignoniceras
bravaisianum (dOrbigny) (Pl. 1: Figs. 1011). The last one
also occurs in the Upper Turonian strata.
Two very important representatives of Romaniceras Spath
were established. Romaniceras (Yubariceras) ornatissimum
(Stoliczka) (Pl. II, Figs. 67) is the zonal index of the Middle
Turonian homonymous zone, while Romaniceras (Roman-
iceras) deverianum (dOrbigny) (Pl. II: Figs. 15) is the
zonal index of the lowermost Late Turonian homonymous
zone (Kennedy 1984, p. 151 gallic view). The last one
occurs in the uppermost Middle Turonian and in the lower
parts of the Upper Turonian sequence in the investigated
The following ammonite taxa characterize the Late Turo-
nian substage in the studied area: Subprionocyclus neptuni
(Geinitz) (Pl. I: Figs. 1314), Subprionocyclus normalis
(Anderson), Subprionocyclus hitchinensis (Billinghurst) (Pl.
I: Fig. 12), Mesopuzosia beloensis Collignon (Pl. III: Figs.
12), Puzosia curvatisulcata (Forbes) (? = P. gaudama) (Pl.
III: Fig. 3), Puzosia hernensis (Schlüter) (Pl. III: Figs. 47),
Tongoboryoceras rhodanicum (Roman & Mazeran) (Pl. IV:
Fig. 1), Tongoboryoceras donovani (Collignon) (Pl. IV: Fig.
2), Lewesiceras mantelli Wright & Wright (Pl. IV: Fig. 3),
Gaudryceras denseplicatum (Jimbo) (Pl. IV: Fig. 5), Gaud-
dle Turonian, as well as the boundary between the Middle
and the Upper Turonian are placed by the first occurrences
of the species Collignoniceras woollgari and Subprionocy-
clus neptuni zonal indexes of the standard Middle and
Late Turonian ammonite zones of the same names.
Bengtson P. (compiler), 1996: The Turonian stage and substage bound-
aries. Bull. Inst. Roy. Sci. Nat. Belg. (Sci. de la Terre), 66, 6979.
Kennedy W.J., 1984: Ammonite faunas and the standard zones of
the Cenomanian to Maastrichtian stages in their type areas,
with some proposals for the definition of the stage boundaries
by ammonites. Bull. Geol. Soc. Denmark, 33, 12, 147161.
Jolkichev N., 1988: Lithostratigraphic units connected with the
Upper Cretaceous in eastern parts of the Moesian Platform.
Rew. Bulg. Geol. Soc., XLIX, 1, 1125 (in Bulgarian with En-
Jolkichev N., 1989: Stratigraphy of the epicontinental type Upper
Cretaceous in Bulgaria. St. Kl. Ochridski Univ. Press, Sofia,
1184 (in Bulgarian with English and Russian abstracts).
Tzankov V., 1982: The fossils of Bulgaria. Va. Upper Cretaceous.
Bulg. Acad. Sci. Press, Sofia, 136, 50 (in Bulgarian with
Tzankov V., Strashimirov B. & Dimitrova N., 1952: Stratigraphical
and palaeontological characteristic of the Cretaceous and Lu-
tetian in Provadia region. Chief Depart. Geol. and Min. In-
vest., A, 5, 5986 (in Bulgarian).
Fig. 2. Ammonite zones and stratigraphic range of the fossils.
ryceras mite (Hauer), Anagaudryceras sacya (Forbes) (Pl.
IV: Fig. 6), Scaphites geinitzii dOrbigny, Sciponoceras bo-
hemicum (Fritsch & Schlöbach). The common presence of
Romaniceras (Romaniceras) deverianum and Subprionocy-
clus neptuni has to be noted, especially when their first oc-
currences are uncertain in respect to the middle-upper Turo-
nian boundary (Bengtson 1996, p. 77). Unfortunately in our
case both species are found in a thin phosphorite bed and it
is difficult to correlate their ranges. Middle Turonian ammo-
nites are also documented from the same bed, a fact ex-
plained by Jolkichev with condensed sections (1989, p. 99).
The review of previously and newly obtained biostrati-
graphic data (Fig. 2) gives reason to consider that the three
Turonian substages are represented in the investigated area.
Several Late Turonian species (Subprionocyclus hitchinen-
sis, Mesopuzosia beloensis, Gaudryceras denseplicatum,
Anagaudryceras sacya, Tongoboryoceras rhodanicum and
Tongoboryoceras donovani) are described for the first time
in Bulgaria. The boundary between the Lower and the Mid-