GEOLOGICA CARPATHICA, 51, 6, BRATISLAVA, DECEMBER 2000
NANNOPLANKTON OF THE TARKHANIAN DEPOSITS
OF THE KERCH PENINSULA (CRIMEA)
AIDA S. ANDREYEVA-GRIGOROVICH
and NATALIA A. SAVYTSKAYA
Department of Geology and Paleontology, Faculty of Science, Comenius University, Mlynská dolina, 842 15 Bratislava, Slovak Republic
Ukrainian State Geological-Research Institute, 57001 Lviv, Ukraine
(Manuscript received May 18, 2000; accepted in revised form October 17, 2000)
Abstract: Tarkhanian calcareous nannoplankton in the area of Crimea have been studied in the sequence of Tarkhan
s.str., new stratotype locality Maly Kamyshlak, Skelia section and in the Sokol-60 well (350.0390.0 m). Associations
of nannofossils are assigned to the zone NN5 and can be correlated with the calcareous nannoplankton associations of
the Lower Badenian deposits of the Central Paratethys and the Langhian sediments of the Mediterranean area.
Paleoreconstructions based on nannofossils have shown that at the beginning of the Tarkhanian transgression a warm
sedimentary area with normal salinity was formed. It was connected with the basins of Western Paratethys and there
is a possibility of connections with the Indian Ocean or Mediterranean Sea. Quantitative, as well as qualitative impov-
erishment of nannoplankton points to change of the basin regime, connected with strong terrigenous input, partial
isolation and salinity decrease (the time of accumulation of Spirialis clays upper part).
Key words: Miocene, Tarkhanian, Kerch Peninsula, nannoplankton.
Tarkhanian deposits were first recognized in the Kerch Penin-
sula by N.I. Andrusov in 1887 as a thin horizon with Pseudoa-
mussium denudatum (Reuss), Nucula placentina Lamk., Os-
trea cochlear (Poli) and others. Later on some investigators
(Zhyzhchenko 1940; Merklin et al. 1964) enlarged the volume
of Tarkhanian horizon, by assigning the overlying succession
of Spirialis clays. As a result of revision of the Neogene re-
gional stages of the Eastern Paratethys, the Tarkhanian se-
quence has got a status of a regional stage of Eastern Parat-
ethys (Nevesskaya et al. 1975) taking into consideration its
widespread occurrence in the Euxinic-Caspian area.
In spite of the long history of studying the Tarkhanian de-
posits and rich paleontological material on different groups of
fossils: mollusks (Davitashvili 1933; Barg et al. 1975; Ana-
niashvili 1985), foraminifers (Bogdanovich 1965; Pishvanova
1978), nannoplankton (Andreyeva-Grigorovich in: Nosovsky
et al. 1976; Minashvili 1981, 1992; Nosovsky & Bogdanovich
1984; Muzylov & Golovina 1987) the problem of the age and
stratigraphical correlation of the Tarkhanian succession is still
In the 70-s the new stratotype of the regional Tarkhanian
Stage was proposed as a result of prospecting in the Kerch
Peninsula. The new stratotype (neostratotype) in the Maly Ka-
myshlak is on the Sea of Azov coast. The Kamyshlak Beds
(lower part), the beds with A. denudatum (middle part) = the
Tarkhan and Yurakov Beds = Spirialis beds (upper part) are in-
cluded in the neostratotype (Nosovsky et al. 1976).
The paper contains a study of new material from the Skelia
section and revision of the old materials (Andreyeva-Grigor-
ovich in Nosovsky et al. 1976). The samples were studied
from the stratotype of Tarkhan near Tarkhan Cape (materials
by Barg), new stratotype section of Maly Kamyshlak (35 sam-
ples), section of Skelia (26 samples) and 20 samples from
Sokol-60 well (material by Nosovsky) (Fig. 1).
All the samples were prepared with the standard smear slide
technique for light microscope observations (LM). The inves-
tigations were carried out under LM at a magnification of
using phase contrast and crossed nicols. Several speci-
mens photographed under SEM (6000
) and LM were
illustrated in Pls. I, II.
Fig. 1. Location map of the studied Tarkhanian sequences.
A z o v S e a
B l a c k S e a
Stratotype locality of Tarkhanian
Maly Kamyslak, new stratotype
400 ANDREYEVA-GRIGOROVICH and SAVYTSKAYA
Nannoflora from the Tarkhanian sequence
Tarkhan s.str. The sequence situated on the western slope
of the Tarkhan Cape on the Azov coast, was proposed by An-
drusov in 1884 (Andrusov 1887) as the stratotype locality of
the Tarkhanian Stage. Paleontological character of the de-
posits was based on the mollusks fauna (Zhyzhchenko 1940;
Davitashvili 1933) only. Samples for the nannoplankton study
were given by I.M. Barg. Depiction of the stratotype follows
from the bottom to the top.
1. Clays, dark-grey, non-carbonate with faded jarosite.
Thickness 1.20 m. Nannoplankton is not found (Maikop Fm.).
2. Clays, dark-grey to black, non-carbonate, shaly. Thick-
ness 1.50 m. Nannoplankton is not found (Maikop Fm.).
3. Clays, grey carbonate. Thickness 0.05 m. Rare species
are found: Coccolithus pelagicus, Helicosphaera cf. carteri,
Braarudosphaera bigelowii, Sphenolithus heteromorphus,
Rhabdosphaera sicca (Kamyshlak Beds).
4. Tarkhan Beds marls dark-grey, dense with A. denuda-
tum. Thickness 0.2 m. They contain: Coccolithus pelagicus
(acme), Helicosphaera carteri, H. waltrans, Braaru-
dosphaera bigelowii, Sphenolithus heteromorphus (acme), S.
cf. abies, Rhabdosphaera sicca (acme), Pontosphaera disco-
pora, Cyclicargolithus floridanus.
5. Clays grey, limy with pteropod remnants. Thickness 6.0
m. In the lower part of the succession they contain (1 m): Coc-
colithus pelagicus, Helicosphaera carteri, H. sp., Discoaster
variabilis, Sphenolithus heteromorphus (acme), S. abies,
Rhabdosphaera sicca, Braarudosphaera bigelowii, Ponto-
sphaera discopora. In the upper part of the succession they
contain impoverished complex with Coccolithus pelagicus,
Helicosphaera carteri, Cyclicargolithus leptoporus, Spheno-
lithus cf. abies, Sphenolithus heteromorphus, Perforocalcinel-
la fusiformis. Sometimes rare re-deposited species of Paleo-
gene algoflora are present (Lower part of the Yurakov Beds).
Associations from the marl beds with A. denudatum and
from the Yurakov Beds are most abundant in species and
quantitative respects. These complexes are contemporaneous
and correspond to NN5
Sphenolithus heteromorphus Zone
(Martini 1971), based on species likeness.
Maly Kamyshlak the new stratotype of the
Tarkhanian Stage. The section is situated along southern
Azov coast, 3 km west of the village of Yurkino.
Depiction of the neostratotype follows, from the bottom to
About the Maikopian (Korolov Beds) non-carbonate clays
pass into the (Fig. 2):
1. Kamyshlak Beds (thickness 3.5 m) dark-grey lightly
carbonate and non-carbonate vague bedded clays with a sprin-
kle of jarosite. The following nannoplankton forms are
present here: Braarudosphaera bigelowii, Coccolithus pelagi-
cus, Rhabdosphaera sicca, Helicosphaera carteri, Spheno-
lithus heteromorphus, Coronocyclus nitescens, Sphenolithus
2. Tarkhan Beds with Amussium denudatum (thickness 0.2
m) dark-grey marls, dense, overfilled with thin walled
shells of mollusks. The association of nannoplankton is repre-
Fig. 2. Distribution of nannoplankton in the Maly Kamyshlak sequence.
NANNOPLANKTON OF THE TARKHANIAN DEPOSITS 401
Plate I: Fig. 1. Helicosphaera granulata (Bukry & Percival); crossed nicols, Tarkhan sequence. Figs. 2, 3. Helicosphaera carteri (Wallich),
crossed nicols; 2 Sample S3, Skelia sequence; 3 Sample MK5, Maly Kamyshlak sequence. Fig. 4. Helicosphaera cf. waltrans Theodo-
ridis, crossed nicols; Sample S7, Skelia sequence. Figs. 58. Sphenolithus heteromorphus Deflandre; crossed nicols; 5 Sample MK5, 6
Sample MK14, 7 Tarkhan sequence, 8 Sample MK31, Maly Kamyshlak sequence. Fig. 9. Sphenolithus cf. abies Deflandre; crossed
nicols; Sample MK26 Maly Kamyshlak sequence. Fig. 10. Calcidiscus premacintyrei Theodoridis, crossed nicols; Sample S26, Skelia se-
quence. Figs. 11, 12. Reticulofenestra pseudoumbilicus (Gartner); crossed nicols; 11 Sample S5 Skelia sequence, 12 Sample MK22,
Maly Kamyshlak sequence. Figs. 13, 14. Rhabdosphaera sicca Stradner; 13 crossed nicols, 14 Sample S3, Skelia sequence. Fig. 15.
Braarudosphaera bigelowii subsp. parvula Stradner, Sample S26 Skelia sequence. Fig. 16. Braarudosphaera bigelowii (Gran & Braarud),
crossed nicols, Tarkhan sequence. Fig. 17. Cyclicargolithus floridanus (Roth & Hay), Sample S3, Skelia sequence. Figs. 18, 19, 20. Perfo-
calcinella fusiformis Bona; crossed nicols, Sample S26 Skelia sequence.
sented by the next species: Coccolithus pelagicus, Heli-
cosphaera carteri, H. cf. mediterranea, H. waltrans, H. gran-
ulata, Cyclicargolithus floridanus, Calcidiscus leptoporus, C.
premacintyrei, Sphenolithus heteromorphus, S. cf. abies, S.
moriformis, Reticulofenestra pseudoumbilicus, Rhab-
dosphaera sicca, Braarudosphaera bigelowii, Thora-
cosphaera saxea, Coronocyclus nitescens. Re-deposited spe-
cies of the Upper Cretaceous and Paleogene are present.
3. Yurakov Beds (thickness to 90 m) grey clays, calcare-
ous or subcarbonate, arenaceous with the relics of the shells of
402 ANDREYEVA-GRIGOROVICH and SAVYTSKAYA
Plate II: Figs. 1, 2. Helicosphaera carteri (Wallich); Sample S5, Skelia sequence. Fig. 3. Helicosphaera waltrans Theodoridis; Sample
MK9, Maly Kamyshlak sequence. Fig. 4. Helicosphaera mediterranea Muller; Sample B60/5, borehole 60, 380385 m. Fig. 5. Calcidiscus
premacintyrei Theodoridis; Sample S26, Skelia sequence. Fig. 6. Cyclicargolithus floridanus (Roth & Hay) Bukry; Sample S3, Skelia se-
quence. Figs. 7, 8. Reticulofenestra pseudoumbilicus (Gartner) Gartner; Sample B60/5, borehole 60, 380385 m; Sample MK9, Maly Kamy-
Mollusks and Pteropods. In the lower part of the succession
(20 m) the nannoplankton complex qualitatively does not dif-
fer from the above mentioned one. In the upper part of the
Yurakov Beds (Spirialis clays) the nannoplankton complexes
becomes sharply poorer: Cyclicargolithus floridanus, Cocco-
lithus pelagicus, Calcidiscus leptoporus, Sphenolithus hetero-
morphus are very rarely present. The number of the Perforo-
calcinella fusiformis and re-deposited Cretaceous and Paleo-
gene nannoplankton increases.
4. Detritic limestones of the Tschokrakian Stage lying un-
conformably on the Yurakov Beds (Spirialis clays). Thickness
up to 15 m. Nannoplankton is absent there.
NANNOPLANKTON OF THE TARKHANIAN DEPOSITS 403
The Skelia section is situated on the Azov coast two km
west of Yurkino village. The next sequence of the beds is
shown from the bottom to the top (Fig. 3):
1. Kamyshlak Beds (thickness 5.0 m). Nannoplankton is not
2. Tarkhan Beds with Amussium denudatum (thickness 0.15
m) shelly limestones, and thin-laminated grey marly clays
(0.3 m). Association of nannoplankton is represented by: Coc-
colithus pelagicus, Cyclicargolithus floridanus, Heli-
cosphaera carteri, H. waltrans, H. cf. walbersdorfensis, Sphe-
nolithus heteromorphus, S. moriformis, S. compactus,
Calcidiscus leptoporus, C. premacintyrei, Rhabdosphaera sic-
ca, Thoracosphaera heimii.
Representatives of the genera Coccolithus, Helicosphaera
and Sphenolithus heteromorphus prevail in the above men-
3. Yurakov Beds (thickness is approximately 90 m.)
dark-grey clays, carbonate or non-carbonate, foliated, fre-
quently sandy, with sprinkles of jarosite. Surfaces of the beds
are often completely covered by Spiratella (Limacina). Some
intercalations among the clays contain siderite concretions.
The intercalation (1.5 m) of greenish-grey bedded marls with
lenses of ferritic clays are present at the top of the succession.
In the carbonate intercalations just above the marls with Amus-
sium denudatum (~ 1.5 m) the next complex of nannoplankton
was found: Coccolithus pelagicus, Cyclicargolithus florida-
nus, Sphenolithus abies, S. heteromorphus, S. moriformis,
Reticulofenestra pseudoumbilicus, Helicosphaera carteri,
Braarudosphaera bigelowii, Pontosphaera multipora, Thora-
cosphaera heimii, Triquetrorhabdulus rugosus.
Fig. 3. Distribution of nannoplankton in the Skelia sequence.
A poor association of nannoplankton has been found at the
top of the succession, with rare Coccolithus pelagicus, Retic-
ulofenestra pseudoumbilicus, Sphenolithus abies, Braaru-
dosphaera bigelowii subsp. parvula, Perforocalcinella fusi-
4. Detritic limestones of the Tschokrakian Stage lies with
the sharp hiatus on the Yurakov Beds (Spirialis clays). Nanno-
plankton is absent there.
Apart from natural sections in the north-eastern part of
Kerch Peninsula borehole-core material from the central part
from the peninsula (south-west of Tschokrak lake) was inves-
tigated. Sokol-60 well is situated 2 km north of Sokol village.
The following sequence of beds is shown from the top to the
1. Yurakov Beds (347375 m) dark-grey clays with abun-
dant Spiratella (Limacina) lies under the grey Tschokrakian
limestones. The Yurakov Beds start at a depth of 347 m (Fig.
4). In the upper part of the clays up to a depth of 347 m a poor
association of nannoplankton is represented by the following
species: Coccolithus pelagicus, Calcidiscus leptoporus, Cycli-
cargolithus floridanus, Braarudosphaera bigelowii subsp.
parvula, Rhabdosphaera sicca, Helicosphaera carteri.
2. Tarkhan Beds (375384 m). In this interval a comparable
association was observed with the same in the beds with
Amussium denudatum. The characteristic species are: Spheno-
lithus heteromorphus, S. cf. abies, S. moriformis, Heli-
cosphaera carteri, H. sp., H. intermedia, Cyclicargolithus
404 ANDREYEVA-GRIGOROVICH and SAVYTSKAYA
floridanus, Calcidiscus leptoporus, Rhabdosphaera sicca,
Braarudosphaera bigelowii, Reticulofenestra pseudoumbili-
cus, Pontosphaera multipora.
3. Kamyshlak Beds (384398.5 m) in dark-grey to
black non-carbonate clays the nannoplankton association is
The Azov coast Tarkhanian deposits can be clearly divided
into three lithological successions, westwards and southwards
of Tarkhan cape there is not sharp difference. They are repre-
sented by monotonous dark-grey clays there. Nannoplankton
associations here are of the same type and age as those from
the stratotype area. Absence of the marl beds in the Tarkhan
sequence in this territory is probably caused by the deeper con-
ditions of sedimentation, in which deposition of flaky dark-
grey and black clays took place (Nosovsky et al. 1976).
Paleoecology of the Tarkhanian sedimentary area
Nannoplankton can be considered as an indicator of the pe-
riods of marine communications between epicontinental seas
and the World ocean. Nannoplankton occurrences in the exact
outcrops of the Kerch Peninsula show direct connections of
the Eastern Paratethys and the World ocean at that time. The
Tarkhanian deposits therefore point out to marine connections
between the Eastern Paratethys and the World ocean. The
study of the nannoplankton association allows us to ascertain
stenohaline conditions, for example normal marine salinity by
presence of Helicosphaera spp., Discoaster spp., Rhab-
dosphaera spp., Sphenolithus spp. and so on, which is in good
agreement with the observation of Muzylov & Golovina
(1987), about the closing and reopening of the marine seaway
between the Eastern Paratethys and World ocean.
The Early Tarkhanian transgression caused considerable
changes in the regime and character of the sedimentation in
the Eastern Paratethys. The accumulation of non-carbonate
clay beds (clays of the Maikop clays) pass into the carbonate
marl deposition bearing abundant remnants of planktonic and
benthic organisms (marls with A. denudatum Tarkhan
Beds). The Tarkhanian sedimentary area in the Eastern Parat-
ethys extended from Bulgaria in the west to Western Turkme-
nia in the east and from Central Ukraine in the north to Kopet-
dag in the south (Goncharova 1991). The abundant and
various associations of nannoplankton with Sphenolithus spp.,
Helicosphaera spp., Rhabdosphaera spp. from Tarkhanian
marls with A. denudatum and from lower part of Yurakov
(Spirialis) Beds witness a wide connection with the World
ocean and characterize this sedimentary area as a normal ma-
rine area. The basin was possibly connected with the Western
Paratethys in the North-West and with the eastern Mediterra-
nean or Indian Ocean in the South-East. The same marine con-
ditions documented by a coeval nannoplankton association
were also observed in the lower part of the Yurakov Beds with
In the Late Tarkhanian sedimentary area (the time of accu-
mulation of upper part of the Spirialis clays), the quantity of
nannoplankton gradually, but very quickly diminished. Rare
Coccolithus pelagicus, Cyclicargolithus floridanus, Calcidis-
cus leptoporus, Braarudosphaera bigelowii occur, and at the
top of the succession the quantity of Perforocalcinella fusifor-
mis increased. These facts suggest a decrease of the inflow of
oceanic waters, this inflow remains on the level sufficient for
Fig. 4. Distribution of nannoplankton in the Sokol-60 Borehole.
NANNOPLANKTON OF THE TARKHANIAN DEPOSITS 405
existence of nannoplankton. Generally, the late Tarkhanian
sedimentary area can be considered marine, but with salinity
deacrease caused possibly by partial isolation of the area or by
strong terrigenous input.
Age and correlation of Tarkhanian deposits
In spite of the fact that Tarkhanian deposits are widely de-
veloped in the Euxine-Caspian area and are varied in litholog-
ical character, there is not a uniform opinion about the age and
correlation of them among the specialists on different groups
of fauna, as well as between the specialists on one group.
On the basis of occurrence of Helicosphaera ampliaperta in
the marls with A. denudatum at the base of the Yurakov (Spiri-
alis) Beds Bogdanovich (Nosovsky & Bogdanovich 1984) as-
signed these deposits to the NN4 Zone and correlated them
with the Karpatian Stage of the Western Paratethys.
Nosovsky, on the basis of Bogdanovichs data attributed the
Kamyshlak Beds and Tarkhan Beds to the NN4 Zone and the
Yurakov Beds to the NN5 Zone and correlated them with the
Lower Langhian Stage of the Mediterranean (Nosovsky 1998).
Minashvili distinguished the lower part of the zone NN5
(Sphenolithus heteromorphus acme) among Tarkhanian de-
posits of Georgia and correlated them with the uppermost
part of the Karpatian and the lowermost part of the Badenian
stages, of the central Paratethys or with the top of the Burdiga-
lian and the base of the Langhian Stage (Minashvili 1992).
The authors opinion is that nannoplankton associations
from the Tarkhan Beds and Yurakov Beds correspond to the
NN5 Zone Sphenolithus heteromorphus. Unfortunately, be-
cause of rare occurrences of nannofossils in the underlying
(Kamyshlak Beds) and overlying (top of the Yurakov Beds
and beds of the Tschokrakian Stage deposites) beds, it was im-
possible to follow the lower and upper boundaries of the zone.
According to the nannoplankton biozonation (Fornaciari et
al. 1996), the boundary between Langhian and Burdigalian in
the Mediterranean area and the boundary between Carpathian
and Badenian are inside the zone NN4 in the Western Parat-
ethys (Berggren et al. 1995). Therefore, the Tarkhanian depos-
its, more exactly both Tarkhan and Yurakov (Spirialis) Beds
containing nannoplankton of the NN5 Zone are correlated
with the Early Badenian and Langhian. The same associations
of nannoplankton with abundance of Sphenolithus heteromor-
phus, Calcidiscus spp., Discoaster spp. have been found in the
Badenian of the Moravian and Lower Austrian sediments
(vábenická & Ètyroká 1999) (Fig. 5). Presence of planktonic
foraminifers characteristic for the zone N8 Globigerina
bollii, Globigerinoides bisphaericus, Praeorbulina aff. transito-
ria in both Tarkhan and lower Yurakov (Spirialis) Beds (Ivano-
va 1999) also allow us to correlate the Tarkhanian Stage with
the lower part of the Badenian Stage in the Central Paratethys.
1. The studied sequences of the Tarkhanian deposits in
Kerch Peninsula are represented by shallow-water limestones
and marls with A. denudatum as well as by deepwater clays in
the typical Maikop facies.
Fig. 5. Comparison of nannoplankton zones and ranges of the most important taxa in stratotype area of Tarkhanian deposits of Kerch
Peninsula (Eastern Paratethys) and Carpathian/Badenian sediments in Moravia and Lower Austria (Central Paratethys vábenická &
tyroká 1999) and Langhian stratotype area in Italy (Mediterranean area Fornaciari et al. 1996).
406 ANDREYEVA-GRIGOROVICH and SAVYTSKAYA
2. Characteristic and abundant associations of nannoplank-
ton from the Tarkhan Beds and the lower part of the Spirialis
Beds document a period of connection of the Early Tarkhanian
sedimentary area with the Western Paratethys in the north-
west and Indo-Pacific in the south-east and characterize this
area as marine with normal salinity.
3. The sharp decrease of the nannoflora at the end of the
Tarkhanian time (upper part, the Yurakov Beds with Spirialis)
may be explained by gradual cessation of the marine connec-
tion of the area and its gradual isolation.
4. The deposits of the Tarkhan Beds and Yurakov Beds
(Spirialis clays) contain nannoplankton of the NN5 Zone
(Sphenolithus heteromorphus) and allow us to correlate the
Tarkhanian Stage with the Early Badenian Stage of the West-
ern Paratethys and Langhian Stage of the Mediterranean area.
List of nannoplankton species
mentioned in this paper
Coccolithus pelagicus (Wallich) Schiller 1930
Calcidiscus macintyrei Bukry & Bramlette 1969
C. leptoporus (Murray & Blackmann) Loeblich & Tappan 1978
Coronocyclus nitescens (Kamptner 1963) Bramlette & Wilcox-
Cyclicargolithus floridanus (Roth & Hay) Bukry 1971
Discoaster variabilis Bramlette & Riedel 1963
Helicosphaera carteri (Wallich 1887) Kamptner1954
H. granulata (Bukrz & Percival1971) Jafar & Martini1975
H. waltrans Theodoridis
H. cf. mediterranea Muller 1981
H. cf. walbersdorfensis Muller 1974
H. intermedia (Martini) Hay & Mohler 1967
Sphenolithus heteromorphus Deflandre 1953
S. moriformis (Bronnimann & Stradner1960) Bramlette & Wilcox-
S. compactus Backman1980.
S. abies Deflandre 1954
S. cf. abies
Braarudosphaera bigelowii (Gran & Braarud 1935) Deflandre 1947
B. bigelowii subsp. parvula Stradner 1963
Rhabdoshpaera sicca Stradner 1961
Reticulofenestra pseudoumbilicus (Gartner 1967) Gartner 1969
R. minuta Roth 1970
Thoracosphaera saxea Stradner 1961
T. heimii (Lohmann 1919) Kamptner 1941
Triquetrorhabdulus rugosus Bramlette & Wilcoxon 1967
Pontosphaera discopora Schiller 1925
P. multipora (Kamptner 1948) Roth 1970
Perfocalcinella fusiformis Bona 1966
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