Maeotian / Pontian ostracods in the Badislava ?Topolog area (South carpathian foredeep-Romania)

Abstract

We present the main characteristics of the ostracod assemblages of the Maeotian and Pontian stages in the Badislava-Topolog area (Getic Depression). The Maeotian ostracods fauna is represented by few species that populated ephemeral aquatic environments. The Pontian ostracod fauna is more diverse with species that developed in stable brackish lakes. This Pontian fauna is characteristic of the Upper Pontian (Bosphorian) stage. Our results indicate that the Maeotian / Pontian boundary in Arges-Topolog region is marked by a hiatus comprising the latest Maeotian, Early and Middle Pontian. This hiatus is probably caused by erosional processes during the Middle Pontian (Portaferrian) sea level drop in the Dacian Basin and local tectonic processes. © 2011, National Research and Development Institute for Marine Geology and Geoecology. All rights reserved.

Full text

177Geo-Eco-Marina 17/2011
IntroductIon
The palaeogeographic and geological evolution of the
Dacian Basin (and Eastern Paratethys, in general) during the
Late Maeotian and Pontian is frequently discussed on the
geological literature, because at this time interval the Medi-
terranean area experienced its so-called Messinian Salinity
Crisis (MSC). Many authors consider that this event had more
or less dramatical eects in the adjacent basins of the Para-
tethys including the Dacian Basin.
This paper presents the main features of ostracod assem-
blages from the Late Maeotian - Pontian sediments in Badisla-
va-Topolog area, Getic Depression. Vasiliev et al., 2005 suggests
that the Maeotian / Pontian boundary from the Eastern Para-
tethys is at c. 5.8 Ma and postdates the onset of Messinian Salin-
ity Crisis (MSC) at 5.96 Ma (Krijgsman et al., 1999). A transgres-
sive moment at the Maeotian / Pontian has previously been
documented from wells and seismic data in the Dacian Basin
(Jipa, 1997; Leever, 2007; Leever et al., 2009) and is biostrati-
graphically marked by a short time migration of salty water
fauna (including benthic and planktonic foraminifers) from the
Mediterranean domain (alternatively Indian Ocean), followed
by a migration of faunal elements from the Pannonian basin
into the Eastern Paratethys, after the brackish conditions have
been re-established (Krijgsman et al., 2010; Vasiliev et al., 2011).
MaterIals and Methods
A number of 140 micropaleontological samples have
been collected from Late Maeotian and Pontian deposits
that crop out on the Badislava and Topolog Valleys (Fig. 1),
from the same location where paleomagnetic samples have
been obtained (Vasiliev et al., 2005). The lithology of the sam-
pled levels consists, mainly, of ne grain sediments (clay and
marls). All samples weighed about 1kg and were boiled ½-1
h with sodium carbonate solution for a better disaggrega-
tion. Before boiling, it was necessary to dry the sediments to
eliminate interstitial water. After that, samples were washed
through a battery of sieves (16-200 mesh). The residues have
been dried in aluminium recipients. Samples have been
picked using a black tray with horizontal and vertical lines
and a ZEISS – GSZ microscope. Ostracods have been stored
in special micropalaeontological slides, now located in the
Laboratory of Paleontology from the Bucharest University. An
electro-scanning microscope Phillips XL30 from the Utrecht
University was used for the illustrations.
Maeotian / Pontian ostracods in the
Badislava –toPolog area
(south carpathIan foredeep-roManIa)
AlinA FlOROiU(1), MARiUs sTOiCA(1), iUliAnA VAsiliEV(2), WOUT KRiJGsMAn(2)
(1)Department of Geology, Faculty of Geology and Geophysics, Bucharest University, Balcescu Bd. 1,010041, Romania
oroiualina@yahoo.com, marius.stoica@g.unibuc.ro
(2)Paleomagnetic Laboratory ‘Fort Hoofddijk’, Utrecht University, Budapestlaan 17, 3584 CD, Utrecht, The Netherlands
vasiliev@geo.uu.nl, krijgsma@geo.uu.nl
Abstract. We present the main characteristics of the ostracod assemblages of the Maeotian and Pontian stages in the Badislava-Topolog area (Getic
Depression). The Maeotian ostracods fauna is represented by few species that populated ephemeral aquatic environments. The Pontian ostracod fauna is
more diverse with species that developed in stable brackish lakes. This Pontian fauna is characteristic of the Upper Pontian (Bosphorian) stage. Our results
indicate that the Maeotian / Pontian boundary in Arges-Topolog region is marked by a hiatus comprising the latest Maeotian, Early and Middle Pontian. This
hiatus is probably caused by erosional processes during the Middle Pontian (Portaferrian) sea level drop in the Dacian Basin and local tectonic processes.
Key words: Ostracods, Maeotian, Pontian, Getic Depression, Dacian Basin
A. FlOROiU, M. sTOiCA, i. VAsiliEV, W. KRiJGsMAn

178 Geo-Eco-Marina 17/2011
A. Floroiu, M. Stoica, I. Vasiliev, W. Krijgsman – Maeotian / Pontian ostracods in the Badislava –Topolog area
GeoloGIcal backGround
The Getic Depression represents the sedimentary basin
that developed at the contact between the South Carpathi-
an nappe pile and the Moesian Platform (Sandulescu et al.,
1984). The Late Miocene-Pliocene sedimentary successions
from Badislava and Topolog Valleys regions are integrated
into a large monoclinal structure with 15o-20o plunge to the
SSE (Fig. 1). This structure is aected by N-S oriented faults
that can generate up to 200 m of horizontal displacements.
The Mio-Pliocene sedimentary successions are very well
exposed in the northern part of the Getic Depression, es-
pecially in the Topolog Valley. A magnetostratigraphic time
scale has been developed for the Maeotian-Romanian depos-
its from this area (Vasiliev et al., 2005). The magnetic polarity
pattern recorded in these sections shows a succession of four
relatively short normal and three reversed zones, followed by
a long reversed interval. The results were later integrated with
biostratigraphical data based on mollusks (Stoica et al., 2007).
The studied sections start in the Late Maeotian and end
in the lower part of the Romanian, south of the conuence
between the Badislava and Topolog Valleys (Fig. 1). The Up-
per Maeotian stage is here developed in a uviatile-deltaic
facies with frequently continental type intercalations. The
sediments are represented by coarse gravels, oblique lami-
nated sands, channel deposits interbedded with “ood-plain”
deposits, fossil soils and lacustrine clay (Figs 2, 4).
The top of the Maeotian sequence is marked by an erosion-
al surface. The overlying Pontian deposits have a transgressive
character. They are represented by a ning-upward sequence
that starts with coarse to medium-grained pebbles and sands
in the lower part, passing to predominant ne-grained depos-
its very rich in mollusks and ostracods in the upper part (Figs 3,
4). This discontinuity in the marginal areas of central part of the
Carpathian Foredeep can also be noticed on the interpreta-
tions of seismic lines from the westernmost part of the Dacian
Basin (Leever, 2007, Leever et al., 2009).
results and dIscussIon
Based on detailed mapping and sampling of the Maeo-
tian and Pontian sequences from the investigated area we
present here the main characteristics of the ostracod assem-
blages from this time interval and a reconstruction of the pal-
aeoenvironments.
The Upper Maeotian deposits from the Badislava and
Toplog sections reach up to 250 m in thickness. Sediments
are represented by coarse gravels, oblique laminated sands,
channel and “ood-plain” type deposits, fossil soils and la-
custrine clays (Figs. 2, 4). The ne-grained intercalations are
Fig. 1. a) Simplied geotectonic map of Romanian Carpathians with the location of the study area; b) Geological map of the Badislava and
Topolog Valleys area with the position of micropaleontological samples; c) North–South schematic cross section on the studied area; Figures a)
and b) modied from Vasiliev et al., 2005

179Geo-Eco-Marina 17/2011
A. Floroiu, M. Stoica, I. Vasiliev, W. Krijgsman – Maeotian / Pontian ostracods in the Badislava –Topolog area
represented by gray or brownish clays and silts with frequent
calcareous concretions, as well as blackish layers rich in plant
debris. They are very scarce in fossil remains, only few bad pre-
served shells of continental or freshwater gastropods (species
of Helicidae and Planorbidae) and bivalves (species of Unio-
nidae) have been observed (Stoica et al., 2007). The micro-
fauna is represented by few species of fresh water ostracods:
Candoniella sp.; Candona sp.; Paracandona albicans (Brady);
Ilyocypris bradyi Sars (Fig 4, Plate 1). These species populated
unstable environments, such as lakes, rivers with temporary
existence and ood-plains. Paracandona albicans, (the adult
specimens show reticulate valves easy to be confused with
juveniles of Pseudocandona Kaufman), lives in fresh-water riv-
ers, lakes and pools. In the Dacian Basin, it has been described
in the Maeotian, Dacian and Romanian fresh water sediments
associated with Cyprideis heterostigma sublittoralis and Cyclo-
cypris sp (Olteanu in Papaianopol et al., 1987; Olteanu, 1995).
This scarce Maeotian ostracod fauna from investigated area
diers essentially from the diversied one of the same stage
from zones that evolved in basinal conditions.
Above the erosional surface, the Pontian starts with sands
and silts, that frequent present wave ripples structures, which
pass to more ne-grained deposits in the upper part. The ne-
grained sediments provided a rich ostracod fauna, indicative
of the Upper Pontian (Bosphorian): Amplocypris dorsobrevis
Sokac; Scottia sp.; Cypria tocorjescui Hanganu; Candona (Cas-
piocypris) ex. gr. alta (Zal.); Candona (Caspiolla) ossoinae Krst.;
Candona (Caspiolla) venusta (Zal.); Candona (Pontoniella) acu-
minata striata Mandelstam; Candona (Pontoniella) excellentis
Olteanu; Candona (Pontoniella) sp.; Candona neglecta Sars;
Bakunella dorsoarcuata (Zal.); Bakunella sp.; Cyprideis sp.1;
Cyprideis sp. 2; Tyrrhenocythere lipescui (Hanganu); Tyrrheno-
cythere motasi Olteanu; Tyrrhenocythere sp.1; Tyrrhenocythere
sp.2; Leptocythere (Amnicythere) palimpsesta Liv.; Leptocythere
Fig. 2. Litho-facial aspects of Maeotian deposits from Badislava Valley section; a) Fluvial deposits with sands and gravel lenses; b) Small channel
cut on ood plain deposits; on the edge of the channel, can be observed fossil roots in original position; c) Interbedded blackish fossil soils and
ood-plain silts; d) Erosional contact between Upper Maeotian ood-plain deposits and Upper Pontian littoral sands and ne gravels

180 Geo-Eco-Marina 17/2011
A. Floroiu, M. Stoica, I. Vasiliev, W. Krijgsman – Maeotian / Pontian ostracods in the Badislava –Topolog area
picturata Liv.; Leptocythere (Amnicythere) multituberculata
(Liv.); Leptocythere sp.; Leptocythere (?) ex. gr. bosqueti (Liv.);
Loxoconcha babazananica Liv.; Loxoconcha schweyeri Suzin;
Loxoconcha petasa Liv.; Loxoconcha sp. (Fig. 4, Plate 1).
The Bosphorian ostracods are more abundant and are
represented by typical species of this sub-stage, as well as by
species that continue to exist in the Lower Dacian (Getian). In
the Dacian Basin, Cypria tocorjescui was described for the rst
time (Hanganu, 1962) from so-called Paradacna abichi levels
(Lower Pontian) and, apparently, it migrated from the Panno-
nian Basin (Pipick in Cziczer et al. 2009). This species was also
noticed in the Upper Pontian sediments with Phyllocardium
planum planum bivalve shells (Hanganu, 1974).
In our samples, we observed the high abundance of
Tyrrhenocythere species. Most of them appeared in the Da-
cian Basin during the Middle Pontian (Portaferrian) and are
well represented in the Upper Pontian (Boshporian), too. The
“bloom” of Tyrrhenocythere lipescui Hanganu in Bospho-
rian is accompanied by the presence of Scottia sp. (Hanganu,
1985). T. lipescui is the most conservative species of the ge-
nus having the most extended distribution in time, from the
base of Middle Pontian up to the Lower Dacian (Olteanu and
Vekua, 1989).
The rst apparition of Bakunella genus is recorded, starting
with the second part of the Lower Pontian. During the Pontian,
this genus is represented by one species: Bakunella dorsoar-
cuata (Zal.). This species seems to be rather conservative con-
cerning the ornamentation pattern along the Pontian, some
changes appearing only during the Dacian (Olteanu, 1989). B.
dorsoarcuata probably evolved in Lake Pannon and was en-
demic to that lake until the Latest Miocene (Pipick in Cziczer et
al. 2009). This species is living today in sublittoral to profundal
depths, in the central and southern Caspian Basin, at salini-
ties of 11.5–13.5% (Gofman 1966, Boomer et al. 2005). Gliozzi,
2007, mentioned the presence of B. dorsoarcuata in the Late
Tortonian - Early Messinian deposits from Mediterranean area
together with other ostracods that migrated from Paratethys
before the onset of MSC. Pontoniella genus emerged with the
Lower Pontian, followed immediately by Bakunella.
Fig. 3. Litho-facial aspects of Upper Pontian deposits from Badislava Valley section a) Sandy littoral deposits with pelitic intercalations transgres-
sively overlaying the Meotian deposits (basal part of Upper Pontian, left bank of Badislava Valley); b) Symmetrical wave ripples on Upper Pontian
sandy deposits; c) Upper Pontian interbedded marls and silts nicely exposed on the Badislava River; d) Silty layer very rich in mollusk shells
(Limnocardiidae bivalves and Vivipariidae gastropods)

181Geo-Eco-Marina 17/2011
A. Floroiu, M. Stoica, I. Vasiliev, W. Krijgsman – Maeotian / Pontian ostracods in the Badislava –Topolog area
Fig. 4. Synthethic log, main litho-logical characteristics and ostracod assemblages of Upper Maeotian, Upper Pontian deposits from
Badislava Valley section

182 Geo-Eco-Marina 17/2011
A. Floroiu, M. Stoica, I. Vasiliev, W. Krijgsman – Maeotian / Pontian ostracods in the Badislava –Topolog area
PLATE 1 Maeotian and Pontian ostracods from Badislava Valley section (all specimens represent adult valves, external lateral views,
LV=left valve, RV=right valve, BBM 09-micropaleontological sample). 1. Candoniella sp., LV, Maeotian, (BBM 09); 2. Paracandona albicans (Brady), LV,
Maeotian, (BBM 11); 3. Iliocypris bradyi Sars, RV, Maeotian, (BBM 09); 4. Amplocypris dorsobrevis Sokac, RV, Upper Pontian, (BBM 41); 5. Cypria tocorjes-
cui Hanganu, RV, Upper Pontian, (BBM 47); 6. Scottia sp., RV, Upper Pontian, (BBM 39); 7. Candona (Caspiocypris) ex. gr. alta (Zal.), LV, Upper Pontian,
(BBM 43); 8. Candona (Caspiolla) ossoinae Krst., LV, Upper Pontian, (BBM 39); 9. Candona (Caspiolla) venusta (Zal.), LV, Upper Pontian, (BBM 40);
10.Candona (Pontoniella) acuminata striata Mandelstam, RV, Upper Pontian, (BBM 28); 11. Candona (Pontoniella) sp., RV, Upper Pontian, (BBM 40);
12. Candona (Pontoniella) excellentis Olteanu, LV, Upper Pontian, (BBM 28); 13. Candona neglecta Sars, RV, Upper Pontian, (BBM 50); 14. Bakunella
dorsoarcuata (Zal.), RV, Upper Pontian, (BBM 52); 15. Cyprideis sp. 1, RV, Upper Pontian, (BBM 40); 16. Cyprideis sp. 2, RV, Upper Pontian, (BBM 41);
17. Tyrrhenocythere lipescui (Hanganu), LV, Upper Pontian, (BBM 33); 18. Tyrrhenocythere motasi Olteanu, LV, Upper Pontian, (BBM 33); 19. Lep-
tocythere (Amnicythere) palimpsesta Liv., RV, Upper Pontian, (BBM 47); 20. Leptocythere (?) ex. gr. bosqueti (Liv.), LV, Upper Pontian, (BBM 38);
21. Loxoconcha schweyeri Suzin, RV, Upper Pontian, (BBM 52); 22. Loxoconcha babazananica Liv., RV, Upper Pontian, (BBM 48)

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A. Floroiu, M. Stoica, I. Vasiliev, W. Krijgsman – Maeotian / Pontian ostracods in the Badislava –Topolog area
An important characteristic of ostracod assemblage
from the investigated area is represented by the high de-
velopment of Amplocypris genus, in the second part of Up-
per Pontian. This genus, with a large shell is represented by
Amplocypris dorsobrevis Sokač, and has been found in several
localities with Pontian sediments from Dacian Basin, as well
as in Yugoslavia (Hanganu, 1976, Sokač, 1989). A similar spe-
cies is described by (Olteanu, 1995) from the Lower Dacian
sediments (Mare Valley-Bengesti) as A. odessaensis (Ilnitzkaia).
However, some additional morphometric studies are need-
ed to nd out which are the real Amplocypris species in the
Dacian Basin. The Cyprideis genus is represented by several
dierent morphotypes, but, for the moment, it is dicult to
mention their specic aliation.
The Upper Pontian (Bosphorian) deposits from the study
area contain also very rich mollusk assemblages dominated
by brackish bivalves and gastropods (Stoica et al., 2007).
conclusIons
The Maeotian / Pontian transition on Badislava Valley sec-
tion comprises an erosional event, with Upper Pontian sedi-
ments discordantly overlying the Maeotian deposits, possi-
bly, as a consequence of the Middle Pontian sea level drop
in the Dacian Basin or local tectonic processes. There are no
indications for the presence of the Lower and Middle Pontian
(Odessian and Portaferrian) substages.
This onset of the Upper Pontian littoral sediments fol-
lowed by shallow basinal ones directly on the Maeotian
uvial deposits is related to a transgressive moment in the
Dacian Basin. This is the last important high stand period
in the Dacian Basin and can possibly be correlated with the
Zanclean transgression (5.33 Ma) of the Mediterranean Basin.
This event marks the Miocene / Pliocene boundary and illus-
trates the complex interactions between the Mediterranean
and Oriental Paratethys Basins (including the Dacian Basin) in
Late Miocene – Early Pliocene times.
The Maeotian ostracod fauna is pore developed and is
represented by few fresh water species able to populate
ephemeral aquatic environments. By contrast, the Upper
Pontian one is more diverse and contains numerous species
characteristic for brackish and more stable shallow water en-
vironment.
references
Boomer I., von GrafensteIn U., GUIchard f., BIeda s., 2005. Modern and
Holocene sublittoral ostracod assemblages (Crustacea) from the
Caspian Sea: A unique brackish, deep-water environment. Pa-
laeogeography, Palaeoclimatology, Palaeoecology, 225: 173–186.
czIczer I., maGyar I., PIPík r., Böhme m., ĆorIĆ s., Bakrač k., sütő-szentaI m.,
Lantos m., BaBInszkI e., müLLer P., 2009. Life in the sublittoral zone
of long-lived Lake Pannon: paleontological analysis of the Upper
Miocene Szák Formation, Hungary. Int. J. Earth Sci (Geol Rundsch),
98: 1741 -1766.
GLIozzI e., cecI m.e., GrossI f., & LIGIos s., 2007. Paratethyan Ostracod im-
migrants in Italy during the Late Miocene. Geobios, 40 (3): 325-337.
Gofman e.a., 1966. Ekologia sovremennykh i novokaspiiskikh ostra-
kod Kaspiiskogo moria (Ecology of the living and new Caspian
ostracodes of the Caspian Sea). Nauka, Moscow, pp. 1-183.
hanGanU e., 1974. Observation sur l‘ostracofaune pontienne de la ré-
gion comprise a la vallée du Danube et la vallée du Motru. Revis-
ta Española de Micropaleontologia VI(3): 335-345.
hanGanU e., 1976. Nouvelles especes de Cyprididae dans le Dacien
superieur de la Muntenie orientale (Roumanie). Bull. Soc. Belge.
Géol. 85(2): 51-61.
hanGanU e., 1985. Un nouveau composant de la faune d‘ostracodes
néogènes post-Méotiens du Bassin Dacique (Roumanie). Rév.
Roum. Géol. Géophys. Géogr., Géol. 29: 65-71.
JIPa d., 1997. Late Neogene–Quaternary evolution of Dacian basin
(Romanian). Ananalysis of sediment thickness pattern. Geo-Eco-
Marina 2, 127–134.
krIJGsman W., hILGen f.J., raffI I., sIerro f.J., WILson d., 1999. Chronology,
causes and progression of the Messinian Salinity Crisis. Nature,
400, p. 652-655.
krIJGsman W., stoIca m., vasILIev I., PoPov v.v., 2010. Rise and fall of the
Paratethys Sea during the Messinian Salinity Crisis. Earth and Pla-
netary Science Letters, 290, p. 183-191.
Leever k., 2007. Foreland of the Romanian Carpathians – controls on
late orogenic sedimentary basin evolution and Paratethys paleo-
geography. PhD thesis, Vrije Universiteit Amsterdam.
Leever k.a., matenco L., răBăGIa t.,cLoetInGh s., krIJGsman W., stoIca m.,
2009. Messinian sea level fall in the Dacic Basin (Eastern Para-
tethys): palaeogeographical implications from seismic sequence
stratigraphy. Terra Nova, 22, 12-17.
oLteanU r., 1989. New Ostracodes in Upper Neogene from Romania.
Mem. Inst. Geol. Geoz. 34: 123-182.
oLteanU r., 1995. Dacian ostracodes. Chronostratigraphie und Ne-
ostratotypen. F. Marinescu and I. Papaianopol eds. Bucuresti, Ed.
Acad. Romane. IX, Pliozän, Dazian: 268-323.
oLteanU r., vekUa m., 1989. Quelques considérations sur les genres
Tyrrhenocythere (Ruggieri, 1995) et Hemicytheria (Pokornyi, 1955)
(Ostracoda, Crustacea) du Négène Supérieur de la Paratéthys.
Geobios, 22 (1), p. 65-79, 9 g., 3 pl.
PaPaIanoPoL I., GrIGoraş m., PoPescU a., oLteanU r., roGGe e., Iva m., costea
c., PîsLarU t., mUnteanU e., 1987. L‘étude du Néogène Supérieur de
la partie orientale de la Plate-Forme Moesienne (secteur d‘entre
la Vallée de Neajlov et le Danube) à considérations sur le Com-
plexe Houiller. D. S. Inst. Geol. Geoz. 72-73(4): p. 209-260.

184 Geo-Eco-Marina 17/2011
A. Floroiu, M. Stoica, I. Vasiliev, W. Krijgsman – Maeotian / Pontian ostracods in the Badislava –Topolog area
sandULescU m., 1984. Geotectonica Romaniei, 450, pp., Editura Teh-
nica, Bucuresti.
sokac a., 1989. Pontian Ostracod fauna in the Pannonian Basin.
Chronostratigraphie und Neostratotypen: Neogen der Westli-
chen (“Zentrale”) Paratethys 8. Pontien . P. Stevanovic, L. A. Ne-
vesskaya, F. Marinescu et al eds, Jazu and Sanu, Zagreb-Beograd:
672–721.
stoIca m., Lazar I., vasILIev I., krIJGsman W., 2007. Mollusc assemblages of the
Pontian and Dacian deposits from the Topolog – Arges area (south-
ern Carpathian foredeep – Romania). Geobios, 40, p. 391-405.
vasILIev I., krIJGsman W., stoIca m., LanGereIs c.G., 2005. Mio-Pliocene
magnetostratigraphy in the southern Carpathian foredeep and
Mediterranean-Paratethys correlations. Terra Nova, 17, p. 376-
384.
vasILIev I., IosIfIdI a.G., vasILIev I., khramov a.n., krIJGsman W., kUIPer k., Lan-
GereIs c.G., PoPov v.v., stoIca m., tomsha v.a., yUdIn s.v., 2011. Mag-
netostratigraphy and radio-isotope dating of upper Miocene–
lower Pliocene sedimentary successions of the Black Sea Basin
(Taman Peninsula, Russia). Palaeogeography, Palaeoclimatology,
Palaeoecology, 310 (3-4): 163-175.