http://france.elsevier.com/direct/GEOBIO

Geobios 40 (2007) 391–405

Original article

Mollusc assemblages of the Pontian and Dacian deposits from the

Topolog-Arges area (southern Carpathian foredeep – Romania)

´

Les associations de mollusques du Pontien et du Dacien de la region

de Topolog-Arges (avant-fosse carpatique meridionale, Roumanie)

Marius Stoica a,b,*, Iuliana Lazar a, Iuliana Vasiliev b, Wout Krijgsman b

a Department of Geology and Paleontology, Faculty of Geology and Geophysics, Bucharest University, Balcescu Bd. 1, 010041, Romaniab Paleomagnetic Laboratory ‘Fort Hoofddijk’, Utrecht University, Budapestlaan 17, 3584 CD Utrecht, The Netherlands

Received 3 March 2005; accepted 21 November 2006

Available online 30 April 2007

Abstract

A better understanding of Mediterranean–Paratethys water-exchange during the Messinian Salinity Crisis has since long been hampered by the

absence of a reliable time frame for the Paratethys. High-resolution magnetostratigraphic studies on the sedimentary sequences of the eastern and

southern Carpathian foredeep recently resulted in an accurate chronology for the Mio-Pliocene deposits of the Dacic Basin of Romania. This

allowed a straightforward correlation of the Pontian and Dacian stages to the geological time scale, which revived earlier discussions on

Mediterranean–Paratethys connectivity. Here, we present Pontian and Dacian mollusc assemblages of the Getic Depression (Topolog-Arges area,

southern Carpathians) of Romania, which are incorporated in a magnetostratigraphic time frame. They indicate that a hiatus – comprising the Early

Pontian – is present in the stratigraphic successions, which could be related to a base level drop of the Paratethys water column or to more local

tectonic processes. The mollusc assemblages furthermore show a gradual transition at the Pontian/Dacian boundary, which is magnetostrati-

graphically dated at�4.9 Ma. This is significantly later (by more than 400 kyrs) than the Mio-Pliocene boundary in the Mediterranean sequences.

# 2007 Elsevier Masson SAS. All rights reserved.

Resume

Une meilleure comprehension des echanges d’eau entre Mediterranee et Paratethys pendant la crise de salinite messinienne etait entravee

depuis longtemps par l’absence d’un cadre chronologique solide pour la Paratethys. Les etudes magnetostratigraphiques a haute resolution sur les

successions sedimentaires de l’est et du sud de l’avant-fosse carpatique ont recemment debouche sur une chronologie precise des depots mio-

pliocenes du bassin Dacique (Roumanie). Cela a permis une correlation directe des etages regionaux Pontien et Dacien avec l’echelle de temps

geologique, qui, de plus, a reanime la discussion sur la potentialite de connexion entre Mediterranee et Paratethys. Ici, nous presentons des

assemblages de mollusques du Pontien et Dacien de la depression Getique (region Topolog-Arges, Carpates meridionales) de la Roumanie, qui sont

inseres dans un cadre chrono-magnetostratigraphique. Ils indiquent dans la succession stratigraphique la presence d’un hiatus du Pontien inferieur

qui pourrait etre rattache a une baisse du niveau de l’eau en Paratethys ou a une intensification locale de la tectonique. Les assemblages de

mollusques montrent en outre une transition graduelle a la limite Pontien/Dacien, qui est datee a�4.9 Ma par la magnetostratigraphie. Cette limite

est significativement plus jeune (plus de 400 ka) que la limite Miocene-Pliocene dans les series mediterraneennes.

# 2007 Elsevier Masson SAS. All rights reserved.

Keywords: Molluscs; Pontian; Dacian; Carpathian foredeep; Eastern Paratethys; Romania

Mots cles : Mollusques ; Pontien ; Dacien ; Avant-fosse carpatique ; Paratethys orientale ; Roumanie

* Corresponding author.

E-mail address: mariuss@geo.edu.ro (M. Stoica).

0016-6995/$ – see front matter # 2007 Elsevier Masson SAS. All rights reserved

doi:10.1016/j.geobios.2006.11.004

1. Introduction

The Late Miocene to Early Pliocene palaeogeographic

evolution of the circum-Mediterranean region is largely

dominated by the dramatic palaeoenvironmental changes

.

M. Stoica et al. / Geobios 40 (2007) 391–405392

related to the Messinian Salinity Crisis (MSC). Progressive

isolation of the Mediterranean from the Atlantic resulted first in

the deposition of massive evaporites (halite, gypsum) all over

the Mediterranean sea floor, followed by a second evaporitic

phase with significantly lower water levels, major erosion at the

margins, and deposition of dominantly non-marine sediments

containing fauna elements indicating Caspi-brackish environ-

ments (Hsu et al., 1973; Clauzon et al., 1996; Krijgsman et al.,

1999). The water level during this second evaporitic phase,

when the Mediterranean was suggested to be a large ‘‘lake sea’’

(Lago Mare), may have been influenced by a major contribution

of fresh water from the Paratethys region (Cita et al., 1990;

Clauzon et al., 2005). The Paratethys (Laskarev, 1924)

comprises the ancient endemic marine-lacustrine bioprovince

that extended from Central Europe to Central Asia, which

became separated from the Mediterranean Tethys bioprovince

(Steininger et al., 1988) by the Alpine-Caucasian orogenic belt

during the Oligo-Miocene (Fig. 1).

The Late Miocene to Early Pliocene palaeogeographic

evolution of the Paratethys region is still ambiguous, mainly

because a reliable time frame has been lacking for its

sedimentary sequences. Ages and duration of the Late Miocene

stages varied in the order of several millions of years according

to the different time scales (Alexeeva et al., 1981; Andreescu,

1981; Semenenko, 1979; Steininger et al., 1996). Consequently,

the exact relation of the palaeoenvironmental events recorded

in the Paratethys region with the Mediterranean MSC events

could not be established or remained highly speculative (Hsu

and Giovanelli, 1979). Recently, however, high-resolution

palynology records and nannofossil data provided new

information about the Paratethys environments and their

relation with the desiccation of the Mediterranean Sea

(Marunteanu and Papaianopol, 1999; Clauzon et al., 2005;

Popescu, 2006; Popescu et al., 2006; Snel et al., 2006).

In the framework of the Dutch research school of Integrated

Solid Earth Sciences (ISES), magnetostratigraphic time scales

Fig. 1. Schematic map of the Late Miocene showing the Mediterranean and its poten

The marine gateways are drawn according to Krijgsman (2002).

Fig. 1. Carte schematique des connexions potentielles de la Mediterranee avec la P

corridors marins sont traces selon Krijgsman (2002).

have been constructed for the sedimentary sequences of the

eastern and southern Carpathian foredeep (Vasiliev et al., 2004,

2005). This resulted in high-resolution chronologies for the

Meotian to Romanian (�7–4 Ma) sediments of the Focsani Basin

(Eastern Carpathians) and the Getic Depression (Southern

Carpathians) (Fig. 2). The main conclusion was that the ages of

the main stage boundaries are roughly synchronous in the entire

Carpathian foredeep of Romania and that the observed

environmental changes are at least of regional importance.

Here, we present the distribution of the mollusc assemblages

from the Pontian and Dacian stages of the Getic Depression in

the southern Carpathian foredeep (Topolog-Arges area). These

assemblages have been incorporated in the magnetostrati-

graphic results from the same sections. This allows us to

accurately date the main palaeoenvironmental changes in this

part of the Eastern Paratethys (Dacic Basin), which can directly

be compared to the detailed event stratigraphy of the

Mediterranean MSC.

2. Geological setting and background

The Carpathian mountain belt mainly resulted from large-

scale plate tectonic processes that closed a Triassic-Jurassic

oceanic basin, called Mures-Vardar, during the Cretaceous

(Sandulescu, 1984; Ciulavu et al., 2000). The Carpathian belt is

geographically located between the Alps in the West and the

Balkan and the Rhodope mountains in the South. The Southern

Carpathian foredeep, also known as Getic Depression (Fig. 2a),

represents the sedimentary basin that developed at the contact

between the South Carpathian nappe pile and the Moesian

Platform (Rabagia and Matenco, 1999; Sandulescu, 1984). The

evolution of the Getic Depression was characterized by

Palaeogene to Early Miocene extension/transtension followed

by large scale Middle to Late Miocene contractional to

transpressional deformation. The entire system is overlain by

1–2 km of Pliocene sediments and is slightly deformed during a

tial water connections with the Central and Eastern Paratethys and the Atlantic.

aratethys centrale et orientale et avec l’Atlantique au Miocene superieur. Les

Fig. 2. (a) Location of the study area in the Romanian Carpathians. (b) Geological map of the Southern Carpathians foredeep (after Bombita et al., 1967). The

sections sampled for magnetostratigraphy are marked with thick grey lines along the river courses. The different types of shading correspond to the different Mio-

Pliocene stages in the area of Badislava and Topolog confluence. According to Steininger et al. (1996), the Sarmatian s.l. from the Carpathians Foredeep contains

Volhynian and Bessarabian which belong to Middle Miocene and Khersonian belonging to Late Miocene. Therefore, in the legend we introduce a distinct pattern for

Sarmatian s.l. The continuous-line rectangle shows the area where both magneto-and biostratigraphic sampling was made. The dotted-line rectangle shows the entire

biostratigraphically sampled area. (c) Detailed topographic map of the magneto-and biostratigraphic sampled area. The stars correspond to palaeontological sites.

Black-white lines along the river represent the polarity pattern inferred from magnetostratigraphy. Mi2 = Middle Miocene, me = Meotian, p = Pontian, dc = Dacian,

rm = Romanian and Q = Quaternary.

Fig. 2. (a) Localisation de la region etudiee dans les Carpates roumaines. (b) Carte geologique de l’avant-fosse des Carpates meridionales (d’apres Bombita et al.,

1967). Les coupes echantillonnees pour la magnetostratigraphie sont indiquees par d’epais traits gris fonce le long des rivieres. Les aires colorees de gris differents

correspondent aux etages du Mio-Pliocene du secteur de la confluence entre les rivieres Badislava et Topolog. Selon Steininger et al. (1996), le Sarmatien s.l. de

l’avant-fosse carpatique inclut Volhynien et Bessarabien qui appartiennent au Miocene moyen et Khersonien qui releve du Miocene superieur. Nous avons donc

introduit un symbole distinct pour le Sarmatien s.l. Le rectangle a contour en trait continu indique le secteur ou les echantillonnages magnetostratigraphiques et

biostratigraphiques ont ete realises. Le rectangle a contour en trait discontinu indique la zone qui ete etudiee du point de vue biostratigraphique. (c) Carte

topographique detaillee du secteur echantillonne pour les analyses magnetostratigraphiques et biostratigraphiques. Les etoiles localisent les sites paleontologiques.

Les figures blanc-noir des traits le long des rivieres illustrent la polarite paleomagnetique. Mi2 = Miocene moyen ; me = Meotien ; p = Pontien ; dc = Dacien ;

rm = Romanien ; Q = Quaternaire.

M. Stoica et al. / Geobios 40 (2007) 391–405 393

Late Pliocene tectonic event (Rabagia and Matenco, 1999). To

the South, the depression is delimited by the surface projection

of the buried Miocene detachment front (so-called ‘‘peri-

Carpathian line’’) (Fig. 2a). The Eastern limit is formed by the

Northern extension of the Intramoesian fault, which separates

the Getic Depression from the thin-skinned belt of the outer

East Carpathians, and the western limit is determined by the

Danube River (Fig. 2a).

Late Miocene and Pliocene sedimentary sequences are very

well exposed in the Northern part of the Getic Depression,

especially West of the Arges River valley (Fig. 2b). A

magnetostratigraphic time scale has recently been developed

for the Meotian, Pontian, Dacian and Romanian deposits of the

Southern Carpathian foredeep, based on the magnetic polarity

sequences of the Badislava and Topolog sections (Vasiliev

et al., 2005). The sections start stratigraphically in Meotian

deposits and end in the lower part of the Romanian, south of the

confluence between the Badislava and Topolog Valleys

(Fig. 2b,c). 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

(Fig. 3). The lengths of the polarity zones are in good agreement

Fig. 3. Correlation of the polarity patterns of the Badislava and Topolog sections to the GPTS (Lourens et al., 2004). In the polarity columns, black and white denotes

normal, respectively reversed polarity intervals. Next to the GPTS are the Stage boundaries according to the 34 Pitesti, 1:200.000 scale map (Bombita et al., 1967).

The dashed lines between the sections and GPTS connect (interpretative) simultaneous polarity boundaries. C (Cochiti), N (Nunivak), S (Sidufjall) and T (Thvera) are

the historical names for the normal subchrons of the Gilbert Chron. The age intervals for the stage boundaries in the Southern Carpathian (SC) foredeep (Badislava

and Topolog) and the Eastern Carpathian (EC) foredeep (after Vasiliev et al., 2004, 2005) are approximately synchronous within uncertainty of �150 kyrs (shaded

areas). On the right-hand side of Badislava and Topolog magnetostratigraphic records, the indicative P followed by a number represents the paleontological sites taken

from the riverbanks. They coincide with palaeomagnetic sites and therefore the exact correlation was possible. The right-hand column shows the Mediterranean

(MED) time scale for the Late Miocene-Early Pliocene with the Late Messinian Lower evaporites (LE) and Upper evaporites (UE) units of the Messinian Salinity

Crisis (after Krijgsman et al., 2001).

Fig. 3. Correlation des enregistrements de polarite paleomagnetique a Badislava et Topolog avec l’echelle geomagnetique et chronologique globale (Lourens et al., 2004),

les episodes normaux sont en noir, les episodes inverses en blanc. Les correlations sont aussi etablies avec les limites des etages regionaux par reference a la carte

geologique de Pitesti (34) au 1/200 000e (Bombita et al., 1967). Les lignes en pointilles tracees entre les coupes et l’echelle globale relient les inversions paleomagnetiques

interpretees comme correspondantes. C (Cochiti), N (Nunivak), S (Sidufjall) et T (Thvera) sont les noms historiques des episodes paleomagnetiques au sein de la periode

Gilbert. L’age des limites des etages regionaux dans la partie meridionale (SC : Badislava et Topolog) et orientale (EC : d’apres Vasiliev et al., 2004, 2005) de l’avant-fosse

M. Stoica et al. / Geobios 40 (2007) 391–405394

carpatique est a peu pres similaire avec des incertitudes de�150 ka (aires grisees). A droite de l’enregistrement paleomagnetique des deux coupes, Badislava et Topolog,

le symbole P suivi d’un nombre situe les faunes fossiles enregistrees le long des rivieres. Leur emplacement coıncide avec les mesures paleomagnetiques ce qui permet des

correlations precises. La derniere colonne a droite donne la chronologie mediterraneenne (MED) pour le Miocene superieur et le Pliocene inferieur avec la localisation des

Evaporites Inferieures (LE) et Superieures (UE) de la crise de salinite messinienne (selon Krijgsman et al., 2001).

Fig. 4. Synthetic log and molluscan content of the Pontian-Dacian deposits of the study area in the Topolog-Arges region, South Carpathian foredeep, Romania.

Fig. 4. Description synthetique des sediments du Pontien et Dacien et de leur contenu en mollusques dans le secteur etudie de la region Topolog-Arges (avant-fosse

carpatique meridionale, Roumanie).

M. Stoica et al. / Geobios 40 (2007) 391–405 395

Fig. 5. Late Pontian gastropods from the Topolog-Arges region, South Carpathian foredeep, Romania: 1–3. Theodoxus (Calvertia) licherdopoli scriptus (Stefanescu),

Topolog Valley; 1a,b, complete specimen with dark coloration, no. LPBIIIg 3417, � 2; 2a,b, complete specimen with almost straight dark lines, no. LPBIIIg 3418,

� 2; 3a,b, poor preserved specimen, with twisted dark lines, no. LPBIIIg 3419, � 2. 4a,b. Theodoxus (Calvertia) sp., Topolog Valley, poorly preserved specimen,

no. LPBIIIg 3420,� 2. 5, 6. Melanopsis decollata Stoliczka, Arges Valley; 5, complete specimen in apertural view, no. LPBIIIg 3421,� 2; 6, complete specimen in

apertural view, no. LPBIIIg 3422, � 2. 7a,b. Viviparus incertus Macarovici, Arges Valley, complete shell, no. LPBIIIg 3423, � 1. 8a–c. Valenciennius facetus

rotundus Taktasvili, Topolog Valley; a, internal mould with fragments of shell, no. LPBIIIg 3424, � 1; b, external mould, no. LPBIIIg 3425, � 1; c, incomplete

internal mould, no. LPBIIIg 3426,� 1. 9a,b. Valenciennius krambergeri Hoernes, Topolog Valley; a, internal mould with fragments of shell, no. LPBIIIg 3427,� 1;

M. Stoica et al. / Geobios 40 (2007) 391–405396

M. Stoica et al. / Geobios 40 (2007) 391–405 397

between the two sections and this characteristic pattern

correlates excellently to subchrons C3n.4n (Thvera), C3n.3r,

C3n.3n (Sidufjall), C3n.2r, C3n.2n (Nunivak), C3n.1r and

C3n.1n (Cochiti) (Fig. 3). Correlation with the astronomically

dated GPTS (Lourens et al., 2004) indicates that the Pontian/

Dacian boundary is dated around C3n.3n (Sidufjall) at�4.9 Ma

and the Dacian/Romanian boundary in the lower part of C2Ar

at �4.1 Ma (Fig. 3). These palaeomagnetic results furthermore

helped to better constrain the tectonic evolution of the

Carpathians by establishing the pattern and timing of tectonic

rotations (Dupont-Nivet et al., 2005).

3. Biostratigraphic considerations

The mollusc assemblages described in this paper were

collected from the Pontian and Dacian units that crop out in the

study area between the Arges and Topolog river valleys and

their affluences (Fig. 2b). This region reveals one of the best

exposed Mio-Pliocene sequences of the Carpathian foredeep of

Romania. Throughout the study area, the sedimentary strata

show a monoclinal structure with a bedding orientation dipping

approximately 15–208 to the south. The sedimentary rocks

consist of alternations of blue to grey sandstones, siltstones and

clays (Fig. 4). The Meotian part of the sequence is relatively

coarse grained, containing mainly blue-grey sandy-silty

deposits. The upper part of the Bosphorian (Late Pontian)

and the lower part of the Getian (Early Dacian) are more fine-

grained consisting predominantly of blue-grey silty clays. The

upper part of the Getian and Romanian deposits are again

progressively coarser, and show intercalations of coal layers.

The Meotian is mainly represented by siliciclastic deposits

and consists of conglomerates and sandstones alternating with

silts and marls. The macrofauna is poorly represented and

predominantly composed of broken shell fragments. Nedelcu

and Mateescu (1962) and Mihaila (1971) described the

following species from these deposits: Congeria panticapea

panticapea Andrusov, C. panticapea tournoueri Andrusov,

C. novorossica navicula (Andrusov), Dreissenomya unionides

rumana (Wenz), Theodoxus crenulatus semiplicatus (Neu-

mayr).

The Pontian deposits crop out in the north on a 2.5 km wide

zone between Arges and Topolog Valley (Fig. 2) and are

represented only by Late Pontian (Bosphorian) molluscs

(Figs. 5 and 6). These Late Pontian deposits are discordantly

overlying (paraconformity) the Meotian deposits and are

b, internal mould with fragments of shell, no. LPBIIIg 3428,� 1. 10. Valenciennius fi

3429, � 1. 11. Valenciennius sp., Topolog Valley, incomplete internal mould, no.

Fig. 5. Gasteropodes du Pontien superieur de la region Topolog-Arges (avant-fosse

scriptus (Stefanescu), vallee de la riviere Topolog : 1a,b, specimen entier avec une c

sombres assez rectilignes, no LPBIIIg 3418, � 2 ; 3a,b, specimen mal conserve,

(Calvertia) sp., vallee de la riviere Topolog, specimen mal conserve, no LPBIIIg 3420

en vue aperturale, no LPBIIIg 3421,� 2 ; 6, specimen entier en vue aperturale, no LPB

complete, no LPBIIIg 3423, � 1. 8a–c. Valenciennius facetus rotundus Taktasvili,

no LPBIIIg 3424,� 1 ; b, moule externe, no LPBIIIg 3425,� 1 ; c, moule interne inc

de la riviere Topolog : a, moule interne avec fragments de coquille, no LPBIIIg 3427

Valenciennius filipescui Hanganu, vallee de l’Arges, coquille incomplete et mal cons

moule interne incomplet, no LPBIIIg 3430, � 1.

followed by Early Dacian sediments. The Bosphorian deposits

can be separated in two distinct lithological units: the lower unit

is mainly represented by weakly cemented, fine to slightly

coarse yellow and grey sands, alternating with thin clay and

marl levels (0.1–0.7 m thick). The total thickness for this lower

unit is around 580 m. The upper unit predominantly consists of

grey marls with intercalations of sands and clays, and has a total

thickness ranging between 25 and 30 m.

The mollusc assemblages collected from the lower part of

the Bosphorian sequence include the following species:

Viviparus incertus Macarovici, V. botenicus Lubenescu,

Melanopsis decollata Stoliczka, Theodoxus (Calvertia) licher-

dopoli scriptus (Stefanescu), T. (C.) sp., T. galeatus Marinescu,

Dacicardium vetustum Papaianopol, D. rumanum (Fontannes),

Pontalmyra (Pontalmyra) dacica Papaianopol, P. (P.) intima

Papaianopol, Zamphiridacna sp., Congeria subcarinata bote-

nica Andrusov, Chartoconcha bayerni (R. Hoernes),

D. rimestiensis Fontannes, D. polymorpha berbestiensis

Fontannes.

The upper part of the Bosphorian sequence is characterized

by several mollusc assemblages, which are clearly influenced

by the different types of sediment. In the lower part of the

succession, especially in Topolog Valley, we have identified

assemblages with Valenciennius sp., Dreissena polymorpha

Pallas, D. rimestiensis Fontannes, Viviparus incertus Macar-

ovici, V. botenicus Lubenescu that were found in delicately

stratified, grey marls. In this part the viviparidae, gastropods

and the dreissenidae bivalves are very abundant.

In the outcrops situated at the junction between the Topolog

Valley and Pietroasa Valley (Fig. 2c) we observed a typical

succession that contained from bottom to top:

� G

lip

LP

c

olo

av

,�II

val

om

, �erv

rey and bluish marls with sandy micaferous intercalations,

very rich in fossils: Unio (Rumanunio) rumanus (Tournouer),

Zamphiridacna cucestiensis (Fontannes), Pseudocatillus sp.,

Melanopsis decollata Stoliczka, Viviparus incertus Macar-

ovici, V. botenicus Lubenescu and small Lymnocardiinae. In

other outcrops, the same fossil assemblage also includes

specimens of Hyriopsis sp. 1 and Cristaria sp.;

� G

rey-bluish marls, 6 m thick, with a faunal assemblage

dominated by the species Caladacna steindachneri (Brusina)

that is represented by a very high number of specimens,

associated with Limnocardium (Tauricardium) petersi nasyr-

ica Ebersin, L. (Arpadicardium) peregrinum Ebersin,

L. (Euxinicardim) sacelum Papaianopol, Lunadacna lunae

escui Hanganu, Arges Valley, poorly preserved, incomplete shell, no. LPBIIIg

BIIIg 3430, � 1.

arpatique meridionale, Roumanie). 1–3. Theodoxus (Calvertia) licherdopoli

ration sombre, no LPBIIIg 3417,� 2 ; 2a,b, specimen entier avec des bandes

ec des bandes sombres courbees, no LPBIIIg 3419, � 2. 4a,b. Theodoxus

2. 5, 6. Melanopsis decollata Stoliczka, vallee de l’Arges : 5, specimen entier

Ig 3422,� 2. 7a,b. Viviparus incertus Macarovici, vallee de l’Arges, coquille

lee de la riviere Topolog : a, moule interne avec des fragments de coquille,

plet, no LPBIIIg 3426,� 1. 9a,b. Valenciennius krambergeri Hoernes, vallee

1 ; b, moule interne avec fragments de coquille, no LPBIIIg 3428, � 1. 10.

ee, no LPBIIIg 3429,� 1. 11. Valenciennius sp., vallee de la riviere Topolog,

Fig. 6. Late Pontian bivalves from the Topolog-Arges region, South Carpathian foredeep, Romania: 1, 2. Limnocardium (Tauricardium) petersi nasyrica Ebersin,

Topolog Valley; 1, right valve internal mould, no. LPBIIIl 1878-1, � 1; 2, internal view of right valve, no. LPBIIIl 1878–2, � 1. 3. Limnocardium (Arpadicardium)

peregrinum Ebersin, Topolog Valley; composite mould of left valve, no. LPBIIIl 1879 � 1. 4. Limnocardium (Euxinicardim) sacelum Papaianopol, Topolog Valley,

external view of right valve, no. LPBIIIl 1880,� 1. 5, 6. Caladacna steindachneri (Brusina), Topolog Valley; 5, composite mould of left valve, no. LPBIIIl 1881,� 1;

6, composite mould of left valve, no. LPBIIIl 1882,� 1. 7. Lunadacna lunae (Voitesti), Topolog Valley, composite mould of left valve, no. LPBIIIl 1883,� 1; 8a,b.

Pontalmyra (Pontalmyra) dacica Papaianopol, Topolog Valley, complete right valve, no. LPBIIIl 1884, � 1; a, external view; b, internal view. 9. Pontalmyra

(Pontalmyra) concina Papaianopol, Topolog Valley, complete left valve, no. LPBIIIl 1885, � 1. 10. Pontalmyra (Pontalmyra) intima Papaianopol, Topolog Valley,

M. Stoica et al. / Geobios 40 (2007) 391–405398

M. Stoica et al. / Geobios 40 (2007) 391–405 399

(Voitesti), Prosodacna (Prosodacna) semisulcata antiqua

Ebersin, Prosodacna (Prosodacna) semisulcata angustata

(Ebersin), Pontalmyra (Pontalmyra) dacica Papaianopol, P.

(P.) concina Papaianopol and rarely, Pseudocatillus sp.,

Valenciennius krambergeri Hoernes, V. facetus rotundus

Taktasvili and fish teeth.

In other outcrops of the upper part of the Bosphorian Stage,

where the sediments are predominantly sandy with only a very

low proportion of argillaceous components, the macrofaunal

assemblage is represented by typical species like: Dreissena

rimestiensis Fontannes, D. polymorpha berbestiensis Fon-

tannes, Unio (Rumanunio) rumanus (Tournouer), Dacicardium

rumanum (Fontannes), D. vetustum Papaianopol, Prosodacno-

mya sturi sabbae Andreescu, Pseudoprosodacna semisulca-

toides (Ebersin), Limnocardium (Euxinicardim) sacelum

(Papaianopol), Theodoxus (Calvertia) licherdopoli scriptus

(Stefanescu), T. galeatus Marinescu.

The Early Dacian (Getian) deposits crop out between Arges

and Topolog Valley on a 1.5 km wide zone (Fig. 2b,c). The

Getian succession can also be split in two lithological units with

characteristic faunal assemblages (Figs. 7 and 8). A lower unit

is represented by weakly-cemented sands alternating with

marls and argillaceous levels, is rich in fossils and has a total

thickness around 50 m. The upper unit is very thick,

approximately 500 m, represented by sands and pebbles or

weakly-cemented conglomerates, and is very poor in macro-

fossils. In addition, it contains four coal beds (xyloid lignite) at

different levels.

In the lower Getian unit, we identified two types of

macrofaunal assemblages. One is associated with sands:

Stylodacna heberti (Cobalcescu), Zamphiridacna cuces-

tiensis (Fontannes), Z. orientalis (Sabba), Prosodacna (Psilo-

don) munieri Sabba, Dreissena rimestiensis Fontannes,

D. polymorpha berbestiensis Fontannes, D. graegata Fontannes,

incomplete right valve, no. LPBIIIl 1886, � 1. 11. Prosodacna (Prosodacna) inaud

12a,b. Dacicardium vetustum Papaianopol, Arges Valley, complete right valve,

(Prosodacna) semisulcata (Rousseau), Topolog Valley, composite mould of right valv

Valley; composite mould of disarticulated shell, no. LPBIIIl 1890, � 1. 15. Prosoda

with shell fragments of right valve, no. LPBIIIl 1891,� 1. 16a,b. Zamphiridacna sp.

internal view. 17a,b. Congeria subcarinata botenica Andrusov, Topolog Valley, le

(Rumanunio) sp., Arges Valley, incomplete left valve, no. LPBIIIl 1894, � 1. 19.

Fig. 6. Bivalves du Pontien superieur de la region Topolog-Arges (avant-fosse ca

nasyrica Ebersin, vallee de la riviere Topolog : 1, moule interne de valve droite, no L

Limnocardium (Arpadicardium) peregrinum Ebersin, vallee de la riviere Topolog,

(Euxinicardim) sacelum Papaianopol, vallee de la riviere Topolog, vue externe de val

de la riviere Topolog : 5, moule reconstitue de valve gauche, no LPBIIIl 1881,� 1 ; 6(Voitesti), vallee de la riviere Topolog, moule reconstitue de valve gauche, no LPBI

riviere Topolog, valve droite entiere, no LPBIIIl 1884, � 1 : a, vue externe, b, vue

Topolog, valve gauche entiere, no LPBIIIl 1885, � 1. 10. Pontalmyra (Pontalmyr

no LPBIIIl 1886, � 1. 11. Prosodacna (Prosodacna) inaudita Papaianopol, vallee d

vetustum Papaianopol, vallee de l’Arges, valve droite entiere, no LPBIIIl 1888, �(Rousseau), vallee de la riviere Topolog, moule reconstitue de valve droite, no LPBI

Topolog ; moule reconstitue d’une coquille disloquee, no LPBIIIl 1890,� 1. 15. Pros

moule interne de valve droite avec des fragments de coquille, no LPBIIIl 1891,� 1. 16� 1 : a, vue externe, b, vue interne. 17a,b. Congeria subcarinata botenica Andrusov,

b, vue interne. 18. Unio (Rumanunio) sp., vallee de l’Arges, valve gauche incomplete

de coquille, no LPBIIIl 1895, � 1.

D. berbestiensis Fontannes, D. rumana Sabba, small-sized

lymnocardiinae, Viviparus rumanus (Tournouer), V. duboisi

(Mayer-Eymar), V. monasterialis (Fontannes), V. berbestiensis

Lubenescu, V. muscelensis Lubenescu.

The assemblages associated with marls and argillaceous

levels contain: Stylodacna heberti (Cobalcescu), Zamphiri-

dacna orientalis (Sabba), Chartoconcha bayerni (R. Hoernes),

Prosodacna (Prosodacna) macrodon minor Ebersin, P. (P.)

parmata Papaianopol and Lubenescu, P. (P.) longiuscula minor

Andreescu, Dacicardium rumanum (Fontannes), D. dacianum

(Papaianopol), Pachydacna (Parapachydacna) serena (Sabba),

P. (P.) cobalcescui (Fontannes), P. (P.) sabbae Ebersin, P. (P.)

mirabilis (Teisseyre), Dreissena rimestiensis Fontannes, D.

polymorpha Pallas, D. polymorpha berbestiensis Fontannes,

Hyriopsis sp. 2, Viviparus rumanus (Tournouer), V. duboisi

(Mayer-Eymar), V. monasterialis (Fontannes), V. berbestiensis

Lubenescu, V. getianus Lubenescu, V. Argesiensis (Sabba), V.

muscelensis Lubenescu, V. dacianus Lubenescu, V. cucestiensis

Lubenescu, Bulimus (Tylopoma) speciosus (Cobalcescu),

Lithoglyphus acutus decipiens Brusina, Hydrobia grandis

Cobalcescu, Gyraulus (Gyraulus) rumanus Wenz.

4. Discussion

4.1. Palaeoenvironmental reconstructions

The poor conservation of the shells and the fact that they

have no preferred orientation – some of them are broken or

disarticulated – indicate accumulation in a high-energy

shoreline environment. The gastropods and bivalves probably

have been transported and accumulated near the margins of a

lake or a marsh during episodic floods. There are only few

levels where genera like Melanopsis, Theodoxus and Unio are

preserved with complete shells. This indicates the presence of

an environment represented by shallow, sparsely vegetated,

ita Papaianopol, Arges Valley, incomplete right valve, no. LPBIIIl 1887, � 1.

no. LPBIIIl 1888, � 2; a, external view; b, internal view. 13. Prosodacna

e, no. LPBIIIl 1889,� 1. 14. Prosodacnomya sturi sabbae Andreescu, Topolog

cna (Prosodacna) semisulcata antiqua Ebersin, Topolog Valley, internal mould

, Arges Valley, complete right valve, no. LPBIIIl 1892,� 1; a, external view; b,

ft valve, no. LPBIIIl 1893, � 1; a, external view; b, internal view. 18. Unio

Hyriopsis sp. 1, Topolog Valley, fragment of shell, no. LPBIIIl 1895, � 1.

rpatique meridionale, Roumanie). 1, 2. Limnocardium (Tauricardium) petersi

PBIIIl 1878–1, � 1 ; 2, vue interne de valve droite, no LPBIIIl 1878–2, � 1. 3.

moule reconstitue de valve gauche, no LPBIIIl 1879, � 1. 4. Limnocardium

ve droite, no LPBIIIl 1880,� 1. 5, 6. Caladacna steindachneri (Brusina), vallee

, moule reconstitue de valve gauche, no LPBIIIl 1882,� 1. 7. Lunadacna lunae

IIl 1883, � 1. 8a,b. Pontalmyra (Pontalmyra) dacica Papaianopol, vallee de la

interne. 9. Pontalmyra (Pontalmyra) concina Papaianopol, vallee de la riviere

a) intima Papaianopol, vallee de la riviere Topolog, valve droite incomplete,

e l’Arges, valve droite incomplete, no LPBIIIl 1887, � 1. 12a,b. Dacicardium

2 : a, vue externe, b, vue interne. 13. Prosodacna (Prosodacna) semisulcata

IIl 1889, � 1 . 14. Prosodacnomya sturi sabbae Andreescu, vallee de la riviere

odacna (Prosodacna) semisulcata antiqua Ebersin, vallee de la riviere Topolog,

a,b. Zamphiridacna sp., vallee de l’Arges, valve droite entiere, no LPBIIIl 1892,

vallee de la riviere Topolog, valve gauche, no LPBIIIl 1893,� 1 : a, vue externe,

, no LPBIIIl 1894,� 1. 19. Hyriopsis sp. 1, vallee de la riviere Topolog, fragment

Fig. 7. Early Dacian gastropods from the Topolog-Arges region, South Carpathian foredeep, Romania: 1a,b. Viviparus dacianus Lubenescu, Arges Valley, complete

specimen; a, apertural view, b. lateral view; no. LPBIIIg 3431,� 1. 2a,b. Viviparus getianus Lubenescu, Arges Valley, almost complete specimen; a, apertural view,

b. lateral view; no. LPBIIIg 3432,� 1. 3a,b. Viviparus cucestiensis Lubenescu, Arges Valley, complete specimen; a, apertural view, b, lateral view; no. LPBIIIg 3433,

� 1. 4a,b. Viviparus monasterialis (Fontannes), Arges Valley, complete specimen; a, apertural view, b, lateral view; no. LPBIIIg 3434, � 1. 5a,b. Viviparus duboisi

(Mayer-Eymar), Topolog Valley, complete specimen; a, apertural view, b, lateral view; no. LPBIIIg 3435,� 1. 6a,b. Viviparus duboisi (Mayer-Eymar), Arges Valley,

complete specimen; a, apertural view, b, lateral view; no. LPBIIIg 3436, � 1. 7a,b. Viviparus Argesiensis Sabba, Topolog Valley, complete specimen; a, apertural

view, b, lateral view; no. LPBIIIg 3437, � 1. 8a,b. Viviparus berbestiensis Lubenescu, Arges Valley, complete specimen; a, apertural view, b, lateral view;

M. Stoica et al. / Geobios 40 (2007) 391–405400

M. Stoica et al. / Geobios 40 (2007) 391–405 401

freshwater lakes. The same association was recently observed

in modern environments (Plaziat and Younis, 2005). Specimens

of Unio (Rumanunio) rumanus (Tournouer) are usually present

with both valves; they are preserved in life position due to their

shallow infaunal or semi-infaunal mode of life. In the lower,

predominantly sandy, Bosphorian unit, two coal layers are

present that are accompanied by very rich fossiliferous beds.

Here, the high diversity of mollusc species indicates slow

flowing water in the channels that drain the marshes where the

coals have been formed. The macrofaunal assemblages

associated with marls of the upper Bosphorian unit indicate

deeper-water sedimentation in a lacustrine environment.

4.2. The Pontian-Dacian boundary interval

There are no evident lithological changes at Pontian/Dacian

boundary in our sections of the southern Carpathian foredeep.

Hence, the transition from Bosphorian to Getian deposits can

only be recorded using palaeontological data (molluscs and

ostracods). The Pontian/Dacian boundary is discussed in detail

by Hanganu and Papaianopol (1977) and Papaianopol and

Marinescu (1995), who claim that the Bosphorian/Getian

boundary in the Carpathian foredeep area could be character-

ized by: (1) a very clear, trenchant limit, assigned by specific

palaeobiologic features such as the flourishing of the subgenus

Pachydacna; the high abundance of the species Zamphiridacna

orientalis (Sabba); the high abundance of the prosodacnae

bivalves and the increase in new species of Pontalmyra,

Euxynicardium, Pseudaocatillus, Dacicardium, Psilunio,

Dreissena and Viviparus genera; (2) a gradual transition in

the faunal assemblages where Early Dacian species of

Stylodacna and Pachydacna (Parapachydacna) genera are still

associated with Pontian species of Tauricardium, Pontalmyra,

Caladacna and Phyllocardium genera. In the study area, the

Pontian/Dacian boundary is difficult to determine on the basis

of macrofaunal content of the fossil assemblages only, because

the Bosphorian and Getian macrofossil assemblages show a

no. LPBIIIg 3438,� 1. 9a,b. Viviparus berbestiensis Lubenescu, Topolog Valley, com

Viviparus macarovicii Lubenescu, Arges Valley, complete specimen; a, apertural

Lubenescu, Arges Valley, complete specimen; a, apertural view, b, lateral view; no.

Valley, complete specimen; a, apertural view, b, lateral view; no. LPBIIIg 3442, �specimen; a, apertural view, b, lateral view; no. LPBIIIg 3443, � 2. 14a,b. Lithogl

view, b, lateral view; no. LPBIIIg 3444,� 2. 15. Hydrobia grandis Cobalcescu, Topo

Gyraulus (Gyraulus) rumanus Wenz, Arges valley, complete specimen; a, umbilic

Fig. 7. Gasteropodes du Dacien inferieur de la region Topolog-Arges (avant-fosse car

l’Arges, specimen entier : a, vue aperturale, b, vue laterale ; no LPBIIIg 3431,� 1. 2avue aperturale, b, vue laterale, no LPBIIIg 3432, � 1. 3a,b. Viviparus cucestiensis L

no LPBIIIg 3433, � 1. 4a,b. Viviparus monasterialis (Fontannes), vallee de l’Arges,

Viviparus duboisi (Mayer-Eymar), vallee de la riviere Topolog, specimen entier : a(Mayer-Eymar), vallee de l’Arges, specimen entier : a, vue aperturale, b, vue lateral

Topolog, specimen complet : a, vue aperturale, b, vue laterale, no LPBIIIg 3437,� 1

vue aperturale, b, vue laterale, no LPBIIIg 3438,� 1. 9a,b. Viviparus berbestiensis L

laterale, no LPBIIIg 3439, � 1. 10a,b. Viviparus macarovicii Lubenescu, vallee de l’

� 1. 11a,b. Viviparus macarovicii Lubenescu, vallee de l’Arges, specimen entier : a, v

speciosus (Cobalcescu), vallee de l’Arges, specimen entier : a, vue aperturale, b(Cobalcescu), vallee de l’Arges, specimen entier : a, vue aperturale, b, vue laterale,

l’Arges, specimen entier : a, vue aperturale, b, vue laterale, no LPBIIIg 3444,� 2. 15vue aperturale, no LPBIIIg 3445,� 5 ; 16a,b. Gyraulus (Gyraulus) rumanus Wenz, v

3444, � 2.

gradual transition. Species like Stylodacna heberti (Cobal-

cescu), Dacicardium rumanum (Fontannes), Unio (Rumanunio)

rumanus (Tournouer), Dreissena rimestiensis Fontannes that

are basically distinctive for the Getian substage have been

recorded also in the uppermost Bosphorian. We furthermore

observed that Bosphorian assemblages also contain species

like: Stylodacna heberti (Cobalcescu), Dacicardium rumanum

(Fontannes), Unio (Rumanunio) rumanus (Tournouer), Dreis-

sena rimestiensis Fontannes, species that are basically

distinctive for the Getian Stage.

Earlier biostratigraphic studies focusing on both mollusc

and ostracod assemblages led to the construction of a detailed

geological map for the southern Carpathian foredeep in which

the Pontian-Dacian boundary is reasonably well determined

(Bombita et al., 1967). Introducing the magnetic polarity

patterns on a georeferenced database and locating these on the

geological map of the region (34 Pitesti, 1:200.000 scale),

allowed us to determine the age of the Pontian/Dacian boundary

around C3n.3n (Sidufjall) at �4.9 Ma (Vasiliev et al., 2005).

High-resolution studies on the microfaunal assemblages,

however, will be necessary to better constrain the exact

location of this stage boundary in our sections.

4.3. Correlation with the Messinian Salinity Crisis

During the last decade, much progress has been made on the

chronostratigraphic framework for the Messinian Stage, when

the entire Mediterranean region experienced the devastating

consequences of the Messinian Salinity Crisis (Gautier et al.,

1994; Krijgsman et al., 1999; Clauzon et al., 1996, 2005). Most

chronological scenarios for the MSC now seem to converge to

the period between �5.6 and �5.3 Ma for the (semi-) isolated

phase of the Mediterranean with significantly lower water

levels. Consequently, the discussions about possible connec-

tions between Mediterranean and Paratethys during the Lago

Mare phase of the MSC also revived (e.g. Clauzon et al., 2005;

Vasiliev et al., 2005; Cagatay et al., 2006; Orszag-Sperber,

plete specimen; a, apertural view, b, lateral view; no. LPBIIIg 3439,� 1. 10a,b.

view, b, lateral view; no. LPBIIIg 3440, � 1. 11a,b. Viviparus macarovicii

LPBIIIg 3441, � 1. 12a,b. Bulimus (Tylopoma) speciosus (Cobalcescu), Arges

2; 13a,b. Bulimus (Tylopoma) speciosus (Cobalcescu), Arges Valley, complete

yphus acutus decipiens Brusina, Arges Valley, complete specimen; a, apertural

log Valley, complete specimen in apertural view; no. LPBIIIg 3445,� 5. 16a,b.

al view, b, apical view; no. LPBIIIg 3444, � 2.

patique meridionale, Roumanie). 1a,b. Viviparus dacianus Lubenescu, vallee de

,b. Viviparus getianus Lubenescu, vallee de l’Arges, specimen quasi complet : a,

ubenescu, vallee de l’Arges, specimen entier : a, vue aperturale, b, vue laterale,

specimen entier : a, vue aperturale, b, vue laterale, no LPBIIIg 3434, � 1. 5a,b.

, vue aperturale, b, vue laterale, no LPBIIIg 3435, � 1. 6a,b. Viviparus duboisi

e, no LPBIIIg 3436, � 1. 7a,b. Viviparus Argesiensis Sabba, vallee de la riviere

. 8a,b. Viviparus berbestiensis Lubenescu, vallee de l’Arges, specimen entier : a,

ubenescu, vallee de la riviere Topolog, specimen entier : a, vue aperturale, b, vue

Arges, specimen complete : a, vue aperturale, b, vue laterale, no LPBIIIg 3440,

ue aperturale, b, vue laterale, no LPBIIIg 3441,� 1. 12a,b. Bulimus (Tylopoma)

, vue laterale, no LPBIIIg 3442, � 2. 13a,b. Bulimus (Tylopoma) speciosus

no LPBIIIg 3443, � 2. 14a,b. Lithoglyphus acutus decipiens Brusina, vallee de

. Hydrobia grandis Cobalcescu, vallee de la riviere Topolog, specimen entier en

allee de l’Arges, specimen entier : a, vue ombilicale, b, vue apicale, no LPBIIIg

Fig. 8. Early Dacian bivalves from the Topolog-Arges region, South Carpathian foredeep, Romania: 1a,b. Pachydacna (Parapachydana) serena (Sabba), Topolog

Valley, complete right valve, no. LPBIIIl 1896, � 1; a, external view, b, internal view. 2a,b. Pachydacna (Parapachydacna) cobalcescui (Fontannes), Arges Valley,

incomplete left valve, no. LPBIIIl 1897, � 1; a, external view, b, internal view. 3a,b. Pachydacna (Parapachydacna) sabbae Ebersin, Arges Valley, complete left

valve, no. LPBIIIl 1898, � 1, a, external view, b, internal view. 4. Pachydacna (Parapachydacna) mirabilis (Teisseyre), Arges Valley, external view of incomplete

right valve, no. LPBIIIl 1899,� 1. 5a,b. Dacicardium rumanum (Fontannes), Topolog Valley, complete left valve, no. LPBIIIl 1900,� 1; a, external view, b, internal

view. 6a,b. Dacicardium dacianum (Papaianopol), Arges Valley, incomplete left valve, no. LPBIIIl 1901, � 1; a, external view, b, internal view. 7. Zamphiridacna

M. Stoica et al. / Geobios 40 (2007) 391–405402

M. Stoica et al. / Geobios 40 (2007) 391–405 403

2006). The recognition of an erosional surface and a Gilbert-

type delta with bottom set beds indicative of the earliest

Zanclean in the area of Turnu Severin led Clauzon et al. (2005)

to conclude that ‘‘a Messinian erosional surface developed

along the Danube course and along its main tributaries whereas

the northern part of the Dacic Basin remained as a perched lake,

fed by Carpathian rivers owing to a regional positive hydrologic

budget’’. These authors consider global sea level fluctuations as

the dominant cause for the observed sedimentological

signatures in both Mediterranean and Dacic basins. Marine

Mediterranean nannoplankton from both NN11b and NN12

zones have been reported from several sections (Marunteanu

and Papaianopol, 1999; Snel et al., 2006), which was later

confirmed by Clauzon et al. (2005) who in addition recorded

Mediterranean dinoflagellate cysts.

Integrated stratigraphic studies in the Carpathian foredeep

basins showed that the Carpathian orogenic system was also

tectonically very active in Messinian times, for example with

accumulation rates increasing by a factor 2–3 around 6 Ma

(Vasiliev et al., 2004). This indicates that caution is warranted

to link observed stratigraphic events in the Dacic Basin directly

to the Mediterranean MSC events. In addition, bio-magnetos-

tratigraphic results from the Badislava and Topolog river

sections, located in the northern part of the Dacic Basin,

showed that the Pontian-Dacian boundary in the Eastern

Paratethys occurred much later than the Mediterranean MSC

and that there was no major lithological or paleoenvironmental

change observed that could be directly linked to the

orientalis (Sabba), Topolog Valley, composite mould with fragment of right valve, n

Topolog Valley, 8, incomplete right valve, external view, no. LPBIIIl 1903, � 1;

(Prosodacna) parmata Papaianopol and Lubenescu, Arges Valley, complete right

longiuscula minor Andreescu, Arges Valley, incomplete left valve, external view, n

Valley; 12, complete right valve, external view, no. LPBIIIl 1907, � 1; 13, complet

Chartoconcha bayerni (R. Hoernes); 14, Arges Valley, complete left valve, no. LP

no. LPBIIIl 1910,� 1, external view. 16. Stylodacna heberti (Cobalcescu), Arges Va

sp. 2, Arges Valley, composite mould with shell fragments of right valve, no. LPBII

Fontannes, Arges Valley, 18, complete left valve, no. LPBIIIl 1913-1, � 1; a, extern

external view, b, internal view. 20a,b. Dreissena rimestiensis Fontannes, Topolog Val

21a,b. Dreissena graegata Fontannes, Arges Valley; a, complete left valve in ext

no. LPBIIIl 1916, � 1; 22a,b. Dreissena berbestiensis Fontannes, Topolog Valley, c

23a,b. Dreissena rumana Sabba, Topolog Valley, complete left valve, no. LPBIIIl

Fig. 8. Bivalves du Dacien inferieur de la region Topolog-Arges (avant-fosse carpatiq

vallee de la riviere Topolog, valve droite entiere, no LPBIIIl 1896,� 1 : a, vue extern

vallee de l’Arges, valve gauche incomplete, no LPBIIIl 1897, � 1 : a, vue externe,

l’Arges, valve gauche entiere, no LPBIIIl 1898, � 1 : a, vue externe, b, vue interne.

externe d’une valve droite incomplete, no LPBIIIl 1899,� 1. 5a,b. Dacicardium rum

1900, � 1 : a, vue externe, b, vue interne. 6a,b. Dacicardium dacianum (Papaianop

externe, b, vue interne. 7. Zamphiridacna orientalis (Sabba), vallee de la riviere Topo

9. Prosodacna (Prosodacna) macrodon minor Ebersin, vallee de la riviere Topolog :

complete, vue externe, no LPBIIIl 1904, � 1. 10. Prosodacna (Prosodacna) parmata

no LPBIIIl 1905,� 1. 11. Prosodacna (Prosodacna) longiuscula minor Andreescu, va

13a,b. Prosodacna (Psilodon) munieri Sabba, vallee de l’Arges : 12, valve droite enti

� 1 : a, vue externe, b, vue interne. 14, 15. Chartoconcha bayerni (R. Hoernes) : 14,

vallee de la riviere Topolog, coquille ouverte incomplete, no LPBIIIl 1910, � 1, vu

incomplete, no LPBIIIl 1911, � 1, vue externe. 17. Hyriopsis sp. 2, vallee de l’Arge

1912, � 1, vue externe. 18a,b, 19a,b. Dreissena polymorpha berbestiensis Fontanne

externe, b, vue interne ; 19, valve droite entiere, no LPBIIIl 1913–2,� 1 : a, vue exte

Topolog, valve gauche entiere, no LPBIIIl 1914,� 2 : a, vue externe, b, vue interne. 2en vue externe, no LPBIIIl 1915, � 1 ; b, valve droite entiere en vue externe, no LP

Topolog, valve droite entiere, no LPBIIIl 1917,� 1 : a, vue externe, b, vue interne. 23no LPBIIIl 1918, � 1 : a, vue externe, b, vue interne.

Mediterranean Messinian event stratigraphy (Vasiliev et al.,

2005). The magnetic polarity pattern of the lower part of these

sections was, however, not conclusive and two possible

correlations where discussed: (1) a continuous succession

from �7 to 4 Ma and (2) a significant (�1 Myr) hiatus in the

lower part straddling the Meotian-Pontian boundary.

The biostratigraphic data presented in this paper indicate that

the Meotian deposits are overlain by Late Pontian (Bosphorian)

deposits and that the Early Pontian deposits are indeed missing

in the stratigraphic successions of the Topolog-Arges area. It is

thus possible that the apparent hiatus in our sections

corresponds to the same event as discussed by Clauzon et al.

(2005); that is, a base level drop of the Paratethys water column

that extends as far as the southern Black Sea region (DSDP Leg

42B; Hsu and Giovanelli, 1979; Popescu, 2006). Unfortunately,

our mollusc assemblages are not conclusive for the exact

duration of the missing interval and detailed microfossil

(ostracod) studies and additional magnetostratigraphic studies

will be necessary to better constrain the chronology in the

Meotian-Pontian interval. Without the presence of an accurate

and reliable time frame, it will not be easy to convincingly

discriminate between tectonic and sea level processes.

5. Conclusions

The Late Miocene to Pliocene sedimentary sequences of the

southern Carpathian foredeep of Romania have previously been

dated by high-resolution magnetostratigraphic studies (Vasiliev

o. LPBIIIl 1902, � 1. 8, 9. Prosodacna (Prosodacna) macrodon minor Ebersin,

9, complete left valve, external view, no. LPBIIIl 1904, � 1. 10. Prosodacna

valve, external view, no. LPBIIIl 1905, � 1. 11. Prosodacna (Prosodacna)

o. LPBIIIl 1906, � 1. 12, 13a,b. Prosodacna (Psilodon) munieri Sabba, Arges

e right valve, no. LPBIIIl 1908, � 1; a, external view, b, internal view. 14, 15.

BIIIl 1909, � 1, external view; 15, Topolog Valley, incomplete, opened shell,

lley, incomplete right valve, no. LPBIIIl 1911,� 1, external view. 17. Hyriopsis

Il 1912, � 1, external view. 18a,b, 19a,b. Dreissena polymorpha berbestiensis

al view, b, internal view; 19, complete right valve, no. LPBIIIl 1913-2, � 1; a,

ley, complete left valve, no. LPBIIIl 1914,� 2; a, external view, b, internal view.

ernal view, no. LPBIIIl 1915, � 1; b, complete right valve in external view,

omplete right valve, no. LPBIIIl 1917, � 1; a, external view, b, internal view.

1918, � 1; a, external view, b, internal view.

ue meridionale, Roumanie). 1a,b. Pachydacna (Parapachydana) serena (Sabba),

e, b, vue interne. 2a,b. Pachydacna (Parapachydacna) cobalcescui (Fontannes),

b, vue interne. 3a,b. Pachydacna (Parapachydacna) sabbae Ebersin, vallee de

4. Pachydacna (Parapachydacna) mirabilis (Teisseyre), vallee de l’Arges, vue

anum (Fontannes), vallee de la riviere Topolog, valve gauche entiere, no LPBIIIl

ol), vallee de el’Arges, valve gauche incomplete, no LPBIIIl 1901, � 1 : a, vue

log, moule reconstitue avec un fragment de valve droite, no LPBIIIl 1902,� 1. 8,8, valve droite incomplete, vue externe, no LPBIIIl 1903, � 1 ; 9, valve gauche

Papaianopol et Lubenescu, vallee de l’Arges, valve droite entiere, vue externe,

llee de l’Arges, valve gauche incomplete, vue externe, no LPBIIIl 1906,� 1. 12,ere, vue externe, no LPBIIIl 1907,� 1 ; 13, valve droite entiere, no LPBIIIl 1908,

vallee de l’Arges, valve gauche entiere, no LPBIIIl 1909,� 1, vue externe ; 15,

e externe. 16. Stylodacna heberti (Cobalcescu), vallee de l’Arges, valve droite

s, moule reconstitue avec des fragments de coquille de valve droite, no LPBIIIl

s, vallee de l’Arges ; 18, valve gauche entiere, no LPBIIIl 1913–1, � 1 : a, vue

rne, b, vue interne. 20a,b. Dreissena rimestiensis Fontannes, vallee de la riviere

1a,b. Dreissena graegata Fontannes, vallee de l’Arges : a, valve gauche entiere

BIIIl 1916, � 1. 22a,b. Dreissena berbestiensis Fontannes, vallee de la riviere

a,b. Dreissena rumana Sabba, vallee de la riviere Topolog, valve gauche entiere,

M. Stoica et al. / Geobios 40 (2007) 391–405404

et al., 2005). This allowed the attribution of accurate ages to the

palaeoenvironmental changes observed from biostratigraphic

analyses. Our biostratigraphic results indicate that the Early

Pontian deposits are missing in the stratigraphic successions of

the Topolog-Arges area. It is possible that this hiatus is related

to a base level drop of the Paratethys water column, similar as

observed in the Turnu Severin region by Clauzon et al. (2005),

but regional tectonic causes can also not be ruled out.

Unfortunately, our mollusc assemblages cannot be used to

derive the age and duration of this hiatus, so the exact relation

with the Messinian event stratigraphy of the Mediterranean

only remains speculative.

Especially the Late Pontian (Bosphorian) and Early Dacian

(Getian) deposits are very rich in fossil molluscs. They indicate

accumulation in a high-energy shoreline environment. In the

Early Bosphorian the high-diversity of mollusc species

indicates slow flowing water in the channels that drain marshes

where coals have been formed, whereas the macrofaunal

assemblages associated with marls of the late Bosphorian unit

indicate deeper-water sedimentation in a lacustrine environ-

ment. These mollusc assemblages furthermore show a gradual

transition at the Pontian/Dacian boundary, which is magnetos-

tratigraphically dated at�4.9 Ma. This is significantly later (by

more than 400 kyrs) than the Mio-Pliocene boundary in the

Mediterranean sequences.

Acknowledgements

This work was carried out in the frame of activities

sponsored by the Netherlands research Centre for Integrated

Solid Earth Sciences (ISES) and the Vening Meinesz Research

School of Geodynamics (VMSG). We thank Werner Piller and

an anonymous reviewer for their critical comments, which

significantly improved the manuscript. WK acknowledges

financial support from the Netherlands Organization for

Scientific Research (NWO) through his Vernieuwingsimpuls

on ‘‘Geodynamics and Climate’’.

References

Alexeeva, L.I., Andreescu, I., Bandrabur, T., Cepaliga, A., Ghenea, C., Mihaila,

N., Trubihin, V., 1981. Correlation of the Pliocene and Lower Pleistocene

deposits in the Dacic and Euxinic Basins. Eclogae Geologicae Helvetiae 8,

143–151.

Andreescu, I., 1981. Middle-Upper Neogene and early Quaternary chronology

from the Dacic Basin and correlation with neighbouring areas. Annales

Geologiques des Pays Helleniques, hors serie 4, 129–138.

Bombita, G., Dessila-Codarcea, M., Giurgea, P., Lupu, M., Mihaila, N., Stancu,

J., 1967. Geologic map of Romania,1:200,000; Pitesti sheet. Geological

Institut of Romania, Bucharest.

Cagatay, M.N., Gorur, N., Flecker, R., Sakinc, M., Tunoglu, C., Ellam, R.,

Krijgsman, W., Vincent, S., Dikbas, A., 2006. Paratethyan-Mediterranean

connectivity in the Sea of Marmara region (NW Turkey) during the

Messinian. Sedimentary Geology 188/189, 171–187.

Cita, M.B., Santambrogio, S., Melillo, B., Rogate, F.S, 1990. Messinian paleoen-

vironments: new evidence from the Tyrrhenian Sea (ODP Leg 107). Pro-

ceedings of the Ocean Drilling Program Scientific Results 107, 211–227.

Ciulavu, D., Dinu, C., Szakack, A., Dordea, D., 2000. Late Miocene to Pliocene

kinematics of the Transylvanian basin (Romania). American Association of

Petroleum Geologists Bulletin 84, 1589–1615.

Clauzon, G., Suc, J.-P., Gautier, F., Berger, A., Loutre, M.-F., 1996. Alternate

interpretation of the Messinian salinity crisis: Controversy resolved?

Geology 24, 363–366.

Clauzon, G., Suc, J.-P., Popescu, S.-M., Marunteanu, M., Rubino, J.-L.,

Marinescu, F., Melinte, M.C., 2005. Influence of the Mediterranean sea-

level changes over the Dacic Basin (Eastern Paratethys) in the Late

Neogene. The Mediterranean Lago Mare facies deciphered. Basin Research

17, 437–562.

Dupont-Nivet, G., Vasiliev, I., Langereis, C.G., Krijgsman, W., Panaiotu, C.,

2005. Neogene tectonic evolution of the southern and eastern Carpathians

constrained by paleomagnetism. Earth and Planetary Science Letters 236,

374–387.

Gautier, F., Clauzon, G., Suc, J.-P., Cravatte, J., Violanti, D., 1994. Age et duree

de la crise de salinite messinienne. Comptes Rendus de l’Academie des

Sciences de Paris 318, 1103–1109.

Hanganu, E., Papaianopol, I., 1977. Les subdivisions du Dacien fondees sur les

associations de malacofaune et l’ostracofaune. Bulletin de la Societe belge

de Geologie 85, 63–88.

Hsu, K.J., Giovanelli, F., 1979. Messinian event in the Black Sea. Palaeogeo-

graphy, Palaeoclimatology, Palaeoecology 29, 75–94.

Hsu, K.J., Ryan, W.B.F., Cita, M.B., 1973. Late Miocene desiccation of the

Mediterranean. Nature 242, 240–244.

Krijgsman, W., 2002. The Mediterranean: Mare Nostrum of Earth sciences.

Earth and Planetary Science Letters 205, 1–12.

Krijgsman, W., Fortuin, A.R., Hilgen, F.J., Sierro, F.J., 2001. Astrochronology

for the Messinian Sorbas basin (SE Spain) and orbital (precessional) forcing

for evaporite cyclicity. Sedimentary Geology 140, 43–60.

Krijgsman, W., Hilgen, F.J., Raffi, I., Sierro, F.J., Wilson, D.S., 1999. Chron-

ology, causes and progression of the Messinian salinity crisis. Nature 400,

652–655.

Laskarev, V., 1924. Sur les equivalents du Sarmatien superieur en Serbie.

Recueil de travaux offert a M. Jovan Cvijic par ses amis et collaborateurs,

pp. 73–85.

Lourens, L.J., Hilgen, F.J., Laskar, J., Shackleton, N.J., Wilson, D.S., 2004. The

Neogene Period. In: Gradstein, F., Ogg, J., Smith, A. (Eds.), A Geological

Timescale. Cambridge University Press, Cambridge, pp. 409–440.

Marunteanu, M., Papaianopol, I., 1999. Mediterranean calcareous nannoplank-

ton in the Dacic Basin. Romanian Journal of Stratigraphy 78, 115–121.

Mihaila, N., 1971. The stratigraphy of the Pliocene and Quaternary deposits

between Oltului Valley and Vilsanului Valley (Rimnicu Valcea – Curtea de

Arges – Vilsanesti area). Studii Tehnico-Ecomice ale Instutului Geologic 7,

1–145 (in Romanian).

Nedelcu, I., Mateescu, E., 1962. Geological researches in the Muscelelor area,

between Vilasnukui Valley and Oltului Valley, Arges County. Dari de Seama

Geologie 51 (1963–1964), 295–314.

Orszag-Sperber, F., 2006. Changing perspectives in the concept of ‘‘Lago-

Mare’’ in Mediterranean Late Miocene evolution. Sedimentary Geology

188/189, 259–277.

Papaianopol, I., Marinescu, F., 1995. Les limites du Dacien. In: Chronos-

tratigraphie und Neostratotypen, Pliozan Pl1, Dazien, Neogen der Zen-

trale Paratethys, Bd. IX, Dacien. Romanian Academy Print house, pp.

38–40.

Plaziat, J.-C., Younis, W.R., 2005. The modern environments of Molluscs in

southern Mesopotamia, Iraq: A guide to paleogeographical reconstructions

of Quaternary fluvial, palustrine and marine deposits. Notebooks on Geol-

ogy – Article 2005/1 (CG2005_A01).

Popescu, S.-M., 2006. Late Miocene and early Pliocene environments in the

southwestern Black Sea region from high-resolution Palynology of DSDP

Site 380A (Leg 42B). Palaeogeography, Palaeoclimatology, Palaeoecology

238, 64–77.

Popescu, S.-M., Krijgsman, W., Suc, J.-P., Clauzon, G., Marunteanu, M., Nica,

T., 2006. Pollen record and integrated high-resolution chronology of the

Early Pliocene Dacic Basin (southwestern Romania). Palaeogeography,

Palaeoclimatology, Palaeoecology 238, 78–90.

Rabagia, T., Matenco, L., 1999. Tertiary tectonic and sedimentological evolu-

tion of the South Carpathians foredeep: tectonic versus eustatic control.

Marine and Petroleum Geology 16, 719–740.

Sandulescu, M., 1984. Geotectonica Romaniei. Editura Tehnica, Bucharest.

M. Stoica et al. / Geobios 40 (2007) 391–405 405

Semenenko, V.N., 1979. Correlation of Mio-Pliocene of the Eastern Paratethys

and Tethys. Annales Geologiques des Pays Helleniques, hors serie 3,

1101–1111.

Snel, E., Marunteanu, M., Macalet, R., Meulenkamp, J.E., Van Vugt, N., 2006.

Late Miocene to Early Pliocene chronostratigraphic framework for the

Dacic Basin, Romania. Palaeogeography, Palaeoclimatology, Palaeoecol-

ogy 238, 107–124.

Steininger, F.F., Berggren, W.A., Kent, D.V., Bernor, R.L., Sen, S., Agusti, J.,

1996. Circum-Mediterranean Neogene (Miocene and Pliocene) marine-

continental chronologic correlations of European mammal units. In: Bernor,

R.L., Fahlbusch, V., Mittmann, H.-W. (Eds.), The Evolution of Western

Eurasian Neogene Mammal Faunas. Columbia University Press, New York,

pp. 7–46.

Steininger, F.F., Muller, C., Rogl, F., 1988. Correlation of Central Paratethys,

Eastern Paratethys, and Mediterranean Neogene Stages. The Pannonian

Basin, a Study in Basin Evolution. American Association of Petroleum

Geologists Memoir 45, 79–87.

Vasiliev, I., Krijgsman, W., Langereis, C.G., Panaiotu, C.E., Matenco, L.,

Bertotti, G., 2004. Towards an astrochronological framework for

the eastern Paratethys Mio-Pliocene sedimentary sequences of the

Focsani basin (Romania). Earth and Planetary Science Letters 227,

231–247.

Vasiliev, I., Krijgsman, W., Stoica, M., Langereis, C.G., 2005. Mio-Pliocene

magnetostratigraphy in the southern Carpathian foredeep and Mediterra-

nean-Paratethys correlations. Terra Nova 17, 376–384.