Mio-Pliocene magnetostratigraphy in the southern ...forth/publications/Vasiliev_2005.pdfMio-Pliocene...

Mio-Pliocene magnetostratigraphy in the southern Carpathianforedeep and Mediterranean–Paratethys correlations

Iuliana Vasiliev,1,2 Wout Krijgsman,1 Marius Stoica3 and Cor G. Langereis11Paleomagnetic Laboratory ‘Fort Hoofddijk’, Faculty of Geosciences, Utrecht University, Budapestlaan 17, 3584 CD Utrecht, The

Netherlands; 2Netherlands Centre for Integrated Solid Earth Sciences (ISES), Faculty of Geology and Geophysics, Bucharest University,

Balcescu Bd. 1, 010041, Romania; 3Department of Geology and Paleontology, Faculty of Geology and Geophysics, Bucharest University,

Balcescu Bd. 1, 010041, Romania

Introduction

Magnetostratigraphy and correlationto the geomagnetic polarity time scale(GPTS) has become a standard tool inearth sciences, especially because itcan be applied to a wide variety ofrock types and in different (marine/continental) environments. There areseveral prerequisites for a successfulapplication of magnetostratigraphy asa dating technique for sedimentaryrocks. A suitable sedimentary se-quence has to be continuous, withoutmajor hiatuses or changes in sedimen-tation rate and must represent a longenough period of time to reveal thecharacteristic pattern of reversals. Inaddition, some approximate agecontrol should be available from bio-stratigraphy or radiometric dating.Once these prerequisites have beenmet, magnetostratigraphy can be usedto obtain reliable and accurate timeconstraints on the age and duration ofgeodynamic and palaeoclimatologicalevents.

In the Mediterranean region, areliable magnetostratigraphic timeframe has been developed for the lateMiocene marine and continental se-quences that straddle the MessinianSalinity Crisis (MSC) (Gautier et al.,1994; Garces et al., 2001). This timescale is essential to understand thefaunal and floral responses of a pro-gressively desiccating MediterraneanSea (Suc and Bessais, 1990; Benammiet al., 1996; Garces et al., 1998) and itsupported the conclusion that tec-tonic processes had been moreimportant than glacio-eustatic proces-ses during the isolation of the Medi-terranean (Hodell et al., 2001;Krijgsman et al., 2004). The latest(Lago Mare) phase of the MSC ischaracterized by the dominance ofcaspo-brackish fauna (mainly ostra-cods), of Paratethyan affinities (Citaet al., 1978, 1990).To fully comprehend the circum-

Mediterranean palaeogeographicalevolution, it is important that theParatethys sequences can be correla-ted in detail to the Mediterraneansequences. However, a reliable timescale for the Miocene–Pliocene sedi-mentary record of the Paratethys isstill lacking. Radiometric datings arescarce and biochronology is hamperedby the dominance of regional endemicspecies. Reliable magnetostratigraphic

studies are also virtually absent,despite the presence of suitablesequences. Consequently, chronostrat-igraphic control for the Paratethys isstill very limited and the various timescales are ambiguously different(Semenenko, 1979; Alexeeva et al.,1981; Andreescu, 1981; Steiningeret al., 1996). Recently, a high-resolu-tion magnetostratigraphic record wasconstructed for the Meotian to Ro-manian (7.2–2.5 Ma) time interval inthe eastern Carpathian foredeep(Vasiliev et al., 2004). In this new timescale, the Pontian Stage comprises theinterval between 5.8 Ma and 4.8 Ma.The main part of the MediterraneanMSC, which was dated to occurbetween 5.95 and 5.53 Ma (Krijgsmanet al., 1999), thus closely – but notexactly – correlates to the lowerpart of the Pontian in the easternParatethys.In this paper, we present the mag-

neto-biostratigraphic results of theUpper Miocene–Lower Pliocene sedi-mentary sequences of the southernCarpathian foredeep. We will test ifthe East Carpathian ages are valid forthe entire foredeep, or that localpalaeoenvironmental conditions areimportant. Our new chronology forthe Carpathian foredeep of Romaniafurthermore allows a direct correla-tion to the marine and continental

ABSTRACT

A full understanding of the Mio-Pliocene palaeogeographicaland palaeoenvironmental changes in the circum-Mediterraneanregion during the Messinian Salinity Crisis (MSC) is at presenthampered by the lack of reliable chronostratigraphic correla-tions between the Mediterranean and Paratethys regions.Here, we present magnetostratigraphic ages for the UpperMiocene to Pliocene deposits of the southern Carpathianforedeep in Romania. These ages are in good agreement withthose recently obtained from the eastern Carpathian foredeepand define a new chronology for the eastern Paratethys.The Meotian/Pontian boundary is not biostratigraphically

constrained in our sections, but according to the geologicalmap of the region arrives at �5.8 Ma. The Pontian/Dacianboundary is dated at c. 4.8 Ma and the Dacian/Romanianboundary at c. 4.1 Ma. The main part of the MSC (5.96–5.33 Ma) is thus represented by the Pontian Stage, but theobserved palaeoenvironmental and biostratigraphic changes inour sections of the eastern Paratethys do not indicate anyrelation with the dramatic desiccation and reflooding eventsof the Mediterranean.

Terra Nova, 17, 376–384, 2005

Correspondence: I. Vasiliev, Paleomagnetic

Laboratory �Fort Hoofddijk�, Utrecht Uni-

versity, Budapestlaan 17, 3584 CDUtrecht,

The Netherlands. Tel.: +31.30.253.1361;

fax: +31.30.253.1677; e-mail: vasiliev@

geo.uu.nl

376 � 2005 Blackwell Publishing Ltd

doi: 10.1111/j.1365-3121.2005.00624.x

sequences of the Mediterraneanregion.

Geological setting and sections

The different faunal evolution of theNeogene epicontinental seas, northand south of the Alpine–Caucasianorogenic belt, motivated Laskarev(1924) to subdivide the Tethys realminto a northern Paratethys bioprov-ince and a southern Mediterranean

bioprovince. In addition, the Paratet-hys itself was again subdivided intosmaller basins and domains, the west-ern Paratethys comprising the Panno-nian and Transylvanian basins andthe eastern Paratethys with the Da-cian, Black Sea and Caspian basins(details in Alexeeva et al., 1981; An-dreescu, 1981; Steininger et al., 1988,1996; Semenenko, 1989; Rogl, 1996).The western and eastern Paratethysdomains were separated by the Car-

pathian orogen, which was tectonical-ly uplifted to become a barrier duringthe Middle Miocene.In late Miocene (Sarmatian–Meo-

tian) times, the palaeogeographicalevolution of the Dacian Basin isclosely related to the eastern Paratet-hys, but in Pliocene (Romanian–Da-cian) times, it shows more affinitieswith the western Paratethys. Conse-quently, the geological time scales forthe Dacian Basin are generally a

Fig. 1 Schematic geological map of the Romanian Carpathians (after Sandulescu, 1988) and the location of the Getic Depression.(a) The study area of Vasiliev et al. (2004) in the eastern Carpathians is indicated by the small oval. (b) Geological map of the studyarea in the southern Carpathian foredeep (after the geological map of Romania, 1978 at 1 : 1 000 000 scale).

Terra Nova, Vol 17, No. 4, 376–384 I. Vasiliev et al. • Mio-Pliocene Mediterranean–Paratethys correlations

.............................................................................................................................................................

� 2005 Blackwell Publishing Ltd 377

combination of western and easternParatethys time scales, resulting inmajor controversies, uncertaintiesand confusion.We have selected the southern Car-

pathian foredeep, or Getic depression(Fig. 1), for a high-resolution integra-ted magneto-biostratigraphic study ofthe western Dacian Basin. The Geticdepression represents the sedimentarybasin that developed at the contactbetween the South Carpathian nappepile and the Moesian Platform (San-dulescu, 1984). We sampled two longsedimentary sequences along theBadislava and Topolog rivers, whichare located between the towns ofRımnicu Valcea and Curtea de Arges(Fig. 1b). A total number of 180 levelswere cored in the 1092 m thick Badis-lava river section, while 62 levels weresampled in the 850 m thick Topologsection. All samples have been takenfrom riverbeds where the rock surfa-ces were freshly cleaned by the stream.The sedimentary sequence has a bed-ding dip between 15� and 20� to thesouth and consists of an alternation ofblue to grey sandstones, siltstones andclays. Our sections start stratigraphi-cally in deposits of upper Meotiandeposits and end at lower Romaniansediments near the confluence ofthe Badislava and Topolog rivers.The sections thus comprise rocks ofthe Meotian, Pontian, Dacian andRomanian stages, which are very wellexposed along the two river incisions.The upper Meotian part of the sectionis relatively coarse grained containingblue-grey sandy-silty units. The Pon-tian and lower Dacian are more finegrained consisting of bluish (silty)clays, while the upper Dacian andlower Romanian become progres-sively coarser again, showing manyintercalations of organic-rich (lignite)layers as well.

Biostratigraphy

Extensive biostratigraphic studieshave been performed in the southernCarpathian foredeep between the Oltand Arges valleys (Fig. 1b), focusingmainly on mollusc and ostracodassemblages (Bombita et al., 1967;Lazar, 1987). Detailed qualitativeand quantitative analysis of the ostra-cod and mollusc species collected fromthis region allowed the establishmentof characteristic assemblages for each

stage. The observed associations fromthe study area indicate the presence ofMeotian, Pontian, Dacian and Roma-nian deposits. The geological maps ofthe southern Carpathian foredeep arelargely based on these fossil assem-blages.

In the Badislava and Topolog val-leys, no fossil localities are reportedin the sedimentary units that arelateral equivalents of the Meotianand lowermost Pontian; the Meo-tian/Pontian boundary is determinedby geological mapping. In contrast,

Table 1 Ostracofauna and macrofauna from the region between Olt and Arges

valleys of the southern Carpathians

Ostracofauna Macrofauna (molluscs)

(Sub) stage – DACIAN

Lithology – marls, clays and sands

Bivalvia

Cyprideis sp.

Cytherissa lacustris

Cytherissa bogatschovi

Heterocypris sp.

Leptocythere sp.

Amnicythere palimpsesta

Loxoconcha ex gr. petasa

Scottia dacica

Scottia ex gr bonei

Scottia sp.

Amplocypris dorosobrevis

Candona neglecta

Candona (Caspiocypris) sp.

Candona (Pontoniella) sp.

Candona (Caspiolla) lobata

Candona (Caspiolla) balcanica

Candona (Caspiolla) ossoinae

Hyriopsis sp.

Zamphiridacna orientalis

Prosodacna (Prosodacna) semisulcata

Prosodacna (Prosodacna) serrena

Dacicardium rumanum

Charthoconcha bayerni

Stylodacna heberti

Dreissena rumana

Dreissena rimestiensis

Dreissena polymorpha

Dreissena berbestiensis

Gastropoda

Viviparus argesiensis

Viviparus muscelensis

Viviparus duboisi

Viviparus berbestiensis

Viviparus monasterialis

Bulimus (Tylopoma) speciosus

Lithoglyphus acutus decipiens

(Sub) stage – PONTIAN

Lithology – marly

Bivalvia

Candona (Caspiocypris) alta

Candona (Pontoniella) acuminata striata



Candona (Caspiolla) venusta



Cypria tocorjescui

Bakunella dorsoarcuata

Amnicythere palimpsesta

Leptocythere sp.


Tyrrhenocythere filipescui

Caladacna steindachneri

Limnocardium (Tauricardium) petersi nasyrica

Limnocardium (Arpadicardium) peregrinum

Lunadacna lunae

Preudocatylus sp.

Prosodacna (Prosodacna) semisulcata antiqua

Prosodacna (Prosodacna) semisulcata angustata

Limnocardium (Euxinicardium) sacelum

Gastropoda

Valenciennius krambergeri

Valenciennius facetus rotundus

Lithology – sandy

Bivalvia

Tyrrhenocythere filipescui

Tyrrhenocythere motasi

Bakunella dorsoarcuata

Amplocypris dorsobrevis

Amplocypris sp.

Candona (Caspiolla) venusta




Dacicardium vetustum

Pontalmyra (Pontalmyra) dacica

Pontalmyra (Pontalmyra) concina

Pseudoprosodacna sp.

Prosodacnomya sturii sabbae

Hyriopsis sp.

Unio (Unio) sp.

Gastropoda

Viviparus incertus

Mio-Pliocene Mediterranean–Paratethys correlations • I. Vasiliev et al. Terra Nova, Vol 17, No. 4, 376–384

.............................................................................................................................................................


the upper Pontian and Dacian sedi-mentary rocks are very rich in well-preserved fossil assemblages. Thecharacteristic ostracod and molluscassemblages of the Pontian is subdi-vided between two distinct facies: (i)the sandy facies type characterized bythe abundance of the ostracod speciesTyrrhenocythere filipescui (HANG-ANU), Tyrrhenocythere motasi OL-TEANU, Amplocypris dorsobrevisSOKAC and Bakunella dorsoarcuata(ZALANYI) and (ii) the marly faciescharacterized by the abundance ofthe Cypria tocorjescui HANGANU,Candona (Pontoniella) acuminatastriata MANDELSTAM, Candona(Caspiocypris) alta (ZALANYI),Amnicythere palimpsesta (LIVEN-TAL) (Table 1). In the molluscassemblages, the presence of Luna-dacna lunae (VOITEST1) is a keyelement because its first occurrencecharacterizes the Upper Pontian(Bosphorian substage). It is associ-ated with Caladacna steindachneriBRUSINA, Chartochoncha bayerni(R. HOERNES), Limnocardium(Tauricardium) petersi nasyricaEBERSIN, Valenciennius faceatusrotundus TAKTASVILI and V. kram-bergeri R. HOERNES.Index species for the Lower Dacian

(Getian substage) are mainly repre-sented by Cyprideis species, which arealways accompanied by Cytherissalacustris (SARS), C. bogatschovi (LIV-ENTAL), Candona (Caspiolla) balca-nica (ZALANYI), Heterocypris sp.,Scottia dacica HANGANU. Thepresence of Zamphiridacna orientalis(SABBA) (Table 1) is especiallyimportant because its first occurrencecorresponds to the Pontian/Dacianboundary and is frequently associatedwith Dacicardium rumanum (FON-TANNES) and Pachydacna (Para-pachydacna) serrena (SABBA).

Palaeomagnetic results

Rock magnetic experiments

Several rock-magnetic experimentswere performed to identify the carriersof the natural remanent magnetization(NRM). Thermomagnetic measure-ments (Fig. 2) were performed in airup to 700 �C for 17 powdered samplesfrom diverse lithologies. Hysteresisloops were measured for 19 samples

of selected lithologies to determine thesaturation magnetization, remanentsaturation and coercive force. TheCurie balance measurements (Fig. 2a)show that the dominant magneticcarrier for a part of the samples is amineral with a maximum blockingtemperature (Tb) in the range of580–620 �C, both at and slightlyabove the Curie temperature of mag-netite (C. 580 �C) (Dunlop and Ozd-emir, 1997). The hysteresis curves forthese samples are almost closed below300 mT (Fig. 2b) and suggest thepresence of a low coercivity mineral,most likely magnetite, possiblyaccompanied by a high coercivitymineral, most likely hematite. Forthe majority of the samples, the Curiebalance measurements show invaria-bly an increase of total magnetizationafter heating above 420 �C (Fig. 2c).The hysteresis loops recorded for thistype of samples have a more rectan-gular shape (Fig. 2d), which is char-acteristic for (pseudo)-single domain

0

20

–20

B (mT)

TP 57

–300 3000–100–200 200100

10

–10

d

TP 57

0 100 200 300 400 500 600 700

Temperature (ºC )

0.01

c0.09

0.08

0.04

0.05

0.06

0.07

0.02

0.03

766.63 m

Bc = 9.085 mTMsr = 2.385 mAm2 kg–1

Ms = 26.88 mAm2 kg–1

Msr/Ms = 0.0887

Bc = 39.05 mTMsr = 7.319 mAm2 kg–1

Ms = 24.37 mAm2 kg–1

Msr/Ms = 0.3003

B 09

Mag

netis

atio

n (m

Am

2 kg

–1)

Mag

netis

atio

n (m

Am

2 kg

–1)

B (mT)–300 3000–100–200 200100

0

30

–20

20

–10

10

–30

b

a

Tot

al m

agne

tisat

ion

(Am

2 kg

–1)

Tot

al m

agne

tisat

ion

(Am

2 kg

–1)

0 100 200 300 400 500 600 7000.00

0.02

0.04

0.03

0.01

Temperature (ºC )

B 09

876.35 m

Fig. 2 Rock magnetic measurements of characteristic samples. (a) Representativethermomagnetic run for an iron oxide type of the magnetic carrier, (b) the hysteresisloop applied for the same (B 09) sample; (c) representative thermomagnetic run for amostly iron sulphide type of the magnetic carrier; (d) the hysteresis loop applied forthe same (TP 57) sample. The Curie balance measurements have been performed inair on a modified horizontal translation type Curie balance (noise level 5 · 10)9 Am2)(Mullender et al., 1993). In the left-down corner is the stratigraphic level. Heating(solid line) and cooling (dashed line) were performed with rates of 10 �C min)1, thecycling field varied between 150 and 300 mT. The hysteresis loops were measured for)2T ¼ B ¼ 2T, on an alternating gradient magnetometer (MicroMag ModelPrinceton, noise level 2 · 10)8 Am2; Princeton Measurements Corp., Princeton,NJ). In the figures, the results up to ±300 mT are shown, and we appliedparamagnetic contribution and mass corrections.

Table 1 Continued

Ostracofauna Macrofauna (molluscs)

Candona (Caspiocypris) alta



Cypria tocorjescui

Scottia sp.1

Scottia sp.2

Cyprideis sp.

Loxoconcha petasa

Amnicythere sp.

Teodoxus sp.

Melanopsis decollata


.............................................................................................................................................................


pyrrhotite (Dekkers, 1988) or greigite.The relatively high coercivity and themaximum Tb in the range 320–340�points to pyrrhotite and greigite aswell.

Magnetostratigraphy

To establish the magnetostratigraphyfor the Badislava Valley and TopologValley sections, at least one specimenper level was stepwise thermallydemagnetized with small temperatureincrements of 5–30 �C up to a maxi-mum temperature of 600 �C, in amagnetically shielded furnace. As therock-magnetic experiments indicatedthe presence of iron sulphides, wechose to apply smaller heating stepsbetween 200 and 400 �C. The direc-tions of the NRM were calculated byprincipal component analysis (Kirs-chvink, 1980). Thermal demagnetiza-tion diagrams generally revealed astable and well-defined characteristicremanent magnetisation (ChRM)(Fig. 3a–c), although in some cases asmall secondary viscous or present-day field component was removedat temperatures below 150–180 �C.Less than 23% of the data presenteda viscous type of magnetization(Fig. 3d) or a total present-day over-print and were not interpreted. In15% of the demagnetization dia-grams, most of the NRM was re-moved after heating at temperatureshigher than 520 �C (Fig. 3a), pointingto an iron oxide type of magneticcarrier. These samples are locatedmostly in the older part of the Badis-lava section and record a continuoussusceptibility decrease without a vis-ible increase upon heating to thehighest temperatures (600 �C). Themajority of the samples (62%) recorda significant increase in susceptibilityand intensity after heating to temper-atures of 360–420 �C, indicating theoxidation of an iron sulphide. In thesediagrams, the NRM is largely re-moved at temperatures of approxi-mately 390–420 �C (Fig. 3b,c). Thisconfirms the rock magnetic conclusionthat an iron sulphide is the maincarrier of the remanence magnetiza-tion. Five levels in the vicinity of apolarity reversal show the antipodalmagnetization of two different com-ponents (Fig. 3e,f). We believe that inthese cases early diagenetic proces-ses cause a delay in acquisition and an

(partial) overprint of the original(earlier acquired) component, sim-ilar to that observed in the easternCarpathian foredeep (Vasiliev et al.,2004). Hence, the direction of thefollowing (younger) polarity intervalwill overprint the original direction.Normal and reversed components

are revealed in both iron oxides andiron sulphides, suggesting a (nearly)primary origin of these magnetic com-ponents. The ChRM directions can bereliably determined from the demag-netization diagrams and reveal 11

polarity reversals in the Badislavasection: five normal and six reversedintervals. The Topolog section recor-ded nine reversals with four normaland five reversed polarity intervals.The long and unambiguous polaritypattern allows an excellent correlationto the GPTS (Fig. 4).

Chronology for the SouthCarpathian foredeep

We used the most recent astronomic-ally dated GPTS (Lourens et al.,

TP 12.1A

th/tcN

up/W

232.65

100

210

240

detailFig. 3f

TP 12.1A

N

up/W

th/tc232.65

D = 321.3º

I = 57.6º

210

240

D = 174.8º

I=–52.6º

Reversed component

BD 045.1A

th/tc

N

up/W

507.05 Grey sandy silt

TP 57.1A

th/tc N

up/W

100

270

420

766.63 Blue clay

BD 114.2A

th/tc

N

up/W

Blue clay

100

270

420

705.97

BD 68.1A

th/tc N

up/W

Grey blue silty clay

Inc = –56.2º

Dec = 193.6º

150

300

520

462.92

a b

c d

e f

Fig. 3 Thermal demagnetization diagrams. The natural remanent magnetization(NRM) was measured on a horizontal 2G Enterprise DC SQUID cryogenicmagnetometer (2G Enterprises, Pacific Grove, CA). The magnetic susceptibility wasmeasured after each step on a Kappabridge KLY-2 (AGICO, Brno, Czech Republic)to monitor mineralogical changes. Closed (open) symbols represent the projection ofthe vector end points on the horizontal (vertical) plane; values represent temperaturein �C; stratigraphic levels are in the lower left-hand corner; lithologies are in theright-hand corner. The diagrams are represented with tectonic correction (th/tc). Theback arrows in (a) and (f) indicate the interpreted ChRM directions, D, declinationsand I, inclinations; (f) illustrates one of the five cases where the ChRM (blackarrows) was partly overprinted by a large reversed magnetization (grey arrows).


.............................................................................................................................................................


2005) to establish the magnetostrati-graphic correlation of our sections.The most striking polarity pattern inthe Badislava and Topolog sections

(Fig. 4) is a very long reversed zonethat comprises the Meotian/Pontianstage boundary from the geologicalmap (Fig. 5). A succession of four

relatively short normal and threereversed zones is followed again byanother long reversed interval. Thelengths of these polarity zones are in

Piacenzian

Zan

clea

nM

essi

nian

Tort

onia

n

Lago Mare of Mediterranean

Erosion (Messinian Gap)

Lower Evaporites

Plio

cene

Mio

cene

UE

LE

MED

Meo

tian

?R

mD

acia

nP

ontia

n

Endof the

section

Startof the

section

Rom

ania

nD

acia

nP

ontia

nM

eotia

n

EC SC

C

N

S

T

Age(Ma)

4.0

5.0

6.0

7.0

3.5

4.5

5.5

6.5

C4n.1n

C3Br.2r

7.5

C2An.3n

C3An.1n

C3An.2n

C3Bn

C3n.4n

C3r

C3Ar

C2Ar

C3n.3n

C3n.2n

C3n.1n

C3An.1r

GPTS

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1000

1050

1100

180 360

Str

atig

raph

ic le

vel (

m)

Dec

Badislava Valley

-90 0 90Inc

Meo

tian

Pon

tian

Dac

ian

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

180 360

Str

atig

raph

ic le

vel (

m)

-90 0 90Dec Inc

Topolog Valley

Pon

tian

Dac

ian

Rm

Fig. 4 Correlation of the polarity patterns of the Badislava and Topolog sections to the GPTS. The ages are according to (Lourenset al., 2005). In the polarity columns, black andwhite denotes normal, respectively, reversed polarity intervals. Solid dots (c) representreliable directions of demagnetisation diagrams.Open circles (s) represent less reliable directions contaminated or largely overprintedby present-day directions and/or viscous NRM. The white stars represent directions of low temperature components (later)magnetized in the opposite direction from the high temperature components (e.g. e and f). Next to the polarity column are the limitsbetween different stages according to the 34 Pitesti, 1 : 200 000 scalemap (Bombita et al., 1967). The dashed lines between the sectionsand GPTS connect (interpretative) simultaneous polarity boundaries. Chron nomenclature follows Cande and Kent (1992), while C(Cochiti), N (Nunivak), S (Sidufjall) and T (Thvera) are the historical names for the normal subchrons of the Gilbert Chron. The ageintervals for the stage boundaries in the southern Carpathian (SC) foredeep (Badislava and Topolog) and the eastern Carpathians(EC) foredeep (after Vasiliev et al., 2004) are approximately synchronous within uncertainty of ±150 kyr (shaded areas). The right-hand column shows the schematic Mediterranean (MED) time scale for the Late Miocene–Early Pliocene with the Upper Messinianlower evaporites (LE) and upper evaporites (UE) units of the Messinian Salinity Crisis (after Krijgsman et al., 2001).


.............................................................................................................................................................


good agreement between the two sec-tions and this characteristic patterncorrelates excellently to subchronsC3r, C3n.4n (Thvera), C3n.3r,C3n.3n (Sidufjall), C3n.2r, C3n.2n(Nunivak), C3n.1r and C3n.1n (Coc-hiti), covering the time span between 6and 3.8 Ma (Fig. 4). The most logicalcorrelation of the two normal polarityzones in Badislava below the longreversed interval of C3r is to C3An.The length of the lowermost normalinterval, however, appears to be tooshort for a correlation to C3An.2n(Fig. 4). Another possible correlationof these two normal zones is to C3Bn,but this implies that a significant(�1 Myr) hiatus would be present inthe lower part of the Badislava sec-tion.For all magnetostratigraphic sites,

the GPS location has been registeredwith a maximum horizontal accuracy

error of 10 m. All sites were introducedon a georeferenced database and lo-cated on the geological map of theregion (34 Pitesti, 1:200 000 scale)(Fig. 5). From the maps, we could thusderive themagnetostratigraphic ages ofthe main Paratethys stage boundaries(Fig. 4). The Meotian/Pontian bound-ary is dated in the lower part of chronC3r at c. 5.8 Ma. Unfortunately, thisboundary is not directly constrained bybiostratigraphic data because no fossilshave been observed in this part of theBadislava and Topolog sections. ThePontian/Dacian boundary is locatedaround C3n.3n (Sidufjall) at c. 4.9 Maand the Dacian/Romanian boundaryin the lower part of C2Ar, at c. 4.1 Ma(Figs 4 and 5). The precision of theseages depends (i) on the accuracy of theGPS measurements; (ii) on the densityof the palaeomagnetic sites in the vicin-ity of the stage boundaries; but (iii)

most of all on the precision of thebiostratigraphically determined stageboundaries.

Discussion and conclusion

Our ages from the southern Carpa-thian foredeep are in very good agree-ment with the ages obtained for thesame stage boundaries in the EastCarpathians (Fig. 4). This implies thatthe palaeoenvironmental changesinducing transformations in the faunalassemblages between different stagesare synchronous (within uncertaintyof c. 150 kyr) between the eastern andsouthern Carpathian foredeep. TheLate Miocene and Early Pliocenestages of the eastern Paratethys areconsequently at least of regional sig-nificance.Our data from the eastern Paratet-

hys suggests that the Meotian/Pontianboundary (c. 5.8 Ma) postdates theonset of Mediterranean Salinity Crisisat 5.96 Ma (Krijgsman et al., 1999).This is in large contrast with previouscorrelations of the Meotian/Pontianboundary to the Tortonian/Messinianboundary (at c. 7.2 Ma) as suggestedby (Rogl and Daxner-Hock, 1996).Slightly after the onset of the MSC,the marine Meotian of the Paratethystransforms to the almost freshwaterenvironment of the Pontian Lake,probably as a result of increased riverinflow or of reduction of the connec-tions with the marine water masses.From our data, it cannot be conclu-ded if there is a causal relationbetween these two events. The LagoMare phase of the Mediterranean at5.50–5.33 Ma took place entirely dur-ing Pontian times, but apparently hasleft no clear signatures in the Carpa-thian foredeep of Romania. We alsofind no (clear) evidence that the re-flooding of the Mediterranean at 5.33(Mio-Pliocene boundary) is reflectedin this region. However, desiccation,reflooding and Gilbert type deltadevelopment have been reported forthe Danube region (Iron Gates),where high sea-level cross-exchangesare suggested to have occurred be-tween the Mediterranean and CentralParatethys just before and after thesalinity crisis (Clauzon et al., in press).The change from the Pontian fresh-water environment towards the brack-ish-marine Dacian at 4.9 Ma does notseem to be reflected by the main

Fig. 5 Geological map of the study area (after Bombita et al., 1967). The different typesof shading correspond to the different Mio-Pliocene stages in the area of Badislava andTopolog confluence. The thick white/black lines along the river trajectory show theobserved reversed/normal polarity intervals. The dotted areas are the imaginaryconnection between two sections. In the ellipses are the magnetostratigraphic ageconstraints for the succession after the GPTS of Lourens et al. (2005). The insetrepresents the geological sketch of the Romanian Carpathians.


.............................................................................................................................................................


palaeoenvironmental changes in theMediterranean. We conclude that ourresults show no evidence for majorwater exchange between the easternParatethys and Mediterranean do-mains during the late Miocene. Thepresent-day connection through theBosphorus opened during the latePliocene (Gorur et al., 1997). Detailedbiostratigraphic and isotopic recordsfrom the eastern Paratethys will berequired to specify and quantify theenvironmental changes more preciselyand to substantiate our conclusions.

Acknowledgements

This work was carried out in the frame ofactivities sponsored by Netherlands re-search Centre for Integrated Solid EarthSciences (ISES). We thank Gabi, Guilla-ume, Adrian and Klaudia for their help inthe field and Dr Iuliana Lazar for providingthe biostratigraphic data from her BScthesis. We acknowledge the helpful com-ments ofFredRogl and JeanMarieRouchy.

References

Alexeeva, L.I., Andreescu, I., Bandrabur,T., Cepaliga, A., Ghenea, C., Mihaila,N. and Trubihin, V., 1981. Correlationof the Pliocene and Lower Pleistocenedeposits in the Dacic and EuxinicBasins. Dan. Ecl. Geol. Helv., 8,143–151.

Andreescu, I., 1981. Middle-Upper Neo-gene and early Quaternary chronologyfrom the Dacic Basin and correlationwith neighbouring areas. Ann. Geol.Pays Hellen., tome hors serie., 4,129–138.

Benammi, M., Calvo, M., Prevot, M. andJaeger, J.-J., 1996. Magnetostratigraphyand paleontology of Ait Kandoula Basin(High Atlas, Morocco) and the African-European late Miocene terrestrial faunaexchanges. Earth Planet. Sci. Lett., 145,15–29.

Bombita, G., Dessila-Codarcea, M.,Giurgea, P., Lupu, M., Mihaila, N. andStancu, J., 1967. Geologic Map ofRomania, 1:200,000; Pitesti Sheet.Geological Institute of Romania,Bucharest.

Cande, S.C. and Kent, D.V., 1992. A newgeomagnetic polarity time scale for thelate Cretaceous and Cenozoic. J. Geo-phys. Res., 97, 13917–13951.

Cita, M.B., Wright, R.C., Ryan, W.B.F.and Longinelli, A., 1978. Messinianpaleoenvironments. Initial Reports ofthe Deep Sea Drilling Project. 1003–1035.

Cita, M.B., Santambrogio, S., Mellillo, B.and Rogate, F., 1990. Messinian paleo-

environments: new evidence from theTyrrhenian Sea (ODP Leg 107). Sci.Results, 107, 211–227.

Clauzon, G., Suc, J.-P., Popescu, S.-P.,Marunteanu, M., Rubino, J.-L., Marin-escu, F., Jipa, D. and Melinte, M.C., inpress. Influence of the Mediterraneansea-level changes over the Dacic basin(eastern Paratethys) in the Late Neogene— The Mediterranean Lago Mare fuciesdeciphered. Basin Res., in press.

Dekkers, M.J., 1988. Some RockmagneticParameters for Natural Goethite,Pyrrhotite and Fine-grained Hematite.Utrecht Universiteit, Utrecht.

Dunlop, D.J. and Ozdemir, O., 1997. RockMagnetism – Fundamentals and Fron-tiers. Cambridge University Press,Cambridge.

Garces, M., 2001. Chronostratigraphicframework and evolution of the Fortunabasin (Eastern Betics) since the lateMiocene. Basin Research, 13, 199–216.

Garces, M., Krijgsman, W. and Agustı, J.,1998. Chronology of the late Turoliandeposits of the Fortuna basin (SESpain): implications for the Messinianevolution of the eastern Betics. EarthPlanet. Sci. Lett., 163, 69–81.

Gautier, F., Clauzon, G., Suc, J.-P.,Cravatte, J. and Violanti, D., 1994. Ageet duree de la crise de salinite messini-enne. C. R. Acad. Sci. Paris, 318, 1103–1109.

Gorur, N., Cagatay, M.N., Sakinc, M.,Senturk, K., Yaltirak, C. and Tchapa-lyga, A., 1997. Origin of the Sea ofMarmara as deducted from the Neogeneto Quaternary Paleogeographic evolu-tion of its frame. Int. Geol. Rev., 39,342–352.

Hodell, D.A., Curtis, J.H., Sierro, F.J. andRaymo, M.E., 2001. Correlation of lateMiocene to early Pliocene sequences be-tween the Mediterranean and NorthAtlantic. Paleoceanography, 16, 164–178.

Kirschvink, J.L., 1980. The least-squaresline and plane and the analysis ofpaleomagnetic data. Geophys. J. R. Astr.Soc., 62, 699–718.

Krijgsman, W., Hilgen, F.J., Raffi, I.,Sierro, F.J. and Wilson, D., 1999.Chronology, causes and progression ofthe Messinian salinity crisis. Nature, 400,652–655.

Krijgsman, W., Fortuin, A.R., Hilgen, F.J.and Sierro, F.J., 2001. Astrochronologyfor the Messinian Sorbas Basin (SESpain) and orbital (precessional) forcingfor evaporite cyclicity. Sed. Geol., 140,43–60.

Krijgsman, W., Gaboardi, S., Hilgen, F.J.,Iaccarino, S., Kaenel, E. and Van derLaan, E., 2004. Revised astrochronologyfor the Ain el Beida section (AtlanticMorocco): No glacio-eustatic control forthe onset of the Messinian SalinityCrisis. Stratigraphy, 1, 87–101.

Laskarev, V., 1924. Sur le equivalents duSarmatien superieur en Serbie: Recueil detraveaux offert a M. Jovan Cvijic par sesamis et collaborateurs, pp. 73–85.

Lazar, I., 1987. The study of coal bearingpost-Sarmatian deposits from Arges–Topolog area. Unpublished BSc thesis.University, Bucharest, Romania.

Lourens, L.J., Hilgen, F.J., Laskar, J.,Shackleton, N.J., and Wilson, D., 2005.The Neogene Period. In: A GeologicTime Scale 2004 (F.M. Gradstein,J.G. Ogg, A.G. Smith eds). CambridgeUniversity Press, UK.

Mullender, T.A.T., van Velzen, A.J. andDekkers, M.J., 1993. Continous driftcorrection and separate identification offerromagnetic and paramagnetic contri-bution in thermomagnetic runs.Geophys. J. Int., 114, 663–672.

Rogl, F., 1996. Stratigraphic correlationof the Paratethys Oligocene and Mio-cene. Mitt. Ges. Geol. Bergbaustud, 41,65–73.

Rogl, F. and Daxner-Hock, G., 1996. LateMiocene Paratethys Correlation. In: TheEvolution of the Western Eurasian Neo-gene Mammal Faunas (L.R. Bernor,V. Fahlbusch, H.-W. Mittmann eds),pp. 47–55. Columbia University Press,New York.

Sandulescu, M., 1984. GeotectonicaRomaniei. Editura Tehnica, Bucharest,450 pp.

Sandulescu, M., 1988. Cenozoic TectonicHistory of the Carpathians. In: ThePannonian Basin, A Study in Basin Evo-lution (L.H. Royden and F. Horvatheds), AAPG Memoir, 28, 17–25.

Semenenko, V.N., 1979. Correlation ofMio-Pliocene of the Eastern Paratethysand Tethys. Ann. Geol. Pays Hellen.,tome hors serie, fasc. III, 1101–1111.

Semenenko, V.N., 1989. Problems of thePliocene correlation of the east Paratet-hys and Tethys. Geol. Carpath., Brati-slava, 40, 75–79.

Steininger, F.F., Muller, C. and Rogl, F.,1988. Correlation of Central Paratethys,Eastern Paratethys, and MediterraneanNeogene Stages. In: The PannonianBasin, A Study in Basin Evolution (L.H.Royden and F. Horvath eds), AAPGMemoir, 28, 79–87.

Steininger, F.F., Berggren, W.A., Kent,D.V., Bernor, R.L., Sen, S. andAgusti, J.,1996. Circum-Mediterranean Neogene(Miocene and Pliocene) Marine – Con-tinental chronologic correlation of theEuropean mammal units. In: The Evolu-tion of the Western Eurasian NeogeneMammal Faunas (L.R. Bernor, V. Fah-lbusch, H.-W. Mittmann eds), pp. 7–46.Columbia University Press, New York.

Suc, J.P. and Bessais, E., 1990. Perennited’un climat thermo-xerique en Sicileavant, pendant, apres la crise de salinite


.............................................................................................................................................................


messinienne. C.R. Acad. Sci. Paris, 310,1701–1707.

Vasiliev, I., Krijgsman, W., Langereis,C.G., Panaiotu, C.E., Matenco, L. andBertotti, G., 2004. Towards an astro-

chronological framework for the easternParatethys Mio-Pliocene sedimentarysequences of the Focsani basin (Roma-nia). Earth Planet. Sci. Lett., 227,231–247.

Received 16 December 2004; revised versionaccepted 10 March 2005


.............................................................................................................................................................


Mio-Pliocene magnetostratigraphy in the southern ...forth/publications/Vasiliev_2005.pdfMio-Pliocene...

Documents

Transcript of Mio-Pliocene magnetostratigraphy in the southern ...forth/publications/Vasiliev_2005.pdfMio-Pliocene...