GeolCarp_Vol62_No1_91

www.geologicacarpathica.sk

GEOLOGICA CARPATHICA

, FEBRUARY 2011, 62, 1, 91—102 doi: 10.2478/v10096-011-0008-9

Introduction

The Middle to Upper Miocene sedimentary succession of the
Transylvanian  Basin  represents  the  upper  megasequence  of
the basin’s fill (Krézsek & Bally 2006). It mostly consists of
marine  siliciclastics  separated  into  several  sedimentary  se-
quences  (Krézsek  &  Filipescu  2005)  belonging  to  the  Bade-
nian  (Papp  et  al.  1978),  Sarmatian  (Papp  et  al.  1974)  and
Pannonian (Papp et al. 1985) regional stages of the Paratethys.

A series of large outcrops are displayed along the right bank

of the Mure  River in the central part of the Transylvanian Ba-
sin (Romania). Section A from Oarba de Mure  (Sztanó et al.
2005),  located  at  N46.45502°,  E24.28598°  (Fig. 1)  preserves
a continuous, thick succession of deep marine Sarmatian and
Pannonian  turbidites.  For  this  reason,  this  section  has  been
considered a very good potential candidate for a facies strato-
type for the Sarmatian-Pannonian boundary.

A few independent projects have investigated the Sarmatian-

Pannonian transition in Section A (Fig. 1), where the boundary
was placed by Vancea (1960). Results on sedimentology were
published by Sztanó et al. (2005), while Sütő & Szegő (2008)
published data on biostratigraphy based on dinoflagellates. Pre-
liminary results on magnetostratigraphy, radiometric dating,
and biostratigraphy were presented by Vasiliev et al. (2006),
Filipescu et al. (2009), and De Leeuw et al. (2009). An inte-
grated study was published by Vasiliev et al. (2010). Our pur-
pose is to present in detail the micropaleontological record for

Micropaleontological response to the changing paleoenviron-

ment across the Sarmatian-Pannonian boundary in the

Transylvanian Basin (Miocene, Oarba de Mure section,

Romania)

SORIN FILIPESCU

, FRANZ WANEK

, ANGELA MICLEA

, ARJAN DE LEEUW

and IULIANA VASILIEV

Babe -Bolyai University, Department of Geology, Str. Kogălniceanu 1, 400084 Cluj-Napoca, Romania;

sorin.filipescu@ubbcluj.ro; miclea_angela@yahoo.com.

Sapientia University, Matei Corvin 4, 400112 Cluj-Napoca, Romania; wanek.ferenc@gmail.com.

Paleomagnetic Laboratory ‘Fort Hoofddijk’, Utrecht University, Budapestlaan 17, NL-3584 CD Utrecht, The Netherlands;

adeleeuw@geo.uu.nl; vasiliev@geo.uu.nl.

(Manuscript received June 7, 2010; accepted in revised form October 13, 2010)

Abstract: The Sarmatian-Pannonian transition has been investigated in Section A of Oarba de Mure  in the central
Transylvanian Basin. Micropaleontological assemblages are diagnostic for different environmental settings and demon-
strate a clear zonation, which was used to reconstruct the genetic units. Five stratigraphic sequences were described and
subdivided based on the microfossil assemblages. Transgressive  intervals were documented by five-chambered and
biserial  planktonic  foraminifera,  normal  regressions  by  assemblages  with  abundant  mysid,  dasyclads,  diatoms,  and
benthic rotaliid foraminifera, while the forced regressions are characterized by reworking. The Sarmatian-Pannonian
boundary (11.3 Ma) is clearly documented by microfossils and is calibrated with radiometric and magnetostratigraphic
data. A new interpretation for the interbasinal correlation is proposed by synchronizing the top of the Central Paratethyan
Sarmatian with the top of the Eastern Paratethyan Bessarabian.

Key words: Sarmatian, Pannonian, Transylvanian Basin, stratigraphy, microfossils, Foraminifera, Ostracoda.

the Sarmatian-Pannonian transition, in relation to the paleoen-
vironmental changes, in order to propose correlation criteria
and to better understand the basin’s evolution.

Material and methods

More than 120 micropaleontological samples were studied

from  the  almost  60 m  thick  Section  A  in  Oarba  de  Mure .
The samples were processed by standard micropaleontologi-
cal  methods  and  the  microfossils  were  recovered  from  a
63 µm  sieve.  After  a  preliminary  observation  under  stereo-
microscope,  the  foraminifera  and  ostracods  were  examined
and  photographed  using  a  scanning  electron  microscope
(JSM-JEOL 5510 LV).

All identified species were counted and the number of spec-

imens ( # /250 g of sediment) was plotted along the section
(Figs. 2, 3). Several diagnostic groups of foraminifera were
used for paleoenvironmental and stratigraphic interpretations.

Results

Microfossil assembla ges

Fossil content and sedimentological features suggest par-

ticular environmental settings, with stratified water (brackish,

FILIPESCU, WANEK, MICLEA, DE LEEUW and VASILIEV

GEOLOGICA CARPATHICA

GEOLOGICA CARPATHICA, 2011, 62, 1, 91—102

oxic surface and dysoxic bottom waters) and deep-sea tur-
biditic systems. Poor oxygenation of the studied interval was
presumed in the previous studies based on the absence of
benthic molluscs (Sztanó et al. 2005), and also by the pres-
ence of greigite mineral (Vasiliev et al. 2006).

The foraminiferal assemblages are dominated by benthic

species,  in  most  cases  with  small  juveniles,  which  were
probably  either  sedimented  during  their  early  stage  of  life
(?meroplanktonic or opportunistic taxa in seasonally unstable
environments)  or  transported  from  the  shallower  environ-
ments by the turbiditic currents (the transport of contempora-
neous taxa was more active during the regressive intervals).
Rare  five-chambered  and  biserial  planktonic  foraminifera
have  been  associated  with  the  transgressive  intervals;  we
also presumed that the bolivinids may have had, at least tem-
porarily,  a  planktonic  behaviour  as  shown  by  Darling  et  al.
(2009) and Smart & Thomas (2006, 2007).

The abundance of microfossil groups is diagnostic for the

changes in the paleoenvironment, as shown in Figs. 2 and

A general trend of salinity decrease can be observed along the
section  (Fig. 2A),  which  is  documented  by  the  initial  domi-
nance  of  the  miliolids,  then  the  dominance  of  the  Ammonia
spp. group and, at the top of the section, the total replacement
of foraminifera by ostracods. Marginal and shallow marine as-
semblages  suggesting  highly  fluctuating  values  of  salinity

correlate with high levels of reworking (Fig. 2A). The good
correlation among the groups of mysids, dasyclads, diatoms,
and  fish  (Fig. 2B,  Fig. 5)  can  also  be  used  to  highlight  the
productive  areas  (eutrophic  environments)  developped  in
front  of  the  deltas.  There  is  a  good  correlation  between  the
marine  benthic  rotaliids  (Nonion,  Porosononion,  Elphidium
groups – Fig. 4), which usually display higher abundances in
connection  to  shallowing  trends  or  progradation  (Fig. 3A).
Planktonic foraminifera (species of Globigerina, Tenuitellinata,
Streptochilus – Fig. 5) were associated with the transgressive
deep-sea environments, while bolivinids and agglutinated for-
aminifera (Figs.  5, 6) document the colonization of the deep
hypoxic to oxic environments during the early highstand and
late lowstand (Fig. 3B).

Microfossil assemblages and potential stratigraphic se-
quences

It is well-known that the sequence stratigraphy is not easy

in  turbiditic  successions.  Our  investigations  on  the  upper
Sarmatian from Oarba de Mure  clearly revealed several cy-
clic  events  in  the  micropaleontological  record,  which  could
be  linked  to  different  stages  of  sea-level  fluctuations  and
consequently  to  the  sedimentary  genetic  units  (systems
tracts). The identified sequences (Fig. 7) are detailed below.

Fig. 1. Oarba de Mure section and its location on the map of Romania and on the simplified geological map of the Transylvanian Basin.

PALEOENVIRONMENT ACROSS THE SARMATIAN-PANNONIAN BOUNDARY IN THE TRANSYLVANIAN BASIN

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GEOLOGICA CARPATHICA, 2011, 62, 1, 91—102

Fig. 4.  Sarmatian  shallow-
water  foraminifera  from
Oarba  de  Mure .  1  –
Elphidium  sp.  –  sample
V96.  2  –  Elphidium
fichtelianum  (d’Orbigny)
–  sample  V83.  3  –
Elphidium

hauerinum

(d’Orbigny)  –  sample
V44.  4  –    Elphidium  aff.
jukovi  Serova  –  sample
V34.  5,  6  –  Elphidium
grilli  Papp  –  5  sample
V44; 6 sample V59.    7 –
Elphidium nataliae Popescu
–  sample  V44.      8  –
Elphidium aff. aculeatum –
sample

V44.

–

Porosononion

granosum

(d’Orbigny)

–

sample

V83.  10  –  Porosononion
sarmaticum  Popescu  –
sample V75. 11 – Discor-
bis effusus Zhizhchenko –
sample  V85.  12,  13  –
Nonion bogdanowiczi Volo-
shinova – 12 sample V83;
13  sample  V80.  14,  15  –
Ammonia  ex  gr.  beccarii
(Linné) – 14 sample V53;
15  sample  M47.  16  –
Trochammina kibleri Ven-
glinski – sample V115.

Sequence

Samples from the lowermost part of the section (e.g. V67)

contain a few juvenile specimens of miliolids (Articulina prob-
lema) and rare rotaliids transported from the shallower areas by
the active erosion during falling stage. The following substrate
colonization, probably supported by the oxygenation produced
by deltaic progradation (fish bones and mysids – Sarmysis sar-
maticus – sample V72), must be related to the slow sea-level
rise during the lowstand. The assemblage becomes progressive-

ly more diverse (samples V74—V59), with mature rotaliid fora-
minifera  (Elphidium  flexuosum,  Porosononion  martkobi,  P.
subgranosum,  Nonion  biporus,  N.  commune,  Fissurina  bessa-
rabica,  Discorbis  efusus)  and  ostracods  (Loxoconcha  cf.
popovi,  Amnicythere  cernajseki,  Aurila  cf.  notata).  The  trans-
gressive interval (samples V74—V81) can be documented by the
presence  of  Bolivina  spp.  and  the  peak  of  globigerinids
(Fig. 4B). The following interval (samples V82—V01) seems to
be related to the highstand parasequences and is characterized
by  shallower  taxa,  mainly  miliolids  (Cycloforina  gracilis,  C.

FILIPESCU, WANEK, MICLEA, DE LEEUW and VASILIEV

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GEOLOGICA CARPATHICA, 2011, 62, 1, 91—102

predkarpatica, Flintina georgii, Pseudotriloculina consobri-
na, Varidentella pseudocostata, V. sarmatica).

Sequence

A possible tectonic uplift produced a forced regression and

associated coarse sediment above sample V01 (volcanic ash
connected to active tectonics and coarse sediment of the ero-
sional  falling  stage  FSS2).  The  lowstand  interval  following
the minimum sea-level (samples V2—V07) continues the re-
gressive trend and only contains very rare rotaliid and mili-
olid foraminifera. A distinct change in the assemblage can be
observed starting with sample V18, probably determined by
a transgression; the migration of planktonics and deeper sea
benthics  into  the  basin  came  in  several  stages  (probably
deepening-upwards  parasequences)  with  abundant  Bolivina
(B. pseudoplicata, B. moldavica, B. sarmatica) and other bu-
liminids  (Buliminella  elegantissima,  Caucasina  sp.).  Pro-
grading  highstand  deltas  installed  just  below  sample  V110,
as proven by abundant populations of mysids (Sarmysis sar-
maticus), dasyclad algae (Halicoryne moreletti), and diatoms
(Coscinodiscus  sp.).  Stable  environments  generated  by  the
high  sea-level  persisted  up  to  the  interval  represented  by
sample  V11.  Diverse  and  mature  foraminifera  (Elphidium
flexuosum, Porosononion hyalinum, P. subgranosum, Nonion
bogdanowiczi,  Ammonia  beccarii,  Articulina  sp.,  Pseudo-
triloculina consobrina) occur together with ostracods (Amni-
cythere  cernajseki,  Loxoconcha  sp.).  Locally  abundant
bolivinids, agglutinated foraminifera, and mysids are in rela-
tion with parasequences.

Sequence

Another falling stage with associated forced regression

(FSST 3) supplied coarser sediments (samples V12—V14) and
very  shallow  foraminiferal  assemblages  with  miliolids
(Varidentella  reussi,  Varidentella  sarmatica).  The  following
diversification  (samples  V16  to  V26)  of  the  ostracods
(Xestoleberis  sp.;  Amnicythere  cernajseki,  Loxoconcha  cf.
popovi), and foraminifera (Ammonia beccarii, Porosononion
subgranosum, Elphidium spp., Bolivina spp.) is related to the
lowstand  deepening  in  shallow  marine  environments.
Prodeltaic  assemblages  (dasyclads,  diatoms,  mysids,  fish
bones  –  sample  V28)  are  followed  by  deeper  marine  taxa
(Bolivina aff. arta, B. sarmatica, B. moldavica, B. pseudopli-
cata, Streptochilus sp. – samples V31, V34) associated with
the transgression. The highstand persisted up to sample V58,
with  sea-level  fluctuations  documented  either  by  shallower
benthic foraminifera (Cycloforina predkarpatica, Pseudotrilo-
culina  consobrina,  Quinqueloculina  fluviata,  Nonion  bogda-
nowiczi, Porosononion martkobi, Porosononion subgranosum,
Elphidium flexuosum,  Elphidium  aff. nataliae,  Elphidium sub-
angulatum  –  samples  V34—V40,  V47—V58)  and  ostracods
(Aurila merita, Aurila cf. schreteri, Graptocythere omphalodes,
Cyprideis  cf.  pannonica,  Amnicythere  spp.)  or  deeper  marine
foraminifera (Glomospira charoides,  Ammodiscus miocenicus,
Bolivina spp., globigerinids – samples V43—V45). Very shal-
low brackish environments with Ammonia flourished at the top
of the sequence (samples V53—V58).

Sequence

Planktonics and deeper-water foraminifera (five-chambered

globigerinids and Bolivina spp.) are present again in the sam-
ples  following  the  interval  with  thick  coarse  sediments
(?FSST4—LST4) above sample V58. These correlate with pro-
gressively  less  reworking  and  lower  abundances  of  shallow
water taxa (e.g. Ammonia spp.), therefore we interpreted this
interval  as  another  transgressive  interval  (TST4  –  samples
M45—M25). As the progradation became more  active  during
the highstand (HST4 – samples M24—M15), shallower fora-
minifera  and  ostracod  assemblages  became  more  abundant
(Ammonia beccarii, Ammonia tepida, Amnicythere sp., Cyp-
rideis pannonica).

Sequence

The sandy interval close to the top of the section (55 m) has

been interpreted as the lower part of the last sequence (FSST5).
The shallow marine miliolid-dominated assemblage (Articulina
sarmatica, A. problema, A. bidentata costata, A. vermicularis,
Sarmatiella moldaviensis, S. prima, and agglutinated Trocham-
mina kibleri  – sample V115) was probably associated with the
late  lowstand  (LST5),  while  the  last  few  globigerinids  docu-
ment  the  last  marine  ingression  at  the  Sarmatian/Pannonian
boundary (TST5 – samples M10—M11). These occur just be-
low the volcanic ashes (Bazna Tuff) near the top of Section A,
which were probably deposited in connection with a tectonic
event. The associated higher sedimentary input (HST5 – sam-
ples  M09  and  above)  and  possible  change  of  salinity  deter-
mined  an  abrupt  change  in  the  micropaleontological
assemblages  (extinction  of  Sarmatian  foraminifera  and  radia-
tion of Pannonian ostracods – sample M09).

Stratigraphic calibration

The Sarmatian/Pannonian boundary was placed by Vancea

(1960)  at  the  last  level  of  volcanic  ash  in  Section  A.  The
Pannonian  Biozone  with  Lymnocardium  praeponticum  was
identified in the lower part of the Section B, and correlated
with the dinoflagellate Mecsekia ultima Biozone and polarity
Zone  C5r  (12—11 Ma;  Magyar  et  al.  1999;  Sztanó  et  al.
2005).  Based  on  dinoflagellate  assemblages,  Sütő  &  Szegő
(2008) placed the boundary at 3.4 m below the top of Section
A, at the massive occurrence of Mecsekia ultima, although they
showed  that  the  index  species  for  the  Pannonian  (Spiniferites
bentonii pannonicus) occurs at 1.4 m below the top.

The foraminiferal assemblages from Oarba de Mure contain

evolved Porosononion species (Porosononion aragviensis,
P.  hyalinum,  P.  sarmaticum),  therefore  we  included  the
whole  interval  opened  by  Section  A  into  the  Sarmatian
Porosononion  aragviensis  Biozone  (Popescu  1995).  Beside
the evolved species of Porosononion, the foraminiferal assem-
blages  contain  all  common  Bessarabian  taxa  (Trochammina
kibleri,  Articulina  problema,  A.  sarmatica,  A.  tamanica,
Bolivina  moldavica,  B.  sarmatica  etc.  –  see  Didkovski  &
Satanovskaya  1970;  Venglinski  1975),  and  for  this  reason
we consider that the Sarmatian sensu Suess (1866) must be

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Fig. 5. Sarmatian micropaleontological assemblages from Oarba de Mure . 1 – Bolivina moldavica Didkovski – sample V18. 2 – Bolivina
aff. arta Macfayden – sample V34. 3 – Bolivina sarmatica Didkovski – sample V34. 4 – Bolivina dilatata Reuss – sample V46. 5 – Bo-
livina pseudoplicata Heron-Allen & Earland – sample V34. 6 – Bolivina hebes Macfayden – sample V46. 7, 8 – Streptochilus latum Brön-
nimann & Resig – 7 sample V28; 8 sample V18. 9 – Streptochilus globulosum (Cushman) – sample V72. 10 – Buliminella elegantissima
(d’Orbigny) – sample V18. 11, 12 – Tenuitellinata pseudoedita (Subbotina) – 11 sample V80; 12 sample V12. 13 – Tenuitellinata selleyi
Li, Radford & Banner – sample V56. 14 – Tenuitella clemenciae (Bermúdez) – sample V51. 15 – Cyprideis pannonica (Méhes) – right
valve, sample V53. 16 – Graptocythere omphalodes (Reuss) – right valve, sample V53. 17 – Aurila merita (Zalányi) – right valve, sample
V45. 18 – Amnicythere sp. – left valve, sample V52. 19 – Loxoconcha cf. popovi Stancheva – right valve, sample V73. 20 – Amnicythere
cernajseki Stancheva – right valve, sample V16. 21 – Coscinodiscus sp. – sample V28. 22 – Halicoryne moreletti (Pokorný) – sample
V28. 23—25 – Fish skeletal fragments: otolith (23) and fish teeth (24, 25) – sample V28. 26 – Sarmysis vancouveringi (Voicu) – sample
V91. 27 – Sarmysis sarmaticus (Khalilov) – sample V28.

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GEOLOGICA CARPATHICA, 2011, 62, 1, 91—102

Fig. 6. Sarmatian foramin-
iferal assemblages from
Oarba de Mure . 1 –
Ammodiscus

miocenicus

Karrer  –  sample  V44.
2 – Glomospira charoides
(Jones  &  Parker)  –  sam-
ple V44. 3 – Varidentella
latecunata (Venglinski) –
sample V01. 4 – Variden-
tella  reussi  (Bogdanowicz)
– sample V64. 5 – Variden-
tella  sarmatica  (Karrer)  –
sample  V01.  6  –  Flintina
georgii  Bogdanowicz  –
sample V01. 7 – Sinulocu-
lina consobrina (d’Orbigny)
–  sample  V28.  8  –
Cycloforina  predkarpatica
(Serova)  –  sample  V45.
9  –    Articulina  problema
Bogdanowicz  –  sample
V115.  10—11  –  Articulina
tamanica  Bogdanowicz  –
sample V115. 12 – Articu-
lina  sarmatica  (Karrer)  –
sample  V115.  13 – Sar-
matiella  costata  Bogdano-
wicz – sample V115. 14 –
Articulina vermicularis Bog-
danowicz – sample V115.

correlated with the Volhynian and the whole Bessarabian
stages of the Eastern Paratethys.

The Sarmatian-Pannonian boundary can be very clearly

traced on the basis of microfossils due to the very distinctive
assemblages of Sarmatian foraminifera vs. Pannonian ostra-
cods. The boundary must be traced at the first occurrence of
ostracod assemblages containing deep-water species of
Amplocypris-Candona group (Fig. 8), at about 2.3 m from
the top of Section A (sample M10, Fig. 4), just below the ash
layers of the Bazna Tuff (Vancea 1960; not “Oarba Tuff” as

considered by Vasiliev et al. 2010). Our boundary can be
very clearly traced between the boundaries of Vancea (1960)
and Sütő & Szegő (2008).

No type species for the base of Zone A of the Pannonian

(large  Amplocypris  ostracods  or  Congeria  ornithopsis  bi-
valve)  have  been  found.  Among  the  ostracods,  Loxoconcha
(Loxoconcha)  dudichi  and  Candona  (?Typhlocypris)  aff.
lunata  are  known  from  the  Pannonian  Zones  B—C,  while
Candona  (Lineocypris)  transilvanica  (Héjjas)  are  found  in
Zones B—D. The absence of typical taxa for Zone A could be

101

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caused by a longer persisting marine facies compared to the
Pannonian Basin, due to a later closure of the Transylvanian
Basin.

Considering the radio-isotopic age of the ash layer from

the  lower  part  of  Section A  (11.62 Ma)  and  the  magneto-
stratigraphic calibration of the top of the section (Vasiliev et
al. 2010), we have a good age approximation for the Sarmat-
ian-Pannonian  biostratigraphic  boundary,  that  is  close  to
11.3 Ma.  This  is  approximately  300 kyr  younger  than  the
age of the Sarmatian-Pannonian boundary traced by Piller et
al.  (2007)  and  about  100 kyr  younger  than  the  boundary
traced by Lirer et al. (2009).

Discussion

A major paleoenvironmental change occurred at the Sarma-

tian-Pannonian  boundary.  The  newly  established  restrictive
conditions  produced  very  distinctive  changes  of  biota  (e.g.
marine  foraminifera  replaced  by  brackish  ostracods)  about
11.3 Myr  ago  (Vasiliev  et  al.  2010).  This  biotic  boundary
seems  to  be  younger  compared  to  other  Central  Paratethyan
basins (e.g. Piller et al. 2007; Lirer et al. 2009), suggesting a
different  position  of  the  Sarmatian-Pannonian  boundary  due
to  persisting  marine  conditions  in  the  Transylvanian  Basin
(possible longer-lasting connections to the open seas).

Indications for a transgressive event (planktonic foramin-

ifera) could be identified even in the vicinity of the Sarma-
tian-Pannonian boundary and probably this event can be
correlated with the early Ser4/Tor1 cycle of Hardenbol et al.
(1998). The sea-level rising trend was probably stopped by
active tectonics (higher sedimentary input and volcanic ash-
es can be observed just above the boundary).

It seems that the cyclicity observed in the sedimentary and

micropaleontological record could have been produced by a
combination  of  tectonic  and  climatic  factors.  The  influence
of compressional tectonics could be inferred by the presence
of volcanic ash in the section, while the climatic/seasonal cy-
clicity  can  be  presumed  by  the  repeated  abundances  of  the
assemblages  with  diatoms,  mysids,  dasyclads,  fish  bones,
and  local  abundances  of  opportunistic  groups  living  in  an
seasonally unstable environment.

Conclusions

Different microfossil taxa and their frequency (Figs. 2, 3)

reflect  with  fidelity  the  environmental  changes  around  the
Sarmatian-Pannonian  boundary.  Particular  micropaleonto-
logical  assemblages  were  used  to  distinguish  several  cyclic
events. The fossil mysids, diatoms, calcareous algae and fish
bones were probably stimulated by eutrophic intervals asso-
ciated with active deltas. The globigerinid assemblages were
associated with transgressive intervals, while the presence of
Bolivina species could have been related to the deep environ-
ments of the early highstand and late lowstand. Diverse ro-
taliids  and  miliolids  (the  shallowest)  are  characteristic  of
normal  regressive  intervals  during  the  highstand  and  low-
stand,  while  strong  reworkings  were  probably  associated

with forced regressions. Linking the particular micropaleon-
tological assemblages to sea-level changes allowed the sepa-
ration  of  five  stratigraphic  sequences  (Fig.  7)  with  their
particular genetic units, which support the increase of strati-
graphic  resolution  for  the  Upper  Sarmatian.  The  sequences
identified in Section A at Oarba de Mure  seem to be lower
order cyclicities within the Ser4-Tor1 cycle (Hardenbol et al.
1998), influenced by regional tectonics and climate.

A clearly marked Sarmatian-Pannonian boundary has been

traced on the basis of very distinctive foraminiferal and os-
tracod assemblages. Based on foraminiferal assemblages, we
consider that the Central Paratethyan Sarmatian should be cor-
related with the Volhynian and the whole Bessarabian of the
Eastern  Paratethys.  Due  to  the  continous  sedimentation  and
good  calibration  given  by  biostratigraphy,  magnetostratigra-
phy, radiometric data and sequence stratigraphy, the section of
Oarba de Mure  seems to be a very good candidate for the fa-
ciostratotype of the Sarmatian-Pannonian boundary.

Acknowledgments: The authors are grateful to S.N.G.N.
Romgaz S.A. and University of Utrecht for funding the study,
to Dr. Csaba Krézsek, Dr. Katarína Holcová, and Dr. Jarosław
Tyszka for the useful comments. We also thank Claudiu
Chende , Florin Borbei, and Josh Ball for helping with sample
processing.

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