GeolCarp_Vol61_No1_55

www.geologicacarpathica.sk

GEOLOGICA CARPATHICA, FEBRUARY 2010, 61, 1, 55—69 doi: 10.2478/v10096-010-0001-8

Introduction

The  western  part  of  the  Sava  Depression  and  the  Bjelovar
Subdepression evaluated in the present study are both located
at  the  southwestern  margin  of  the  Pannonian  Basin  (Figs. 1
and  2).  The  primary  difference  in  these  depressions  is  their
scale. The Sava Depression is an independent regional geotec-
tonic  unit,  while  the  smaller  Bjelovar  Subdepression  repre-
sents only the southern part of the Drava Depression (Fig. 1).
Both basins were formed contemporaneously by Neogene ex-
tension (Velić 1980, 1983; Prelogović et al. 1995, 1998; Vrba-
nac 1996; Malvić 2003; Saftić et al. 2003; Kovačić & Grizelj
2006; Grizelj et al. 2007), but subsidence in the Bjelovar Sub-
depression  occurred  later  than  in  the  Sava  Depression.  The
source  area  of  detrital  material  for  both  depressions  was  the
Eastern Alps; however, paleotectonic movements created two
different  depressions  with  different  total  amounts  of  subsid-
ence  and  thicknesses  of  deposits.  Additionally,  paleorelief,
which was created by tectonic movements, directed turbidity
currents  in  the  Drava  and  the  Sava  Depressions.  Paleorelief
exerted similar effects in the Bjelovar Subdepression.

Besides the geological analysis of the well logs available

from wells drilled in the deep basinal areas, Upper Pannonian
sediments are also found in numerous outcrops on the basin

Sedimentation of deep-water turbidites in the SW part of the

Pannonian Basin

BORIS VRBANAC

, JOSIPA VELIĆ

and TOMISLAV MALVIĆ

2,3

INA-Industry of Oil, Plc. Exploration and Production of Oil and Gas, Sector for Exploration and Production of Oil and Gas in

Southeastern Europe, Šubićeva 29, 10000 Zagreb, Croatia; boris.vrbanac@ina.hr

University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Pierottijeva 6, 10000 Zagreb, Croatia; josipa.velic@rgn.hr

INA−Industry of Oil, Plc. Exploration and Production of Oil and Gas, Sector for Geology and Reservoir Management, Šubićeva 29,

10000 Zagreb, Croatia; tomislav.malvic@ina.hr

(Manuscript received April 14, 2009; accepted in revised form October 2, 2009)

Abstract:  The  Sava  Depression  and  the  Bjelovar  Subdepression  belong  to  the  SW  margin  of  the  Pannonian  Basin
System, which was part of the Central Paratethys during the Pannonian period. Upper Pannonian deposits of the Ivanic-
Grad Formation in the Sava Depression include several lithostratigraphic members such as Iva and Okoli Sandstone
Member or their lateral equivalents, the Zagreb Member and Lipovac Marlstone Member. Their total thickness in the
deepest part of the Sava Depression reaches up to 800 meters, while it is 100—200 meters in the margins of the depres-
sion. Deposits in the depression are composed of 4 facies. In the period of turbiditic activities these facies are primarily
sedimented as different sandstone bodies. In the Bjelovar Subdepression, two lithostratigraphic members (lateral equiva-
lent) were analysed, the Zagreb Member and Okoli Sandstone Member. The thickness of the Bjelovar Subdepression
ranges from 50 meters along the S and SE margins to more than 350 meters along the E margin. Generally, detritus in
the north-west part of the analysed area originated from a single source, the Eastern Alps, as demonstrated by sedimen-
tological and physical properties, the geometry of the sandstone body and the fossil content. This clastic material was
found  to  be  dispersed  throughout  the  elongated  and  relatively  narrow  Sava  Depression  and  in  the  smaller  Bjelovar
Subdepression. Sedimentation primarily occurred in up to 200 meters water depth and was strongly influenced by the
sub-aqueous  paleorelief,  which  determined  the  direction  of  the  flow  of  turbidity  currents  and  sandstone  body  geo-
metries. The main stream with medium- and fine-grained material was separated by two independent turbiditic flows
from N-NW to the SE-E. Variability in the thickness of sandstone bodies is the result of differences in subsidence and
cycles of progradation and retrogradation of turbidite fans.

Key words: Upper Pannonian, Croatia, Sava Depression, Bjelovar Subdepression, deep-water environment, turbidites.

margins and were analysed for the present study. These out-
crops are located along the Zrinska gora Mountain, as well as
along the Papuk and Psunj Mountains to the east, Medvednica
Mountain to the west, Kalnik Mountain to the northwest, and
Moslavačka gora Mountain. The latter is located between the
Sava Depression and the Bjelovar Subdepression.

The lithostratigraphic units’ subdivision for the Sava De-

pression and the Bjelovar Subdepression are different (Fig. 3).

The entire Upper Pannonian sequence is lithologically rep-

resented by alterations of marls, siltstones and sandstones
(Fig. 3). The total thickness of these sediments in the deepest
part of the study area reaches up to 800 meters, while it rang-
es from 100 to 200 meters along the margins of the depres-
sion (Fig. 4).

Pure sandstones are deposited only in the central parts of the

(sub)depressions. Sandstone members are completely substi-
tuted by marls in marginal areas as a result of the usual basin
plain sedimentation. There are two main sandstone members
in these depressions:

Okoli Sandstones, which can be found in both regions;
Iva Sandstones, which are found only in the Sava De-

pression.

Evaluation of the sedimentological characteristics of the

cored deposits (lithology, bedding, structures and sandstone/

VRBANAC, VELIĆ and MALVIĆ

marl ratio) enables identification of four different
facies: facies of thick-layered to massive sand-
stones (F

), facies of thin sandstone layers (F

), fa-

cies of laminated sandstones, siltstones and marls
(F

), and facies of massive marls (F

Separated facies are recognized on the diagrams

of well logs based on the curve describing sponta-
neous potential and resistivity. Comparison of the
various spontaneous potential curves and the char-
acteristics of well logs revealed four different facies
associations: turbidite channel fill facies associa-
tion (F

), turbidite overbank-levee facies associ-

ation (F

), lateral or distal turbidite facies

association (F

), and massive marls facies asso-

ciation (F

The aim of this study was to reveal the main

sedimentological characteristics of the facies as-
sociations and to settle their areal distribution in
the study area. All conclusions regarding the spa-

Fig. 1. Geographical positions
(location map) of the Sava De-
pression and the Bjelovar Sub-
depression.

Fig. 2. Location map of wells and oil fields, as well as
other used localities.

SEDIMENTATION OF DEEP-WATER TURBIDITES IN THE SW PANNONIAN BASIN

tial distribution of the separated facies associations in this
study are based on data obtained from approximately 2000
wells in the study area.

Generally, the explored sediments are very rarely charac-

terized by fossils. Consequently, the content of macrofos-
sils in well cores can be only found in wells drilled in
marginal depression parts. This fossil assemblage indicates

Fig. 3. Correlation table of the chronostratigraphic and lithostratigraphic units and positions of EL-markers.

Fig. 4. Isopach maps of the Rs5-Z’ interval (Ivanić-Grad Formation of the Late Pannonian period) in the Sava Depression (A) and Bjelovar
Subdepression (B).

fresh  to  brackish  water,  relatively  shallow  environment.
Cores  collected  from  deeper  depression  parts  are  some-
times characterized only by fragments of Ostracodes. More
detailed  conclusions  are  obtained  mostly  based  on  palino-
logical analyses, which are described and interpreted in sub-
chapter  ‘Depositional  environments – basin  plain  and/or
near-shore mechanisms’.

Note to Fig. 3: Both the above mentioned units – the Moslavacka gora Group and Moslavacka gora Formation are accepted in formal Croatian
lithostratigraphic nomenclature. One (group) is a formal unit in the Sava Depression and another (formation) in the Drava Depression. The
name comes from the “Moslavacka gora” Mountain that divided the Sava and Drava Depressions and was the field trip area with outcrops in
both depressions. Sava Depression: The Moslavacka gora Group is the unit of the highest rank and comprises two formations – Precec
Formation (of Sarmatian and older ages) and Prkos Formation (of Early Pannonian age). Drava Depression: The Moslavacka gora Formation
is the oldest formal lithostratigraphic unit with the rank of formation and it is divided in two lithostratigraphic members – Mosti Member (of
Sarmatian and older ages) and Koprivnica Sandstone Member (or Krizevci Member) (of Early Pannonian age).

VRBANAC, VELIĆ and MALVIĆ

Thickness and description of facies

As previously mentioned, depositions from the Late Pan-

nonian period are lithologically represented by alterations of
marls, siltstones and sandstones.

The Upper Pannonian members include the Iva (older) and

Okoli  Sandstones  (younger)  Member.  In  the  western  part  of
the  Bjelovar  Subdepression,  the  Okoli  Sandstones  grade  into
the Zagreb Member and partially in the Lipovac Marls Mem-
ber  (the  lateral  equivalent  of  the  Zagreb  Member;  Fig. 3).
However, sedimentation of the Upper Pannonian deposits did
not occur in the south-eastern part of the subdepression.

Sandstones in the study area are fine-grained, rarely medi-

um-grained (diameter up to 0.5 mm), have a porosity ranging
from 10 to 33 % and it decreases from NW to SE (in the direc-
tion  of  paleotransport).  The  petrographic  composition  of  the
sandstones in the study area is very homogeneous. Specifical-
ly, the composition is primarily quartz ( > 60 %) and rock frag-
ments  including  carbonates,  cherts,  schists,  gneisses  and
granites (18—35 %). The source area was determined to be the
Alps  based  on  the  presence  of  accessory  minerals  indicating

metamorphic rocks (from epi- and mesozones), limestones
and cherts (Šćavničar 1979).

Siltstones in the study area have a mineral composition iden-

tical to those of sandstones, but the mica content is increased.

Marls in the study area are characterized by a matrix con-

sisting of clay and cryptocrystalline carbonate. The CaCO

content of the marls is approximately 60 %.

Four clearly distinguishable facies were observed in the

studied Upper Pannonian sediments, based on outcrop and
core studies (Vrbanac 1996, 2002a, 2002b). The different fa-
cies range from pure, medium-grained sandstones (F

through laminated sandstones, siltstones and marls (F

2—3

) to

pure marls (F

). The description of these main facies is pre-

sented below.

Facies of thick-layered to massive sandstones

Facies of thick-layered to massive sandstones (F

) – This

facies includes thick-layered to massive, homogeneous sand-
stones, rarely with thin beds or laminae of siltstones and marls
(Fig. 5). The thickness of the sandstone intervals varies from 0.5

Fig. 5. Facies F

, F

and F

based on core samples.

SEDIMENTATION OF DEEP-WATER TURBIDITES IN THE SW PANNONIAN BASIN

to 6 m, with thicker beds most likely formed by amalgamation.
Gradation and cross-bedding are hardly visible. Convolution is
more often recognizable. Lower bedding surfaces are character-
ized by erosional marks. Sedimentation is the result of directed,
fast and massive deposition from suspension.

The internal structure and texture of the particular bed is the

result of the final stage of detritus transport and its deposition-
al epoch. These strata characteristics are especially important
for  interpretation  of  depositional  environments  and  condi-
tions.  Thick  sandstone  strata  are  mostly  massive,  and  only
some  strata  show  upwardly  decreasing  grain  size  and  transi-
tion  to  thin,  horizontal  laminated  or  cross-laminated  sand-
stones or siltstones covered by marl. These sequences, which
resulted from flows of decreased energy, can be compared by
Bouma sequence type A—D. The large amount of sandstones
(thick  strata)  indicates  high  energy  and  a  capacity  for  deep-
water flow, which was also turbulent (based on the marl clasts
and erosional base). All of these characteristics describe gravi-

coarser grains close to the base. It is result of the grain colli-
sion as the dominant factor that supported transport (Bagnold
1954). This mechanism leads to the formation of a basal bed
of  grains  supported  by  strong  dispersive  pressure  and  sedi-
mentation  of  grains  on  the  base,  which  can  be  named  as  a
“carpet  bed”  (Dzulynski  &  Sanders  1962).  According  to  the
decreasing  flow  energy,  such  carpet  strata  will  be  collapsed
and “frozen”, and inverse graduate sands of proximal turbid-
ites will be created (Hiscott & Middleton 1979). The thickness
of the carpet strata is proportional to the diameter of the grain
(Bagnold  1954;  Lowe  1976).  Similar  deposits  can  be  inter-
preted as “sandy debris flows” as they were described in Shan-
mugan (2000, 2002).

Facies of thin sandstone layers

Facies of thin sandstone layers (F

) are represented by

sandstone layers up to 0.5 m thick (Fig. 5). Horizontal and

Fig. 6. Facies association based on core samples and indicated by spontaneous potential
(SP) and resistivity (R) curves in the Sava Depression.

tationally dense currents (turbidites) includ-
ing  detritus  from  different  populations
(Lowe 1982) supported by an upward com-
ponent  of  turbulent  flow  (Middleton  1967;
Lowe  1979,  1982).  The  flows  also  left
marks  in  flow  the  base,  due  to  the  large
shearing that likely occurred in response to
dispersive pressure (Middleton 1967; Lowe
1976, 1982).

Thick beds without groove mark structures

that were completely massive and deposit-
ed in sequence by previously interpreted
strata were likely created in a fashion simi-
lar to that of interval Ta. Their massive char-
acter is probably the result of erosion of the
upper parts of a complete deposited turbid-
ites interval. This is confirmed by the char-
acteristics of the lower erosional planes and
frequent amalgamation of thick sandstone
units (up to 6 m).

The horizontal lamination observed in

some parts of the thick amalgamated units
also supports the suggestion that the charac-
teristics of the thick beds are the result of
erosion. Some of these strata were also cre-
ated by liquefaction deformation.

Additionally, these facies include thick

strata without groove mark structures that are
completely  massive  and  overlain  by  marls
(without  transitional  siltstones).  These  strata
were likely created by the same processes as
the  previously  described  massive  beds.  The
sharp transition from sandstones to marls can
be explained by a rapid decrease in flow ve-
locity, which led to instantaneous deposition
of the remaining coarser detritus. There was
not  time  for  grain  separation  based  on  their
size;  therefore,  the  silt  detritus  was  incorpo-
rated into the sand particles.

Inversed gradation can rarely be ob-

served. Such features indicate increasing

VRBANAC, VELIĆ and MALVIĆ

cross-bedded lamination can be easily observed in sandstones
and siltstones. Erosional marks are frequently observed on the
upper bedding planes.

Convolution and marl clasts are frequently found. These de-

posits were also deposited from turbidites, but in areas distal
from the main currents.

This facies is composed of alternating sandstones and marls.

Lower bed planes of sandstones are sharp, but upward there is
a gradual transition to the top marl. These characteristics con-
firm the activity of dense currents, which gradually weakened
in strength. The current that supported this facies was weaker
than the flow that was responsible for the deposition of the
previous facies, F

. Internal structures and uninterrupted se-

quences can be compared by Bouma sequences and interpret-
ed as turbidites. The index of proximity is lower in facies F

than in facies F

due to the significantly lesser portion of detri-

tus from the Ta interval (Bouma 1962, 1972).

Facies of laminated sandstones, siltstones and marls

Facies of laminated sandstones, siltstones and marls (F

)

is  composed  of  a  monotonous  alternation  of  thin  sandstone
layers, which are gradually substituted by siltstones and marls
in the upper portion of the facies (Fig. 5). Textures encompass
horizontal  and  cross-lamination,  convolution  and  sandstone
veins and dykes. These rocks were deposited from low-densi-
ty turbidites; however, some of these strata are likely the result
of  redeposition  caused  by  normal  submarine  currents  along
the sea bottom.

Thin alternating beds of laminated fine-grained sandstones

and  siltstones  are  often  represented  as  intervals  of  Tc—Te  of
the Bouma sequence. This suggests that at least part of these
beds were deposited from low-concentrated turbidity currents,
which indicates that deposits of this facies can be compared to
thin-stratified sediments from low energy deposits of channel
banks  (Mutti  &  Ricci-Lucchi  1975;  Walker  1978)  including
intervals Tc, Td, Te or distal turbidites. This interpretation can
also be supported by the presence of sandy veins and dykes as
result of instability on levee surface. However, there are sever-
al other possible depositional models. For example, some thin
sandstone and siltstone strata may have formed in response to
re-deposition  of  turbidites  on  the  basin  bottom  as  a  result  of
normal bottom currents. Such processes are known to occur in
deep  marine  environments  where  sandy  contourites  are
formed as a result of a combination of sedimentation and re-
sedimentation  of  bottom  sediments  in  response  to  deep  cur-
rents (Stow & Lovell 1979; Stow 1982). Similar processes of
sediment reworking could have occurred in sandy contourites.

Facies of massive marls

The facies of massive marls (F

) includes homogeneous,

massive,  mostly  unstratified  marls  with  clearly  visible  bio-
turbations. Occasionally, stratification can be recognized based
on  relics  of  lamination,  colour  changes  and  thin  siltstone
films.  Marls  were  formed  by  continuous  sedimentation  of
pelitic detritus (Fig. 5).

These marls differ from marls that represent a gradual

transition from the sandstone layers and resulted from the

deposition  of  pelitic  detritus  from  the  tail  of  the  dense  cur-
rents. Such massive marls are the result of sedimentation of
the  finest  detritus  that  is  part  of  the  continuous  activity  of
turbiditic current in the paleo-basin. Massive marl sedimen-
tation can be connected to transport and deposition from in-
ner  and  shallow  currents  (Orton  &  Reading  1993)  that  also
carry suspended detritus. These continuously active currents
in the Upper Pannonian are composed of permanent material
transported by rivers to the subbasins of the Pannonian Basin.
The transport energy of these permanent currents can be ex-
pressed by the flow velocity and maximal size of the trans-
ported detritus. The area of the river mouth and deposition of
material  brought  by  paleo-rivers  was  located  outside  the
analysed area. The uniform petrographic composition of de-
tritus  indicates  that  there  is  a  single  source  area  for  all  the
turbidite  currents,  but  that  the  depositional  mechanism  of
particular  facies  was  different.  The  thicknesses  of  the  mas-
sive marls are higher in proximal areas of the depression and
lower in the distal (far away from the source) or morphologi-
cally  uplifted  areas.  This  indicates  that  bottom  (inner)  cur-
rents were the primary mechanism by which the detritus was
carried,  while  surface  currents  were  the  secondary  mode  of
transport. Of course, the flow directions and depositional ar-
eas  were  determined  by  the  paleo-morphology,  water  depth
and temperature gradient.

Facies associations

In the course of the analysis of the study area four facies as-

sociations were recognized (based mainly on well-logs and/or
core samples) (F

, F

), which are shown in Fig. 6 (def-

inition of the association in the Sava Depression) and Fig. 7
(definition of the association in the Bjelovar Subdepression).

Turbidite channel fill facies association

Turbidite channel fill facies association (F

) – This fa-

cies association (Figs. 6 and 7) consists of thick-bedded sand-
stone facies (F

) and thin-bedded sandstone facies (F

). The

channel axis is characterized by thick sandstone beds with rare
marl layers. The number of marl layers is greater in the chan-
nel margins, while the basin plain sandstones are thinner and
contain  more  fine-grained  sediments.  Channel  sedimentation
is  described  by  a  spontaneous  potential  log  (SP  log),  which
has a bell shaped curve for channels with continuous decrease
of energy (meandering channels) or box shape for rapidly fill-
ing  sandy,  perhaps  braided,  channels  (Pirson  1970).  This  is
because the facies in the lower part of the study area is com-
posed  of  thick-bedded  sandstones  (F

), while it is composed

of thin-bedded sandstones (F

) in the upper parts (when the

channel began to be inactive). If the channel is abandoned rap-
idly, which means that there is no observed upward fining and
thinning,  the  SP  log  is  characterized  by  a  cylindrical  shape
(Pirson  1970).  The  thickness  of  particular  depositional  se-
quences  is  10—20 m,  and  several  sequences  are  often  amal-
gamated  in  a  single  sandstone  body  in  which  sequences  are
also divided by marls.

SEDIMENTATION OF DEEP-WATER TURBIDITES IN THE SW PANNONIAN BASIN

Erosion was strongest in the central parts of the channels

and weaker in the margins, which indicates that the positions
of  the  channel  can  be  determined  based  on  the  marl  layers.
Specifically, the positions can be deduced based on the direc-
tion of the main current during different periods. The energy
of currents was strongest inside the channel, which resulted in
strong bottom erosion. Therefore, the missing marl that could
be deposited by the previous current due to erosion and amal-
gamations later was probably eroded, which is the result of lo-
cation  along  the  channel  axis  where  the  current  was  the
strongest.  Such  features  describe  channels  as  depositional

Fig. 7. Facies associations found within core samples and indicated by sponta-
neous potential and resistivity curves in the Bjelovar Subdepression.

(Hamilton  1967)  and  erosional  (Laughton  1968)
environments in which the main current mass was
transported.  In  the  lower  parts  of  the  current  the
particle  concentration  was  highest,  while  the  ma-
jority of suspended detritus was deposited in distal
areas  due  to  the  decreasing  current.  This  resulted
in  the  maximum  sandstone  thicknesses  being  de-
veloped in channels that were formed according to
basin morphology and sedimentary tectonics.

Turbidite overbank-levee facies association

) – This facies association is composed of F

facies in the lower part and F

facies in the upper

part (Figs. 6 and 7). Sediments of this facies asso-
ciation  were  deposited  outside  the  distributary
channels, where the turbidity currents were signifi-
cantly  weaker,  which  created  overbank-levee,
fringe and channel bank deposits. These character-
istics resulted in the erosional effects being smaller
than  in  the  channel  facies.  As  a  result,  amalgam-
ations  are  very  rare  and  the  thickness  of  eroded
marls is probably not higher than several to several
dozen centimeters. In addition, the total thickness
of  the  sandstone  body  in  this  association  can  be
more than 30 m and shows upward thickening.

This association is characteristic of the marginal

parts of channels and the channel’s banks. The
characteristics of this association indicate that the
distribution was not restricted to the channels, but
also occurred in the wider channel area, which re-
sulted in thick sandstones occasionally being de-
posited in bank (levee) areas.

Lateral or distal turbidite facies association

or lateral or distal turbidite facies associ-

ation – This facies association consists of a mo-
notonous alternation of very thin, thin and
medium-thick sandstone beds passing into silt-
stones and marls (Figs. 6 and 7). The association
is represented by facies F

and F

. In this associa-

tion,  erosion  on  the  upper  bedding  plane  is  al-
most  completely  absent.  In  addition,  the
sub-layers  of  marls  and  sandstones  are  so  thin
that  they  are  beyond  the  resolution  of  well-log
curves. This also indicates that the SP curve gives

a  larger  scale  representation  of  the  sedimentary  succession.
Sediments of this association are recognized in distal areas,
such  as  those  in  which  the  maximal  range  of  turbidites  oc-
curred.  Moreover,  such  sediments  are  discovered  on  mor-
phologically  uplifted  parts  between  channels  and  can
probably  be  found  on  the  banks  of  flume  channels  (Walker
1978). These sediments can be found further away from the
channels for great distances (i.e. from the area of sub-chan-
nel and fringe sandstones), consequently, the portion of silt-
stones and marls in the facies is increased and the portion of
marly sandstones and sandstones is decreased.

VRBANAC, VELIĆ and MALVIĆ

The total thickness of this association can reach several doz-

ens of meters, and can cover several hundreds of meters later-
ally. Moreover, these distal turbidites can be compared with
classical turbidites that are deposited (Walker 1978) at the end
of the distal part of a lower fan in the basin plain, which is the
area in which the maximal extensions of the turbidity current
exist. Distal turbidites can also be found on the banks of the
upper fan (Walker 1978). Generally, such turbidites are the re-
sult of the deposition of sandy and fine-grained detritus in the
marginal, transitional parts of the basin, between the main cur-
rent flow and morphologically uplifted areas. These results in-
dicate that deposition was active in areas where turbidity
current is still active, but only from a thin portion of the cur-
rent cloud. This activity occurred due to the low energy in the
area, which resulted in only small quantities of sandy detritus
being transported.

Massive marls facies association

or massive marls facies association – This associa-

tion is primarily represented by massive marl facies F

with

rare  intercalations  of  thin  siltstone  or  sandstone  laminae  or
beds  (Figs. 6  and  7).  Sediments  in  this  association  are  con-
tinuously  deposited  in  marginal  areas  of  the  contemporary
Sava  Depression  or  areas  outside  the  range  of  turbidites.
However,  deposition  of  these  marls  was  also  active  in  the
central parts of the depression during calm periods in which
there were no turbidite activities.

Fig. 8. Vertical and lateral facies correlation section over SW part of the Žutica field in the Sava Depression.

This association can be compared to hemipelagic sediments

of open seas deposited on the continental shelf; however, in
the case of the Sava Depression and the Bjelovar Subdepres-
sion, such hemipelagic deposits can be found in entire basins.

Lateral and vertical facies alteration

Facies recognition of spontaneous potential (SP) and resis-

tivity  (R)  curves  is  especially  reliable  in  the  oil  and/or  gas
fields, where there is a relatively high number of wells located
in a small area. As a result, the lateral and vertical sedimentary
facies  associations  can  be  easily  followed  on  the  section
drawn for the Ivanić-Grad Formation of the Žutica oil and gas
field (Figs. 8, 9). There was clearly expressed channel migra-
tion through time in this area. In addition, vertical and lateral
facies  transitions  are  sometimes  gradual  and  sometimes  very
sharp in this region. Such transitions were particularly evident
in areas of rapid transition of channel sediments into massive
marl  associations  (Figs. 8  and  10).  These  characteristics  re-
flect the rapid changes in the location of the channel.

The size of single channel depends on the width of the chan-

nel bottom and the slope dip of the channel margins. For ex-
ample, in the Žutica field, sediments of association F

are

extended laterally in a thickness of several dozen meters, but
laterally they grade into a narrow zone of association F

(up to

10 m) and later to association F

(thickness 2—5 m).

The results of this study revealed the general characteristic

of the distribution of facies associations in the study area. Evi-

SEDIMENTATION OF DEEP-WATER TURBIDITES IN THE SW PANNONIAN BASIN

dently, parallel to the channel directions (channel fill facies as-
sociation) we mostly found the sediments of the turbidite
overbank-levee facies association. Laterally it passes into dis-
tal turbidite sediments and finally into the massive marl facies
association (Figs. 8 and 10).

The distribution of the identified facies associations con-

forms to the general distribution of facies in an ideal turbiditic
fan (Walker 1978). The central depositional area is the chan-
nel, which is filled with thick, stratified to massive sandstones.
The facies distribution in Fig. 9 suggests that the Žutica field
is on the marginal part of a submarine fan and decreasing of
sandy facies is a result of deposition on channel-overbank ar-
eas. In fringe areas, there are thin and thick stratified sand-

Fig. 9. Lateral facies correlation section over the Žutica
field in the Sava Depression.

stones. More distally, in the direction of turbidite flow and in
areas far from the channel axis, thin-stratified sandstones and
distal and lateral turbidites are present.

Massive marls are deposited in all parts of the depression

that  were  outside  the  route  of  the  turbidity  current,  such  as
geomorphologically uplifted parts of the depression. Such up-
lifted  lake-bottom  areas  are  also  occasionally  located  in  the
central (sub) areas of the depression. In addition, marl associa-
tions  can  be  incorporated  into  the  more  abundant  channel
sandstone  association;  if  they  had  not  been  eroded  (such
mechanism is described earlier).

Inside the Iva Sandstone Member lithostratigraphic unit

there are eight sandstone layers saturated with oil and gas that

VRBANAC, VELIĆ and MALVIĆ

are known as the

γ series (γ

—

). Fig. 8 shows the ex-

tension of the sandstone body

(Žutica field). The fa-

cies association transition can be clearly followed in
this area. The sandstone body (reservoir),

, is mapped

only in the central part of the field, namely in the chan-
nel (Fig. 9). The channel direction in the northern part
of the reservoir is N—S, while it eventually transitions to
a NW—SE direction. The direction and contact with
younger (

) and older (

and

) sandstones have been

mapped in the channel. The contact of these sandstone
bodies has occurred in response to (inter-sandstones)
marl erosions caused by turbidite activities.

The thickness of

sandstones in the channel reaches

up to 15 m, and extends up to 12 m laterally. In areas in
which several sandstone reservoirs are connected as a
result of erosion, the total thickness of such sandstone
bodies can reach up to 60 m.

Two presentations of facies lateral extension are

shown in Figs. 10 and 11. The slightly different distri-
bution of the facies association has been mapped in the
Bjelovar Subdepression (Fig. 11) in sandstone reservoir
E of the Late Pannonian age. The direction of the chan-
nel in this area is approximately W—E and is character-
ized by a relatively large channel width. The association
of massive marls (F

) is located on the north part of the

channel in this area, and the transitional association of

Fig. 10. Vertical and lateral facies correlation section over Letičani, Galovac-Pavljani and Velika
Ciglena fields in the central part of the Bjelovar Subdepression.

Fig. 11. Lateral facies correlation within the Šandrovac field in
the Bjelovar Subdepression (modified after Bokor et al. 2000).

SEDIMENTATION OF DEEP-WATER TURBIDITES IN THE SW PANNONIAN BASIN

and F

is very irregular in this area. In addition, the transi-

tion from F

to F

is not complete and regular in some areas

of the channel. These characteristics are due to differences in
the paleotectonic position of the Bjelovar Subdepression.

Paleogeography during the Late Pannonian

(7.8—10.8 Ma) in the studied subbasins

In the Late Pannonian (7.8—10.8 Ma), the Sava Depression

and the Bjelovar Subdepression were parts of the Pannonian
Basin System. Investigations of the western part of the Sava
Depression revealed a narrow, elongated basin with a width of
25 km and a length of 100 km.

The Bjelovar Subdepression is a branch of the Drava De-

pression, with an approximately 50

×25 km rhomboidal shape.

This subdepression is separated from the Sava Depression by
the Moslavačka gora Mountain and two uplifted basement
highs as two subsurface continuations of the mountain range
(Fig. 12).

The Pannonian Basin System in the Late Pannonian was an

open lake system, composed of several connected basins with
active inflows and outflows (rivers) that have been described
in detail by Bérczi et al. (1988). The chemical composition of
water was determined by the continuous inflows of fresh wa-
ter from rivers. The result was the development of a fresh or
slightly brackish lake environment.

Paleogeographic position of the Sava Depression

Based on the present-day structural and tectonic relation-

ships and those that are evident in the geological history of the
region, it is possible to determine the depositional mechanism
of particular lithostratigraphic members. It is also possible to
interpret the paleogeography that was present during the stud-
ied Late Pannonian period (7.8—10.8 Ma).

The Sava Depression had a very complex paleorelief. There

was a tectonic graben in the central part of the depression, lo-
cated between uplifted parts of sub-aqueous paleorelief. The
bottom of the depression was indented and probably dipping
slightly towards the SE and E. The present-day sediment

Fig. 12. Schematic lateral facies correlation between the Sava Depression and Bjelovar Subdepression.

thickness  indicates  that  in  the  centre,  the  deepest  part  of  the
depression was formed by the subsidence of the pre-Neogene
basement.  The  subsidence  probably  started  in  the  NW,  al-
though the strongest tectonic activity later occurred in the NE.
The  facies  distribution,  thickness  of  the  particular  members
and the tectonic activity indicated that the deepest part of the
Upper  Pannonian  (period  of  Iva  Sandstone  Member  deposi-
tion) started in the western part of the Obedište locality. This
deep  area  continued  away  along  the  Martinska  Ves  horst,
south  from  the  Žutica  field  and  ended  in  the  Donja  Jelenska
sag (Vrbanac 1996).

Some shallower, transitional plateau was also located in the

NE area of the depression near the Kloštar, Ivanić, Žutica and
Okoli fields. Shallowing continued toward the NE in the area
of the Križ field and finally, at the Moslavačka gora Mountain
the underwater paleorelief controlled the direction of turbidite
flows through the (sub)depression. This is the reason why dif-
ferent depositional areas (filling from different currents) had
similar lateral characteristics; however, there were two prima-
ry channels – northern and southern.

Later, during the time of sedimentation of the Okoli Sand-

stones Member, deposition in the NW part of the Sava De-
pression was inclined toward the SW (Hernitz & Jurak 1973).
This was likely the result of the uplifting of Moslavačka gora
Mountain and stronger subsidence of the Donja Jelenska and
Ilova sags in the NE as well as existence of the Martinska Ves
horst in the SW. In these uplifted areas, the thickness of mas-
sive marls is small. Currently, Upper Pannonian sediments
can be found on the surface of the Moslavačka gora Mountain.

In addition, the Sava Depression was closed to the N by

Medvednica  Mountain,  or  rather  by  the  paleorelief  of  the
Medvednica  and  Moslavačka  gora  Mts  (mostly  located  in
shallow water). South of these uplifted areas turbidites trans-
ported material and filled the depression (Šimon 1980). North
of this buried paleorelief were the source areas from where the
clastic  material  were  occasionally  transported  to  the  central
parts of the Sava Depression.

The E side of the Sava Depression was closed by an under-

water paleorelief chain located between the Psunj and Prosara
Mountains (Blašković 1982). This is also the pinchout zone of
the turbidites, and only a few sandstone bodies are found

VRBANAC, VELIĆ and MALVIĆ

along the E part of the depression. The paleogeographic situa-
tion at the end of the Late Pannonian is shown in Fig. 13.

Paleogeographic position of the Bjelovar Subdepression

The Bjelovar Subdepression was a relatively closed basin

of moderate paleorelief. At the beginning of the studied peri-
od (Late Pannonian, 7.8—10.8 Ma), only hemipelagic marls
were deposited (facies of massive marls, F

). Later, this area

was opened toward the NE, which resulted in re-direction of
a part of the turbidite currents into the Bjelovar Subdepres-
sion, and deposition of coarse-grained sediments there
(Figs. 12 and 13).

Due to the relatively flat bottom of the sub-depression, was

not only active pronounced (Fig. 11); consequently, the depo-
sitional area was much larger, and the transition among facies
was different and irregular (Figs. 12 and 13).

The deepest parts of the Bjelovar Subdepression are current-

ly known as the Rovišće syncline (northwest of Bjelovar) and
the Velika Ciglena syncline, which is the deepest part of the
subdepression (southeast of Bjelovar) and contains more than
2500 m  of  Neogene  sediments.  These  were  the  routes  of  the
main  turbidity  current  longitudinally  along  the  depression.
Conversely,  the  southern  and  eastern  parts  of  the  subdepres-
sion formed the relatively shallow flanks of the trough, with-
out any sedimentary channels. This resulted in current activity
occurring  only  in  the  northern  and  north-eastern  parts  of  the
subdepression. In other areas, only marls were deposited and
sandstones are very rare or completely absent.

The northern margin of the Bjelovar Subdepression, the

Bilogora  Mountain  was  uplifted  relatively  recently,  only
during  the  Pliocene  and  Quaternary.  This  indicates  that  a
passage  between  the  western  part  of  the  Drava  Depression
and the Bjelovar Subdepression was open until 2—3 Ma ago.

Depositional environments – basin plain and/or near-shore
mechanisms

Reconstruction of the approximate paleorelief shape can

indicate  the  paleowater  depth  of  the  lake  in  the  study  area.
The  most  reliable  indicator  of  water  depth  and  the  deposi-
tional  environment  are  the  remains  of  animals  and  plants
(biotop)  that  characterize  particular  environments.  Unfortu-
nately, the Upper Pannonian sediments contain very few fos-
sils. However, some macrofossils occur at the point at which
the transition from fresh-water to brackish water occurred, and
some others indicate the presence of shallow water (Pletikapić
1965). The majority of microfossils were found in the cores
of  older  wells  located  on  the  margins  of  the  depressions.
Based  on  the  distribution  of  microfossils  in  the  study  area,
Pletikapić (1965) concluded that marginal marls were depos-
ited in marsh and swamp environments. Other authors such
as Lučić et al. (1995) came to the same conclusion based on
palinological analysis and evaluation of additional core sam-
ples  from  the  Ivanić-Grad,  Žutica,  Okoli  and  Lipovljani  oil
and gas fields located in the deep parts of the Sava Depres-
sion. They found phytoplankton species common to shallow
water, such as Spiniferites sp., as well as species associated
with deeper water such as Impagidinium sp. and Gonyaulax
sp.  In  addition,  they  suggested  that  deep-water  organisms
were  transported  into  the  littoral  zone  by  bottom  currents,
which  explains  why  they  are  currently  found  together  with
shallow-water  plankton.  Based  on  these  results,  they  con-
cluded  that  the  sediments  containing  these  organisms  were
from  near-shore  areas,  shoals,  beaches,  lagoons  and  tidal
channels. Relatively rare samples of sporomorphs would in-
dicate that land was relatively far, but the presence of kero-
gen  type III  (terrestrial)  supports  the  authors’  (Lučić  et  al.
1995) conclusion that the shore was close. This explains why

Fig. 13. Schematic paleogeographic situation at the end of Late Pannonian.

sediments of deeper water (turbidite)
are  only  found  occasionally.  Other
possible  mechanisms  allow  that  the
clastic  materials  could  be  derived
from a near-shore environment, and
then  delivered  either  by  turbidity
currents  to  the  deeper  parts  of  the
basin  or  they  were  reworked  from
the elevated flanks.

Other facts also support the view

that  the  presence  of  marls  indicates
shallow  water  and  near  shore  sedi-
ments.  The  almost  perfect  correla-
tion  of  massive  marls  (using  SP
logs)  in  the  interval  between  EL-
markers  Rs5  and  Z’  throughout  the
Sava  Depression  and  the  Bjelovar
Subdepression  indicate  that  these
areas  were  surrounded  by  a  belt  of
marshes and lagoons filled with fine
mud  detritus.  Regarding  the  rela-
tively  narrow  depositional  areas,
such  as  those  in  the  Sava  Depres-
sion  that  are  only  10 km  wide,  it  is
not  clear  where  the  beaches  and

SEDIMENTATION OF DEEP-WATER TURBIDITES IN THE SW PANNONIAN BASIN

shoals were located and where the transported material was
eroded from the land.

Generally, marls defined as sediments of swamps and la-

goons  do  not  include  any  characteristics  that  indicate  the
presence  of  close  land  areas,  but  they  could  be  reworked.
Moreover,  it  is  difficult  to  accept  the  statement  that  the  in-
flux  of  detritus  via  subsidence  that  occurred  throughout  the
Late Pannonian, which was about 3 Ma long and occurred in
a  tectonically  active  depression(s),  was  so  ideally  synchro-
nized that the water level did not change. Indeed, this would
indicate that no parts of the shallow water (marsh, lagoons)
were exposed to the air and subjected to erosion throughout
this period at all.

The second option by which the shallow-water sediments

were deposited may have been through the activity of the del-
ta.  Sandstones  are  distributed  throughout  the  delta,  and  mud
and  marls  are  deposited  in  marshes,  flooded  areas  of  aban-
doned  channels  and  levees  (e.g.  the  on-shore  environment).
However, this suggestion is also contradicted by the absence
of evidence of erosion and near-shore, land material.

Deep-water mechanism

A complete sequence of massive marl has been described

and confirmed in SP logs of the marginal and central parts of
the Sava Depression (Figs. 6, 8). These marls were deposited
under  the  same  conditions  and  at  the  same  time  intervals,
which indicates that deep-water deposition occurred in a calm
environment via the same depositional mechanism. Only such
an  environment  can  explain  all  of  the  rapid  changes  and  the
nearly  identical  conditions  that  were  observed  over  a  long
geological period. In such deep areas, even changes in depth
of several hundred meters would not necessarily lead to dras-
tic changes in the depositional environments and mechanism
if the depth was maintained at more than 200 m. Detection of
the complete sedimentary sequences of the Late Pannonian in
wells  located  throughout  the  (sub)depression(s)  confirm  that
the  depositional  environment  was  definitely  deep  water,  ex-
cept in the transitional zones at a depression flanks.

The deep-water mechanism is contradicted by the presence

of relicts of palynomorphs that indicated a shallow deposition-
al area. However, they can also be reworked. We accepted the
fact that all of the siliciclastic material originate from one
source (Eastern Alps). Furthermore, the last slope, which con-
tained detrital material that was accumulated with varying in-
tensity, was probably located into the Mura Depression (north
of Varaždin). From this point, due to tectonic events, sediment
was relocated and transported to the Drava and Sava Depres-
sions and the Bjelovar Subdepression. The water depth in
marginal depression areas (slopes) was (significantly?) lower
than in the depression, which resulted in a shallow-water envi-
ronment characterized by skeletal and plant remains that had
been re-deposited in the deeper depression.

Furthermore, distribution of particular lithological members

was strongly pre-determined by the paleorelief. The central
parts of the depressions were surrounded by basement highs,
where water depths could have been lower than 200 m (some-
times these highs could be uplifted above the water level as is-
lands). These areas may have produced biotopes suitable for

shallow-water  plant  and  animal  associations.  Their  remains
could  have  then  been  transported  by  permanent,  slight  cur-
rents from the N toward the S, SE and E in all of the depres-
sions,  independently  from  the  periodical  turbidites.  Finally,
the only traces of erosion, which were observed in cores and
well-logs, appear to have been the result of turbidite activity
on older sediments at the base of the turbiditic deposits.

Source and paleotransport of detritus

Some conclusions about the source areas of the sediments

are given in previous chapters. Additional information can be
obtained from the petrographic composition, which can enable
identification of the source areas of the sediments, or the re-
gion from which source material originated. In addition,
granulometric parameters, the geometry of sandstone bodies,
the areal distribution of facies, and depositional environments
and mechanisms can provide additional information regarding
the location of a possible source.

The sedimentary, mineralogical and petrographic charac-

teristics of the Upper Pannonian and Pontian of the Sava De-
pression  and  the  Bjelovar  Subdepression  are  very  similar.
The majority of the detritus originates from the Alpine min-
eral association (Šćavničar 1979). Conversely, the influence
of  local  horsts  as  a  source  of  detritus  was  limited  as  they
were  probably  under  water  at  that  time.  These  results  indi-
cate that transport took a very long time, and that the materi-
al  was  re-deposited  several  times.  This  explains  why  the
sandstones  are  mostly  medium-  to  fine-grained,  with  rela-
tively rounded grains.

Clastic material of Late Pannonian age found in the out-

crops of the surrounding hills primarily consists of marls that
are very rarely interbedded with sandstone laminae.

The distribution of sandstone bodies only in the central

parts of the depression, their thickness, shape and location
clearly indicate a single source area. Sandy detritus was trans-
ported from the NW in the first phase of turbiditic activity,
while later on it was transported from the N or N/NE.

The Upper Pannonian sediments are also present on moun-

tains that surround the Sava Depression and the Bjelovar
Subdepression. These sediments are composed of calcitic
marls and limestones, but contain no evidence or deposits of
nearby land, such as surface erosion or deposition character-
istic of a near-shore, shallow-water environment.

Regarding paleotransport, the strongest indicator of tur-

bidite direction is the geometry of the sandstone bodies. No
surface  marks  identifying  direction  were  evident  in  the
present  study.  The  sandy  detritus  was  transported  into  the
depression  exclusively  by  turbidites,  and  the  primary  flow
direction had an arching (curved) shape from the NW, to N,
NE  and  finally  toward  the  SE  and  E.  This  material  came
from a relatively uplifted area north of the Medvednica-Mo-
slavačka Mountain range. During a period of inactivity, per-
manent  inside  basin  currents  resulted  in  transport  and
deposition  of  the  finest  detritus  throughout  the  entire
(sub)depression(s). One branch of the main turbidite flow in
the  late  period  of  the  Late  Pannonian  was  turned  into  the
Bjelovar Subdepression. In both areas, the primary pathways
of the paleotransport directions were pre-determined by shal-

VRBANAC, VELIĆ and MALVIĆ

low channels. These channels carried along the main part of
the sandy material, while the minor part was deposited in the
inter-channel areas. In addition, the channel locations were
changed through space and time, continually migrating,
thereby defining the inter-channel area pattern.

Conclusion

Two mechanisms of transport and deposition in the Upper

Pannonian were proposed: massive marls are the product of
“normal” basin hemipelagic deposition (F

facies), while pe-

riodic turbidity currents transported coarser-grained materi-
al, as well as finer grained detritus of silt size as a turbidite
facies (F

—F

). These results indicate that the depositional

environment was calm and stable due to the sufficient water
depth  (more  than  200  meters)  compensating  for  all  water
level changes caused by tectonic movements and cyclic cli-
mate  changes.  This  low-energy  environment  was  disturbed
only by temporary turbidity currents, which deposited most
of the detritus in the deepest parts of the depression. Deposi-
tions of the Iva Sandstone Members (lower part of the Upper
Pannonian) occur only in the Sava Depression. Contempora-
neous deposits of the Bjelovar Subdepression are represent-
ed  only  by  basin  marls.  The  younger  Okoli  Sandstone
Members  are  found  in  both  depressions  as  a  result  of  the
deepening  and  opening  of  the  Bjelovar  Subdepression  to
source areas and transport by turbidity currents.

Acknowledgments: This work represents part of a multidisci-
plinary  geological  investigation  that  was  performed  in  2008
and 2009 within the project entitled ‘Stratigraphical and geo-
mathematical  researches  of  petroleum  geological  systems  in
Croatia’  (Project  No. 195-1951293-0237),  which  was  fi-
nanced  by  the  Ministry  of  Science,  Education  and  Sports  of
the Republic of Croatia.

References

Bagnold R.A. 1954: Experiments on gravity-free dispersion of large

solid spheres in a Newtonian fluid under shear. Proc. R. Soc.
Lond., Ser. A 225, 49—63.

Bérczi I., Hamor G., Jambor A. & Szentgyörgyi K. 1988: Neogene

sedimentation in Hungary. AAPG, Mem. 45, 57—67.

Blašković I. 1982: The Neogene of the Ilova River depression

(Northern Croatia). Acta Geologica Zagreb 12, 2, Prir. istraž.
JAZU 46, 23—67.

Bokor N., Hernitz Z., Sečen J. & Steiner I. 2000: Bypassed oil: Šan-

drovac oilfield (Northern Croatia). EAGE, 62

EAGE Confer-

ence & Technical Exhibition, Glasgow, 29.5.—2.6. 2000.
Extended Abstracts Proceedings.

Bouma A.H. 1962: Sedimentology of some flysch deposits: a graphic

approach to facies interpretation. Elsevier Pub. Comp., Amster-
dam, 1—168.

Bouma A.H. 1972: Recent and ancient turbidites and contourites.

Gulf Coast Assoc. Geol. Soc. 22, 205—221.

Dzulynski S. & Sanders J.E. 1962: Current marks on firm mud bot-

toms. Connecticut Acad. Arts and Sci., Trans. 42, 57—96.

Grizelj A., Tibljaš D. & Kovačić M. 2007: Mineralogy and geochem-

istry of Upper Miocene pelitic sediments of the Zagorje Basin

(Croatia): implication for evolution of the Pannonian Basin.
Geol. Carpathica 58, 3, 263—276.

Hamilton E.L. 1967: Marine geology of abyssal plains in the Gulf of

Alaska. J. Geophysics. 101, 725—728.

Hernitz Z. & Jurak V. 1973: Application of palaeostructural analysis

of Late Tertiary sediments in the area of Ivanić-Grad (northern
Croatia). Nafta 24, 78, 343—367 (in Croatian).

Hiscott R. & Middleton G.V. 1979: Depositional mechanics of thick-

bedded sandstones at the base of a submarine slope, Tourelle
Formation (Lower Ordovician), Quebec, Canada. In: Doyle L.J.
& Pilkey O.H. (Eds.): Geology of continental slopes. Soc. Econ.
Paleontol. Mineral., Spec. Publ. 27, 307—326.

Kovačić M. & Grizelj A. 2006: Provenance of the Upper Miocene

clastic material in the southwestern part of the Pannonian Basin.
Geol. Carpathica 57, 6, 495—510.

Laughton A.S. 1968: New evidence of erosion on the deep ocean

floor. Deep-Sea Research 15, 21—29.

Lowe D.R. 1976: Subaqueous liquefied and fluidized sediment flows

and their deposits. Sedimentology 23, 285—308.

Lowe D.R. 1979: Sediment gravity flows: their classification and

some problems of application to natural flows and deposits. Soc.
Econ. Paleontol. Mineral., Spec. Publ. 27, 75—82.

Lowe D.R. 1982: Sediment gravity flows: II depositional model with

special reference to the deposits of high-density turbidity cur-
rents. J. Sed. Petrology 52, 1, 279—297.

Lučić D., Krizmanić K. & Dalić N. 1995: Lithofacies and sequence

stratigraphy of Upper Miocene siliciclastic deposits in Okoli Re-
gion (Sava Depression, Croatia). 1

Croatian Geological Con-

gress, Abstract Book, 1—57.

Lučić D., Saftić B., Krizmanić K., Prelogović E., Britvić V., Mesić I. &

Tadfej J. 2001: The Neogene evolution and hydrocarbon potential
of the Pannonian basin in Croatia. Mar. Petrol. Geol. 18, 133—147.

Malvić T. 2003: Oil-geological relations and probability of discover-

ing new hydrocarbon reserves in the Bjelovar Sag. Unpubl. PhD
Thesis, Faculty of Mining, Petrol. and Geol., Univ. Zagreb,
Zagreb, 1—123 (in Croatian and English).

Middleton G.V. 1967: Experiments on density and turbidity currents.

III. Deposition of sediment. Canad. J. Earth Sci. 4, 475—505.

Mutti E. & Ricci-Lucchi F. 1975: Turbidite facies and facies associa-

tions. In: Examples of turbidite facies and associations from se-
lected formations of the northern Apennines. IX Int. Congress of
Sedimentology, Nice, Field Trip A-11, 21—36.

Orton G.J. & Reading H.G. 1993: Variability of deltaic processes in

terms of sediment supply, with particular emphasis on grain
size. Sedimentology 40, 3, 475—512.

Pirson S.J. 1970: Geologic well log analysis. Gulf Publ. Co., Hous-

ton, 1—370.

Pletikapić Ž. 1965: Stratigraphy, palaeogeography and hydrocarbon

potential of Ivanić-Grad formation on the margin of the Mosla-
vačka gora Mt. Unpubl. PhD Dissertation, Faculty of Mining,
Geology and Petroleum Engineering, Univ. Zagreb, Zagreb, 1—71
(in Croatian).

Prelogović E., Jamičić D., Aljinović B., Velić J., Saftić B. & Dragaš

M. 1995: Dynamics of structures forming in the southern part
of the Pannonian Basin. 1

Croatian Geological Congress,

Proc., 481—486 (in Croatian).

Prelogović E., Saftić B., Kuk V., Velić J., Dragaš M. & Lučić D.

1998: Tectonic activity in the Croatian pert of the Pannonian ba-
sin. Tectonophysics 297, 283—293.

Saftić B., Velić J., Sztanö O., Juhász G. & Ivković Ž. 2003: Tertiary

subsurface facies, source rocks and hydrocarbon reservoirs in
the SW Part of the Pannonian Basin (Northern Croatia and
South-Western Hungary). Geol. Croatica 56, 1, 101—122.

Shanmugam G. 2000: 50 years of the turbidite paradigm (1950s—

1990s) deep-water processes and facies models – a critical per-
spective. Mar. Petrol. Geol. 17, 285—342.

SEDIMENTATION OF DEEP-WATER TURBIDITES IN THE SW PANNONIAN BASIN

Shanmugam G. 2002: Ten turbidite myths. Earth Sci. Rev. 10, 3,

311—341.

Stow D.A.V. 1982: Bottom currents and contourites in the North At-

lantic. Bull. Inst. Geol. Bassin d’Aquitaine 31, 151—166.

Stow D.A.V. & Lovell J.P.B. 1979: Contourites: their recognition in

modern and ancient sediments. Earth Sci. Rev. 14, 251—291.

Šćavničar B. 1979: Pliocene and Miocene sandstones of Sava depres-

sion. III God. Znanstveni Skup ZSN JAZU, Novi Sad, Zagreb,
1977, II, 351—382 (in Croatian).

Šimon J. 1980: Contribution in stratigraphy and depositional system

of the sandstone reservoirs of the Sava group of deposits of
Younger Tertiary in the Pannonian basin of the northern Croatia.
Unpubl. PhD Dissertation, Faculty of Mining, Geology and Pe-
troleum Engineering, Univ. Zagreb, Zagreb, 1—66 (in Croatian).

Velić J. 1980: Geological framework of the western part of the Sava

depression. Unpubl. PhD Thesis, Faculty of Mining, Petroleum
and Geology, Univ. Zagreb, Zagreb, 1—137 (in Croatian).

Velić J. 1983: The neotectonic relations and development of the west-

ern part of the Sava river depression. Acta Geologica Zagreb 13,
2, 26—65.

Vrbanac B. 1996: Palaeostructural and sedimentological analyses of

Late Pannonian sediments of Ivanić Grad formation in the Sava
depression. Unpubl. PhD Thesis, Faculty of Natural Sciences,
Geol. Dep., Univ. Zagreb, Zagreb, 1—303 (in Croatian).

Vrbanac B. 2002a: Chronohorizons based on resistivity curve varia-

tions – Upper Miocene sediments of the Ivanić Grad Forma-
tion in the Sava Depression (NW Croatia). Geol. Croatica 55,
1, 11—24.

Vrbanac B. 2002b: Facies and facies architecture of the Ivanić Grad

Formation (Upper Pannonian) – Sava Depression, NW Croatia.
Geol. Croatica 55, 1, 57—78.

Walker R.G. 1978: Deep-water sandstone facies and ancient subma-

rine fans; model for exploration for stratigraphic traps. AAPG
Bull. 62, 6, 932—966.