crossing the carpathians
TRANSCRIPT
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PETROM S.A. PLOIESTI
- June 2008 -
Authors: RADU OLARU - PETROM S.A. E&R Geoscience Office
RELU ROBAN - University of Bucharest - Faculty of Geology
MARIUS STOICA - University of Bucharest - Faculty of Geology
CROSSING THE CARPATHIANS
Field trip
Guide Book
June 2008
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CONTENTS
INVITATION pg. 1
GENERAL GEOLOGICAL SETTING pg. 2
REGIONAL GEOLOGY OF THE EAST CARPATHIANS pg. 5
DEPOSITIONAL FRAMEWORK pg. 26
PETROLEUM POTENTIAL pg. 28
FIELD TRIP ITINERARY AND STOP DESCRIPTIONS pg. 33
FIRST DAY pg 35
Stop 1 - Berca Arbnai Oilfield Mudy Volcanoes pg 37
Stop 2 Loptari Pg.39
Stop 3 Mnzleti pg. 41
Stop 4 Beslii VintilVod pg. 46
SECOND DAY pg. 50
Stop 5 Vidra pg. 52
Stop 6 Valea Srii pg. 54
Stop 7 La Grumaz pg. 57
Stop 8 - Brseti pg. 58Stop 9 Cascada Putnei (Putnei Waterfall) pg. 59
Stop 10 Lepa 1 pg. 60
Stop 11 Lepa 2 pg. 62
THIRD DAY pg. 67
Stop 12 Rsnov Castle pg. 69
Stop 13 - Bucegi Piatra Craiului Geologic Park pg. 73
Stop 14 - Dealul Sasului pg. 78
Stop 15 Dmbovicioara Gorges pg. 80
Stop 16 - Ceteni pg. 81
Bibliography pg. 83
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INVITATION
Why field trip?
In the field, geology looks different than it does in textbooks, lab benches or on the
display of the work-station. A valuable aspect of the field trip is approaching an outcrop and
knowing what to do next. Even an incorrect solution to a field problem or a faulty interpretation
of a geological event is of value because it prepares the way for a better solution or
interpretation next time. As you get better at your job through practice, you gain confidence in
your abilities. For this reason, a geological field trip must stress individual effort and personalinitiative.
Why field trip?
Because we usually are working in teams, and the teams become strong not only in the
office.
Why field trip?
Because it is a good chance to escape from offices.
So, we propose to you:
work in - and see - a lot of great geology...
relax in and see a lot of great landscapes
enjoy in and feel a great team
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1. GENERAL GEOLOGICAL SETTING
Romania's territory, which belongs to the geological structural ensemble of central and
south-eastern Europe, consists of a chain segments from the Alpidic Pericratonic Belt of the
Carpathians-Balkans-Rhodopes-Pontides, from the Alpine Intercratonic Belt North Dobrudja -
South Crimeea the Great Caucasus, as well as from their Foreland represented by the East-
European Platform, the Central European (Scythian) Platform and the Moesian Platform. The
last two platforms and their intercratonic chain also extend on to the Black Sea Continental
Shelf. (Fig. 1)
According to Sndulescu (1980, 1984, 1994, 2004) the Folded Area can be divided intoseveral major tectonic ensembles (Fig 2):
The Main Tethyan Suture Zone which groups together tectonic units constituted by
Middle Triassic-Middle Jurassic ophiolitic complexes overlapped by sedimentary formations
whose age (Middle and Upper Triassic, Jurassic or Upper Jurassic-Lower Cretaceous) is
different from the age of the ophiolites they cover. The Main Tethyan Suture which runs along
the Vardar Zone (between the European and the Apulian continental margins) splits from
Beograd toward north or north-west - into two branches: the South Pannonian (separating the
Apulian microplate from the Fore-Apulian one) and the Transylvanidian-Pienidian (situated
between the European and the Fore-Apulian margins).
The Fore-Apulian Microcontinent is situated on the opposite side with respect to the
European margin, considering the Main Tethyan Suture a major geotectonic axis of symmetry ofthe Tethyan Chains. The Fore-Apulian Microcontinent groups together the Austroalpine, the
Central West Carpathians and the North Apusenide units, as well as the units covered by the
Pannonian Depression.
The European Continental Margin groups together the main part of the East
Carpathians (the Pienides belong to the Main Tethyan Suture) and the South Carpathians. There
are two basic types of units: basement shearing nappes and cover nappes. The first type is built
up of crystalline formations (metamorphics and sometimes acid and/or intermediate granitoids)
and their normal sedimentary envelope (sediment on the continental margin). This type of unit,
which developed in the Fore-Apulian Microcontinent too, constitutes the Central East
Carpathians (the Crystalline-Mesozoic Zone excepting the Transylvanian nappes which are
obducted from the Main Tethyan Suture), its correspondent in the South Carpathians (Getic-
Supragetic ensemble and the Danubian). The cover types of nappes are well developed in the
Flysch Zone of the East Carpathians and in the Subcarpathians. In the South Carpathians only
the Severin Nappe (situated tectonically between the Getic Nappe and the Danubian) is of this
type.
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Fig. 1 Romania Geological Map (according to G.I.R.)
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Fig. 2 - The major Tethyan sutures and continental areas in the Carpathian realm
(according to Sndulescu, 2004).Fore-Apulian Microcontinent [Inner Dacides, and Austroalpine].
Main Tethyan Suture Zone [Vardar, South Pannonian, Transylvanides, Pienides, etc]
European Continental Margin [Mgura Group, Median Dacides (Central East -Carpathians, Getic & Supragetic nappes), Outer Dacides (Ceahlu - Severin), Marginal Dacides
(Danubian), Moldavides].
The Alpine geotectonical evolution of the Carpathians kicked off by setting in two
expansion zones: an oceanic rift, with passive continental margins (Atlantic type) and an
intracontinental rift (Afar-Red Sea type) located to the east as compared to the former. This
distension period developed during the Middle Triassic Lower Cretaceous interval. The
oceanic rift got unconfined in the Lower Triassic, whereas the intracontinental one in the Lower
Jurassic, the two rifts evolving in an expansion regime till the Upper Jurassic (the oceanic one)
and respectively the Lower Cretaceous (the intracontinental one).
Since the Lower Cretaceous (Barremian), the direction of the movements is changed,
setting in a compression regime in both basins.
Depending on the intensity of the deformations, two major compression periods could be
distinguished, which generally affected different orogenic areas: Dacidic period, characterized
by two deformational paroxysms (MesoCretaceous and Late Cretaceous) and the Moldavian
period, generally Miocene, but also within it, recognizing three tectogenetic phases. The two
compression periods are responsible for setting up melting paleoplanes, oceanic and/or
continental crust shields and tectonic nappes structuring.
1.1. REGIONAL GEOLOGY OF THE EAST CARPATHIANS
East Carpathians represent an arched orogene, having a complex structure wherein the
flysch nappes modify their trend with 200 from the northernmost area (Poland) down to the
south, in the curvature zone of Romania.
The segment of the Alpine belt comprised between the Tisza springs in the north and
Dambovita Valley in the south represents the Romanian Eastern Carpathians. This orogene is
continued with Ukraines Eastern Carpathians to the north and with the Southern Carpathians tothe south.
The geotectonic units that border the Eastern Carpathians are: to the east, up to Bistria
Fault, the East European Platform, with a Precambrian basement, known across the Romanian
territory under the name of the Moldavian Platform; to the south and east (to the south of Bistria
Fault) the Paleozoic Platform, consisting of two segments separated by the transcrustal
PeceneagaCamena Fault, one of the segments being called the Scythian Platform to the east and
the other one, the Moesian Platform to the south-west; to the west the Transylvanian Basin, a
post-tectonic depression.
I neous
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The East Carpathians are characterized by the geosynclinal polarity typical to the Alpine
orogenes. Thus, it is worth noticing a structural polarity expressed through the eastward verging
of the major units and an orogenic polarity given by the migration during the folding, from old to
young and from inside (west) to outside (east). At the same time and in the same way, the
depocenter of the sedimentary basin also migrated. This polarity is responsible for a remarkable
cross-sharing. From outside to inside, the Subcarpathian Zone, the Flysch Zone and the
Crystalline-Mesozoic Zone are distinguished.
As far as the oil generation and accumulation potential is concerned, only in few of the
Moldavides (Tarcu Nappe, Marginal Folds Nappe and Subcarpathian Nappe) and respectively
the Foredeep in front of this assemblage present a remarkable interest. This is the reason why we
will focus on them.
In East Carpathians, the following major structural units are developed (Fig. 3):
THE TRANSILVANIDES proceed from the Main Tethyan Suture Zone obducted
during the Meso-Cretaceous tectogeneses. There are three main nappes (Hghima Nappe,Perani Nappe and Olt Nappe) with different lithostratigraphic successions and ages of the
ophiolitic complexes from the basal part of the nappes (excepting the Perani one proceeding
from the rifting zone which precedes the opening of the Tethyan Ocean). They are overlain by
sedimentary piles (mostly limestones but starting with radiolarites of cherty limestones). The
youngest sedimentary levels known in some Transylvanian nappes are of Barremian (Lower
Aptian ?) age. Transitional successions between these three basic units may be also recorded.
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Fig. 3 Geotectonic structure of the East Carpathians, (according to Bdescu, 2005)
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THE PIENIDESare a group of units, which relay the Transylvanides en echelon and
consist of cover nappes overthrusted above the Upper Cretaceous-Paleogene-Lowermost
Miocene post-tectogenetic cover of the Median Dacides (Crystalline-Mesozoic Zone), during the
Burdigalian.
The Pienides consist ofBotiza Nappewith thePoiana Botizei Klippen Zonein its frontal
part (southeast prolongation of the Pieniny Klippen Belt), the Petrova and Leordina Nappes
(equivalent of the Magura Nappe).In Poiana Botizei Klippen Zone, a Middle Jurassic Upper Cretaceous pelagic
succession (radiolarites/cherty and Calpionella-bearing limestone/dark shale/couches rouges)
is known.
In Petrova and Leordina nappes, a Maastrichtian-Paleocene flysch is developed
(Inoceramia Beds type); well-developed Paleogene flysch formations are known in all
Pienidian nappes.
The actual general structural shape of the Pienides is due to the Lower Miocene
(Burdigalian) tectogeneses, when the nappes were overthrusted above the post-tectogenetic
cover (neoautochton) of the Median Dacides (Central East Carpathians nappes). The traces of
the Cretaceous tectogeneses are visible only in the Poiana Botizei Klippen Zone (where
formations of this age were preserved). The Lower Miocene transport of the Pienidian nappes
was directed and/or accentuated by several important fractures with strike-slip components,mainly the North Transylvanian Fault and the Bogdan VodFault.
THE MEDIAN DACIDESare situated on the opposite side of the Main Tethyan Suture
Zone in respect with the Inner Dacides. The Median Dacides units were structured in Lower
Cretaceous by compressive sequential movements break back type (Bdescu, 2005) and crop
out in the Central East Carpathians and within an important part of the South Carpathians. These
units are basement-shearing nappes, each of them involving metamorphic rocks and their
sedimentary envelops.
In the Central East Carpathians, the nappes are (upside/downside): Bucovinian,
Subbucovinian, and Infrabucovinian nappes. The latest correspond to the Getic Nappe
(Domain), the former two to the Supragetic nappes, of the South Carpathians. The
mesometamorphic series with a complex premetamorphic composition and a polymetamorphic
pre-Cambrian and Paleozoic history are dominant within the metamorphic formations. The
epimetamorphic series proceeds from terrigenous or volcano-sedimentary formations (Lower
and Middle Paleozoic); their metamorphism could be Caledonian and/or Hercynian.
The Median Dacides sedimentary formations show several sequences which are more or
less expressive sedimentary cycles: Upper Carboniferous and/or Permian molasses (locally
developed), quartzitic Lower Triassic followed by carbonate Middle Triassic, detrital Lower
Jurassic, sandy marl Middle Jurassic (locally ending with radiolarites), neritic or pelagic
calcareous Upper Jurassic Neocomian. With the Lower Cretaceous (wildflysch in Bucovinian,
calcareous in Infrabucovinian nappes) the Median Dacides succession ends in the Central East
Carpathian nappes. There the Upper Cretaceous (molassic Cenomanian, almost marly Turonian-
Senonian) represents the post-tectonic (post-nappe) cover.In the South Carpathians, the Lower Cretaceous is mostly calcareous ending with
glauconitic Albian.
The Upper Cretaceous rocks are molassic in the lower part, followed by marl-sandy
formations and ending with turbiditic or volcano-sedimentary sequences. The Upper Cretaceous
rocks seal some Mid-Cretaceous compressive structures, but are also involved into the end-
Cretaceous deformations.
The post-tectonic cover of the East Carpathians Median Dacides are preserved in some
subsiding areas (gulfs) on their western slope, being partly covered by the eastern parts of the
Transylvanian Depression and the East Carpathians volcanic arc.
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The Upper Cretaceous formations are followed by Lutetian molasses, Priabonian
limestones, marls or flysch and Oligocene Lower Miocene (alternating), pelitic (partly
bituminous) and arenitic sequences. The post-tectonic cover of the South Carpathians Median
Dacides starts in Paleogene molasses followed on their southern slopes by Oligocene marl-sandy
formations and Lower Miocene conglomerates.
THE OUTER DACIDESgroup together a strip of units, which proceed from a Jurassic Lower Cretaceous paleo-rift, developed within the European continental margin.
In the East Carpathians the Outer Dacides (Black Flysch, Baraolt and Ceahlu nappes)
are built up of Jurassic intraplate basalts and/or Tithonian-Lower Cretaceous flysch formations
(locally with conglomerates in the Upper Aptian and Albian). Some marlz Upper Cretaceous
formations are known in the Ceahlu Nappe. The Outer Dacidian units (nappes) were twice
deformed: during the Mid-Cretaceous and Late-Cretaceous tectogenetic moments. They are
partly overthrusted by the Median Dacides and run parallel with their external border, and
represent a satellite suture in respect to theMain Tethyan Suture.
In the South Carpathians the Outer Dacides (Severin Nappe) are sandwiched between the
Getic Nappe and the Marginal Dacides (Danubicum). Here, the Jurassic ophiolites are followed
by Tithonian-Lower Cretaceous flysch.
THE MOLDAVIDESare the outermost Carpathian units. They correspond to a major
part of the East Carpathian Flysch Zone (excepting the Outer Dacidian nappes).
The term of Moldavides was introduced to designate the tectonic units which make up
the Eastern Carpathians external flysch and molasse. The Moldavides complex is a succession
of N-S trending imbricate thrust nappes which consist of Cretaceous-Tertiary sedimentary rocks.
The oldest nappes of the complex consist of Cretaceous rocks and lie in the westernmost area
(inner). The nappes of the Moldavidic complex are (W-E; fig 4): i) Teleajen (Curvicortical or
Convolute Flysch Nappe), Macla and Audia all consisting of Cretaceous rocks; ii) Tarcuand Marginal Folds (Vrancea) they consist of both Cretaceous and Tertiary rocks; iii)
Subcarpathian exclusively consisted of Tertiary rocks. These nappes are sedimentary
allochtonous bodies overthrusted progressively on foreland elements.
The sedimentary basin, herein called the Moldavides Basin, was characterized by either
the oceanic crust or thinned continental crust which, in the end, was subducted underneath Tisia-
Dacia Block (Zweigel et al. 1998).
Fig 4. Schematic geological section in central part of East Carpathians (according to
Maenco and Bertotti, 2000).
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The Moldavides Basin has an evolution characteristic to a remnant oceanic basinwhich
was flanked at the inner part by a convergent margin and wherein the sedimentation had a strong
turbiditic character. The term of remnant oceanic basin is quite general and denotes that the
basin was sequential narrowed progressively due to tectonic events (Ingersoll et al., 1995). The
basins main source areas were placed in the orogene (Anastasiu, 1984 and 1992) and supplied
sediments at a rate increasing concurrently with the basin narrowing due to the rather continuousconvergence. The high sedimentation rates and the strong subsidence are mirrored nowadays in
the large thickness (thousands of meters) of the rock-stacks (Sndulescu, 1984; Mutihac, 1990)
which make up the tectonic units (nappes) of the Moldavides. Most of the facies in the
Moldavidic units lying within the Cretaceous Eocene interval (Lower Oligocene) are
characteristic to depositional deep sea-turbiditic (Contescu, 1974), hemipelagic or even pelagic
environments. The flexural loading (Maenco et. al, 1997) of the basin determined the formation
of one (or even more?) basin(s) of peripheric foreland (sensu Miall, 1995) beginning with the
uppermost Oligocene through Miocene. Thus, a great facies change is especially noticed on the
eastern basin margin, where shallow marine facies (which occur within Kliwa-type lithofacies)
are followed in a stratigraphic succession (Miocene) by continental and transitional facies.
The compressional deformations (Fig. 5) began with the Lower Miocene (Lower
Burdigalian), concurrently with the thrusting of the Curvicortical Flysch/Audia Nappes,followed by shortening along approx. E-W trend (Upper Burdigalian). The effect thereof resided
in thrusting of the Tarcu Nappe, the Marginal Folds Nappe as well as of the inner part of the
Subcarpathian Nappe. A second shortening took place in the Sarmatian and led to Subcarpathian
Nappe thrusting over the non-deformed foredeep as well as to the deformation of the post-
Burdigalian sequences deposited over the Tarcu and Marginal Folds Nappes domain.
The next deformational stage (Upper Miocene: Upper Sarmatian-Lower Meotian) was
characterized by a regime of compressional strike-slip movements along NNE-SSW to N-S
trend. To the N, beyond Trotu Fault, the strike-slip deformations were taken over by E-W
senestral faults, whereas, in the south of the Eastern Carpathians by NW-SE dextral faults. The
transition zone underwent a shift towards ESE, estimated to 40-50 km, (Maenco and Bertotti,
2000).
Along the Pliocene-Pleistocene interval, the curvature zone experienced thusting
processes accompanied by shortening along NNW-SSE trend (Hippolyte and Sndulescu, 1996),
of approx. 22 km (Roure et al., 1993) or 15 km (Maenco and Bertotti, 2000). While Roure et al.,
(1993) suggest that the shortening also involved the basement, Maenco and Beetotti, (2000),
consider that only the sedimentary cover was deformed.
The significant uplifts recorded throughout the Upper Badenian Lower Sarmatian
interval, in the central area of the Eastern Carpathians, resulted in the erosion of an approx. 5 km
sedimentary stack.
The main uplifted area in the curvature zone is younger and it began with the Upper
Miocene (Pontian), coeval with the youngest compressional moments (Sanders et al, 1999).
The stratigraphic succession, showing different lithofacies, extends from the Lower
Cretaceous up to the Lower Miocene. During this interval, the detrital rocks were supplied bytwo main sources: an external source situated in the foreland, and an internal source represented
by the cordilleras or, mostly in Cenozoic, by the still structured internal units of the East
Carpathians.
The highly subsiding trough migrated from inside to outside since Lower Cretaceous
(Convolute Flysch area) until the Paleogene (Tarcu area) and even Lower Miocene
(Subcarpathian area).
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Fig. 5 Stratigraphic columns in the external Moldavides units and the main tectonic
events (according to Maenco and Bertotti, 2000)
The Lower Cretaceous formations display two main lithofacies: the external Black Shales
development, covering the Audia, Tarcu and Marginal Folds domains, relatively thin (600
900 m) dominated by euxinic sedimentation and the inner, Convolute Flysch developments,
several kilometers thick (5 6 km), developed in a subsiding flysch trough supplied by an inner
source area (the Peri-Moldavian Cordillera). In the Convolute Flysch Trough, the turbiditic
subsiding sedimentation continues up to the Turonian (even Lower Senonian?), while in the
Black Shales domain, a condensed variegated very thin sequence, partly deposited below theCCD level, sedimented in the Upper Vraconian Lower Senonian time span.
In Senonian, the main flysch lithofacies migrated to the exterior, the most specific of
them being known in the Tarcu domain (calcareous flysch). Sandy flysch developed to the
exterior (Audia domain) while the external lithofacies are of pelagic nature. The highest
subsiding flysch area migrated again in the Paleogene (Tarcu domain) determining the
development of many lithofacies, from the proximal sandy one in the inner part, to the distal
shaly-calcareous one in the external part. The double source areas, in foreland and hinterland,
still existed.
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During the Oligocene and Early Miocene a specific bituminous-quartzitic sandy
lithofacies developed in the external part of the Moldavides (external Tarcu, Marginal Folds
and Subcarpathian nappes). Synchronously, the flysch development is known in the inner part of
the Tarcu Nappe. Following an evaporitic event (salt and gypsum), of (Middle) Burdigalian
age, the Lower and Middle Miocene molassic formation began to accumulate (Tarcu, Marginal
Folds and Subcarpathian nappes) being included in the thrust-sheets.
The post-nappes molasses are developed in the Foredeep. The main tectogeneticmoments, which structured the Moldavides, are of Burdigalian, Badenian and Sarmatian age.
Some precursory folding events are recorded in the Convolute Flysch and Audia nappes during
the End-Cretaceous time.
Tarcu NappeThe Tarcu Nappe is a polyfacial nappe (Dumitrescu 1948, 1952). It is also known as the
Medio-Marginal Unit (Bncil, 1955, 1958) and corresponds to the Skibas and Krosno zones of
the Ukraine Carpathians. Several facial zones were distinguished in the Tarcu Nappe
(Dumitrescu, 1952; Popescu, 1952; Joja, 1952; Grigora, 1955; Ptru, 1954; Dumitrescu et.al.,
1971). The inner zone (Tarcu Sandstone Zone) is the best areally developed and shows the
complete lithostratigraphic succession known in the whole nappe, from Lower Cretaceous to
Lower Miocene (Fig 6).In the more external zones, the Lower or even Upper Cretaceous deposits are absent due
to the subsequent position of the overthrust plane.
The Lower Cretaceous is developed in the Silesian lithofacies (Black Shales
Formation, Hauterivian Lower Vraconian) followed by variegated shales and marly limestones
(the Lupchianu Beds, Vraconian - Turonian).
The Senonian - Lower Paleocene is of flysch type, sandy marly inwards (the Horgazu
Flysch) and more calcareous outwards (the Hangu Flysch). The sedimentation of the Tarcu
Sandstone starts in Paleocene and follows up to the Middle Eocene, included. In the outer facial
zones, the Paleocene Lowermost Eocene is represented by a variegated flysch (the Straja
Flysch) followed by different Lower and Middle Eocene flysch types, getting richer in arenites,
inwards. Hieroglyphic Beds flyschtype is known in the Uppermost Lutetian and Priabonian
more limy inwards (the Podu Secu Flysch) and with red shales outwards (the Plopu Flysch). Inthe Buzu Valley basin, a constant shaly sandy flysch (Coli Flysch) developed during the
whole Eocene. The Lucceti sandstone interbeds from the Globigerina marls, develop all over
the previous mentioned facies.
Oligocene Lowermost Miocene display two lithofacies: in the inner part of the Tarcu
Nappe, flysch formations develop with a thick sandy flysch sequence (the Fusaru Sandstone)
followed by a convolute sandy marly flysch (the Vineiu Flysch), similar to the Middle and
Upper Krosno Formations.
South west of the Buzu Valley, the Fusaru Sandstone, a menilitic bituminous
lithofacies with several levels of cherts (menilites) and bituminous shaly clays or silts (dysodile
shales) with two main sequences of quartzose sandstones (Kliwa) is developing in the Oligocene
Lower Miocene.
South and southwards, Lower Kliwa gets thinner in favour of the flysch sequences (Podu
Morii Beds). In compensation, the Upper Kliwa sandstone gains thickness, reaching approx. 500
m in Teleajen Valley.
Throughout the Tarcu and Marginal Folds Nappes, but in the same stratigraphical
position, two cineritic levels develop. The lower one is interbedded in the Vineiu and Podu
Morii Flysch as well as in their external stratigraphical equivalents (Upper Dysodilic Shales).
The Upper Cineritic level (mainly benthonites) develops within the Upper Menilites and their
inner (Dysodilic Shales overlying the Vineiu Flysch) and outer correspondents (Upper
Dysodilic Shales).
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Fig. 6 Litho-stratigraphic column of Tarcu Nappe (according to Butac et al, 1998)
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A peculiar lithofacies is known in the innermost parts of the Tarcu Nappe synchronous
with the Vineiu Flysch. It is a chaotic formation (Slon Facies) described either as Olistostroma
or Wildflysch, represented by piles of argillaceous or marly breccias in which mainly Senonian
and Paleocene allochtonous rocks are involved. In some places breccias and/or re-deposited
lutites are only intercalations both in the uppermost part of the Fusaru Sandstone and the
Vineiu Flysch.The Lower and Middle Miocene outcrop only in the East Carpathians Bend area
generally displaying a molasse facies with evaporites (both gypsum and salt), thin stromatolites,
cineritic and breccias intercalations.
The first general folding of the Tarcu Nappe area was intra Burdigalian, but the
overthrust was intra Badenian, when it covers and even overpassed the whole Marginal Folds
Nappe and, locally, the inner part of the Subcarpathian Nappe. The amplitude of Tarcu Nappe
overthrusting reaches over 35 km, as proved by exploration wells.
The polyfacial character of the Tarcu Nappe has overprinted its different tectonic types
of folding, following the lithology of the different flysch piles. Where the Tarcu and Fusaru
Sandstones are present, more or less large folds, sometimes faulted, were generated. With the
decrease of the sandy flysch content more narrower and imbricated folds develop.
Marginal Folds Nappe
The outermost nappe of the so called flysch zone is the Marginal Folds one; it is also
known as Marginal Unit (Dumitrescu, 1952) (Fig. 8), External Unit (Bncil, 1958), or Vrancea
Unit (Ionesi, 1971). It shows a complex construction and a peculiar tectonic style: overturned
and recumbent folds, duplexes, imbricated fans or even anti-formal stacks are developed.
The Marginal Folds Nappe outcrops in several half windows (Putna, Bistria, Oituz and
Vrancea) or window (Dumesnic), but it was also found between them in wells, below the Tarcu
Nappe. (Fig. 7).
Inside the Vrancea half-window the Marginal Fold Nappe shows a more complicated
structure. There, two tectonic subunits (digitations) are developed (Dumitrescu, 1963), the
internal one (Greu) overthrusting the more external one (Coza). The former can be considered a
correspondent of the Pocutian Folds (according to Sndulescu, 1984).
The Greu subunit overthrusting reaches an important extent covering, partially, both the
external flank of Coza and the inner margin of the Subcarpathian Nappe.
While Greu Digitation displays a more intensive folding, up to imbricated structure, Coza
Digitation has a large shape with tight folds and anti formal stack tipe structures with Lower
Cretaceous deposits, in the axial zone.
Northwards of Vrancea half-window, the two digitations can be followed, in wells, up to
Moineti region. Southwards, the Marginal Folds Nappe sinks rapidly beneath the flysch piles of
Tarcu Nappe formations, as proved by some exploratory wells drilled in the area.
The oldest deposits known in the Marginal Folds are of Lower Cretaceous age, Streiu
and Lower Tisaru Beds, in Vrancea half window. They show an euxinic, shaly lithofacies withsome rhythmic sequences and black cherts.
The sequence of Vraconian Turonian variegated shales (Upper Tisaru Beds), then
Senonian Lower Eocene limy shaly pelagic rocks (Lepa and Cain Beds) and a thin bedded
flysch, rich in silica and partly with variegated shales (Piatra Uscat and Tisaroid Beds)
overlie the Lower Cretaceous deposits. Huge lenses of Paleocene conglomerates (Piatra
Streiului), rich in Green-schist fragments, develop between Lepa and Cain Beds.
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Fig. 7 Litho-stratigraphic column of Marginal Folds Nappe (according to Butac et
al, 1998)
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Lower Middle Eocene rocks are of different lithofacies and display limy detrital,
silico pelagic (Buciau Beds) or flysch (Greu) developments in the outer and inner parts of the
nappe, respectively.
They are followed by variegated shales and grey black shaly formations (Bisericani
Beds). The Globigerina Marls and the Lucceti Sandstone (quartzous) develop in the
Uppermost Eocene.
The Oligocene and Lowermost Miocene show a menilitic bituminous lithofacies withseveral levels of cherts (menilites) and bituminous-shaly clays or silts (dysodilic shales) with
quartzous sandstones (Kliwa) and conglomerates.
The Lower Miocene Salt Formation is known mostly in the outer part of the Bistria half-
window. Its peculiar feature is represented by the presence of K- halites.
Red (the Hrja Molasse) or Grey (sandy - conglomeratic) molasses are locally developed.
The folding of the Marginal Folds Nappe started in Lower Miocene (Burdigalian), the
main overthrust moment was in Middle Miocene (IntraBadenian) and it was remobilised in the
Moldavian phase (Middle Sarmatian).
Fig.8 Geological map -Marginal Folds Nappe Vrancea Half-window
(according to Dumitrescu, 1952)
After tefnescu and Micu (1987), Bdescu, (2005), the stratigraphy of the Marginal
Folds Nappe in Vrancea window is the following: (fig 9).
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- Streiu Beds, Lower Cretaceous-Lower Turonian, 300-360 m, represented by black
bituminous shales, calcareous sandstones, rarely polymictic conglomerates with green
elements;
- Tisaru Beds, Upper Turonian-Senonian, 100-150 m, separated into: Lower Member,
represented by black radiolarites, blackish-green shales and glauconitic sandstones and the
Upper Member, consisting of red, green or variegated radiolarites, red marls, polymictic
conglomerates with green elements;- Lepa Beds, Senonian, 250-300 m, consisting of thin beds of detrital limestones and
gray marls, red marls and interbeds of sandstones and conglomerates with green elements at
the upper part.
The Paleogene deposits are represented by two synchronous facies: Bucia facies and
Greu facies.
BuciaFaciescomprises:
- Cain Beds,Paleocene, 600 m, in their turn they contain: The Lower Member, 100 m,
consisting of argillaceous limestones and/or conglomerates of Piatra Strei (polygenous
conglomerates with green elements); Median Member, 150 m, consisting of marls and
subordinately calcareous sandstones and the Upper Member, 350 m, consisting of bituminous
sandy limestones, shales and polymictic conglomerates with green elements - conglomerates
of Piatra Cornii;-Piatra UscatBeds, Upper Paleocene. Lower Ypressian, 100 -150 m. They consist
of gray marls, gray-green quartzose sandstones, sandy limestones, silicolites, (gaizes-
spongolites), shales, rarely argillaceous limestones, red calcareous shales and polymictic
conglomerates with green elements;
- Bucia Beds, Ypressian-Lutetian, 400-500 m, green or white marls, subordinately
calcareous sandstones and red marls.;
-Bisericani Beds, Priabonian, 250-300 m: Lower Member, 5-20 m consists of red and
green shales, subordinately lithic sandstones and graywackes; Median Member, 100-150 m,
consists of gray and green shales, rarely lithic sandstones and graywackes, breccias with green
elements, whereas the Upper Member (locally with variable thickness) consists of
globigerina-bearing marls;
- Globigerina-bearing Marls and Lucceti Sandstone, Priabonian, 15-20 m, consist of
white globigerina-bearing marls with interbeds of quartzose sandstones;
GreuFaciescomprises:
- Upper Member of Cain Beds, 200 m;
- Tisaroid Beds, Upper Paleocene-Lower Ypressian, 50-110 m, equivalent with Piatra
UscatBeds, consisting of variegated sandstones and shales;
- Greu Beds, Ypressian-Lutetian, 300-500 m, alternation of calcareous sandstones and
greenish marls and conglomerates with green schists;
- Red Marls, Lutetian, 5-15 m, consisting of red and green marls, shales and thin
interbeds of sandstones;
- Bisericani Beds (Priabonian), 150-200 m, consisting of an alternation of green shales
and thin calcareous sandstones. At the upper part, ther are consisting of gray shales and siltites;- Globigerina-bearing Marls and Lucceti Sandstone, Priabonian, 15-20 m, similar to
the ones belonging to Buciafacies.
Oligocene Deposits and the Lower Miocene ones are developed in a bituminous facies .
They comprise the following members:
- Lower Menilites Member, with bituminous marls;
- Lower Dysodiles Member;
- Kliwa Sandstone Member;
- Upper Menilites Member;
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- GoruMiina Beds: calcareous sandstones, silts, sandy marls and locally conglomerates
with green schists.
- Uppermost Menilites.
- Salt formation and Hrja Beds, molasse deposits better developed in the Subcarpathian
Nappe.
Fig. 9 Litho-stratigraphic Correlation Chart - Tarcu and Marginal Folds Nappes(according to Bdescu 2005)
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Vrban (2003) assigned the Piatra Strei Conglomerates to Lepa-Piatra Strei unit, (fig.
10). Structurally, near Lepa locality, the units are displayed in an anticlinorium-type structure
(Coza), namely the western flank of the overturned Plaiul Faa Mare Anticline, which has in its
axis the Streiu, Tisaru, Lepa Beds and Piatra Streiului Conglomerates and Cain and Piatra
UscatBeds in the flanks.
Fig. 10 Stratigraphy of the Lower Cretaceous- Eocene (Priabonian) deposits (according to
Vrban, 2003)
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Subcarpathian Nappe
Known also as Pericarpathian Nappe (Mrazec, Voiteti, 1914; Bncil, 1958), the
Subcarpathian Nappe is the youngest and the outermost unit of the Moldavides. It is built mainly
of Lower Miocene deposits, which have preserved at their bottom Oligocene and (local) Eocene
formations and are overlapped in some synclines by Middle Miocene and Lower Sarmatian ones.
Three subunits (digitations) were distinguished (Sndulescu at. al, 1977) in the
Subcarpathian Nappe which is, from west to east: the Mgireti Perchiu, the Pietricica and theValea Mare subunits.
The oldest rocks outcropping or known from boreholes in the Subcarpathian Nappe are
of Oligocene age (Fig.11), developed in a bituminous facies, similar to that of the Marginal
Folds or of the outer part of the Tarcu Nappe. In very few places Priabonian shales (Bisericani
Beds) were preserved bellow the Oligocene (Tescani field).
In the Mgireti Perchiu Digitation, a Lower Miocene Salt Formation follows after the
bituminous deposits. The main part of these digitations is built up of the Red Formation
(Mgireti Molasse) and Grey Formation of Lower Miocene age, the last one passing to Lower
Badenian.
Red Formation consists, mainly, of calcareous sandstones with red cement, variegated
and red marls, as well as local developments of conglomerates (Brsesti conglomerates).Two main evaporitic levels are known in the Grey Formation: the Perchiu Gypsum
(the lower one, developed at the base) and the Stufu Gypsum (situated more or less at the
Lower/Middle Miocene Boundary). Connected with the Stufu Gypsum and above it, thin
dolomitic limy shales are known. The lower part of the Badenian deposits consists of Cinerites
(Slnic Tuff) interbedded with Globigerina marls and a calcareous formation (Rchitau
Sandstone). Evaporitic deposits (gypsum and salt) follow. Quartzitic fine sands and sandstones
associated with Radiolarian Schists of Kossovian age (HaloBeds) are developed at the upper
part.
Molassic (conglomerates and sands) Volchynian and Lower Bessarabian deposits are
preserved in some deeper folds in all the three digitations of the Subcarpathian Nappe.
South of TrotuRiver, Valea Mare and a part of Pietricica Digitation are covered by theinner limb of the Focani Depression. Farther south and south westward, the whole
Subcarpathian Nappe is unconformably covered by the Upper Sarmatian Pleistocene molasses
of the folded part of the Foredeep s. str. namely the Diapiric Folds Zone, which cover even the
frontal part of the Tarcu Nappe (west of Buzu River).
The molasse deposits of the Subcarpathian Nappe have two different source areas: the
Lower Miocene molasses rich in Greenschists and other foreland fragments and the Sarmatian
molasses with arenites of Carpathian origin.
The main overthrusting moment of the Subcarpathian Nappe is intra Sarmatian (the
Moldavian phase Dumitrescu, Sndulescu, 1968). It was folded, before the overthrust, at least
in the intra Burdigalian and intra Badenian tectogenesis. The latest tectonic movements
occurred during the Pleistocene (Wallachian phase).
North of the Buzu Valley, where the Lower Miocene deposits are largely outcropping,parallels alignments of relatively narrow imbricated folds develop. Diapiric phenomena are
present along the longitudinal faults.
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Fig. 11 Litho-stratigraphic column of Subcarpathian Nappe
(according to Butac et al, 1998)
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THE FOREDEEP. In the acceptance of the Romanian geologists, only the formations
younger than the last tectonogenesis of the Moldavides, namely Neosarmatian Pleistocene
molasses, were assigned to the Foredeep (Sndulescu et al. 1981; Sndulescu, 1894).
The Foredeep is filled with Upper Miocene Pliocene Lowermost Pleistocene
molasses entirely supplied by deformed rising Carpathians. They cover the most of the externalparts of the East and South Carpathians and a part of the neighbouring platforms.
In this acceptance, the Foredeep (s.str.) was divided in two zones: an unfolded and a
folded one.
In the Carpathian Bend area and in the southern Subcarpathians, the inner part of the
Foredeep is folded (Plio-Quaternary deformations). The folded Foredeep deposits are developed
in the Bend Area (Diapiric Folds Zone), where, as mentioned before, they overlay the
Subcarpathian Nappe and partialy, the outer margin of the Tarcu Nappe. A more diversified
lithology is known here (excepting the molasse, neritic limestones in Kersonian, Schlier facies in
Pontian, etc.). In this area, the Upper Sarmatian Pliocene arenitic sequences proved to be the
most important for the existence of oil and gas fields discovered so far (Fig 12).
The folding of this part of the Foredeep took place in the Wallachian (intra-Pleistocene)
phase, and was characterised by the halokinetic processes involving the Lower Miocene salt
deposits. As a result, four regional diapiric folds alignments, with various piercing stages of the
salt were built up.
Two of these alignments i.e. Gura Ocniei Moreni Bicoi intea (exaggerated
diapirs) and Bucani Ariceti Ceptura Urlai (attenuated diapirs) had a particular
importance in the hydrocarbon entrapment.
The Unfolded Foredeep is superposed on the Foreland units. South of the TrotuValey a
narrow strip of the inner limb of the Unfolded Foredeep overlaps the front of the SubcarpathianNappe (Fig 13). The most typical sector and the most subsiding segment of the Unfolded
Foredeep is the so-called Focani Depression, of lop-sided shape and filled with thick molasse
sediments (more than 10 km in the central part). Northwards and south-westwards, in the axial
trend, it gets narrower and has a reduced thickness.
Inside the Focani Depression, the molasses formations show a monotonous lithology:
mostly sandy molasses with andesitic cinerite layers at the Sarmatian/Meotian boundary and
richer in gravels. In the Upper Pliocene Pleistocene, coal lenses are also known.
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Fig 12. Litho-stratigraphic column of Folded Foredeep
(according to Butac et al, 1998)
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Fig. 13. Restoration of the post-nappe stacking evolution along the Putna cross section.
The restoration shows the two different stages of late orogenic evolution: Latest Miocene -
Pliocene general subsidence (d-b) followed by 5 km of Quaternary shortening and tilting
(a).(according to Matenco 2007)
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Fig. 15. Graphic restoration of the geological section Putna Valley (according to Bdes
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Fig 14. Geological cross section in East Carpathians - Putna Valley
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1.2. DEPOSITIONAL FRAMEWORK
The depositional area of the geological formations encountered in East
Carpathians was part of a collisional basin, largely filled with flysch type sediments,
during the Cretaceous and Paleogene and with molasse formations in Miocene and
Pliocene.
The basin entrapped sediments from two main source areas:
- western (inner) sources belonging to the Carpathian folded units;
- eastern and southern (outer) sources, located on the Foreland regions (East
European, Scythian and Moesian Platforms, North Dobrudja Orogene).
Intrabasinal sources, supplying magmatic and metamorphic lithoclasts were
also active during the Cretaceous.
The sedimentary supply of the bordering areas was unequal in time. The
contribution of the western sources extended gradually, since the Upper Cretaceous,
as a result of orogenetic movement which led to the successive uplifting of the
internal areas and to the shifting of the basin axis towards the foreland regions.
The Carpathian sources supplied large volumes of clastic material
predominantly transported by gravity mass flows and sometimes, via submarine
canyons.
The sediments from external sources, were more fine grained, with calcareous
and siliciclastic material. The sediment transport was mainly via submarine canyons.
In the Lower Cretaceous, the internal sources delivered terrigenous material
which formed classic turbidites with more or less Bouma sequences (Sinaia Beds,
Bobu Flysch) overlain by a huge pile of molassic conglomerates (Bucegi
Conglomerates). The outer sources led to the formation of an euxinic black-shalylithofacies (Black Shales Formation and Streiu Beds), followed by more sandy
sequences (glauconitic siliceous sandstones and Lower Tisaru Beds, respectively).
In the Upper Cretaceous the western sources supplied large mud rich
sediments (Dumbrvioara Series and Gura Beliei Marls) as well as material for
rhythmic (Macla, Horgazu) series.
The outer source input was fine grained leading to the formation of calcareous
(Lepa Beds) and limy flysch deposits (Hangu Beds).
In the Paleogene, the Carpathian sources have led to the formation of fan
deltas in proximal area (Tarcu, Fusaru Sandstones) and turbidites in distal area (Coli
facies, in Eocene and Pucioasa, Vineiu Beds, in Oligocene). The eastern supply is
represented by a marginal prograding complex of a siliciclastic carbonatic platform
(Doamna Limestone and Buciau Beds) in Eocene and by sand mud rich, and sandrich turbidites with channel levee and lobes complexes (Kliwa Sandstone) in
Oligocene.
In the innermost part of the basin, to the west of Teleajen Valley the Eocene is
represented by the marly calcareous otrile flysch.
In the basin axial area, longitudinal transport directions were recorded,
amalgamated sequences were accumulated (Lesunt facies, in Eocene and mixed
Pucioasa (Fusaru) Kliwa facies, in Oligocene).
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The Oligocene Lowermost Miocene contains mud rich sediments with
condensed intervals (Bituminous Marls, Lower Menilites and Dysodilic Shales, in the
lower part of the Oligocene and Upper Menilites and Dysodilic Shales in the
Lowermost Miocene) formed during the rising stage or highstand, that strongly
alternate with sand turbidites (Kliwa Sandstone) formed at times of lowstand stage
while contain the best reservoirs.
The Oligocene basin is characterized by restrictively anoxic conditions, Kliwasandstone is mainly represented by quartzose sandstones with silica cement, having a
characteristic bimodal distribution (with fine-grained quartz clasts less rounded and
coarsegrained quartz clasts well rounded). The specific heavy mineral assemblage is
rutile-turmaline-zircon.
The latest flysch type deposits are represented by the Upper Podu Morii Beds
and Gura oimului Beds (Goru Miina Beds=Tranziia) with eastern supply, of the
Lowermost Miocene.
The molasse deposits have two different source areas: the Foreland for the
Lower Miocene molasse rich in green-schists present today in Subcarpathian and
Marginal Folds Nappes, and internal sources for the Lower Miocene post tectonic
cover common to the internal Moldavides and Tarcu Nappe.
The Lower Miocene accumulated in evaporitic basins predominantly filledwith shallow marine to continental molasses deposits including alluvial fans and fan
deltas.
These deposits overlie the evaporitic Salt Formation and start with coarse
grained sediments (Red Formation with Brsesti Conglomerates) that grade
upwards to fine grained deposits with some evaporitic levels (Grey Formation).
The Badenian molasse deposits are mud rich (Slnic Molasse) containing
interbedded condensed intervals (Globigerina Marls and Radiolarian Schists) as
well as an evaporitic sequence.
During the Sarmatian, the depositional environment evolved from marine to
brackish and, finally, to a fresh water basin which lasted as such up to the Pleistocene.
Starting with the Upper Pliocene, fluviodeltaic deposits are predominant.
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1.3. PETROLEUM POTENTIAL
HISTORY
The East Carpathians bend area is the oldest and most prolific oil producingprovince in Romania. The extraction of crude for domestic uses (fuel, grease,
medication) has been mentioned since the 16th
century and the first commercial
production officially recorded in 1857 (275 tons) resulted, mostly, from this area.
So far, 31 % of the total proven oil resources of Romania (oil in place) are
related to the 40 fields discovered in this region and their contribution to the
cumulative production of the country was of about 37 %.
Until 1950, the region provided almost the whole amount of oil production of
the country, reaching a yearly peak of about 8.3 million tons, in 1936, when Romania
was the sixth oil production country in the world.
Notwithstanding this, the interest for future exploration maintains unchanged,
supported by the up to date evaluations of the undiscovered petroleum potential.
All the commercial oil and gas fields discovered so far are related to the threemost external nappes, i.e. Tarcu, Marginal Folds and Subcarpathian (the overlying
Foredeep sedimentary cover included).
Nevertheless, elements of petroleum system are present in more internal
nappes (Ceahlu, Bobu, Teleajen Macla, Audia) including source rocks, reservoir
rocks, seals and traps, but due to the unfavourable timing between peak generation
and trap formation, to the uplift and partial erosion of the traps, the hydrocarbon
accumulation could not be formed or were destroyed, if existed. Consequently the
remaining potential may be related to the underthrusted areas of the above mentioned
nappes.
As for Tarcu, Marginal Folds and Subcarpathian Nappes the main elements
and processes of petroleum systems could be summarised as follows:
SOURCE ROCKS
The most important, source rocks are associated to the Oligocene
Lowermost Miocene formations, mainly to the pelitic bituminous sequence forming
the Lower and Upper Dysodilic Shales Formations in Tarcu and Marginal Folds
Nappes and to their equivalents in the Subcarpathian Nappe. The argillaceous shales,
marls and marly limestones interbedded within Podu Morii Beds, or within Kliwa
Sandstone, also proved to be source rocks.
The average cumulative thickness of source rock sequences is from 600 m in
Tarcu Nappe to 500 m and 400 m in Marginal Folds and Subcarpathian Nappes,
respectively.
The Total Organic Carbon content is, generally, higher than 0,7 %, up to 9 %,
the highest values pertaining to bituminous dysodilic shales and marls.
The organic matter is of Type II, or II/III, with Hydrogen Indexes ranging
between 122 and 548 mg/g TOC.
Geochemical analyses carried out on the dysodilic shales taken from the
outcrop showed a TOC content of 1.16 2.78 % and a predominantly type II Organic
Matter, with subordinate terrestrial influence.
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Apart from the Oligocene Lowermost Miocene, organic matter-rich
interlayerings are present in Lower Miocene, Badenian, Sarmatian and even Pliocene
formations.
MATURITY, GENERATION AND EXPULSION TIME
The Oligocene Lowermost Miocene source rock shows different maturitylevels, depending on burial history, organic matter type and geothermal gradients.
Therefore, R0 values of 0.4 up to 1.25 were measured on samples from
different wells, at depths ranging from 1500 m to 7021 m.
According to these values, the Oligocene entered the oil window (R0> 0.65) at
depths greater than 3500 m, in all of the three nappes.
Burial history diagrams are in match with R0maturity data, pointing out the
depth, and duration of hydrocarbon generation and expulsion.
Both in Tarcu and Subcarpathian Nappes the hydrocarbon generation started
16 MY ago, after the tectonic burial of the Oligocene source rocks, as a result of
intraBurdigalian folding movements.
In Marginal Folds Nappe, the maturation depths were reacher later, during the
Badenian, when the Tarcu Nappe overthrusting took place.In Marginal Folds Nappe maturation depths were reached by the Oligocene
source rocks on areas much larger than in Tarcu Nappe.
The younger potential source rocks are still immature excepting the Lower
Miocene ones, which could reach maturation depths (more than 5000 m) in a few
limited areas of the Subcarpathian Nappe. Therefore, their possible contribution to the
generated hydrocarbons is considered unimportant, as compared to that of the
Oligocene source rocks.
RESERVOIRS
With one exception (the calcareous Doamna Formation) all producing
reservoir rocks are of clastic origin (sandstones, sands or even conglomerates),occurring in a large stratigraphic interval, from the Eocene to the Upper Pliocene.
The Oligocene Lowermost Miocene reservoir rocks provided the largest
amount of hydrocarbon reserves discovered so far in the Marginal Folds domain.
The contribution of the Oligocene Lowermost Miocene reservoirs to the
producing fields diminishes in Tarcu Nappe and is the smallest in the Subcarpathian
Nappe. Upper Miocene (Sarmatian) and, particularly, Pliocene reservoirs are the most
important in these two units.
In the case of the Subcarpathian Nappe, the small volume of oil reserves
discovered in the Oligocene reservoirs should be explained by the limited number of
exploration wells drilled so far in the relatively large areas where such reservoirs
interbedding with good source rocks are located at depths of 5000 7000 m.
TRAPS
Structural traps prevail in all three hydrocarbon producing nappes.
On the outer margin of the Tarcu Nappe and in Marginal Folds Nappe,
longitudinally faulted folds, forming alignments parallel to the regional bend of the
Carpathians, are characteristic to the structure of the Paleogene deposits.
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PETROLEUM SYSTEMS
The basinal continuity of the Oligocene Lowermost Miocene source rocks
was broken early, before the beginning of maturation expulsion processes, by the
intra Burdigalian tectonic movements. Later on, during the Badenian, the source and
some reservoir rocks were completely separated into three domains, one for eachoverthrusting nappe (Tarcu, Marginal Folds, Subcarpathian), which evolved
independently from the point of view of maturation expulsion migration
entrapment processes, leading to the existence of three main petroleum systems.
The Tarcu Nappe Petroleum System is developed mostly on the externalareas of the unit, where some of the source rocks reached the deepest position, due to
the more intensive folding and underthrusting. At the same time, younger seal and
reservoir rocks (Miocene - Pliocene), were deposited, while the more internal areas of
the nappe were exposed to erosion, since the Upper Burdigalian.
In the existing fields, the Oligocene reservoir rocks as well as those belonging
to younger, overlying formations, above the Miocene, are oil producing.
Source rocks: argillaceous schists with high organic matter content(Oligocene).
Reservoir rocks: sandstones (Oligocene, Eocene); calcareous sandstones
(Eocene).
Seal rocks: evaporites (Miocene salt); pelites (Oligocene).
Trap styles: structural.
Fields: Pcuria (oil).
The Marginal Folds Nappe Petroleum Systemis related to the areas where
the preservation conditions where realised by the Tarcu Nappe overthrusting.
The largest region with such conditions is located between Oituz and Bistria
tectonic half window, Moineti area.
Nevertheless, a few fields are protected only by the Lower Miocene normal
cover, after the local erosion of the Tarcu Nappe, as a result of Pleistocene tectonic
movements.
Source rocks: argillaceous schists with high organic matter content
(Oligocene);
bituminous limestones, argillaceous marls (Paleocene).
Reservoir rocks: sandstones (Oligocene, Eocene); limestones (Eocene).
Seal rocks: evaporites (Miocene salt); pelites (Oligocene, Miocene).
Trap styles: structural.
Fields:Ghelina, Slnic-Bi, Cerdac, Dofteana, Nineasa, South Nineasa (oil),
Lepa (gas).
The Subcarpathian Nappe Petroleum Systemis, by far, the most important
for the southern part of the Eastern Carpathians. At the same time, the system
underwent the most complex evolution, due to the many stages of reservoir deposition
and trap formation. Most of these events occurred after the beginning of the
generation migration processes, when thick piles of impervious sediments separated
the new traps from the generating source rocks.
In Moineti area there are four hydrocarbon accumulations: Tescani
(Oligocene and Lower Miocene), Cmpeni (Lower Miocene), Cain (Sarmatian),
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Cmpeni (small accumulation in Badenian). Cmpeni field has been exploitated since
1903.
Source rocks: argillaceous schists with high organic matter content (Oligocene
Lower Miocene).
Reservoir rocks: sandstones and conglomerates [Oligocene (Kliwa), Lower
Miocene (Condor, Brsesti, Grey Fm)
Seal rocks: evaporites (Lower Miocene salt and gypsum); pelites (Oligocene,Miocene)
Trap styles: structural.
Fields: Moineti area, Gura Ocniei, Moreni, Filipeti, Tei, Ochiuri, Gorgota.
The Foredeep Petroleum Systemis developed mostly on the inner part of the
Foredeep. As a result of the Wallachian (intra-Pleistocene) phase, regional diapiric
folds alignments, with various piercing stages of the salt were built up (Diapiric
Folds Zone).
Two of these alignments i.e. Gura Ocniei Moreni Bicoi intea
(exaggerated diapirs) and Bucani Ariceti Ceptura Urlai (attenuated
diapirs) had a particular importance in the hydrocarbon entrapment.
In this area, the Upper Sarmatian Pliocene arenitic sequences proved to bethe most important for the existence of oil and gas fields discovered so far.
Source rocks: argilites (rich organic mater) (Sarmatian)
Reservoir rocks: sandstone interbeding (Meotian, Pontian, Dacian, Romanian)
Seal rocks: pelites interbedings (Sarmatian, Pontian, Dacian, Romanian)
Trap styles: structural
Fields: Boldeti, Moreni, Gura Ocniei, Bicoi, Pcurei, Mgurele, intea,
Brbunceti, Berca-Arbnai.
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Fig. 16 East Carpathian Geological Map, - PETROM Blocks and Oilfields.
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2. FIELD TRIP ITINERARY AND STOP DESCRIPTIONS
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FIELD TR
First Day Stop 1 BercaBerca Oilfield - Mudy Volcanoes (Pclele Mari) Stop 2 Lopatari - Lower Burdigalian Sandstone and Salt
Formation.
Stop 3 ManzalestiGeological profile - Slnic Valley - Miocene(Upper Burdigalian, Badenian, Sarmatian and Lower Meotian)
Subcarpathian Nappe and Carpathian Foredeep (Upper
Molasse) Stop 4 Beslii - VintilVod- Geological profile Upper Meotian
Pontian - Slnic Valley - Carpathian Foredeep
Second Day Stop 5 Vidra Milcov Fm Pontian - Putna Valley Upstream
- The Carpathian Foredeep
Stop 6 Valea Scrii-Marly and Sandy-Marly Formations, Sarmatian - Putna Valley - Carpathian Foredeep
Stop 7 La Grumaz Grey Formation - Upper BurdigalianPutna Valley - Subcarpathian Nappe
Stop 8 Brsesti- Red Formation, Brsesti Conglomerates -Lower Burdigalian - Subcarpathian Nappe
Stop 9. Putna Fall- Lower Oligocene, Lower Disodile Member- Marginal Folds Nappe
Stop 10 Lepa- Upper Tisaru Beds, Lepa - Piatra Strei Unit -Marginal Folds Nappe
Stop 11. Lepa:BuciaBeds, Bisericani Beds - Marginal FoldsNappe
Third Day Stop 12 Rsnov CastleSedimentary cover of Getic Nappe -
Upper Jurassic (Kimmeridgian-Tithonic), Cretaceous
(Vraconian-Cenomanian)
Stop 13 Fundata- Bucegi - Piatra Craiului Geologic Park panorama
Stop 14 Dealul Sasului (Belvedere), Jurassic, Cretaceous -Sedimentary cover of the Median Dacides
Stop 15 Dmbovicioara Gorges- Dambovicioara FormationJurassic, Cretaceous - Sedimentary cover of the Median
Dacides
Stop 16 Ceteni- Albian Conglomerates Sedimentary coverof the Median Dacides
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First Day
Departure: Bucharest 07:00 Bucureti - Ploieti - Buzu - Berca 07:00 10:30 Stop 1 Berca
BercaArbnai Oilfield, visit to the Mudy Volcanoes (Pclele Mari), 10:30-12:00
Berca - Loptari 12:00 13:00 Stop 2 Loptari
Lower Burdigalian Sandstone and Salt Formation 13:00 14:00
Field Lunch 14.00 14:45 Loptari Mnzleti 14:45 15:00 Stop 3 Mnzleti
Geological profile - Slnic Valley - Miocene (Upper Burdigalian to Lower Meotian)
Subcarpathian Nappe and Carpathians Foredeep (Upper Molasse) 15:00 16:30
Mnzleti VintilVod16:30 16:45 Stop 4 Beslii - VintilVod
Geological profile - Slnic Valley - Upper Meotian Pontian lithostratigraphy -
Carpathians Foredeep 16:45 18:00.
VintilVod- Berca Buzu Focani 18:00 18:30 Accomodation Dinner 20:00
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Fig. 17 Geological Map Slnic Valley area (Romania Geological Map - fragment IGR)
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Stop 1 - Berca Arbnai Oilfield Muddy VolcanoesUnit: Subcarpathian Nape
Age: Miocene Pliocene
Formation: folded sedimentary deposits
The structural Berca Pcle - Beciu Arbnai alignment is developed along approx.30 km within the Subcarpathian Nappe and it consisting of of an anticlinal fold longitudinallyand transversaly tectonized through a fault system which makes that the relation between thestructure flanks differs from one zone to another.
Fig 18. Berca Arbnai BlockGeological map 1:200.000 RGI
(fragment).
Fig 19. Berca Arbnai structure
Geological Sketch map.
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In the axial zone of the fold, Meotian and Sarmatian sedimentary deposits outcrop.The drilled wells (the deepest one has a TD greater than 3330m) cross a succession of
beds belonging to the Sarmatian, Meotian, Pontian, Dacian and Romanian. The lithological bedsuccession comprises more arenaceous levels than the adjacent areas (Moreni, Boldeti); theMeotian includes 27 sand levels among which most of them are productive. The Meotianhydrocarbon accumulations are accommodated in a number of sand beds different from one
block to another. The nature of the fluids in the accumulations and their distribution within thealignment are different; the eastern flank is productive in all sectors of the structure (with oil,with or without primary gas cap and more rarely free gas), while the western flank is producingonly at Pcle and Beciu (oil with primary gas cap and free gas).
The existence of numerous faults as well as the outcropping or the very high structuralposition of the hydrocarbon-saturated Meotian deposits led locally to the partial deterioration ofthe conditions of fields sealing. The longitudinal and transverse fault system created pathways ofhydrocarbon (especially gas) migration to the surface, what brought about the occurrence of thespectacular phenomenon of Muddy Volcanoes. Along their way to the surface, the gas and theformation water drive the pelitic material and form mud which erupts in the area, in a fewspots.
The phenomenon of the Mud Volcanoes crops up in a striking way close to Berca, at
Pclele Mari and Pclele Mici. This area hasbeen included in the list of the protectedareas in Romania.
The geological and botanicalreservation Muddy Volcanoes covers anarea of approx. 30 hectares and comprisestwo areals: Pclele Mici and Pclele Mari.
The Pclele Mici plateau representsa 9.4 ha natural reservation ever since 1924.The object of the protection is the landscapedisplayed by the relief and the presence oftwo halophile plant species -Nitrariaschoberi and Obione verrucifera.
At Pclele Mici, there is the largestnumber of volcanoes having cones, craterswith highly varied sizes as well as complexmorphology, on one hand resulted from themud accumulation and on the other hand byrain water streaming.
The volcanoes occur in groups of 3-5 units being of 2-8 m high, with craters of10-100 cm diameters wherefrom viscousmud comes out, flowing as tongues which
reach 20-50 cm in length.Pclele Mari is situated at a few
kilometers to the north-east. The name isconnected to the very large sizes of threemain volcanoes having diameters of over 100 cm, which are lying in the centre of the plateau.The flanks of the cones are very widely spread, several cones of secondary volcanoes and longviolet-blue mud tongues occur onto the former. The external half of the plateau is fragmented byravines, torrents, developing scenery of badlands. The natural reservation covers an area of19.6ha.
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Stop 2 LoptariUnit: Tarcu NappeFormation: Lower Miocene (Lower Burdigalian) Sandstone
Unit: Subcarpathian Nappe Lower Miocene (Lower Burdigalian)
Formation: Lower Salt Formation
The contact between Tarcu and Subcarpathian Nappes
Lower Burdigalian, Tarcu NappeWithin Tarcu Nappe, in the proximity of the contact with the Subcarpathian Nappe, a
succession of Lower Burdigalian sand deposits outcrops. The succession represents a 15 mfining up and thinning up sequence, whose basis comprises sandstones and it is continued withsilts and shales.
The sandstones are of metre- and decimetre-thickness, with massive structures, parallellaminations and symmetrical wave ripples on top (fig. 20-23). Occasionally, the base iserosional. It represents a succession deposited in a marine shallow water setting.
Fig.20 Burdigalian sand deposits in Tarcu
Nappe at the contact with the SubcarpathianNappe, Slnicul de Buzu Valley
Fig. 21Fining up and thinning up sequence
consisting of massive sandstones, parallellaminated and with wave traces at the upper
part. It is continued with thin sandy beds
further consisting of silts and shales.
Fig. 22Detail, section in a sandstone bed with
wave traces. In the lower zone, there are fine-
grained accumulations of organic matter
phytoclasts.
Fig. 23 Detail, top of sand bed with wave
traces.
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Lower Burdigalian - Subcarpathian Nappes, salt diapir at Loptari
In the proximity of the contact with Tarcu Nappe, within the Subcarpathian Nappe,along Slnicul de Buzu Valley, a Burdigalian salt diapir structure outcrops.
The salt is massive, but in certain points there have been noticed reddish argillitic andsiltic interbeds, thus imprinting a parallel lamination-type structure. At the upper part and on theexternal flanks of the diapir structure, chaotic deposits are to be found, of the salt breccia type,
consisting of a reddish dominantly sand matrix and green elements of Dobrudja type as well asfragments of marly sand beds, belonging to younger formations pierced by salt.
In this area, the diapirism is due to both the tectonic causes and the differences in thedensity.
Fig. 24Salt Diapir at Loptari, Aquitanian.Relation with salt breccia.
Fig. 25Detail, salt interbedded with
reddish shales and siltites, with parallel
lamination.
Fig. 26Lapiazs, actual structures of salt
dissolution
Fig. 27Salt breccia, detail. Dobrudja-type
green schists elements and reddish sand
matrix.
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Casin-Bisoca Fault
Sucarpathian
Nappe
External Foredeep
Tarcau Nappe
Fig. 28 Geological map of
Loptari Mnzleti -VintilVodarea.- Main tectonic units- The analyzedgeological profile.
(Geological Map 1:200
000, IGR.)
*Note: On the map are used oldstratigraphic terms. Using theInternational Stratigraphic Scale,is necessary to understand thestratigraphic age from the mapaccording to the followingscheme:Aquitanian (aq) = Aquitanian +Earliest Burdigalian;Burdigalian (bd) = LowerBurdigalian(bd1);Helvetian (he) = UpperBurdigalian(bd2);
Tortonian (to) = Badenian (ba).
Stop 3 Mnzleti
Unit: Subcarpathian Nappe and Carpathians Foredeep (Upper Molasse)
Age: Miocene (Upper Burdigalian, Badenian, Sarmatian and Lower Meotian)
Geological profile along Slnic Valley at Mnzleti
The scope of this profile is to point out the main characters of Middle and UpperMiocene deposits as well as the complicate geological structure of the Sucarpathian Nappe andits tectonical relations with the External Foredeep along the Cain Bisoca Fault.
In this section the Upper Burdigalian* and Badenian* sequences of the SubcarpathianNappe crop out into a complicated succession of few narrowed tectonic imbrications.
The Upper Burdigalian is represented by so called The Gray Formation, a sandy-marly complex containing several gypsum layers and marly intercalations.
The Badeniansequence develops in this sector into an intermediate facies between theSlnic Tuff Facies and Rchitau Sandstone Facies. It is represented by whitish or greenishdacitic tuffs (equivalent of Slnic Tuff) and interbeds of these calcareous matrix sandstones(Rchitau Sandstone) with quartz, green schists, limestone grains and authigenous glauconite.The Badenian age sandstone is proved by the Globigerinidae associations identified in marlyintercalations. In the lower part or interbeded with the tuff layers it can be noticed the so namedglobigerina marls represented by gray-brownish or greenish marls very rich in planktonicforaminifers: Praeorbulina glomerosa, Orbulina universa, Globorotalia mayeri,Globigerinoides trilobus, etc.
The profile starts at the bridge to Poiana Vlcului village where the Badenian Slnic -type tuff and marls in relation with the Rchitau sandstone are exposed in a spectacularerosional outcrop. The whole succession from the tuffitic globigerina-bearing marls, whitish tuffand Rchitau Sandstone seams to be overturned due the effect of the proximity of major Cain-Bisoca Fault that marks the overthrust between Subcarpathian Unit and Foredeep.
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From this point on our geological trip will continue downstream, on the left bank ofSlnic Valley where the Upper Burdigalian sediments of the Gray Formation are exposed.They are represented by interbeds of calcareous, micaceous or gypsiferous sandstones, silts, graymarls with few thin gypsum intercalations or lenses. Frequently, inside this sequence,microfolds can be seen, due to the anhydrite hydration.
Close to the concrete bridge that crosses the Slnic River, a new Badenian sequence witha thicker layer of green tuff and few interbeds of tuffitic sandstones, consolidated green silts andmarls can be noticed in talweg.
Fifty metres downstream of the bridge, this sequence comes into a tectonical contact withSarmatian deposits along the Cain - Bisoca Fault. On Slnic Valley Section this fault is marked
by a faults system and a disturbed zone where the Badenian tuffitic sandstones and marlstonesare in angular contact with the Sarmatian(Upper Bessarabian) calcareous sandstones and siltsrich in Mactra shells. The mlange zone is marked on landscape.
Badenian tuff
Badenian marls
Fig. 29 The outcrop with
Badenian Tuff and
Rchitau Sandstone -
Mnzleti (Slnic Valley)
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Badenian green tuff
The Gray Formation
sequence
Downstream of this faulted zone (CainBisoca Fault) lots of big blocks of calcareoussandstones very rich in Mactra shells can be seen: Sarmatimactra fabreana, S. podolica, S.
pallasi. The first Sarmatian deposits in place, crop out approximately 60-70 m downstream ofthe fault zone and are represented by interbeds of gray-greenish calcareous sandstones separatedby gray marls and silts. At some levels, rich fossil intercalations with Mactra shells or thin layerswith vegetal material can be observed. The sandstone beds frequently show sedimentarystructures (oblique or cross- laminations on base, parallel lamination or wave-ripples on top).Few sandy levels have a mass flow aspect or present rounded or lens-shaped concretions.
Fig. 30 The Grey Formation
sequence (Upper Burdigalian)exposed on the left bank of
Slnic Valley at Mnzleti
Fig. 31 Massive green tuff and
tufitic sandstones (Badenian) atMnzleti Brige on Slnic
Valley
Fig. 32 The fault zone (Cain-BisocaFault) seen on the talveg of Slnic
River. Downstream of this, the
Sarmatian (Upper Bessarabian-Kersonian)deposits of the ForedeepZone crop out
Badenian tufitic
silts and
sandstonesMiddle Sarmatian calcareous
sandstone blocks
with Mactra shells
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d
c
To the upper part of this profile, sandstone layers are thicker and contain frequent shellsof Sarmatimactra caspia, S. balcica, S. bulgarica that prove the presence of Upper Sarmatian(Kersonian).
Fig. 33 Middle Sarmatian (Bessarabian) deposits exposed on Slnic Valley(Mnzleti Village) a) Calcareous sandstone block very rich in Mactra shells. b) sandintercalation with concretions and deformed sandstone lenses that suggest a mass flow type
deposit; c) Consolidated gray-yellowish sandstone with cross-laminations (d) and Mactra
shells.
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A particular aspect of this upper sequence is represented by an interval (10-12 m) withinterbeds of greenish, reddish and blackish silty-clays. These variegated clays represent a markerfor the top of Sarmatian in all over the East Charpathians Foredeep. The clays contain a porefresh water or continental fauna. Formerly, this interval has been assigned to the base ofMeotian, but later a few levels with small Mactra above it have been found (Dumitrescu, 1951)that lead to the conclusion that this marker interval must be placed in the uppermost Sarmatian.
Few tens of metres above it, after the last levels with Mactra shells, a succession of thick graysandstones separated by gray clays and silts crops out downstream of Slnic Valley and itrepresents the Lower Meotian sequence.
Fig. 34 Late Sarmatian (Upper Kersonian) sequence with an intercalation of greenish andred clays (marker level) covered by few cycles of sandstones (some of them with wave
ripples on top) separated by gray silts and clays. Few levels rich in Mactra shells occur on
top of some sandstone.
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Stop 4 Beslii VintilVod
Unit: The Carpathians Foredeep
Age: Upper Meotian -Pontian
Geological profile along Slnic Valley between Beslii and VintilVodVillages
The scope of this geological profile is to illustrate the transition between Upper Meotianshallow water detrital deposits to more basinal fine - grained Lower Pontian ones. Also, alongthe section, it can be noticed the evolution and changes of sedimentary conditions in thePontian interval that start with a transgression at the uppermost Meotian / lowermost Pontian
boundary, followed by a setting up of more basinal sedimentary conditions in the LowerPontian. The Middle Pontian interval represents a low-stand system tract when shallow water(littoral, fluvial, lacustrine) sedimentary conditions developed (this can be correlated with theMessinian Salinity Crisis -MSC- when the Mediterranean Sea experienced its dramaticallydesiccation). The Upper Pontian sequence starts with a new transgression (this can be correlatedwith the Zanclean transgression) and again pelitic sediments of basinal type developed. To the
upper part of Late Pontian, it can be noticed the reinstallation of more shallow-watersedimentary conditions.
Upper Meotian
In this section, the Upper Meotian deposits are represented by few cycles of deltaic andlittoral sediments. The gray-yellowish bodies of sandstones (front deltas) are separated by graysilts and clays (of flood plain and lacustrine type). At few levels, sandstones present waveripples on top (littoral). Coarsening-upwards aspects can be noticed in this sedimentarysequence. Few fossils layers rich in mollusks can be noticed in the upper part of sequence.Fossils are represented mainly by bivalves and gastropods of deltaic and littoral type: Psilunio(Psilunio) subrecurvus , P. (P.) subhoernesi, Unio subatavus, Leptanodonta rumana, Anodonta
sp., Viviparus moldavicus, Valvata(Atropidina) turislavica, Theodoxus (Calvertia) stefanescui,
Hydrobia dif. spp.. Pyrgula hungarica etc.
Fig. 35 a) Upper Meotian deposits on the left
bank of Slanic Valley. b) coarsening-upwards
sequence; c) fossil level with Viviparus
moldavicusWenz
a
c
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Upper MeotianLower Pontian
Fig. 36 a) Upper Meotian /Lower Pontian boundary on the left bank of Slnic Valley; b)Pseudoprosodacna littoralis littoralis, from the Lower Pontian sediments; c) Congeria
novorossicalayer in the Uppermost Meotian sediments
c
a
The Meotian/Pontian boundary
The Uppermost Meotian sequence ends with a succession of dark-gray silts, clays andfew intercalations of thin sandstone rich in Congeria novorossicaSinzow. This is a marker levelfor all the Dacian Basin (and for the Eastern Paratethys, too) and it represents the start of animportant transgression into the basin. Above the last Congeria beds, a strong association of
benthic agglutinated and calcareous foraminifera develops (Stoica et al., in press).The Lower
Pontian starts with gray marls rich in Limnocardiidae bivalves, especially Pseudoprosodacanaspecies.
The Lower Pontian, develops into pelitic facies represented by gray fine-bedded ormassive marls (approx. 250 m) with rare thin intercalations of brownish silts and sandstones. Allthis succession is very rich in mollusks: Paradacna abichi, Caladacna steindachneri, Didacna
sucarinata, Limnocardium (Tauricardium) subsquamulosum, Limnocardium (Euxinicardium)
subodessae, Monodacana (Pseudocatillus) pseudocatillus, Congeria zagrabiensis, Congeria
rumana, Dreissena rostriformis, Prosodacna littoralis littoralis, Pseudoprosodacna
semnisulcatoides, Valenciennius annulatus, Viviparus incertus etc.. Also, this interval is veryrich in ostracod species, mostly Pontoniella, Caspiolla, Bakunella and Leptocythere species.
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Fig. 38 a) Lower Pontian (Odessian) / Middle
Pontian boundary on Slanic Valley Section;
can be noticed the transition between high
stand system tract (Odessian) and low standsystem tract (Portaferrian); b)-d) sedimentary
aspects of Middle Pontian sequence; e) big
sandstone body with erosional features on the
sole (transport channel)
Lower Pontian( marls and silts
high -stand system)
Middle Pontian( sandstones with wave ripples, silts
low- stand system)
Transport channel
Fig. 37 Lower Pontian marls withParadacna abichi
The Middle Pontian (low stand system tract)
As a result of water level lowering in the Middle Pontian, the dominantly basinal peliticsequence of the Lower Pontian is replaced by a more proximal one developed in littoral andfluvial-deltaic environments. The Middle Pontian sediments are represented especially by littoral
sandstones with wave-ripples on top, silts and clay formed in flood plain areas, thin coal layers(lignite), lacustrine clays with freshwater mollusks. To the top of this interval few big sandybodies with erosional features on sole suggest an important development of transport channels.
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Middle Pontian= Late Miocene(low stand system)
Upper Pontian = Early Pliocene(high stand system)
Fig. 40 The Middle Pontian/Upper
Pontian boundary - Slnic Valleysection
Fig. 39 Late Pontian sediments
represented by few cycles of grey
pelitic intervals and sandstone
layers on top (outcrop on the leftbank of Slnic River).
The Middle Pontian (Portaferrian) / Upper Pontian (Bosphorian) boundary
The Slnic Valley Section is one of the best profiles to illustrate the transition betweenpredominantly shallow water proximal environments (littoral, fluvial or deltaic) of the MiddlePontian (low stand system tract) to the more basinal ones in the first part of Upper Pontian.
The big sandy bodies of Portaferrian (transport channels, littoral sands) are abruptlyreplaced by a rich interval of gray marls with very few intercalations of silts and sandstones.
This new transgression in the Dacian Basin seams to be synchronous (according to thepaleomagnetic data) with the Zanclean transgression when Mediterranean Sea has been refilledwith water after the Messinian Salinity Crisis event. In these circumstances we can consider theMiocene/Pliocene boundary at this level on the section.
The Late Pontian sequence (close to the boundary with Dacian) developed again intoshallow water and continental environments. These sedimentary conditions (littoral, fluvial,deltaic, lacustrine) will be the dominant features in the Dacian and Romanian stages as aconsequence of the progressive filledup with sediments of the Dacian Basin.
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Second Day
Breakfast 07:30 08:30 Focani Vidra 08:30 10:00 Stop 5 Vidra
Upper Pontian Cicles 10:00-10:30
Vidra Valea Scrii 10:30 11:00 Stop 6 Valea Scrii (facultative)
Cain-Bisoca Fault; Sarmatian formations
Vatea Sarii La Grumaz 11:00 11:15 Stop 7 La Grumaz (facultative)
Upper Burdigalian Sandstone and Gypsum 11:15 12:00
La Grumaz Brseti 12:00 12:15 Stop 8 Brseti
Lower Burdigalian Brseti Conglomerates 12:15 12:45
Brseti Gresu 12:45 13:00 Lunch 13.00 14:00 Gresu Cascada Putnei 14:00 14:30 Stop 9 Cascada Putnei (Putna Waterfall)
Oligocene Disodilic Shales 14:30 15:15
Cascada Putnei Lepa 15:15 15:30 Stop 10 Lepa 1
Eocene BuciaBeds and Bisericani Beds; Oligocene