Crossing the Carpathians

7/22/2019 Crossing the Carpathians

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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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Crossing the Carpathians Field Trip Guide Book

June 2008

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).


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)


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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June 2008 35

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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June 2008 36

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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June 2008 38

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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June 2008 42

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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June 2008 43

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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June 2008 44

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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June 2008 45

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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June 2008 46

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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June 2008 47

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

lowstand 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

Crossing the Carpathians

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