The position and age of the youngest deposits in the Mszana Dolna and Szczawa tectonic windows (Magura Nappe, Western Carpathians, Poland)

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A cta Geologica Polonica, Vol. 54 (2004), N o. 3, pp. 339-367

The position and age of the youngest deposits in the Mszana Dolna and Szczawa tectonic windows (Magura Nappe, Western Carpathians, Poland)

MARTA O SZC ZY PK O -CLO W ES & N E ST O R O SZC ZY PK O

Institute o f Geological Sciences, Jagiellonian University, Oleandry 2a, PL-30-063 Kraków, Poland

ABSTRACT:

O s z c z y p k o - C l o w e s , M. & O s z c z y p k o , N. 2004. The position and age of the youngest deposits in the Mszana Dolna and Szczawa tectonic windows (Magura Nappe, Western Carpathians, Poland). A cta Geologica Polonica, 54 (3), 339

367. Warszawa.

The Mszana Dolna and Szczawa tectonic windows are composed o f deposits belonging to the Fore-Magura Group of units. The central and most uplifted part of these windows are dominated by relatively flat laying deposits belong

ing to the Krosno Formation (Oligocene) o f the Dukla Unit. The western, eastern and southern marginal parts of the Mszana Dolna tectonic window are occupied by strongly tectonized, Cretaceous-Oligocene deposits assigned to the Grybów Unit. The Szczawa tectonic window is entirely built up o f Oligocene deposits o f the Grybów Unit. The youngest deposits of the Mszana Dolna tectonic window are correlated with zone NP24 (Dukla Unit) and NP23- NP25 (Grybów Unit). In the Szczawa tectonic window (Grybów Unit), the NP22-NP24 Zone was determined in the Grybów Beds, whereas the Cergowa Beds belong to zone NP24.

Such age determination corresponds well with that of the southern part of the Silesian and Dukla units. The deposits of the Dukla and Grybów units are tectonically covered by the Cretaceous-Eocene deposits of the Magura Nappe.

During the latest Oligocene a thrusting of the Magura Nappe onto the Fore-Magura sedimentary basin began (Grybów and Dukla). This process was probably initiated under the submarine condition. The last of the over thrusting stages took place probably during the Middle Miocene, and resulted in the development of the Mszana-Dolna duplex structure.

Key words: T e c to n ic w in d o w s, O lig o c e n e , D u k la , G ry b ó w a n d M a g u r a u n its , W e s te rn C a r p a th ia n s .

IN T R O D U C T IO N

In th e Polish sector of th e M agura N appe eleven tectonic windows have been recognized (Text-fig. 1, see also Ks i ą ż k i e w i c z 1977). T he m ajority o f these win

dows are situated betw een the Kraków m eridian on the west, and th e Polish/Slovak frontier in th e east (Text-fig.

1). To the w est of this area Si k o r a & Ży t k o (1959) dis

covered a small tectonic window in Sopotnia Mala, w hereas in E astern Slovakia the Smilno tectonic win

dow is known since 1880s ( Uh l i g 1888, Ne mCo k & al.

2000). T hese windows belong to th e Fore-M agura G roup of units, and occupy th e interm ediate position

betw een th e Silesian and the M agura nappes. In th e tec

tonic windows occur the Obidowa U nit, which is reg ard ed as the w estern prolongation o f th e D ukla U nit ( Ci e s z k o w s k i & al. 1985) and th e Grybów U n it ( Św i d z i ń s k i 1963), know n also as th e K lęczany- Pisarzowa U nit ( Ko z i k o w s k i 1953, 1956a, b) These units are com posed predom inantly of th e L ate Eocene- O ligocene, som etim es o f th e L a te C retaceous- P alaeocene deposits. T here is a com m on understanding (see Ks i ą ż k i e w i c z 1962, Bi e d a& al. 1963, Ge r o c h &

al. 1967, Ko r a b & Du r k o v iC 1978), th a t the Fore- M agura G roup of units displays transitional litho-facies, which linked th e Silesian and M agura basins. According

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to these opinions the U pper Cretaceous-M iddle Eocene deposits o f the Fore-M agura G roup of units reveal a similarity to the M agura N appe facies, w hereas the L ate Eocene-O ligocene deposits have similar lithological features to those from the Silesian U nit. T here is a com

m on opinion th at the Grybów succession was deposited betw een the M agura and Dukla-Silesian sedim entary areas (see Bi e d a & al. 1963, Ks i ą ż k i e w i c z 1977, Ol s z e w s k a1981).

T he L ate Eocene-O ligocene facies relationships betw een th e Silesian, F ore-M agura group of units and M agura units suggest proximity betw een th e Silesian and M agura basins. This opinion concurs with th a t on th e L ate C retaceous to E ocene, w here th e interaction betw een these basins was controlled by vertical m ove

m ents of th e Silesian Ridge, which separated the w est

ern p a rt o f th e M agura basin from the Silesian basin ( Ks i ą ż k i e w i c z 1956). This concept was recently ques

tioned by Ne m ć o k & al. (2000), who reg ard the M agura basin a w estern prolongation of th e Silesian basin, explaining th e presen t-d ay p o sitio n o f th e M agura N appe to b e a result of th e M iddle M iocene, eastw ard escape o f th e A lcapa terrain together with the Pieniny K lippen Belt and th e M agura N appe against th e Fore-M agura/Silesian group o f units. T he M agura N appe is flatly overthrust onto th e F ore-M agura G roup of units and partly onto the Silesian units (western seg

m ent). T he results of deep boreholes and th e tectonic windows provide us with an idea about th e m inimal am plitude o f th e M agura N appe overthrust, which is at least 35 km on th e K raków -Zakopane geo-traverse ( Si k o r a 1980). T he age of the youngest deposits b en eath the M agura N appe sole thrust determ ine the tim e w hen th e overthrusting o f this unit begun. Taking into account th e occurrence of th e O ligocene Krosno Form ation in the tectonic windows, th e L ate Oligocene onset o f th e M agura N appe overthrust should be accepted. T he discovery of folded L ate O ligocene- E arly M iocene deposits in th e M agura N appe ( Os z c z y p k o & al. 1999a, Os z c z y p k o- Cl o w e s 2001, Os z c z y p k o & Os z c z y p k o- Cl o w e s 2002) necessitates the revision o f the traditional m odel o f the tectonic evolution o f th e W estern C arpathians ( Ks i ą ż k i e w i c z

1977, Bi r k e n m a j e r 1986, Os z c z y p k o 1992, Go l o n k a

& al. 2000).

T he aim of this study was to recognize the age and tec

tonic position of the youngest deposits of the Mszana Dolna and Szczawa tectonic windows, and their relation to the M agura Nappe.

M S Z A N A D O L N A T E C T O N IC W IN D O W (M D W )

A characteristic feature of the middle p art o f the M agura N appe in th e Polish O uter Carpathians is the p rese n ce o f th e M szana D o ln a tectonic window (M DW ). The area o f the M D W (Text-fig. 2) and its sur

roundings were the subject of basic geological investiga

tions (see Bu r t a n & al. 1976, 1978; Ma s t e l l a 1988).

According to Bu r t a n & al. (1976, 1978) the M D W is com posed of the N orth and South For-M agura units, w hereas Ma s t e l l a (1988) referes to them as the M szana D olna and Grybów units, respectively. It seems th at th e central and m ost uplifted p art of this window is dom inated by th e O ligocene K rosno Form ation of th e D ukla (O bidowa-Slopnice) U nit ( Ży t k o & al. 1989), w hereas the narrow, marginal p art of the window is occupied by th e Cretaceous-O ligocene deposits of the Grybów U nit (Text-fig. 2). Po l t o w i c z (1985) referred all of th e O ligocene deposits of th e M D W to the Grybów Unit.

Recently, th e so u th ern m argin o f th e M D W has b ee n th e subject o f geological investigations o f a sec

ond au th o r and his students (see Os z c z y p k o & al.

1999b).

T he southern periphery o f th e M D W is one o f th e best-exposed areas in th e Polish O u ter C arpathians.

C onsequently, its lithostratigraphy and architecture o f th e flysch deposits are relatively well known. T he fo r

m al and inform al lithostratigraphic units are used in parallel for th e description o f these deposits (see Bi r k e n m a j e r & Os z c z y p k o 1989, Os z c z y p k o 1991, Os z c z y p k o & al. 1999b).

Magura Nappe

T he southern m argin of the M D W is com posed of th e Cretaceous-Palaeogene deposits of th e M agura U nit, which belong to the so-called “south peri-window”

zone ( Bu r t a n& al. 1976,1978). According to the m ost recent geological study, this zone belongs to th e Poręba- Koninki and Konina-Lubom ierz thrust sheets, which can be correlated with the R aca and Bystrica subunits, respectively (Text-figs 2-3, see also Ma s t e l l a 1988, Os z c z y p k o & al. 1999b). T he m ore internal tectonic elem ents: Tobołów-Turbaczyk th ru st sh e et o f th e Bystrica and Krynica Subunits do not directly join with MDW.

Fig. 2. Geological sketch-m ap of the middle p art of the Polish C arpathians (after Os z c z y p k o & al. 1999b, supplem ented); 1 - P odhale Flysch, 2 - Pieniny K lippen Belt; M agura N appe: 3 - Krynica Subunit, 4 - Tobolów-Turbaczyk thrust sheet, 5 - Bystrica Subunit, 6 - R ac a Subunit, 7 - Siary Subunit, 8 - Grybów U nit, 9 - D ukla U nit, Silesian & Sub-Silesian units, 10 - M iocene onto th e C arpathians, 11 - M iocene andesites, 12 - faults, 13 - sam pled area,

14 - isobathe o f M agura N appe overthrust, 15 - boreholes, 16 - geological cross-section

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MSZANA DOLNA AND SZCZAWA TECTONIC WINDOWS OF TH E WESTERN CARPATHIANS 341

Fig. 1. Tectonic map o f th e N orthern C arpathians [compiled by Os z c z y p k o-Cl o w e s2001); 1 - crystalline core of the Tatra Mts., 2 - H igh Tatra and sub-Tatra units, 3 - Podhale flysch, 4 - Pieniny Klippen Belt, 5 - M agura N appe, 5a - Malcov Formation, 6 - Grybów Unit, 7 - Dukla Unit, 8 - Fore-M agura Unit, 9 - Silesian U nit, 10 - Sub-Silesian Unit, 11 - Skole U nit, 12 - Lower Miocene, 13 - M iocene deposits upon the C arpathians, 14 - Stebnik (Sambir) U nit, 15 - Zglobice U nit, 16 - M iocene of the C arpathian Foredeep, 17 - andesite, 18 - studied area; Su - Siary, R u - R aća, Bu- Bystrica, and Ku - Krynica subunits

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Hulina Fonnation

This form ation is known from th e basal portion of the M agura N appe (Poręba-K oniki th ru st sheet, Text-figs 4-5). T he deposits of th e form ation are re p re sented by green, spotty shales and are exposed only on

the slum ped b ank o f the K oninki stream (Text-fig. 3, see also Bu r t a n & al. 1 9 7 8 , Bi r k e n m a j e r &

Os z c z y p k o 1 9 8 9 ) . T he thickness o f these deposits, reduced tectonically, does n o t exceeds 5 m. T he H ulina F o rm atio n is d ated for th e ?A lbian-C enom anian ( Ma l a t a 2 0 0 1 ) .

Fig. 3. Geological m ap o f the southern p art of Mszana D olna tectonic window (after Bu r t a n & al. 1976, Os z c z y p k o & al. 1999b, changed and supplem ented), D ukla U nit; K rosno Beds (Oligocene): 1 - thick-bedded sandstones, 2 - sandstone-shaley facies, 3 - shaley facies; Grybów Unit: 4 - Grybów U nit, undi

vided, 5 - M enilite Beds (Oligocene); M agura N appe: 6 - Albian-Cenom anian deposits, 7 - Cenom anian-Pälaeocene udivided; Eocene: 8 - Łabowa Form ation, 9 - Zarzecze Form ation, a - variegated shales, 10 - Beloveza Formation, 11 - Bystrica and Żeleźnikowa formations, 12 - M agura Formation, 13 - Krynica Subunit (Palaeocene-Eocene), 14 - Grybów overthrust, 15 - M agura overthrust, 16 - Bystrica overthrust, 17 - Bystrica Subunit internal overthrusts,

18 - Krynica overthrust, 19 - faults, 20 - borehole, 21 - cross-section

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Malinowa Shale Formation

The Hulina Formation is overalaid by variegated, mainly red shales of the Malinowa Formation, which usu

ally form the base of the M agura N appe sequence (Bi r k e n m a j e r & Os z c z y p k o 1989; Ma l a t a & Os z c z y p k o 1990). In the Poręba Góma-Koninki-Lubomierz area the thickness of this formation is at least 30 m (Text- figs 4-7). In the Koninki section the Malinowa Formation is of the Turonian-Santonian age (Ma l a t a2001).

Kanina Beds

The Campanian-Palaeocene turbiditic deposits, over

lying the Malinowa Formation, followed by the Early

Eocene variegated shales of the Łabowa Formation, are traditionally referred to as the “Inoceram ian Beds”, though the nam e Ropianka Beds has also been used. O n the southern margin of the MDW, these deposits may fur

ther be subdivided lithostratigraphically ( Os z c z y p k o

1992, Os z c z y p k o & al. 1999b; see also Bu r t a n & al.

1976, 1978). In the Olszówka-Lubomierz area these deposits are 100-250 m thick and can be subdivided into three members.

The lower member ( = K anina Beds) (see B urtan 1976, 1978; O s z c z y p k o 1992, O s z c z y p k o & al. 1999b) is com posed of thin- to m edium -bedded, very fine to fine-grained calcareous sandstones, displaying B oum a’s Tbc, T c+ conv turbidite intervals. T he basal portion of the

Fig. 4. G eological cross-section through the southern m argin o f th e M szana D olna tectonic window, along the Poręba G órna stream ; 1 - spotty shales, 2 - variegated shales, 3 - spherosiderites, 4 - m arls, 5 - turbidite limestones, 6 - calcareous shally flysch facies, 7 - black m arly sheles, 8 - thin to m edium - b ed d ed turbidites, 9 - thick-bedded sandstones, 10 - subm arine slumps, 11 - chaotic deposits, 12 - M agura overthrust, 13 - Grybów thrust, 14 - fault, 15 - sample, 16 - lithostratigraphic units: 1 - H ulina Formation, 2 - Malinowa Shale Form ation and Haluszowa Formation, 3 - K anina Beds, 4 - Szczawina Ss., 5 - R opianka Beds, 6 - Łabowa Shale Form ation, 7 - Beloveza Form ation, 8 - Bystrica Form ation, 9 - Żeleźnikow a Form ation, 10 - Maszkowice

M em ber of the M agura Form ation, 11 - Jaworzynka Beds, 12 - Grybów Beds, 13 - Cergowa Beds, 14 - K rosno Beds

Fig. 6. Geological cross-section through the southern margin of the Mszana Dolna tectonic window, along the Mszanka stream (For explanation see Text-fig. 4)

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m em ber is com posed of a few m etres of green-grey non- calcareous shales (Text-fig. 7). T he middle p art of the sequence is dom inated by dark-grey m udstone/siltstone couplets and very fine, thin-bedded muscovite sand

stones. T he u pper p art of this sequence is com posed of

thin- to m edium -bedded sandstones, intercalated by dark grey silt/shelly couplets, green/yellowish if w eath

ered. T he yellowish siltstones are often calcareous and strongly b io tu rb a te d (H e lm in th o id a facies see

Ci e s z k o w s k i & al. 1989). In th e Poręba G órna section

Fig. 7. Lithostratigraphic logs of Cretaceous-Palaeocene of the K oninki-Poręba G orna thrust sheet (R aca Subunit); 1 - spotty shies, 2 - red shales, 3 - green shales, 4 - grey shales, 5 - turbidite limestones, 6 - slurry structure, 7 - palaeotrasport direction

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the K anina Beds, with a few thin intercalations of red shales, resem ble th e H aluszow a F o rm a tio n (see

B i r k e n m a j e r & O s z c z y p k o 1989) from the Zasadne section ( M a l a t a & O s z c z y p k o 1990). T he lower m em b e r contains intercalations of tu rb id ite lim estones

( C i e s z k o w s k i & al. 1989). In th e Poręba G órna section (PKTS) frequent intercalations of turbidite lim estones have been observed in the upper p art of th e Beds (ca 12

15 cm thick). T he thickness of th e lower m em ber varies from around 10 m in Poręba-Koninki to around 50 m in the K onina-Lubom ierz thrust-sheets (Text-figs 7-8, see also O s z c z y p k o & al. 1999b). It reveals a coarsening- and thickening-upward sequence, and contains heavy zircone-tourm aline-rutile m inerals, som etim es w ith chrom ite spinels (Lubom ierz section, see S a l a t a 2003) displaying palaeotransport from the SE. T he age of the lower m em ber, based on foram iniferal studies, is early- m iddle C am panian ( B ą k & O s z c z y p k o 2000, M a l a t a

2001).

The middle member ( = Szczawina Sandstones): The K anina Beds are followed by thick-bedded sandstones and granule conglom erates, commonly known as the Szczawina Sandstones. In the Poręba G órna section these sandstones, up to 20 m thick, reveal im portant sedimentological differences betw een th e Koninki and

E

LUBOMIERZ KONINA

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Poręba G órna sections (Text-fig. 7). In th e Koninki sec

tion th e beds are represented by 5-8 m thick, fining and thinning upw ard sequences. T he lower p art o f the sequence (3-4 m thick) is com posed of thick-bedded sandstones (0.50-1.5 m ), very coarse to m edium - grained, som etim es am algam ated with T ab intervals. In this section th e thick-bedded sandstones (partly glau

conitic) reveal some similarities to th e thick-bedded sandstones of th e Jaworzynka Beds in the Grybów U nit, and display p alaeotransport from the N W and from th e SE. In th e Poręba G órna section (Text-fig. 7) the Szczawina Sandstones are dom inated by thick and very thick-bedded (0.4-2.5 m), m edium - to very coarse

grained sandstones with w eak carbonate cem ent. T he basal p art of the beds is com posed o f light-coloured quartz-glauconitic, coarse-grained sandstones. A t the top o f th e beds occur grey, calcareous sandstones and m udstones, rich in flakes of muscovite and coalified plants. T he muscovite sandstones display palaeotrans

p o rt from th e SE.

In all o f th e studied sections o f th e K onina- Lubom ierz thrust sheets th e thickness o f the Szczawina Sandstones reached 100 (125) m etres (Text-fig. 8).

T hese sections are dom inated by thick-bedded muscovitic sandstones, which display palaeotransport from

Fig. 8. Lithostratigraphic section o f the Konina-Lubom ierz thrust sheet (Bystrica Subunit of M agura Nappe), after Os z c z y p k o & al. (1999b); 1 - red shales, 2 - turbidite limestones, 3 - turbidite marls, 4 - hornstones, 5 - thin-to m edium -bedded turbidites, 6 - thick-bedded turbidites, 7 - thick bedded sandstones and conglomerates, 8 - palaeotransport direction, 9 - litostratigraphic units: 2 - M alinowa Shale Form ation and Haluszowa Form ation, 3 - K anina Beds, 4 - Szczawina Sandstones, 5 - R opianka Beds, 6 - Łabowa Shale Form ation, 7 - Beloveza Form ation, 8 - Bystrica Form ation, 9 - Żeleźnikowa Formation,

10 - Maszkowice M em ber of the M agura Form ation

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the S and SE and contain heavy zircone-tourm aline- ru tile m inerals ( S a ł a t a 2003). T he Szczawina Sandstones are of the ?M aastrichtian-Palaeocene age (see O s z c z y p k o 1992, M a l a t a & al. 1996, M a l a t a 2 0 0 1).

The upper member: The upperm ost m em ber of the

“Inoceram ian Beds” belongs to the R opianka Beds (Palaeocene) and is com posed of fining- and an thin

ning-upward sequence of thin-bedded turbidites with a few thin intercalations of variegated shales. T heir thick

ness varies between 50 and 80 m etres (Text-fig. 8). The flute casts reveal palaeotransport from the SE, and con

tain th e heavy zircone-tourm aline-rutile m inerals

( S a l a t a 2003).

According to Bu r t a n & al. (1976, 1978) the north

ern slopes o f the G orce Range are com posed of the E ocene deposits of th e Bystrica Subunit (Szumiąca- Frączkow a-L ubom ierz th ru st sheet). H ow ever, th e results o f Os z c z y p k o & al. (1999b) docum ented the presence of two sequences, approxim ately of the same age: K onina-Lubom ierz (N) and Tobołów-Turbaczyk (S). In this pap er only the Konina-Lubom ierz sequence will be discussed.

Łabowa Shale Foimation

D eposits belonging to the Łabowa Shale Form ation of the Palaeocene-Low er E ocene age (see Os z c z y p k o

1991, Os z c z y p k o & al. 1999b) occur in a narrow belt betw een Olszówka and Lubom ierz (Text-fig. 3). The lowerm ost portion of the form ation is represented by a few m etres o f red shales passing upwards into very fine- bedded turbidites. Very fine-grained, green, carbonate- free sandstones (Tc) pass upwards into green shales, and finally to a few cm of red shales, mainly soft and free of carbonate. In the Poręba G órna section the lowermost part of this form ation contains one or two layers of thick-bedded sandstones (up to 2 m) and intercalations o f grey marls. T he thickest sandstone bed reveals palaeotransport from ESE. T he thickness of the form a

tion attains up to 50 m.

Beloveza Formation

This form ation is dom inated by thin- to medium- bedded turbidites (Tc+conv and Tcd). The vari-coloured shales distinctly prevail over sandstones. The yellowish and brown shales are usually calcareous, while th e green ones are, as a rule, carbonate-free. The accompanying m edium -bedded Tbc sandstones (20-40 cm) appear less frequently. T he thickness of the Early-M iddle Eocene Beloveza Form ation ( Os z c z y p k o & al. 1999b) reaches 50 to 120 m (Text-fig. 8).

Bystrica Formation

This M iddle E ocene form ation ( Os z c z y p k o 1991,

Os z c z y p k o & al. 1999b) is well seen in morphology, forming W -E trending round-off hills. It is com posed of thick-bedded sandstones with intercalations of Łącko marls. The sandstones, 80-200 cm thick, are massive, m edium to coarse-grained, glauconite/m uscovite with cem ent free of carbonate. T he flute-casts reveal palaeo

transport from the SW. T he sandstone layers pass into massive marls, sometim es silicified, brown o r blue-to- grey and whitish, w hen w eathered. T he thickness of the individual beds of th e Łącko marls ranges from 2 to 5 m.

In th e Koninki section (Text-figs 3, 8) the marls contain 1-20 cm intercalations of black hornstones. The thick

ness of the form ation is up to 150 m (Text-fig. 8).

Zeleźnikowa Foimation

The equivalents of the M iddle E ocene Zeleźnikowa F orm ation (see Os z c z y p k o 1991, Os z c z y p k o & al.

1999b) have been found in a few stream sections east of th e Koninki stream . As a rule, these deposits occur betw een the Bystrica Form ation and th e Maszkowice M em ber of the M agura Form ation. They are com posed o f th e thin- to m ed ium -bedded tu rb id ites o f th e Beloveza lithofacies with num erous intercalations of Łącko marls. T he thickness of the form ation is up to 50 m etres (Text-fig. 8).

Magura Formation - Maszkowice Member

T he M iddle E ocene Maszkowice M em ber (see

Os z c z y p k o 1991, Os z c z y p k o & al. 1999b) is exposed exclusively in the Lubomierz and Konina sections (Text- figs 2-3,8). This m ember is represented by thick and medi

um-bedded muscovite sandstones with infrequent interca

lations of Łącko marls. The sandstones are 0.4-2.0 m thick, medium- to coarse-grained, muscovite with ilhte-carbonate cement. They are massive, sometimes amalgamated and often contain muddy intraclasts and coalified flakes in the upper portion of the member. The intercalations of the Łącko marls range from 0.8 to 2.0 m in thickness. The marls are greyish and whitish if weathered. In the Konina section thick-bedded sandstones and marls are followed by a 60-100 m sequence of thin- to medium-bedded sand

stone/marly turbidites. The tectonically reduced thickness of the Maszkowice M ember is up to 200 m. The flute casts reveal palaeotransport from the SE (Text-fig. 8).

Grybów Unit

T he Grybów U nit o f th e M D W occurs as an erosional outliers at the top of the elevated p art of the

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MSZANA DOLNA AND SZCZAWA TECTONIC WINDOWS OF THE WESTERN CARPATHIANS 347

D ukla U n it as well as a narrow thrust sheet edged betw een the D ukla and M agura units along the south

ern m argin of th e tectonic window. T he tectonically reduced succession of the Grybów U nit of th e M DW is com posed o f the Low er C retaceous to O ligocene deposits. According to Bu r t a n & al. (1976, 1978, 1992a) the Grybów unit is com posed of the following strata: Lgota Beds (Albian-Cenom anian), Inoceram ian (Cisna) Beds (Senonian), Jaworzynka Beds (Senonian- Palaeocene), black shales with siderites (Palaeocene), variegated and green shales (Eocene), dark shales and glauconitic sandstones (“black E ocene”, see Bu r t a n &

al. 1992a); Ł użna-K oniaków lim estones (E ocene), M enilite shales with thick-bedded sandstones at th e top (O ligocene), and K rosno B eds-shales (O ligocene), known also as Cergowa Beds ( Bu r t a n & al. 1992a).

M ajority of these divisions are known only from the syn

clinal erosional outlier n ear Podobin (Text-fig. 3), though their ages w ere assumed based only on lithologi-

cal analogies. O n th e geological m ap ( Bu r t a n & al.

1976) th e majority of the geological boundaries display a tectonic character. According to Bu r t a n & al. (1992a) th e total thickness o f th e Grybów U nit reached around 1500 m. In th e studied sections (P oręba W ielka, Koninki, D om agalow y stream s, K onina and Lubom ierz) th e total thickness of the Grybów U nit is a few times smaller. This concurs with Ma s t e l l a (1988) in so far that, in these areas, we could only determ ine two lithostratigraphic units.

Jaworzynka Beds

In the Koninki, Poręba G órna and Lubom ierz sec

tions (Text-figs 3, 9) the basal p art o f the Grybów U nit is com posed of the Jaworzynka Beds, represented by 30

50 m thick packets of fine conglom erates and thick-bed

ded, biotite-feldspar sandstones, with intercalations of

Fig. 9. Litostratigraphic logs of th e Grybów U nit in the Mszana D olna tectonic window; 1 - thick-bedded, feldspare-glauconite sandstones, 2 - thick-bedded, muscovite sandstones, 3 - marly claystones and m udstones with intercalations of very thin- bedded sandstones, 4 - dark-gray lam inated marly m udstones and black shales with intercalation of very thin-bedded sandstones, 5 - dark-gray massive marls, 6 - lam inated marls, 7 - dark-grey non-calcareous mudstones,

8 - black and brown M enilite type shales, 9 - siderites, 10 - sub-m arine slump, 11 - paleocurrent dirrection, 12 - samples localites

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dark, non-calcareous m udstones and siltstones. In the K oninki section th ese Beds contain P alaeocene foram inifers (E. Ma l a t a, personal inform ation, 2002).

The sandstones reveal palaeotransport from the NW, and contain heavy zircone-tourm aline-rutile minerals

( Sa l a t a 2003). H igher up in the sections occur strongly deform ed dark shales and m icaceous m udstones (Text- fig. 10A) with intercalations of thin- to thick-bedded,

muscovite sandstones and sporadic intercalations of siderites. This p art of the sequence probably can be cor

related with “Palaeocene shales and sandstones with siderites” (see Bu r t a n & al. 1992a).

The second thrust-sheet of the Koninki section is com posed probably exclusively o f th e P alaeocene deposits. The lower p art of the thrust-sheet is re p re sented by im bricated folds com posed of thick-bedded,

Fig. 10. A -B la c k shales with intercalations of thin-bedded, very fine-grained sandstones (Tc turbidite) of the lower part of the Grybów Beds (Oligocene). Giybow U nit - Poręba G órna stream (see Text-fig. 4); B - Strongly tectonized dark grey marly shales with intercalations of thin-bedded, calcareous sandstones of the upper part of Grybów Beds (Oligocene). Grybów Unit-Koninki stream (see Text-fig. 5); C - D ark calcareous mudstones with intercalations of thin-bedded, calcareous sandstones o f the upper part of the Grybów Beds (Oligocene). Poręba G órna stream (see Text-fig. 4); D - Very fine, thin-bedded calcareous sandstones of the

the Cergowa Beds (Late Oligocene). Giybow Unit, Mszanka stream at Lubomierz (Text-fig. 6).

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coarse-grained sandstones and rich in muscovite flakes.

T he sandstones are intercalated with black, non-calcareous shales with a siderite layer. The sandstones are followed by black, poorly calcareous shales with spo

radic intercalations of very thin-bedded sandstones and siltstones. A ccording to Bu r t a n & al. (1976, 1978) these shales belong to shaley facies of th e Krosno Beds (Oligocene). U nfortunately, num erous samples taken

by authors for nannofossil investigations from these Beds were sterile (Text-figs 5, 9). Since Palaeocene foram inifers w ere determ ined two hundred m etres higher up in th e section (E. Ma l a t a personal inf., 2002) in the sam e beds b en eath the Poręba-Koninki TS of the M agura N appe (Text-figs 5, 9). In our opinion

“Shaley facies of the K rosno” belong to th e Jaworzynka Beds of the Grybów succession.

Fig. 11. A - D a rk grey, m arly shales o f the upperm ost p art o f th e K rosno B eds (O ligocene) o f the D ukla U nit. K onina stream (Text-fig. 3); B - Left bank o f the K oninki stream (150 m below the Grybów th ru st) - shally facies o f th e K rosno Beds (O ligocene) o f th e D ukla U n it (Text-fig. 3); C - Base o f th e M agura thrust-breccia o f the ? K anina Beds (C am panian). K oninki stream (Text-fig. 4); D - C haotic deposits (U p p e r C retaceous) in the basal p a rt of the M agura N appe (P oręba B eds-tectonic m elange, see Bu r t a n & Ły d k a 1978, Bu r t a n& al. 1978). P oręba stream around 15 m above th e M agura

thrust (Text-fig. 4)

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Grybów Beds

In th e Koninki section the Jaworzynka Beds are bounded tectonically by a repetition of dark and grey, lam inated, marly mudstones, intercalated by thin- and medium - bedded, fine-grained, calcareous sandstones and thin-bedded siderites of the Grybów Beds (Text-fig.

10B). In th e Poręba G órna section the lower portion of the Grybów Beds are developed as black, non calcareous

Fig. 12. Lithostratigraphic log o f D ukla U n it in M szana D olna tectonic window (based on Bu r t a n& al. 1978, supplem ented); 1 - thick-bedded, feldspare-glauconite sandstones, 2 - thick-bedded, m uscovite sand

stones, 3 - grey, marly claystones and m udstones w ith intercalations of very thin- bed d ed sandstones, 4 - dark-grey non calcareous m udstones, 5 - variegated shales, 6 - black shales, 7 - hornstones, 8 - siderites,

9 - paleocurrent direction, 10 - location of samples

shales with intercalations o f thinl-bedded sandstones with a SW dipping block of massive, muscovite sand

stone of the Cergowa type. H igher up in the section, the upper portion of the Grybów Beds are represented by black shales and marly m udstones with intercalations of thin-bedded sandstones and thick-bedded dark, calcare

ous m udstones (Text-fig. IOC) with siderite nodules (Text-figs 4-5, 9). In the Lubom ierz section deposits of the Jaworzynka Beds type are tectonically bounded by a 50 m thick succession of dark grey, calcareous, mus

covite m udstones with intercalations of very thin-bedded sandstones. Subordinately, thick-bedded sandstones are also observed (Text-fig. 6). These are massive, mus

covite-glauconitic sandstones, up to 2 m thick and are very coarse to coarse. The upperm ost part of th e section is dom inated by dark-grey marls with intercalations of very fine, thin-bedded, parallel lam inated, muscovite sandstones (Text-fig. 10D). T hese deposits resem ble the Cergowa Beds from the Szczawa section.

Dukla (Obidowa - Słopnice) Unit

T he oldest C retaceous-P alaeocene and E ocene deposits of th e D ukla U nit are known exclusively from the boreholes (Text-figs 3, 12-13): P oręba W -l, Poręba W -IG1 ( Bu r t a n & al. 1978) and N iedźwiedź-1

( Po ł t o w i c z 1985). According to Bu r t a n & al. (1992a, b) these deposits are represented by: th e Senonian- Palaeocene Jaworzynka Beds (“Inoceram ian” Beds in the b io tite facies), varieg ated shales (P alaeocene- M iddle Eocene), Hieroglyphic Beds (M iddle/U pper E o cen e), “Black U p p e r E o c e n e ” and M enilite (Grybów ) B eds w ith h o rn sto n e in tercalatio n s (Oligocene).

Krosno Beds

T he Oligocene K rosno Beds are well known from the surface exposures (Text-fig. 3). These deposits gen

erally dip towards th e SE. T he lower p art o f this form a

tion is com posed of grey, fine- to m edium -grained, m edium- to thick-bedded (up to 1. 5 m), calcareous sandstones of the Cergowa type with intercalations of dark-grey, marly shales and subordinate siderites (8-12 cm thick). T he m edium -bedded sandstones display mainly Tbc Boum a intervals and palaeotransport from W SW (exposures are observable in the cliff, on the left bank of the M szanka stream in the northern p art of the village of Niedźwiedź). T he m ost frequent lithofacies of th e Krosno Beds are represented by thin- to medium- bedded turbidites. The u pper portion of the Krosno Beds, at least 450 m thick, belongs to dark-grey marly m udstones with sporadic intercalations of thin- to m edi

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um -bedded, muscovite, calcareous sandstones (Text-fig.

11A, B). T he base of th e Krosno Beds was reached at depths between 1355 and 1591 m in the Niedźwiedź 1 and Poręba W ielka IG-1 boreholes, respectively (Text- figs 2 , 13). The total thickness of these Beds in M DW is at least 2000 m. The base of the D ukla U nit was pierced in th e Niedźwiedź 1 borehole at 2790 m, which term i

nated at a depth of 4478.3 m in the U pper C retaceous- Palaeocene flysch deposits, which probably belonged to the Silesian U nit (Text-fig. 13).

Structure of the southern margin of the Mszana Dolna tectonic window

The studied area is located in the middle part of the M agura N appe on th e southern m argin of the M DW and about 15 km south of the front of the nappe (Text- fig. 2). The M agura N appe is very flatly overthrust onto the Oligocene Krosno Beds of M DW (see Bu r t a n & al.

1978, Ma s t e l l a 1988).

T he relationships betw een the D ukla, Grybów and M agura units can be observed along the southern m ar

gin of the MDW. T he best contact exposures are locat

ed in th e Poręba G órna, K oninki and Lubom ierz sec

tions (Text-figs 4-6). In these sections (100-300 m in length) one or two thrust-sheets of th e Grybów U nit are edged betw een th e D ukla and M agura units. The Grybów U nit is separated by th e two m oderately inclined or sub-horizontal, south deepening th ru st su r

faces.

In the Koninki stream the upperm ost part of the D ukla sequence is com posed of th e Krosno Beds shaly facies. Towards the south the beds reveal an increasing degree of tectonic deform ation (Text-fig. 11B) of m eso

scopic, thrust-fault propagating folds to a few m eter thick breccia zone of shales with sandstone lamps. In this section the Grybów U nit is built up of two thrust- sheets com posed o f the Jaworzynka Beds (Palaeocene) and the Grybów Beds (Oligocene, see Text-fig. 11B).

The contact of the Grybów and M agura units is m arked by a zone of strongly brecciated rocks (Text-fig. 11 C).

Fig. 13. Geological cross-section Obidowa IG 1 - Niedźwiedź 1 boreholes (based on Polish Geological Survey m aps ( Bu r t a n & al. 1976, Ci e s z k o w s k i1985, Po ł t o w i c z1985); D ukla Unit: 1 - U p p er Cretaceous-Palaeocene, 2 - sub-menilite Eocene, 3 - M enilite Beds (Oligocene); K rosno Beds (Oligocene):

4 - thick-bedded sandstones and sandstone-shaley facies, 5 - shaley facies; Grybów Unit: 6 - Grybów U nit undivided, 7 - Jaworzynka Beds, 8 - Black Eocene;

M agura Nappe: 9 - A lbian-Cenom anian deposits and M alinowa Shale Form ation (Thronian Santonian), 10 - C am panian-Palaeocene (Kanina, Szczawina and R opianka Beds); 11 - Szczawnica Form ation (Palaeocene-Lower E ocene), Eocene: 12 - Łabowa Form ation, 13 - Zarzecze Form ation, a - variegated shales, 14 - Beloveza Form ation, 15 - Bystrica and Żeleźnikowa form ations, 16 - M agura Form ation, 17 - Dukla overthrust, 18 - Grybów overthrust, 19 - M agura

overthrust, 20 - faults, 21 - boreholes

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In the lower course (Text-figs 3-4) of the Poręba G órna stream section, the basal portion of the Grybów U n it begins with blocks of the Jaworzynka Beds (Palaeocene), passing upwards into the Grybów Beds, which display num erous NWN-SES to N-S trending, mesoscopic, sub-vertical thrust-fault propagating folds.

T he southerly deepening D ukla and Grybów units have been found beneath the M agura Nappe, in the Obidowa IG-1 borehole (Text-fig. 13, see also Ci e s z k o w s k i1985).

B etw een Olszówka and L ubom ierz th e fro n tal p art o f th e M agura N appe consists o f th re e thrust-sheets

which contain characteristic sequences o f deposits

( Os z c z y p k o & al. 1999b). F rom th e n o rth to th e so u th th ese are: P o ręb a W ielka-K oninki (A lbian- P alaeo cen e), K o n ina-L ubom ierz (T uronian-M iddle E o ce n e) and Tobolów -Turbaczyk (L o w er-M id d le/

?U p p er E ocene) th rust-sheets (Text-figs 3, 11). The lower, P oręba W ielka-K oninki thru st-sh eet belongs probably to th e R a ca Subunit. T he basal p o rtio n of th e P oręba W ielka-K oninki th ru st-sh ee t reveals a com plex o f ch a o tic type “m e la n g e ” d e fo rm a tio n (Text-figs 4-5), described by Bu r t a n & Ły d k a (1978,

Fig. 14. A - T h e chaotic deposits o f the Poręba B eds with two-type of boundaries; fluidal-and shear fracture plane boundaries. P oręba G órna stream -around 20 m above the M agura thrust (Text-fig. 4); B - T he upper “stratified” part of the Poręba Beds. Poręba G órna stream - around 40 m above the M agura thrust (Text-fig. 4); C - Recum bed fold o f the u p p er p a rt o f the M alinowa Form ation (T uronian-Santonian) o f the Poręba-K oninki thrust-sheet. Poręba G ó rn a stream (Text-fig. 4); D - T he right bank o f the M szanka stream at Lubom ierz. T he K anina Beds (C am panian) o f the K onina-Lubom ierz thrust sheet

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see also Bu r t a n & al. 1978) as t h e P oręba W ielka Beds ( “wild f l y s c h ” ) .

In the Poręba W ielka section the M agura N appe (Poręba-IConinki thrust-sheet) begins with a SW dip

ping (inclination is around 30°) sole trust, com posed of a 3 m thick packet of m edium -bedded sandstones and grey-greenish shales. This stratified unit is covered by a 40-50 m thick complex of chaotic deposits (Text-fig.

H D ; Text-fig. 14A), known as the Poręba W ielka Beds of the Turonian-Senonian age (see Bu r t a n & al. 1978).

These deposits contain fragm ents of blue-greyish, m edi

um -grained non-calcareous sandstones o f various size (from 1 cm to 1.5 m boulders) and shape, which are dis

persed in a green-greyish and dark-greyish, non-calcareous, clay-claystone matrix. A m ong sandstone fragments, small lumps of drag-folds have been observed. The sandstone fragm ents show primary fractures, often with calcite mineralization. The sandstone blocks and shales sometim es reveal the rem nants of prim ary stratification (Text-fig. 14B). T he chaotic deposits occur in layers ranging from a few cm up to 0.5 m thick, with two types of boundaries; fluidal- and shear fracture plane bound

aries. T he shear plane-type boundaries are accom pa

nied by calcite veins. B oth types of boundaries are gen

tly dipping and are alm ost parallel to each other towards th e N E and SW in the basal and top p art of the chaotic body, respectively. T hese sub-horizontal planes are cut occasionally by W -E trending sub-vertical, south dipping inverse faults with calcite m ineralization. The lower, strongly chaotic p art is covered by the upper, less chaotic p art with a m ore frequent, primary type of strati

fication. Towards the top of this unit, random -dispersed sandstone fragm ents are progressively replaced by boudin-like fragments.

T he Poręba W ielka Beds are tectonically followed upw ard by the 50 m thick unit, characterized by an occurrence at outcro p scale, N W N -SES trending recum bed and im bricated folds (Text-fig. 14C) o f the M alinowa Form ation (Turonian-Santonian) and K anina Beds (Cam panian). This unit passes into the steep, south-west dipping, thin-bedded flysch of the Kanina B eds and th ick-bedded Szczawina S andstones (M aastrichtian-Palaeocene). T he sandstones reveal a brittle-typed deform ation, with num erous small-scale W -E and W N W -ESE trendings, and S-SWS dipping inverse faults. T he Szczawina sandstones are followed by strongly tectonized R opianka Beds (Palaeocene) with a degree of deform ation the same as th a t from the Poręba Beds. T he R opianka Beds are overthrust by the M alinowa Shale F orm ation (Turonian-Santonian) and com pose a basal p o rtio n of th e B ystrica Subunit sequence.

The front of the Bystrica Subunit is built up o f the next Konina-Lubom ierz thrust sheet, which is 1.5-2 km

wide and forms a m oderately south-dipping homocline (Text-figs 2-6; Text-fig. 14D). Along this thrust, num er

ous mesoscopic W NW -ESE and NW -SE trending folds have been observed. A t th e boundary betw een the com plexes with different com petence, inverse faults, paral

lel to th e fro n ta l th ru st, have b ee n d ocum ented

( Os z c z y p k o & al. 1999b). T hese caused a reduction in th e thickness of th e Łabowa and Beloveza formations.

T he Tobołów-Turbaczyk thrust sheet of th e Bystrica Subunit is characterized by th e strongly deform ed Z arzecze F o rm atio n and south-dipping M agura Form ation. T he Tobolów-Turbaczyk thrust sheet is over

thrust by the Krynica Subunit, com posed of Palaeocene- E ocene deposits o f the Szczawnica, Z arzecze and M agura form ations (see Os z c z y p k o & al. 1999b). All of these M agura N appe subunits have been pierced in the Obidowa IG-1 borehole, which is located 15 km SW from the m argin of th e M szana D olna tectonic window (Text-fig. 13).

SZCZAWA TECTO N IC W IN D OW

The M szana D olna and Szczawa tectonic windows belong to the same, m ost highly elevated zone in the M agura N appe (Text-fig. 2). T he Szczawa tectonic win

dow is situated 15 km SE of th e M szana D olna, within the NW -SE trending elevation th a t is bounded by a NW-SW transversal fault (Text-fig. 15). T he triangular

shaped, tectonic window (ca. 1.1 sq km) is com posed of th e O ligocene deposits o f th e Grybów U nit. T he Grybów U n it dips below th e U p p e r C re ta c e o u s- Palaeocene deposits of th e M agura N appe ( Ch r z ą s t- k o w s k i1971; Pa u l 1980, Ci e s z k o w s k i& al. 1987,1989;

Os z c z y p k o & al. 1991). T he M agura thrust surface dips steeply towards the south but flatly to the west, not exceeding 7° (Text-figs 15-17, see also Os z c z y p k o & al.

1991). In the SZCZAW A IV borehole, on th e w estern periphery of the window, the Grybów U n it was pierced at a depth of 97 m in th e Kam ienica valley.

Magura Nappe

T he Szczawa tectonic window is located inside the Bystrica Subunit. O n account of this, th e stratigraphy of the Bystrica Subunit in the Szczawa and M szana D olna areas is generally th e sam e. For this reason, th e Turonian-Palaeocene deposits will be described just briefly.

In th e studied area, th e oldest deposits of th e Bystrica S ubunit o f th e M agura N appe belong to th e u p p er p a rt o f th e M alinow a Shale F o rm atio n (see

Os z c z y p k o & al. 1991). T he lowest p a rt o f the fo rm a

tion is known from th e Z asa d n e section, located 3-4

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Fig. 15. Geological m ap o f the Szczawa tectonic window; 1 - M agura N appe: Tiironian-Palaeocene 1 - M alinowa Shale Form ation (Turonian-Santonian), 2 - K anina Beds (Cam panian), 3 - Szczawina Sandstones (M aastrichtian), 4 - Ropianka Beds (M aastrichtian-Palaeocene), a - varigated shales; Grybów Unit:

5 - E ocene variegated shales; U p p er Eocene-O ligocene: 6 - Grybów B eds - black non calacareous shales, a - hornstones, 7 - black and grey m arly shales and marls, 8 - Cergowa Beds- grey m arls and thick-bedded sandstones, 9 - deep and strike, 10 - overthrust, 11 - faults, 12 - borehole, 13 - cross-section,

14 - samples localites, 15 - m ineral springs

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MSZANA DOLNA AND SZCZAWA TECTONIC WINDOWS O F TH E WESTERN CARPATHIANS 355

km SE o f Szczawa. In this section th e age o f th e fo r

m ation was determ in ed as L a te T uronian-Santonian

( Ma l a t a & Os z c z y p k o 1990, Ci e s z k o w s k i & al.

1999). This form ation is com posed of red, non-calcareous shales, w hich are overlain by graded calcare

ous m arls w ith re d in te rc a la tio n s (H aluszow a F orm ation, see Ma l a t a & Os z c z y p k o 1990) o r by thin- to m edium -bedded flysch deposits o f th e K anina Beds (C am panian) w ith intercalations o f turbiditic lim estones ( Ci e s z k o w s k i & al. 1989). T he H aluszow a F orm ation contains to u rm aline/zircone/apatite/garnet spectrum o f heavy m inerals ( Ci e s z k o w s k i & al. 1999).

T he H aluszow a/K anina Beds, up to 100 m thick, dis

play p alae o tra n sp o rt from th e SE and are overlain by thick-bedded, Szczawina S andstones (M aastrichtian- Palaeocene). T he beds are com posed of 0.5-4.0 m thick beds, of coarse- to m edium -grained, muscovitic sandstones, in te rc a la te d by th in m u d sto n e shales (Text-fig. 18A). In th e Z asad n e section th e Szczawina S andstones are 30 m thick, and display p ala e o tra n s

p o rt from th e SE. T he heavy m inerals are re p rese n ted by g a rn e t/a p a tite /z irc o n /to u rm a lin e an d ru tile

( Ci e s z k o w s k i & al. 1999). T he Szczawina Sandstones, up to 200 m thick are overlain by R o pianka Beds (Palaeocene). T hese Beds are com posed o f thin- to m edium -bedded calcareous, 100-150 m thick. H igher up in th e section occurs a 40-50 m thick series of th e P alaeocene-E arly E ocene variegated shales o f the Ł abow a F orm ation. T he beds are overlain by very th in -b e d d e d tu rb id ite s, 200-400 m thick, o f th e Beloveza F o rm ation of th e E arly-M iddle E ocene age and Bystrica Beds (M iddle E ocene). T he youngest p o rtio n o f th e Bystrica Subunit is rep rese n ted by a coarsening and thickening upw ard tu rb id ite sequence with 1-6 m thick in tercalations o f th e Łącko m arls

( Os z c z y p k o & al. 1991). T he beds belong to th e B ystrica F o rm a tio n (M iddle E o ce n e) an d to th e M aszkowice M em ber (M iddle E o cen e) o f th e M agura F orm ation. T hese lithostratigraphic units are 150-200 and 350-400 m thick, respectively.

Fig. 16. Geological cross-section along the Głębieniec stream in Szczawa; 1 - variegated shales, 2 - hornstones, 3 - spherosiderites, 4 - black and grey lami

nated marls, 5 - grey thick-bedded marls, 6 - black non-calcareous sheles, 7 - thin-to m edium -bedded turbidites, 8 - thick-bedded sandstones, 9 - M agura overthrust, 10 - fault, 11 - samples, 12 - borehole, 13 - lithostratigraphic units: 1 - M alinowa Shale Form ation and Haluszowa Form ation, 2 - K anina Beds,

3 - Szczawina Sandstones, 4 - R opianka Beds, 5 - Giybów Beds - black non-calcareous shales, 6 - black marly shales and marls, 7 - Cergowa Beds

Fig. 17. Geological cross-section along the Kamienica stream in Szczawa. For explanation see Text-fig. 16

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Grybów Unit

Grybów Beds

Similarly to the Poręba Górna-Koninki sections, the succession of the Grybów Beds in the Szczawa tectonic window can be subdivided into two members. The basal part of these Beds is exposed in the lower flow of the

Glębieniec stream (Text-figs 15-16), and developed as black, sometimes brown, massive, non-calcareous shales, with a few 1-2 cm thick intercalations of black hornstones with a FeS2 mineralization. Very thin (1-2 cm) layers of hornstones are exposed in the small road-cut on the right slope of the stream. These shales contain sporadic interca

lations of fine-grained, glauconitic, thin- to medium-bed

ded quartzite sandstones (Text-fig. 18 B). The lower mem-

Fig. 18. A - R ight bank o f the G lębieniec stream in the Szczawa. T he basal p a rt o f the M agura N appe com posed o f m edium to thick-bedded turbidites o f th e Szczawina Sandstones (M aastrichtian - C am panian); B - R ock B eds of the G lębieniec stream in the Szczawa. T h e lower p a rt o f Grybów Beds (O ligocene) - black non-calcareous shales, with thin-bedded quartzitic sandstones; C - T h e basal p o rtion o f th e u p p er p a rt o f the Grybów B eds in the K am ienica stream in Szczawa. Thick-bedded sandstones passing upw ards into thick-layer of dark calcareous m udstones; D - T h e u p p e r m ost p art of the Grybów B eds (O ligocene) in the K am ienica stream section at th e Szczawa. D ar-grey lam inated m arls w ith intercalation o f thin-bedded sandstone

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ber of the Grybów Beds, at least 60 m thick, passes upward into a sequence of dark mudstones, with siderite lenses and intercalations of thick-bedded, dark-grey marls.

T he deposits of the u pper m em ber of the Grybów Beds are very well exposed in th e Kam ienica river (Text-figs 15, 17). The basal part of th e m em ber con

tains intercalations of dark grey, calcareous shales and dark, lam inated m udstones with intercalations of very thin-bedded siltstones and very fine-grained sandstones

(Tbcd, T cd turbidites). H igher up in the section occurs a 75 cm layer of fine- to m edium -grained, quartzite san d stones with T abc+conv intervals (Text-fig. 18C). These sandstones pass upwards into dark-brow n lam inated marls, intercalated by fine-grained, thin-bedded san d stones with cross-ripple lam ination (Text-fig. 18D).

H igher up in the section occur thick-bedded (up to 2. 5 m ) brown and dark, massive or fine-lam inated marls, yellowish or rusted if w eathered. T hese turbidite marls

Fig. 19. A - T he upperm ost p art of the Grybów B eds in the Kamienica stream section at the Szczawa. D ark grey lam inated marls w ith intercalations o f very thin-to thin-bedded sandstones; B - B oundary between the upper p a rt of the Grybów Beds (Oligocene) and thick-bedded sandstone o f th e Cergowa Beds (Oligocene); C - T he left bank o f the K amienica stream in the Szczawa. Thick-bedded sandstones a t the base of the Cergowa B eds (Oligocene); D - Lower portion o f the Cergowa Beds (Oligocene) at the Kam ienica stream section in the Szczawa. Marly shales with intercalations of m edium -bedded sandstones

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Fig. 20. LM m icrophotographs o f calcareous nannofossils from the Oligocene deposits of the M szana D olna and Szczawa tectonic widows. 1 - Braarudosphaera bigelowii sam ple 48/97/N, 2 - Braamdosphaera bigelowii sample 61/02/N, 3 - Coccolithuspelagicus sam ple 43/00/N, 4 - Cyclicargolithus abi- sectus sam ple 31/97/N, 5 - Cyclicargolithus abisectus sam ple 61/02/N, 6 - Cyclicaigolithus abiseclus sam ple 66/02/N, 7 - Cyclicargolithus flońdanas sam ple 39/97/N, 8 - Dictyococcites bisectus sam ple 70/00/N, 9 - Diclyococcites bisectus sam ple 2/01/N, 10 - Dictyococcites bisectus sam ple 70/02/N, 11 - Discoaster tanii sam ple 71/00/N, 12 - Discoaster deflandrei sample 70/02/N, 13 - Helicosphaera compacta sam ple 33/97/N, 14 - Isthmohlithus recum is sam ple 71/00/N, 15 - Neococcolithes dubius sam ple 71/00/N, 16 - Ponlosphaera plana sam ple 47/97/N, 17 - Reticulofeneslra loclcerii sam ple 31/97/N, 18 - Reliculofenesda lock- erii sam ple 47/97/N, 19 - Reticulofenestra umbilica sample 71/00/N, 2 0 -Reticulofeneslra umbilica sample 71/00/N, 21 - Sphenolilhus conicus sam ple 70/02/N, 22 - Sphenolithus conicus sam ple 70/02/N, 23 - Sphenolithus conicus sample 70/02/N, 24 - Sphenolilhus dissimilis sample 70/00/N, 25 - Sphenolithus dissim

ilis sam ple 31/97/N, 26 - Sphenolithus dissimilis sam ple 30/00/N, 27 - Sphenolithus dissimilis sam ple 30/00/N, 28 - Sphenolithus morifonnis sam ple 70/00/N, 29 - Zygrhablithus bijugatus sample 13/01/N, 30 - Zygrhablilhus bijugatus sam ple 33/97/N

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are intercalated with thin layers of black, marly shales and thin-bedded, cross-ripple, lam inated sandstones.

The thick-bedded, coarse-grained massive sandstones have been observed sporadically. T he sandstones dis

play p alaeotransport from the N E (70°). These types of deposits are about 50 m thick and are followed by cou

plets, up to 2 m thick of dark-grey, softy-lam inated m arls and marly shales with sporadic intercalations of very fine-grained, thin-bedded sandstones (Text-fig.

19A-B).

Cergowa Beds

In the middle part of the section (Text-figs 15, 17;

19B-C) occur two layers of very thick-bedded, coarse

grained, channelled, conglomeratic sandstones. These sandstones reveal palaeotransport from the N E (70°). The sandstones are overlain by laminated marls with thin bed

ded sandstones (Text-fig. 19D). The upperm ost part of the section (above the bridge) is composed of dark-grey coloured (yellowish if w eathered), massive, hard marls with sporadic intercalations of thick-bedded, Cergowa- type sandstones. The beds are up to 200 m thick.

CALCAREOU S NANNOFOSSIL

Sample preparation

All samples w ere prepared using the standard sm ear slide technique for light microscope (LM) observations.

The investigation was carried out under LM - Nikon -E clipse E 600 POL, at a magnification o f 1000 x using parallel and crossed nicols. Several of the specimens photographed in LM are illustrated in Text-fig. 20.

Results

The majority o f th e examined samples yielded a very po o r and badly preserved nannofossil m aterial. Some specim ens could not be identified because o f strong etching and m echanical dam age of the placoliths, espe

cially of their central areas. T he abundance of particu

lar taxa is usually low. T he scarcity of the species most im portant stratigaphically makes age determ inations very difficult. However, some of th e samples were rich enough, enabling zonal assignment.

Grybów Beds

In the Grybów Beds nannofossils are poorly p re served and represented by low diversity assemblages

with a low num ber of specimens. N on-calcareous or slightly calcareous shales and m arls are barren of n a n nofossils (Tables 1-2). Relatively rich assemblages are noted exclusively in samples from the Szczawa section.

Rich assemblage was found in sample 71/00/N (Text- fig. 21, Table 1). In other samples m ost of these species are missing. The im portant feature of this sample is the appearance of rare Reticulofeneslra omata. Higher up in the Szczawa section first appears Cyclicargolithus abisec- tus. Additionally, a rich association was found in sample 31/97/N (Text-fig. 21, Table 1).

Cergowa Beds

Again a relatively rich assemblage comes from the samples of the Szczawa section. A low diversity assem blage with a poorly preserved nannofossil association was found in samples from the L ubom ierz section (Text- fig. 21, Table 1). T he m ost im portant species found in both sections is Cyclicargolithus abisectus, accom panied by Cyclicargolithus floridanus, Dictyococcites bisectus, Reticulofenestra lockerii, Reticulofenestm dictyoda and Reticulofenestra omata. A dditionally some o f th e sam  ples from th e Szczawa section contained Helicosphaera euphratis, Helicosphaera compacta, Pontosphaera multi- pora, Pontosphaera plana, Sphenolithus dissimilis and Sphenolithus moriformis. The straigrpahically youngest species, Sphenolithus conicus, was found in th e u p p er

m ost p art of the Cergowa Beds in th e Lubom ierz sec

tion.

Krosno Beds o f the Dukla Unit

Nannofossils o f these units are poorly preserved and are represented by low diversity assemblages w ith a low num ber of specimens (Table 3). The nannofossil associ

ation from sam ple 58/02/N does not contain any zonal m arker. T he o ther samples are characterised by th e co

occurence o f Coccolithus eopelagicus, Coccolithus pelag

icus, Cyclicargolithus abisectus, Cyclicargolithus flori

danus, Dictyococcites bisectus, Sphenolithus moriformis, Zygrhablithus bijugatus. A dditionally samples 30/00/N and 33/00/N contain rare specim ens of Sphenolithus dis

similis.

Biostratigraphical interpretation

For the purpose of biostratigraphic analysis the standard zonation of Ma r t i n i(1971) was used.

T he nannofossil association described form the Grybów Beds enabled the recognition of zones NP22, NP23 and NP24. T he zone NP22 is docum ented by a con

tinuous range of Reticulofenestra umbilica ( Le v i n) follow-