Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 The structural position and tectonosedimentary evolution of the Polish Outer Carpathians Nestor Oszczypko* Ab str act. The sedimentary basins of the Outer Carpathians are regarded as the remnant oceanic basins that were transformed into the foreland basin. These basins developed between the colliding European continent and the intra-oceanic arcs. In the pre-orogenic and syn-orogenic evolution of the Carpathian basins the following prominent periods can be established: Middle Jurassic — Early Cretaceous opening of basins and post-rift subsidence, Late Cretaceous —Palaeocene inversion, Palaeocene to Middle Eocene subsidence, Late Eocene-Early Miocene synorogenic closing of the basins. In the Outer Carpathian sedimentary area the important driving forces of the tectonic subsidence were syn- and post-rift thermal processes as well as the emplacement of the nappe loads related to the subduction processes. Similar to the other orogenic belts, the Outer Carpathians were progressively folded towards the continental margin. This process was initiated at the end of the Palaeocene at the Pieniny Klippen Belt Magura Basin boundary and completed during Early Burdigalian in the northern part of the Krosno flysch basin. Key words: rifting, inversion, subsidence, tectonosedimentary evolution, Outer Western Carpathians The Polish Carpathians are a part of the great arc of mountains, which stretches for more than 1300 km from the Vienna Forest to the Iron Gate on the Danube. In the west the Carpathians are linked with the Eastern Alps, while in the east they pass into the Balkan chain (Fig. 1). Traditionally, the Western Carpathians have always been subdivided into two distinct ranges. The Inner Carpathians are the older range and the Outer Carpathians are the younger (Ksiazkiewicz, 1977). The Pieniny Klippen Belt (PKB) is situated between the Inner and Outer Carpathians. The belt is a Neogene suture zone about 600 km long and 1-20 km wide with a strike-slip boundary (Birkenmajer, 1986). The Outer Carpathians are built up of stacked nappes and thrust-sheets, which reveal a different lithostratigraphy and structure (Fig. 2). Traditionally, three groups of nappes could be distinguished (Ksiazkiewicz, 1977). The Marginal Group consists mainly of folded Miocene rocks, which are well represented at the front of the Eastern Carpathians, whereas the Middle Group (Early/Middle Miocene accre-tionary wedge) consists of several nappes that form the corn of the Western and Eastern Carpathians. The Magura Group (Late Oligocene/Early Miocene accretionary wedge) is flatly overthrust onto the middle group which consists of several nappes: the Fore-Magura-Dukla group, Silesian, Sub-Silesian and Skole units (Fig. 3). In the Outer Carpathians the main decollement surfaces are located at different stratigraphic levels. The Magura Nappe was uprooted from its substratum at the base of the Turo-nian-Senonian variegated shales (Oszczypko, 1992), whereas the main decollement surfaces of the middle group are located in the Lower Cretaceous black shales, with the exception of the Fore-Magura group of units, which were detached at the Senonian base. All the Outer Carpathian nappes are flatly overthrust onto the Miocene deposits of the Carpathian Foredeep (Oszczypko, 1998; Oszczypko & Tomas, 1985). However, along the frontal Carpathian thrust a narrow zone of folded Miocene (marginal group) deposits developed (Pouzdfany, Boryslav-Pokuttya, Steb-nik (Sambir) and Zglobice units). In Poland these are represented mainly by the Zglobice and partially by the Stebnik *Jagiellonian University, Institute of Geological Sciences. 01eandry2a, 30-063 Kraków, Poland; nestor@geos.ing.uj.edu.pl units. The detachment levels of the folded Miocene units are usually connected with the Lower and Middle Miocene evaporites. The basement of the Outer Carpathian is the epi-Va-riscan platform and its cover (Figs 3-4). The depth of the platform basement, known from boreholes, changes from a few hundred metres in the marginal part of the foredeep up to more than 7000 m beneath the Carpathians. The magneto-telluric soundings in the Polish Carpathians have revealed a high resistivity horizon, which is connected with the top of the consolidated-crystalline basement (Žytko, 1997). The top of magneto-telluric basement reaches a depth of about 3-5 km in the northern part of the Carpathians, drops to approximately 15-20 km at its deepest point and then peaks at 8-10 km in the southern part (Figs 5-6). The axis of the magneto-telluric low coincides, more or less, with the axis of regional gravimetric minimum. This was documented by the integrated geophysical modelling along the Rzeszów-Bardejov geotraverse (Fig. 6). South of Krosno this gravimetric low is a result of the combined effect of the thick Carpathian nappes, thick Early Miocene molasses, and possibly the Mesozoic and Paleogene deposits related to passive margin of the European Platform (Oszczypko, 1998; Oszczypko etal., 1998). South of the gravimetric minimum and, more or less parallel to the PKB, a zone of zero values related to of the Wiese vectors was found in geomagnetic soundings (Jan-kowski et al., 1982). This zone is connected with a high conductivity body at a depth of 10-25 km and is located at the boundary between the North European Plate and the Central West Carpathian Block (Žytko, 1997). In the Polish Carpathians, the depth of the crust-mantle boundary ranges from 37-40 km at the front of the Carpathians and increases to 54 km towards the south before peaking along the PKB to 36-38 km (Fig. 5). Main structural units and the problem of the SE prolongation of the Magura Nappe Since the 1970s the principal structural units of the Outer Western Carpathians have been well correlated (see Žytko et al., 1989; Lexa et al., 2002). From the west of the Polish state boundary to the Valaške Mezerice area, where the Silesian Unit disappears, there is a direct continuity of 780 Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 Carpathian foreland Carpathian foredeep molasse Folded Miocene molasse Borislav-Pokuttya Unit Skole/Skyba Unit Sub-Silesian-Zdanice units Silesian-Chornohora Unit DuklaUnit Porkulets Unit ^ Marmarosh Crystalline Massif Magura group of nappes f Pieniny Klippen Belt and other klippes | Tatricum and its sedimentary cover I Veporicum, Zemplinicum, Hronicum, Gemericum, Meliaticum, Turnaicum and Silicicum J Inner Carpathian and Buda Paleogene [Neogene Alpine volcanics Fig. 1. Structural sketch-map of the Northern Carpathians — based on Lexa et al. (2000), Kuzovenko et al. (1996), and Aroldi (2001) all main structural units (Fig. 1). Further to the SW the position of the Silesian Unit is occupied by a thin-skinned Zdanice-Sub-Silesian Unit. At the same time new and more external, allochthonous tectonic units (Pouzdrany Unit and then Waschberg zone), have appeared at the front of Sub-Silesian Unit. The correlation between the structural units of the middle group in the Polish and Ukrainian Carpathians has been discussed in detail by Zytko (1999). This particular correlation is more difficult because in the Ustrzyki Dolne area (Figs 1, 2), close to the Polish/Ukrainian boundary, the Sub-Silesian/Silesian overthrust is overlapped by the Lower Miocene Upper Krosno Beds. The eastern prolongation of the Sub-Silesian facies is sporadically marked by the occurrence of variegated marls (Rozluch and Holyatyn folds). The southern part of the Silesian Unit in Poland (i.e., Fore-Dukla Unit and Bystre thrust sheet) could be correlated with the Chornohora Unit. According to Zytko (1999), the SE prolongation of the Dukla Unit is related to the Porkulets (Burkut) Nappe, whereas Ukrainian authors (Shakin et al., 1976; Burov et al., 1986) link the northern boundary of the Dukla Unit to the Krasnoshora and Svidovets subunits. The southernmost units of the Ukrainian Carpathians belong to the Rakhiv and Kamianyj Potik units, which are correlated with the Ceahleu and Black Flysch units of the Romanian Eastern Carpathians, respectively. In the Western Outer Carpathians there are no equivalents of these units. The Magura Nappe is composed mainly of Upper Cretaceous to Eocene deposits. The oldest Jurassic-Early Cretaceous rocks are known from the peri-Pieniny Klippen Belt in Poland and few localities in Southern Moravia (Birkenme-jer, 1977; Svabenicka et al., 1997), whereas the youngest deposits (Early Miocene) have been recently discovered in the Nowy Sacz area (Oszczypko et al., 1999; Oszczypko & Oszczypko-Clowes, 2002). The Magura Nappe is separated from the PKB by a subvertical Miocene strike-slip boundary, and flatly thrust at least 50 km towards the north over its foreland (Figs 2-6). This nappe has been subdivided into four structural subunits: Krynica, Bystrica, Raca and Siary (Fig. 2), which coincide to a large extent with the corresponding facies zones. On the west the Magura Nappe is linked with the Rheno-Danubian flysch of the Eastern Alps. Towards the east this nappe extends to Poland and runs through Eastern Slovakia before disappearing beneath the Miocene volcanic rocks, east of Uzhhorod (Trans-Carpathian Ukraine). In the SE part of the Ukrainian and Romanian Carpathians, the zone of the Marmarosh (Maramures) Flysch has been distinguished (Smirnov, 1973; Sandulescu, 1988; Aroldi, 2001). Between the Latorica and Shopurka rivers this zone is bounded from NE by the Marmarosh Klippens and further to SE by the the Marmarosh Massif, which are thrust over the Lower Cretaceous flysch of the Rakhiv and Porkulets units (Fig. 7). In the Marmarosh Flysch zone two facies-tectonic units have been distinguished: the external Vezhany, and the internal Monastyrets units (Smirnov, 1973). The basal part of the Vezhany Unit is built up of oli-stostrome, up to 100-200 m thick and is composed of Meso-zoic carbonate rocks, serpentinites, basic volcanites, granitoids and metamorphic rocks. The olistostroma is followed by a 200 m thick sequence of the Upper Albian-Cenoma-nian grey and dark grey marly mudstones with intercalations of fine-grained, thin-bedded sandstones of the Soimul 781 Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 - [Krakow - .................rc:.......^ Ru / Krynica'J. Jasio Krosno Rzeszów1 ■ L poland ŕ . Przetnys >.. S u _ . Maß Su - Siary Subunit, Ru - Rača Subunit, Bu - Bystrica Subunit, Ku - Krynica Subunit ^] crystalline core of the Tatra Mts. ^GrybówUnit j Škole Unit I 1 High Tatra and Sub-Tatra units | | Dukla Unit Lower Miocene ^ Podhale Flysch ^ Fore-Magura Unit ^ Miocene deposits upon the Carpathian |. ■ -| Miocene of the Carpathian Foredeep Pieniny Klippen Belt ^ Silesian Unit Tl Stebnik (Sambir) Unit Magura Nappe, a - Malcov Formation ^1 Sub-Silesian Unit *~| Zgtobice Unit A. andesite B \ cross-section line Fig. 2. Geological map of the Polish Carpathians (after Zytko et al., 1989 and Lexa et al., 2000 — supplemented) Formation, around 180 m of the Turonian-Campanian pelagic red marls of the Puchov type and 30 m of the Maastrichtian thin-bedded flysch with intercalations of red shales of the "Jarmuta beds" (Dabagyan et al., 1989). The upper part of this sequence, 200-300 m thick, is composed of dark shaly flysch and thick-bedded sandstones of the Metove Beds (Eocene) with the Upper Eocene variegated marls at the top (Smirnov, 1973). Higher up in the section these beds are overlapped by black marls of the Luh Beds. In the Terebla River section, Oligocene (Rupelian) calcareous nanoplankton was recently discovered (Oszczypko & Oszczypko-Clowes, 2004). The Luh Beds resemble the Grybow and Dusyno bituminous marls known from the Fore-Magura units in Poland and Ukraine. In our opinion, the Vezhany succession could be regarded as an equivalent of the Jaslo Unit and the North Fore-Magura thrust sheet in Poland (Oszczypko & Oszczypko-Clowes, 2004). The Monastyrets Unit is composed of Coniacian-Pala-eocene calcareous flysch with red shales (Kalyna beds, Vialov etal., 1988) at the base. These deposits are followed by thin-bedded flysch and variegated shales of the Shopur-ka Beds (Lower-Middle Eocene) and thick-bedded Dra- B SSE MAGURA UNIT Zawoja 1 hovo Sandstones (Middle-Upper Eocene, see Smirnov, 1973; Andreyeva-Grigorovich etal., 1985). From the south this unit joins the PKB along the sub-vertical fault. Towards the NE it is thrust over the Vezhany Unit or directly onto the Rakhiv or Porkulets nappes. In the Romanian Maramures equivalents of the Monastyrets Unit are known as the Leordina and Petrova units and are composed of Maastrichtian-Chattian deposits (Aroldi, 2001). South of the Bohdan Foda Fault position of the Petrova Unit is occupied by the the Wild Flysch Unit. According to Aroldi (2001) this unit is a SE prolongation of the Petrova Unit. All these units have been included by Aroldi (2001) to the Magura Group of units, which are flatly overthrust towards the NE and S onto the Paleoge-ne-Lower Miocene deposits of the Borsa Beds. Between the Botiza-?Krichevo Unit (Late Cretaceous-Oligocene) and the Wild Flysch Unit, the Middle Jurassic-Oligocene Poiana Botizei Klippens are wedged. These klippes are regarded by Aroldi (2001) as the SE termination of the PKB, but according to Bombita et al. (1992) they represent the intra-Magura klippens (like Hluk Klippe in S Moravia). OUTER CARPATHIANS CARPATHIAN FOREDEEP A Andrychdw 2 i SILESIAN UNIT , Sucha IG 1 I Potrana IG 1 Andrychčjw 2 Pszczyna a ■ consolidated basement I of the Inner Carpathians I Proterozoic-Lower Paleozoic I of the Bruno-Vistulicum J Upper Carboniferous | Triassic | High Tatra/Sub-Tatra Units I Pieniny Klippen Belt | Lower Palaeozoic Fig. 3. Geological cross-section (A-B) Orawa-Sosnowiec (after Oszczypko et al., in print) Upper Cretaceous-Paleocene of the Sub-Silesian Unit Senonian-Paleocene Eocene Lower Miocene Lower Badenian-Sarmatian Upper Miocene thrust and overthrust H boreholes ic Inner Carpathians pf Podhale Flysch 782 Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 C S -z. ď < OUTE MAGURA Krynica Subunit R P A T H I NAPPE MSZANA DOLNÁ TECTONIC WINDOW D N SILESIAN UNIT Nowy Targ IG1 Bystrica Subunit Poroba Görna IG1 Miedžwiedž IG1 Inner Carpathians ■ High Tatra crystalline basement Jand its sedimentary cover (Tatricum) V |Sub-Tatricum units (Fatricum) Eocene and Oligocene of the Pod hale Flysch ■ Upper Cretaceous variegated marls 'of the Sub-Silesian Unit | Palaeocene-Eocene I Eocene jKrosno & Malcov Formations ]Waksmund Formation (Lower Miocene) ] Upper Miocene post-tectonic cover Outer Carpathians ' I ' | Pieniny Klippen Belt | | Lower Cretaceous | | Upper Cretaceous-Palaeocene ^s^^Carpath ian overthrust |~^— "| Eocene variegated shales | |Gryb6w Unit | | Menilite shales (Oligocene) ura overthrust Platform basement and Carpathian foredeep rp—7-iVendian-Lower Cambrian IZ—Z-lof the Matopolska Massif 1-1 Platform carbonate cover I-1 (Meso-Palaeozoic) I Lower/Middle Miocene ^s^^Magur; other overthrusts Fig. 4. Geological cross-section (C-D) Nowy Targ IG 1 — Wisniowa IG 1 The Marmarosh Flysch of the Eastern Carpathians (Ukraine ad Romania) revealed several similarities to the Magura Nappe of the Western Carptahians in Slovakia and Poland. These nappes occupied the same geotectonic position and they are bounded from the north and south by the Fore-Magura group of units and PKB, respectively. The Magura and Marmarosh flysch successions revealed the same basin development trends, palaeocurent direction and location of source areas. Both these successions revealed a prominent, northward progradation of the Eocene/Oligoce-ne thick-bedded muscovitic sandstones (see Zytko, 1999). In the Marmarosh Flysch this is manifested by occurrence of the Secu Sandstones (Lutetian-Priabonian) in the Botiza Unit, Stramtura/Drahovo Sandstones (Priabonian) in the Petrova/Monastyrets Unit and the Voroniciu Sandstones (Rupelian-Chattian) in the Leordina Unit (Aroldi, 2001). According to Zytko (1999) the Petrova/Monastyrets, Botiza and Wild Flysch units of the Marmarosh Flysch could be the equivalents of the Raca, Bystrica and Krynica subunits of the Magura Nappe respectively. Taking into account facies prolongation of the Petrova/Monastyrets Unit into the Wild Flysch Unit (Aroldi, 2001) and the lack of Lacko Marls in the Botiza Unit, these correlations should be modified. It appears that there are no equivalents of the Bystrica succession in the Marmarosh Flysch, and the Botiza succession better fits the Krynica succession than that of the Wild Flysch (see Oszczypko & Oszczyp-ko-Clowes, 2004). In view of the internal position of the Marmarosh Flysch in relation to the Marmarosh Massif, as well as the above mentioned similarities between: 1) the Vezhany and Fore-Magura/Jaslo successions, 2) the Monastyrets/Petrova and Raca and 3) the Botiza and Krynica successions, it is possible to conclude that the palaeogeographical positions of the Marmarosh Massif and the buried Silesian Ridge were almost the same (see Sandulescu, 1988; Oszczypko, 1992,1999). The Evolution of the Outer Carpathian basins The Outer Carpathians are composed of Late Jurassic to Early Miocene mainly flysch deposits. The sedimentary sequences of the main tectonic units differ in the facies development as well as in the thickness. The thicker sedimentary cover belongs to the Silesian Unit, which varies from 3000 m, in its western part, to more than 5000 m in the east. The stratigraphic thickness of the other tectonic units is distinctively thinner and varies between 3000 and 3800 m in the Skole Unit, around 1000 m in the Sub-Silesian Unit, 2300-2500 m in the Dukla Unit and 2500-3500 m in the Magura Nappe (Poprawa et al., 2002a). Taking into account the distribution of facies, the thickness of the deposits and the palaeocurrent directions (see Ksiazkiewicz, 1962) only the Magura, Silesian and Skole basins could be considered as independent sedimentary areas (see also Nemcok et al., 2000). During the Late Cretaceous-Eocene times, the Sub-Silesian depositional area formed a submarine high dividing the Skole and Silesian basins. The history of the Dukla sedimentary area, which played the role of a transfer zone between the Magura and Silesian basins, was more complex. According to the reconstructions of Roure et al. (1993) and Behrman et al. (2000), the Outer Carpathian basins during the Early Oligocene were at least 380 km wide across the Przemysl-Hanusovce geotraverse. This restoration does not include the Silesian Ridge, at least 20-50 km wide (see Unrug, 1968), located between the Magura and Silesian depositional areas. This suggests 783 Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 E SE INNER CARPATHIANS SLOVAKIA I POLAND Krynica MAGURA OUTER NAPPE CARPATHIANS Nowy Sijcz F NW faults and overthrusts | boreholes ! C02 ascension M Mono dk Krynica dislocation Fig. 5. Geological cross-section (E-F) Krynica-Bochnia (after Oszczypko & Zuber, 2002 — suplemented) that the entire width of the Outer Carpathian domain reached at least 500 km. Traditional opinions suggest that the Magura and Sile-sian basins were situated parallel to each other (see Ksiqzkiewicz, 1962; Unrug, 1968, 1979; Birkenmajer, 1986). This view was recently questioned by Nemcok et al. (2000) who placed the Magura depositional area as the south-western neighbour of the Silesian depositional area, whereas the present-day position of these units is a result of the Miocene eastwards escape of the Magura Nappe. This model does not fit the facies distribution in the Polish Outer Carpathians (Bieda et al., 1963), palaeocurent measurements, nor the transitional position of the Dukla succession, between the Magura and Silesian basins. The sedimentary succession of the Outer Carpathians (Table 1) reveals three different megasequences of deposits, reflecting the main stages of the basins development (Poprawa et al., 2002a). The first (long lasting) and third (relatively short) periods were characterized by the unification of sedimentary conditions, whereas the intermediate periods were characterized by a maximal differentiation of sedimentary conditions. Middle Jurassic-Early Cretaceous opening of basins and post-rift subsidence (125-150 My) The Outer Carpathian basins can be regarded as remnant ocean basins, which developed between the colliding European continent and the intra-oceanic arcs (Oszczypko, 1999). The Early/Middle Jurassic opening of the Magura Basin was probably coeval with the timing of the Ligurian-Penninic Ocean opening and its supposed pro- longation towards the east (Oszczypko, 1992; Golonka et al., 2000, 2003). This oceanic domain was divided by the submerged Czorsztyn Ridge into the NE and SE arms. The Czorsztyn Ridge and the Inner Carpathian domain were separated by the SE arm of the Pieniny Ocean, known also as the Vahicum Oceanic Rift (south Penninic domain), whereas NE arm was occupied by the Magura deep-sea basin situated south of the European shelf, an equivalent of the north-Penninic (Valais) domain (see also, Plasienka, 2003). This stage of the Magura Basin evolution is rather speculative, because the Magura Nappe was uprooted roughly at the base of the Upper Cretaceous sequence. The Jurassic-Lower Cretaceous deposits of the Magura Basin were probably represented by deep water, condensed pelagic limestones and radiolarites. At the end of the Jurassic in the southern part of the European shelf, the palaeorifts were floored by a thinned continental crust (Birkenmajer, 1988; Sandulescu, 1988). This rifted European margin was incorporated into the Outer Carpathian Basin (Skole, Sub-Silesian/Silesian basins). The rifting process was accompanied by a volcanic activity (teschenite sills, dykes, and local pillow lavas), which persisted up to the end of Hauterivian (Lucinska-Anczkiewicz et al., 2002; Grabow-ski et al., 2004). This part of the rifted continental margin probably extended in the Eastern Carpathian (basic effu-sives —Tithonian-Hauterivian), see Lashkevich et al. (1995) of the "Black Flysch", Kamyany Potic, and Rakhiv beds) as well as to the Southern Carpathian (Sandulescu, 1988). During the initial stage of development, the Silesian Basin was filled with calcareous flysch followed by silicic-lastic flysch and pelagic shales. The Early Cretace-ous-Cenomanian deposition took place during relatively 784 Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 low sea levels (Table 1) and was characterized by a low and decreasing rate of sedimentation from 40-20 m/My to 115-40 m/My (Figs 8, 9) for the Skole and Silesian basins respectively (Poprawa et al., 2002a). The Late Juras-sic-Hauterivian deposition of the Silesian Basin was controlled by normal fault and syn-rift subsidence, and later (Barremian-Cenomanian) by a post-rift thermal subsidence, which culminated with the Albian-Cenomanian expansion of deep-water facies (Poprawa et al., 2002a, b; Nemcok et al., 2001). The Cenomanian high stand of the sea level resulted in unification of the sedimentary condition in all Outer Carpathian basins, and deposition of the green radiolarian shales (Cenomanian Key Horizon) followed by the Turonian variegated shales (Table 1). Late Cretaceous-Palaeocene inversion (35 My) During the Turonian in the central part of the Outer Carpathian domain, the Silesian Ridge was restructured and uplifted (Fig. 8). The inversion affected most of Silesian, Sub-Silesian and Skole sub-basins. Since the Campa-nian, an inversion effect is also visible in the northern part of the Magura Basin. The amplitude of the Silesian Ridge uplift reached several hundreds meters (Poprawa et al., 2002a). This was accompanied by an increase in the rates of deposition to 25-55 m/My and 50-100 m/My (Fig. 9) in the Skole and Sub-Silesian-Silesian basins, respectively (Poprawa et al., 2002a). A maximal increase in sedimentary rates took place in the western part of the Silesian area, up to 400 m/My in the Godula Beds (Poprawa et al., 2002 a, Oszczypko et al., 2003). In the Magura Basin, during the Maastrichtian-Palaeocene, coarse material derived from the Silesian Ridge supplied deposition of the Solan Beds (Svabenicka et al., 1997), Jaworzynka Beds and Mutne Sandstones (deposition rate 60 do 100 m/My, Fig. 9). The uplift of the Silesian Ridge was coeval with a regional uplifting in the southern margin of continental Europe from the Carpathian and Alpine foreland to Spain (Poprawa et al., 2002a). This was caused by regional, early orogenic compression in the Inner Carpathians and the Northern Alps (see Ksiqzkiewicz, 1977; Sandulescu, 1988; Poprawa et al., 2002a) and the rift development in the Biscay Bay (Golonka & Bocharova, 2000). In the Northern Carpa- thians the development of the Silesian Ridge was probably related to the inversion of pre-existing extensional structures (Roure etal., 1993; Roca etal., 1995; Kusmierek, 1990; Krzywiec, 2002). The development of the We_gl6wka High, dominated by deposition of pelagic variegated marls, could also be associated with the uplift of the Silesian Ridge. The Weglowka High (like peripheral bulge) separated Silesian and Skole basins during the Santonian-Eocene time. The suggested shortening of the Silesian Basin (Oszczypko, 1999) can be also regarded as a westwards continuation of the pre-Late Albian subduction of the Outer Dacides (Sandulescu, 1988). In the southern (peri-PKB) part of the Magura the coarse clastic deposition began with the Jarmuta Formation (Maastrichtian/Palaeocene, see Birkenmajer, 1977; Birkenmajer & Oszczypko, 1989), which was up to 500 m thick. This formation is composed of thick- to medium-bedded turbidites, contains conglomerates and sedimentary breccias composed of the Jurassic-Cretaceous sedimentary rocks, and exotic crystalline and basic volcanic rocks (Birkenmajer, 1977; Birkenmajer & Wieser; 1992; Misiketal., 1991). Towards the north, the upper portion of this formation alternates with medium-bedded, calcareous turbidites of the Szczawnica Formation (Palaeoce-ne-Lower Eocene, Birkenmajer & Oszczypko, 1989). In the Jarmuta and Szczawnica formations (rate of deposition 20-50 m/My, Fig. 9) significant amounts of SE-supplied chromian spinels have been found (Oszczypko & Salata, 2004). The Jarmuta formation is regarded as the synoroge-nic wild flysch, derived both from the erosion of the PKB as well as of the Andrusov Exotic Ridge (Birkenmajer, 1986, 1988; Birkenmajer & Wieser, 1992). These deposits probably reflect the collision of the Inner Western Carpathian Orogenic Wedge (IWCW) with the Czorsztyn Ridge (Plasienka, 2002, 2003). Palaeocene to Middle Eocene subsidence (25 My) At the end of Palaeocene the Carpathian basins were affected by general subsidence and the rise in sea level (Poprawa et al., 2002a, b). During the Eocene, a wide connection of the Outer Carpathian basins and the world ocean was established (Golonka et al., 2000). This resulted in uni- 785 Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 fication of facies, including the position of the CCD level and low sedimentation rates. This general trend dominated during the Early to Middle Eocene time in the northern basins (Skole, Sub-Silesian, Silesian and Dukla ones) as well as in the northern part of the Magura Basin. During the Palaeocene, the IWCW reached the southern margin of the Magura Basin. Its load caused sub- sidence, collapse of the PKB and southwards shift of the Magura Basin margin. This explains the deposition of the deep-water facies in the PKB (see Leško & Samuel, 1968; Bystrická et al., 1970; Ksiqžkiewicz, 1977), and allows us to explain the transfer of clastic material to Magura Basin via PKB, from the source area located in the SE part of the Inner Carpathian domain. This also enables the explanation Pieniny Klippen Belt (PKB) The eastern equivalents of the Magura Nappe ^ Botiza Nappe (Krynica Subunit) ~\ Poiana Botizi Klippens (PBK) _I Petrova-Monastyrets and Wildflysch units (Raca Subunit) ~a I a - Drahovo-Stramtura Sandstones H Leordina Nappe (Siary Subunit?) _I Vezhany Unit (Fore-Magura Unit?) a - Sojmul Beds and olistolithes blocks Median Dacides and their postectonic cover ] Marmarosh Crystalline Massif [ Sojmul (Albian Cenomanian) and Velyka Banska (Eocene) conglomerates 1 Senonian-Eocene pelagic deposits and Oligocene-Early Miocene Borsa Flysch Outer Dacides Black Flysch Nappe - basic volcanites and Late Jurrasic-Neocomian carbonate flysch of the Kamianyi Potik and Chyvchyn formations H Rakhiv Cahlau Nappe - black flysch (Houterivian-Barremian) with silles of diabases I Porkulets Nappe Moldavides I Upper Cretaceous-Palaeocene flysch I Upper Cretaceous-Oligocene flysch Trans-Carpathian (back-arc) Basin and Hutin Volcanic Belt H~The Late Miocene-Pliocene andesites, basalts and tuffs ^ Early-Late Miocene deposits tectonic blocks - basalts S2> tectonic blocks - limestones <*» exotic pebbles main thrusts thrusts faults Fig. 7. Geological sketch-map map of the SE part of the Ukrainian Carpathians and adjacent part of the Romanian Maramures —based on Shakin et al. (1976), Burov et al. (1986) and Aroldi (2001) 786 Przeglqd Geologiczny, vol. 52, no. 8/2, 2004 JURASSIC LOWER CRETACEOUS UPR CRETACEOUS 190 180 170 160 150 140 130 120 110 100 absolute age (Ma) 90 PALAEOGENE 1 50 1000 - 2000 - 3000 - 4000 -ľ ■the Late Cretaceous-Palaeocene Itectonic uplift events ■the Late Eocene-Early Oligocene Itectonic uplift events Skole Unit Sub-Silesian Unit Silesian Unit Dukla Unit4 Siary Sub-Unit Raca Sub-Unit Bystrica Sub-Unit Krynica Sub-Unit Grajcarek Unit Fig. 8. Tectonic subsidence curves for selected synthethic profiles from the Polish Outer Carpa thians (after Poprawa et al., 2002a; Oszczypko et al., 2003) of provenance of the huge amount of crystalline clasts derived to the Palaeocene/Eocene deposits of the Magura Basin. The migrating load of the Magura and PKB accretiona-ry wedge caused further subsidence and a shift of depocen-tres to the north. As a result, narrow and long submarine fans developed. The northern deepest part of the basin, often located below the CCD was dominated by basinal turbidites and hemipelagites. The rate of sedimentation varied from 6-18 m/My on the abyssal plain to 103-160 m/My in the outer fan and between 180 and 350 m/My (Fig. 9) in the area affected by the middle fan-lobe systems (Oszczypko, 1999). The total amount of these deposits, can be estimated at least 3750-4500 km3 (250-300 km x 15 km x 1 km). These were supplied from the southeast, probably from the Inner Carpathian/Inner Dacide terrains (Oszczypko et al., 2003). During the Late Eocene and Oligocene, the axes of subsidence of the Magura Basin shifted to the north towards the Raca and Siary sedimentary areas (Fig. 8). Synorogenic Late Eocene-Early Miocene closing of the basins (15 My) In the Outer Carpathian sedimentary area, the Late Eocene brought about drastic changes of depositional con- ne0gewe a-*-