Ra dio-iso to pic age and biostratigraphic po si tion of a lower Badenian tuffite from the west ern Pol ish Carpathian Foredeep Ba sin (Cieszyn area)
Krzysztof BUKOWSKI1, *, Karin SANT2, Monika PILARZ1, Klaudia KUIPER3 and Ma³gorzata GARECKA4
1 Fac ulty of Ge ol ogy, Geo phys ics and En vi ron men tal Pro tec tion, AGH Uni ver sity of Sci ence and Tech nol ogy, al.
A. Mickiewicza 30, 30-059 Kraków, Po land
2 Utrecht Uni ver sity, Paleomagnetic Lab o ra tory Fort Hoofddijk, De part ment of Earth Sci ences, Utrecht, The Neth er lands
3 VU Uni ver sity Am ster dam, Fac ulty of Sci ences, De Boelelaan 1085, 1081 HV Am ster dam, The Neth er lands
4 Pol ish Geo log i cal In sti tute – Na tional Re search In sti tute, Skrzatów 1, 31-560 Kraków, Po land
Bukowski, K., Sant, K., Pilarz, M., Kuiper, K., Garecka, M., 2018. Ra dio-iso to pic age and biostratigraphic po si tion of a lower Badenian tuffite from the west ern Pol ish Carpathian Foredeep Ba sin (Cieszyn area). Geo log i cal Quar terly, 62 (2): 303–318, doi: 10.7306/gq.1402
The early Badenian in ter val in the Cen tral Paratethys realm is char ac ter ized by a ma jor ma rine trans gres sion into the Pannonian and Carpathian Foredeep bas ins. In the west ern part of the Pol ish Carpathian Foredeep, Badenian sed i men ta - tion started gen er ally with con glom er ates (Dêbowiec For ma tion) pass ing into a thick suc ces sion of claystones and mudstones with rare sand stone interbeds (Skawina For ma tion). Pro files con tain ing a full se quence of lower Badenian strata are rel a tively rare, and are mainly known from bore holes. In this pa per, we pres ent new re sults on sam ples taken from such a bore hole (Kaczyce K2/07) lo cated near the town of Cieszyn. We fo cus on re con struct ing the chro nol ogy of the lower Badenian ma rine sed i ments at the be gin ning of the trans gres sion in the Carpathian Foredeep (lower Skawina Fm.) us ing ra - dio-iso to pic dat ing (40Ar/39Ar) of a volcanoclastic layer (tuff and tuffite) and biostratigraphy of cal car e ous nannoplankton and foraminifera.The weighted mean 40Ar/39Ar age for sanidine sep a rates from the tuff pro vided an age of 14.27 ± 0.03 Ma. This age is con sis tent with the NN5 and MNN5a nannofossil zones de ter mined in this study. Our foraminiferal as sem blages show that the basal beds of the Skawina For ma tion up to the tuffites cor re spond to the Orbulina suturalis–Praeorbulina glomerosa Zone (ac cord ing to Cicha et al., 1975) and cover the in ter val of the Lower Lagenidae Zone–low er most Up per Lagenidae Zone (Grill, 1941). The petrographic data from the tuffite al low cor re la tion of the tuffite from the Kaczyce K2/07 bore hole to the level of the Che³mek Tuffite Bed (Alexandrowicz, 1997) pro vid ing a re gional cor re la tion ho ri zon for fu ture stud ies.
Key words: Mio cene, Badenian, Carpathian Foredeep, tuffites, 40Ar/39Ar dat ing, biostratigraphy.
INTRODUCTION
The Paratethys was an au ton o mous zone that in cluded a chain of ma rine bas ins ex tend ing at its wid est from the Al - pine-Carpathian re gion to the mod ern Aral Sea dur ing Oligocene to Mio cene times. The semi-re stricted bas ins were pe ri od i cally con nected with the Med i ter ra nean, the Indo-Pa cific Ocean and the At lan tic Ocean (Rögl and Steininger, 1983;
Rögl, 1998, 1999). The Paratethys is usu ally di vided into a West ern, Cen tral and East ern seg ment (e.g., Seneš et al., 1961).
The re gional time scale of the Cen tral Paratethys is mostly based on en demic fos sil as sem blages and its stage bound aries are com monly cor re lated with the third-or der sea level cy cles (e.g., Haq et al., 1988) and/or the se quence strati graphic cy cles
(Hardenbol et al., 1998) and pro posed by Piller et al., (2007) or Harzhauser and Piller (2007). Re cent stud ies have shown that the lack of in de pend ent age con straints may lead to in con sis - tent palaeogeographic re con struc tions (Kovaè et al., 2017a;
Sant et al., 2017).
This pa per fo cuses on tuffites of the re gional Badenian stage, cor re spond ing to the Langhian and early Serravallian stages. The early Badenian was char ac ter ized by a diachronous ma rine trans gres sion that grad u ally ex panded from the west to the south-east of the Cen tral Paratethys realm (Rögl, 1998, 1999). By the late Langhian, wa ter cov ered the Carpathian Foredeep and most of the Pannonian, Transylvanian, and Getic bas ins. It likely also con nected with the East ern Paratethys (Hamor and Halmai, 1988; Rögl, 1999;
Fig. 1A).
The wide spread trans gres sion was as so ci ated with a very ac tive tec tonic phase in clud ing up lift of the Carpathians, orog - eny-par al lel and per pen dic u lar ex ten sion and east ward subduction roll back stretch ing the Pannonian back-arc ba sin (Horváth, 1993; Mazzolki and Helman, 1994; Fodor et al., 1998;
Horváth et al., 2006, 2015; Kováè et al., 2017b and ref er ences therein). In the south-west (Aus tria) this phase is re ferred to as
* Corresponding author, e-mail: buk@agh.edu.pl
Received: January 5, 2018; accepted: February 9, 2018; first published online: March 26, 2018
the Styrian tec tonic phase (Stille, 1924). The Neo gene tec tonic evo lu tion of Carpatho-Pannonian re gion was ac com pa nied by erup tions of var i ous mag mas (e.g., Szabó et al., 1992; Pécskay et al., 2006; Harangi and Lenkey, 2007). Very large ex plo sive erup tions of silicic mag mas oc curred dur ing the Early to Mid dle Mio cene, co eval with the main lithospheric thin ning and for ma - tion of the Pannonian Ba sin. This silicic vol ca nism ap pears to have pro duced one of the most vo lu mi nous vol ca nic de pos its in Eu rope (vol ume es ti mate over 10 km3) dur ing the Mio cene (Lukács et al., 2015).
Var i ous au thors have sug gested that the dif fer ent steps of the Badenian trans gres sion were as sisted by eustatic changes (e.g., Oszczypko et al., 2006; Kováè et al., 2007; Hohenegger et al., 2014), such as the Mi2a and Mi3a sea level rises (Kominz et
al., 2008; John et al., 2011) or TB 2.3 high stand (Haq et al., 1988). In the Pol ish Carpathian Foredeep, depocentres mi grated north wards dur ing the Badenian, and the sea cov ered the fore - land plate and mar ginal parts of the Carpathians (Ney et al., 1974; Fig. 1). Pro files con tain ing a full se quence of early Badenian de pos its are rel a tively rare, and are mainly known from bore holes (e.g., Oszczypko and Oszczypko-Clowes, 2011).
Sed i men ta tion started gen er ally with con glom er ates (Dêbowiec For ma tion; Bu³a and Jura, 1983). In the west ern part of the Foredeep these passed into an up to 1,000 m thick suc ces sion of claystones and mudstones with rare interbedded sand stones (Skawina For ma tion; Alexandrowicz et al., 1982). To wards the north and east, the thick ness of those de pos its mark edly de - creased to tens of metres or even to sev eral metres.
Fig. 1. Location of exploration borehole Kaczyce K2/07 in the geological setting of the Carpathian Foredeep
A – palaeogeographic reconstruction of the Central Paratethys (early Badenian; after Rögl, 1998); B – extent of the early Badenian marine basin in the Polish Carpathian Foredeep (after Ney et al., 1974); C –
geological cross-section of the study area (after Bogacz et al., 1984)
In this pa per, we pro vide new re sults on sam ples taken from such a bore hole (Kaczyce K2/07) lo cated near the town of Cieszyn (Fig. 1C). We fo cus on re con struct ing the chro nol ogy of the lower Badenian ma rine de pos its at the be gin ning of the trans gres sion in the Carpathian Foredeep (lower Skawina Fm.) us ing ra dio-iso to pic dat ing (40Ar/39Ar) of a vol ca nic tuff ho ri zon and the biostratigraphy of cal car e ous nannoplankton and foraminifera. The new age data will help to better un der stand the na ture of the Badenian trans gres sion in the north ern part of the Cen tral Paratethys.
GEOLOGICAL SETTING
The Pol ish Carpathian Foredeep can be sub di vided into two parts: the in ner (south ern) and the outer (north ern) bas ins (Ney et al., 1974). The in ner foredeep, lo cated be neath the Carpathian nappes, is >50 km wide and is com posed of Early to Mid dle Mio cene autochthonous and allochthonous de pos its.
The width of the outer foredeep (out side the Carpathians) var - ies be tween 30–40 km in the west ern seg ment and reaches up to 90 km in the east ern part. The outer foredeep is filled with Mid dle Mio cene ma rine de pos its, rang ing from a few hun dred metres in thick ness in the north ern part to up to 3,000 m in the south east ern part.
The study area is lo cated in the south west ern part of the outer Carpathian Foredeep in Po land (Fig. 1). In this area, the base ment be low the Mio cene com prises Car bon if er ous de pos - its with sand stones, con glom er ates, and shale with coal seams (Ruda Beds and Za³ê¿e Beds), be long ing to the south ern rim of the Up per Silesian Coal Ba sin. This base ment is strongly mor - pho log i cally dif fer en ti ated, with ero sional palaeovalleys, can - yons, and ridges. The bore hole ex am ined is lo cated on the east ern slope of the Ostrava–Karvina Ridge (e.g., Jachowicz and Jura, 1987; Picha et al., 2006), gen er ally run ning in a east-west di rec tion.
The Car bon if er ous rocks are over lain by youn ger de pos its of the so-called Red Beds (e.g., Wag ner, 1983; Dopita and Kumpera, 1993). They are Ju ras sic and Cre ta ceous re sid ual de pos its formed dur ing weath er ing of Car bon if er ous rocks, as in di cated by e.g., the red col our of the beds and the oc cur rence of ero sional brec cia in the roof of the Car bon if er ous rock for ma - tion. The thick ness of the weath er ing-zone cover is vari able and amounts is >12 m in the study area.
Mid dle Mio cene de pos its lie di rectly on top of the weath er - ing cover, and are rep re sented by a 40–90 m thick suc ces sion of transgressive Dêbowiec con glom er ates and sand stones, con tain ing Up per Car bon if er ous clasts. The spa tial ex tent of the con glom er ates and sand stones is re lated to the palaeo-mor - phol ogy of the sub strate (Bu³a and Jura, 1983). A char ac ter is tic
fea ture of the con glom er ates is the pro por tion of clastic ma te rial from the north ern pe riph ery of the ba sin, mainly of Car bon if er - ous and De vo nian rocks (Doktor, 1992, 1994). These de pos its rep re sent an al lu vial fan sys tem. The old est oc cur in the south - ern part of the area, and the youn gest in the north. The con - glom er ates reach up wards into the Skawina For ma tion. Ac - cord ing to Oszczypko and Oszczypko-Clowes (2003), the Dêbowiec con glom er ates are of early Badenian– late Kar patian age (late Burdigalian–Langhian).
The Skawina For ma tion in cludes ma rine clayey sed i ments with a rich micro fauna (Gonera, 1997, 2000; Gonera and Bukowski, 2012) and nannoplankton (e.g., Peryt, 1997) pre vi - ously as signed to the “sub-evaporitic clays”. Its stratotype was iden ti fied in the Borek Szlachecki bore hole near Skawina (Alexandrowicz et al., 1982). Three main lithofacies were dis tin - guished (Alexandrowicz, 1963a, 1997). Grey fossiliferous marly clays (Tegel fa cies), reach ing up to ~200 m in thick ness, are most com mon; they oc cur in the cen tral part of the ba sin. In the south ern part of the ba sin, up to 650 m of grey clays (Schlier fa - cies) oc cur, interbedded with silty and fine-grained sands. In the north ern part of ba sin a shal low wa ter ma rine fa cies was iden ti - fied, char ac ter ized by the pres ence of shelly and organodetrital Lithothamnium lime stone and marl in ter ca la tions, abun dant in macro- and microfossils, within marly clays.
The foraminiferal as sem blages de scribed by Alexandrowicz (1963a) are lo cally used for the Badenian de - pos its (Ta ble 1). The old est foraminiferal as sem blage rec og - nized (IIA, IIB) ap pear in the lower part of the Skawina For ma - tion. It is known as the Lanzendorf or the Cra cow As sem blage (Alexandrowicz, 1957). In the lower part of the Skawina Fm., con tain ing this rich and char ac ter is tic foraminiferal as sem blage IIA or IIAB, a thick vol ca nic ash layer (tuffite; up to 2 m thick) was found. It has been de scribed in many pro files (10 bore - holes) in the west ern part of the Pol ish Carpathian Foredeep (Parachoniak, 1960, 1962; Alexandrowicz, 1963a, b, 1997;
Alexandrowicz and Pawlikowski, 1978), and it is called the Che³mek Tuffite Bed (Alexandrowicz, 1997) or level tf-2 (see Bukowski et al., 2010: fig. 2).
The ex plor atory bore hole, Kaczyce K2/07, is lo cated within the range of the Schlier Fa cies and dis plays lower Badenian de - pos its. In the lower part of the Skawina For ma tion a layer of tuffite (1.6 m) oc curs.
There are also older Lower Mio cene de pos its, be long ing to the in ner foredeep, lo cated to the south-east and east of the study area. These de pos its are called the sub-Dêbowiec beds (Konior and Krach, 1965; Konior, 1981), the Zebrzydowice For - ma tion (Bu³a and Jura, 1983), or Stryszawa and Sucha for ma - tions (Œl¹czka, 1977). There was no ev i dence of such de pos its in the Kaczyce K2/07.
Chronostratigraphy Cen tral Paratethys (Papp et al., 1978; Rögl, 1996)
Plank tonic foraminiferal zone (Cicha et al., 1975)
Ben thic foraminiferal zone (Papp et al., 1978; Rögl and Steininger, 1984; Steininger et al.,
1985)
Foraminiferal as sem - blage zone (Alexandrowicz, 1958,
1963a)
NAINEDAB
Late Badenian
Kosovian Velapertina indigena Bulimina–Bolivina Zone IIIB
Wielician Globigerina druryi–Globigerina
decoraperta Zone with ag glu ti nated foramnifera
IIIA evaporites
IID IIC Early Badenian Moravian Orbulina suturalis/Praeorbulina
glomerosa Lagenidae Zone IIB
IIA
T a b l e 1 Cen tral Paratethys foraminiferal zonation of the Badenian de pos its in the west ern part of the Carpathian Foredeep
LITHOSTRATIGRAPHY OF THE KACZYCE K2/07 BOREHOLE
The Kaczyce K2/07 bore hole was drilled by the OKD Com - pany in 2007 as an ex plo ra tion bore hole in search of coal in the Ostrava–Karvina coal field in the west ern part of the min ing area of the aban doned “Morcinek” Coal Mine. The bore hole is lo - cated ~2 km north of the fron tal thrust of the Carpathians, in the vi cin ity of the Pol ish-Czech bor der, and ~10 km north of Cieszyn (Fig. 1). The bore hole is 1,000 m deep. Full cores are avail able only for the sec tion 600–1,000 m (Fig. 2).
The Kaczyce K2/07 bore hole cuts through 30 m of Qua ter - nary de pos its (loams, clays and grav els) and then through the autochthonous Mio cene foredeep de pos its of the Skawina For - ma tion (30–684 m), rep re sented by a suc ces sion of grey and green ish marly clays with in ter ca la tions of sands and sand - stones (Fig. 2). The pro por tion of sandy ma te rial in the suc ces - sion de creases in the lower part of the pro file (from 632 m depth). A thick layer of white and pale grey tuffite was found in the depth in ter val 648.5–650.1 m. The Mio cene de pos its of the Skawina For ma tion are un folded and lie al most hor i zon tally.
From 684 to 728 m depth, pale grey, coarse-grained sand - stones and con glom er ates are pres ent (Fig. 3C). The sand - stones are frag ile, crum bling, and po rous. They con tain quartz grains and nu mer ous frag ments of Car bon if er ous rocks: sand - stones, dark slates and clasts of coal (reach ing up to 50 mm, or 15 mm on av er age), orig i nat ing from the Westphalian AB mudstone suc ces sion (Jachowicz and Jura, 1987).
In the in ter val 728–744.3 m, there are coarse, polymictic con glom er ates with nu mer ous boul ders (5–20 cm across) of grey-green sand stone, red dish and cream col oured meta mor - phic rocks, and black slate (Fig. 3B). Based on li thol ogy, the en - tire unit of pale grey sand stones and polymictic con glom er ates (684–744.3 m) can be in cluded in the Dêbowiec For ma tion (To³wiñski, 1950; Kuciñski et al., 1975; Garecka et al., 1996).
This for ma tion lies un con form ably (at depth 744 m) on de pos its of the weath er ing zone of the Car bon if er ous sub strate (Red Beds), in the form of green ish con glom er ates, with a char ac ter - is tic red binder.
In the depth range 745–751 m, the green con glom er ate grad u ally turns into a rusty red con glom er ate (Fig. 3A). Within that weath er ing zone, very large white blocks of sand stone (up to 80 cm in size) are found at the depth in ter vals 751–753 and 760.1–762 m. Be low the weath er ing zone there are typ i cal Car - bon if er ous de pos its formed by the Mudstone se ries (Za³ê¿e Beds, 762–794 m) and the Up per Silesian Sand stone se ries (Ruda Beds, 794–1,000 m).
TUFFITE
A thick layer of pyroclastic ma te rial oc curs within marly clays in the depth in ter val 648.5–650.1 m (Fig. 3). It in cludes lam i nated white tuff and tuffite with a to tal thick ness of 160 cm.
Mac ro scop i cally, the white and pale grey vol ca nic ash layer has hor i zon tal lam i na tion and is graded. The in ter val does not con - tain car bon ates (as tested with HCl).
Bin oc u lar ob ser va tions showed that the tuff in ter val con - tains some fin ing up ward lay ers: fine-grained at the top and me - dium to coarse-grained (sand-size) at the bot tom. At the bot tom (649.5–650.1), the pro por tion of terrigenous (siliciclastic) ma te - rial is min i mal. These de pos its could be re ferred to as crys tal tuff ac cord ing to the def i ni tion of Pettijohn (1949). Some flakes of bi o tite, quartz grains and glass shards are vis i ble to the na - ked eye.
Higher in the in ter val (648.5–649.5), the ad mix ture of the non-pyroclastic ma te rial rises, and these rocks could be de - scribed as tuffites (Parachoniak, 1962). Their rel a tively large
Fig. 2. Lithostratigraphic profile of the Kaczyce K2/07 borehole
thick ness and strati graphic po si tion in the lower part of the Skawina For ma tion sug gests that the ho ri zon ex tends re gion - ally. It was pre vi ously rec og nized in other bore holes and ex po - sures in the Carpathian Foredeep (e.g., Parachoniak, 1962;
Alexandrowicz, 1997; Bukowski, 2011).
MATERIAL AND METHODS
Two tuffite sam ples were taken from the Kaczyce K2/07 core; one fine-grained, lam i nated, and slightly bentonized (sam ple K2/3) from a depth of 648.8 m, and one coarse-grained
tuff with finely ex cel lently pre served pyroclastic min er als from a depth of 650.1 m (sam ple K2/4).
Chem i cal anal y ses of vol ca nic glass, plagioclases and K-feld spars, by SEM/EDS microprobe, was per formed on both sam ples (K2/3 and K2/4). SEM/EDS anal y ses were con ducted in the FESEM Lab o ra tory of the In sti tute of Geo log i cal Sci - ences, Jagiellonian Uni ver sity us ing a NORAN Van tage spec - trom e ter cou pled with a HITACHI S-4700 scan ning elec tron mi - cro scope op er ated at 15 kV.
Min er als from K2/4 were ex tracted for 40Ar/39Ar dat ing by us ing stan dard min eral sep a ra tion pro ce dures. The heavy min - eral con cen trate was first sep a rated into a heavy (>2.62 g/cm3), Fig. 3. Core Kaczyce K2/07 shows Middle Miocene deposits lie directly on top of the weathering
cover of Carboniferous rocks (photo J. Misiak)
A – Red Beds, de pos its of the weath er ing zone of the Car bon if er ous sub strate, in the form of con glom er - ates, with a char ac ter is tic red binder; B – polymictic con glom er ates with nu mer ous boul ders of grey-green sand stone and red dish and cream col oured meta mor phic rocks; C – coarse-grained po rous sand stones and con glom er ates con tain ing quartz grains and nu mer ous frag ments of Car bon if er ous rocks and clasts of coal; D – layer of tuffite (white in ter val on top of pic ture) within grey and green ish marly clays (Skawina Fm.) from the bore hole stud ied, Kaczyce K2/07
me dian (2.62–2.4 g/cm3) and light frac tion (<2.4 g/cm3) by use of dif fer ent tetrabromoethane (C2H2Br4, d = 2.97 g/cm3) so lu - tions at the Fac ulty of Ge ol ogy, Geo phys ics and En vi ron men tal Pro tec tion, AGH Uni ver sity of Sci ence and Tech nol ogy in Kraków. At this stage, pre lim i nary anal y sis on sanidine crys tals in the me dian min eral frac tion was per formed by the Raman method.
40Ar/39Ar DATING
The ma te rial of sam ple K2/4 was fur ther pro cessed at the Min eral Sep a ra tion fa cil ity of the Fac ulty of Earth and Life Sci - ences of VU Uni ver sity Am ster dam in or der to sep a rate bi o tite and sanidine min er als for 40Ar/39Ar dat ing. It was la belled as sam ple KAC. Sanidine grains were sep a rated from the 2.54–2.59 g/cm3 den sity frac tion (us ing di-iodomethane). The ma te rial was then cleaned in an ul tra sonic wa ter bath and dry sieved into the frac tions 250–400 mm and 400–500 mm. Both were fur ther pu ri fied by mag netic sep a ra tion over a Frantz isodynamic sep a ra tor, and sub se quently cleaned by a 15 min - ute ul tra sonic HNO3 bath, and a 10 min ute di luted HF bath. A fi - nal se lec tion step in volved hand-pick ing of the size frac tions 250–400 mm and 400–500 mm un der an op ti cal mi cro scope.
Only trans par ent sanidine grains were se lected.
Bi o tite grains were sep a rated from the den sity frac tion
>3.0 g/cm3. Af ter an ad di tional clean ing step in an ul tra sonic wa ter bath, the re main der was dry sieved into two size groups:
<90–200 mm and 200–500 mm. Dur ing the fi nal hand-pick ing step the thick est, most an gu lar hex ag o nal bi o tite min er als with - out vis i ble in clu sions un der an op ti cal mi cro scope were se - lected for ra dio-iso to pic dat ing from the size frac tion >200 mm.
Min eral sep a rates were packed in a 6 mm ID AI vial to - gether with Fish Can yon Tuff sanidine (FCs) stan dards. Sam - ples and stan dards were ir ra di ated at the Or e gon State Uni ver - sity TRIGA re ac tor in the cad mium shielded CLICIT fa cil ity for 18 hours in two ir ra di a tions (VU107 for sanidine and VU109 for bi o tite). Af ter ir ra di a tion sam ples and stan dards were un packed and loaded in a 185 hole Cu tray and baked over night at 250°C un der vac uum. This tray was then placed in a dou bly pumped vac uum cham ber with Zn-S win dow and baked over night at 120°C un der high vac uum. This cham ber was con nected to a ThermoFisherNGPrep gas pu ri fi ca tion line that orig i nally was equipped with four SAES-NP10 get ters, a cold fin ger, an ion gauge, two in lets and two pi pette sys tems. Sam ples were heated us ing a 25W Synrad CO2 la ser. Sam ple gas was ex - posed to three of the NP10 get ters (two hot and one cold) dur - ing 3 min and let into the an ARGUS VI+ no ble gas mass spec - trom e ter for anal y ses.
40Ar/39Ar anal y ses were car ried out at the geo chron ol ogy lab o ra tory of the VU Uni ver sity on a ARGUS VI+ no ble gas mass spec trom e ter, which is a high sen si tiv ity, low res o lu tion multi-col lec tor no ble gas mass spec trom e ter with an in ter nal vol ume of 710 ml. The mass spec trom e ter is equipped with four Far a day cups at the H2, H1, AX and L1 po si tions and two com - pact dis crete dynodes (CDDs) at po si tions L2 and L3. The sys - tem is equipped with a 1012 Ohm am pli fier on H2 and 1013 Ohm am pli fi ers on H1, AX and L1 cups. The res o lu tion of the sys tem is ~200 and there fore does not re solve hy dro car bon or chlo rine in ter fer ences. The ARGUS VI+ has a NP10 get ter and ion gauge on the source of the mass spec trom e ter. The NP10 get - ter is run cold and the ion gauge is turned off dur ing anal y ses, be cause of its pump ing ca pac ity for ar gon. Sam ples were run on the H2-L2 col lec tors (m/e40 on H2, m/e39 on H1, m/e38 on AX, m/e37 on L1 and m/e 36 on L2). Bias be tween the dif fer ent de tec tors was mon i tored by (1) mea sure ment of 40Ar air pi - pettes across the dif fer ent Far a day cups; (2) mea sure ment of
40Ar blanks on all de tec tors and (3) by mea sure ment of mass 44 CO2 in dy namic mode on all de tec tors. Sys tem atic bias of up to 14% be tween the de tec tors was found, but this was re pro duc - ible over pe ri ods of weeks. As with Phillips and Matchan (2013) we did not ap ply bias cor rec tions, but ana lysed sam ples and stan dards in the same tray (and thus at more or less the same time) al ter nat ing with air pi pettes of dif fer ent in ten si ties in the same range as the sam ples and stan dards. Line blanks were mea sured ev ery 2–3 un knowns and were sub tracted from suc - ceed ing sam ple data.
Sin gle grain fu sions were per formed on 25 bi o tite and 15 sanidine sam ples (only size frac tion 400–500 mm). Data re duc - tion was done in ArArCalc (Koppers, 2002). Ages were cal cu - lated with Min et al. (2000) de cay con stants and 28.201 ± 0.022 My for FCs (Kuiper et al., 2008). The at mo spheric air value of 298.56 from Lee et al. (2006) was used. The cor rec tion fac tors for neu tron in ter fer ence re ac tions are (2.64 ± 0.02) ´ 10–4 for (36Ar/37Ar)Ca, (6.73 ± 0.04) ´ 10–4 for (39Ar/37Ar)Ca, (1.21
± 0.003) ´ 10–2 for (38Ar/39Ar)K and (8.6 ± 0.7) ´ 10–4 for (40Ar/39Ar)K. All er rors are quoted at the 2s level and in clude all an a lyt i cal er rors. All rel e vant an a lyt i cal data for age cal cu la tions can be found in the on line sup ple men tary ma te rial.
BIOSTRATIGRAPHY
Four sam ples ex tracted from the depths 684.0, 650.2, 648.8 and 648.5 m were used in the micropalaeontological anal y sis of cal car e ous nannoplankton. The rock sam ples were used to pre pare smear slides by the stan dard method de - scribed by Báldi-Beke (1984) to carry out mi cro scopic ob ser va - tions. For the pur pose of light mi cro scope ex am i na tion, a fine wa ter sus pen sion of each sam ple was spread on a glass slide.
A drop of the sus pen sion was placed on the slide af ter stir ring and a short pe riod of set tling. Once the drop had dried, the slide was cov ered with Can ada bal sam and cov ered with glass. The smear slides were in spected with a Nikon Eclipse LV100POL light mi cro scope at 1,000´ mag ni fi ca tion. Biostratigraphic de - ter mi na tions fol lowed the nannoplankton lev els of Mar tini (1971), Mar tini and Müller (1986), Young (1998) and Švábenická (2002).
Foraminifers were stud ied in 4 core sam ples col lected from the depths 684.0, 650.2, 648.8 and 648.5 m. The rock sam ples were fairly small in vol ume: 684.0 m: 250 g, 650.2 m: 350 g, 648.8 m: 209 g, 648.5 m: 450 re spec tively. All sam ples were sub jected to stan dard mac er a tion and levigation meth ods (Na2SO4, sieve: 0.063 mm). Ow ing to in ad e quate re sults ad di - tional pro cesses us ing liq uid ni tro gen were ap plied to the sam - ples col lected from 648.5 and 648.8 m. Spe cies iden ti fi ca tion was con ducted by use of a HUND-TECH Mi cro SST mi cro - scope with foraminifer tax on omy gen er ally ac cord ing to Cicha et al. (1998). Pho to graphs of the se lected foraminifera were taken with out spec i men spray ing, us ing a FEI en vi ron men tal scan ning elec tron mi cro scope (ESEM), model QUANTA 200FEG, at the Lab o ra tory of the Fac ulty Ge ol ogy, Geo phys ics and En vi ron men tal Pro tec tion, AGH Uni ver sity of Sci ence and Tech nol ogy in Kraków.
RESULTS
PETROGRAPHIC STUDY
The tuffite rep re sents typ i cal vitroclastic and vitrophyric tex - ture and par al lel-lam i nated, fine- to coarse-grained struc tures (pyroclasts <2 mm across). Vol ca nic glass shards and smaller pro por tions of bi o tite, plagioclase, sanidine, and pyroclastic
quartz crys tals dom i nate. Oc ca sion ally, heavy min er als such as zir con, al la nite (a min eral of the epidote group), and ap a tite oc - cur. In thin sec tion, the glass shards are rel a tively thick with sharp edges. Platy and cuspate bub ble-wall types of shards are colour less and iso tro pic. They vary in size from 0.05 to 0.2 mm across (Fig. 4). They are usu ally well-pre served and show some traces of devitrification in the outer parts of the grains only (Figs. 4 and 5).
The SEM/EDS anal y sis showed that the SiO2 con tent of the glass is rel a tively sta ble: 76.3–79.0%. Sim i larly, the Al2O3 con - tent shows no sig nif i cant dif fer ences (12.0–14.3%). The con - tents of K2O, Na2O, CaO, and Fe2O3 dis play slight fluc tu a tions, within gen er ally con stant ranges (Ap pen dix 1*). In ter est ingly, the bar ium con tent is rel a tively high (0.8–2.2%) in the vol ca nic glass. These re sults in di cate that the chem i cal com po si tion of the vol ca nic glass is typ i cal of ash of rhyolitic or i gin.
Euhedral crys tals of bi o tite, in the form of black hex ag o nal tab lets and blocks, are ar ranged unidirectionally and emphasise the lay ered rock tex ture. Some bi o tite plates are bent or bro ken (Figs. 4 and 5), but most are un dam aged and reach up to 1 mm across. Quartz grains are an gu lar with sharp edges. They ex hibit dis tinct traces of mag matic cor ro sion (Fig. 5A, D) in di cat ing their vol ca nic or i gin (pyroclastic quartz, Alexandrowicz, 1957). The quartz grain di am e ter reaches 2 mm.
Plagioclase feld spar grains (~An20-30) oc cur com monly and are usu ally non-weath ered and rarely cracked. They in clude abun dant polysynthetic (al bite law) or mul ti ple twinning. The SEM/EDS anal y ses showed that most of the plagioclases are an de sine and oligoclase, with var i ous chem i cal com po si tions ob served in sin gle crys tals. Sanidine crys tals (up to 1 mm across) oc cur less fre quently; usu ally twinning was vis i ble, in ac cor dance with the Carlsbad law (Figs. 4C and 5E).
Mag ne tite and py rite, be ing opaque min er als, oc cur rarely in the sam ples. In di vid ual, large crys tals of al la nite (2 mm) with small in clu sions of monazite and zir con (Fig. 5G) were iden ti fied by the SEM/EDS method.
The tuffite ma trix con sists mainly of fine-grained glass and its trans for ma tion prod ucts, and clay min er als. The coarse-grained tuffite is grain-sup ported with sparse ma trix.
The fine-grained tuffite is dom i nantly ma trix-sup ported. The pro por tion of clay min er als in creases grad u ally be tween the two types (Fig. 5).
RADIO-ISOTOPE DATING
For the sanidine min eral anal y ses, all 40Ar/39Ar mea sure - ments with a high per cent age of ra dio genic 40Ar* (>85%) and a K/Ca>5 are con sid ered re li able. This is valid for 9 out of 15 sin - gle grain mea sure ments of the Kaczyce-2 tuff. Their com plete age range is 14.22 ± 0.02 and 14.31 ± 0.01 Ma. Three groups with mean ages of 14.22 (n = 1), 14.26–14.27 Ma (n = 3) and 14.29–14.31 Ma (n = 5), re spec tively, are dis tin guished. Due to the volcanoclastic na ture of the tuff, re worked, de tri tal grains might be pres ent in the sam ple. These com po nents are older than the erup tion age, so the old est group likely does not rep re - sent the erup tion age. Fol low ing this rea son ing, the youn gest re li able re sult with an age of 14.22 ± 0.01 Ma is the best es ti - mate of the erup tion age. Al ter na tively, we could as sume that some 40Ar loss oc curred, and that the erup tion age is ap prox i - mated best by a sta tis ti cally sound mean value (data points are in cluded un til MSWD > T-test sta tis tic us ing a 2s con fi dence limit). This ap proach is sim i lar to U/Pb stud ies where the youn - gest grain(s) might rep re sent Pb loss and the old est grain(s)
xenocrystic com po nents (see e.g., Sahy et al., 2015). In this case the tuff has an age of 14.27 ± 0.03 Ma in clud ing all er rors us ing the ap proach of Kuiper et al. (2008).
For the bi o tite sep a rate, the per cent age of 40Ar* of the 25 mea sured ranges from ~30–99% where the lower ra dio genic
40Ar yields sug gest some de gree of al ter ation. The 40Ar in ten si - ties range from 18–196 fA and with blank val ues of ~10fA this is close to the de tec tion lim its of the sys tem (Ap pen dix 2). An a lyt i - cal un cer tain ties are there fore rel a tively large for these bi o tite grains and sin gle crys tal anal y ses do not yield re sults that can be used for high-res o lu tion age de ter mi na tion. Nev er the less, the age range of the six youn gest grains over laps with the sta - tis ti cally sound mean age value de ter mined from 40Ar/39Ar dat - ing on sanidine grains from the same sam ple (Fig. 6).
MICROPALAEONTOLOGICAL STUDY
Cal car e ous nannoplankton. In the sam ple col lected of the bot tom part of the Skawina lay ers (684 m), di rectly above the Dêbowiec con glom er ate level, nu mer ous but poorly pre - served cal car e ous nannoplankton as sem blages with Coccolithus pelagicus (Wallich) Schiller, Helicosphaera carteri (Wallich) Kamptner, Reticulofenestra pseudoumbilica (Gart ner) Gart ner, and small Reticulofenestra spe cies oc curred. Less fre - quent were Pontosphaera multipora (Kamptner) Roth, Umbilicosphaera rotula (Kamptner) Varol, Helicosphaera waltrans Theodoridis, and H. aff. walbersdorfensis Müller, Cyclicargolithus floridanus (Roth et Hay) Bukry, Cy. abisectus (Müller) Wise, Calcidiscus premacintyrei Theodoridis, Umbilicosphaera jafarii Müller, Coccolithus miopelagicus Bukry, Sphenolithus heteromorphus Deflandre, C. macintyrei (Bukry et Bramlette) Loeblich et Tappan, H. sellii (Bukry et Bramlette) Jafar et Mar tini, and Braarudosphaera bigelowii (Gran et Braarud) Deflandre ap peared as in di vid u als.
In a shal lower sam ple (650.2 m), a sparse Mio cene nannoplankton as sem blage in clud ing H. carteri, C. pelagicus, R. pseudoumbilica, small-sized Reticulofenstra spe cies, and sin gle spec i mens of Cy. floridanus, U. rotula, U. jafarii, C.
miopelagicus, P. multipora, H. walbersdorfensis, Cd.
premacintyrei, S. heteromorphus, Holodiscolithus macroporus (Deflandre) Roth, and S. abies Deflandre was indentified.
An even more tax o nom i cally im pov er ished nannoplankton as so ci a tion was found in the sam ple col lected from the green - ish silts at a depth of 648.5 m. The sam ple con tains mainly nu - mer ous frag ments of placoliths, among oth ers Reticulofenestra and C. pelagicus dom i nated. Sin gle oc cur rences of poorly pre - served H. carteri, U. jafarii, H. waltrans, Cy. floridanus, and Discoaster sp. were ob served. The edges and sur faces of the coccoliths’ plates bear traces of dis so lu tion and cor ro sion.
No cal car e ous nannoplankton were found in the sam ple col lected from the thin mudstone layer from 648.8 m depth. Re - de pos ited spe cies from the Eocene, Eocene–Oligocene, and Cre ta ceous were iden ti fied in the sam ples ex am ined.
Foraminifera. The low er most rock sam ple from the Skawina For ma tion (684 m) con sists of a foraminiferal as sem - blage with a vari able pres er va tion and recrystallization grade.
Many spec i mens could not be de ter mined. The de ter mi na ble as sem blage is char ac ter ized by a mass oc cur rence of plank - tonic spe cies (Fig. 8) rep re sented mainly by Globorotalia bykovae Pishvanova, Globigerinita glutinata (Aisenstat), Globigerina tarchanensis Subbotina et Chutzieva, G. bulloides d’Orbigny, G. praebulloides Blow, Paragloborotalia cf.
pseudopachyderma (Cita, Premoli Silva et Rossi),
* Supplementary data associated with this article can be found, in the online version, at doi: 10.7306/gq.1402
Fig. 4. SEM images of separated grains of pyroclasts
A – euhedral crystals of biotite, in the form of hexagonal tablets; B – biotite plate with an ingrown crystal of apatite; C – twinned sanidine crystal; D – plagioclase crystal within volcanic glass; E – separated grains of
volcanic glass; sample K2/4, depth 450.1 m, Kaczyce K2/07
Fig. 5. Light microscope images of the coarse-grained tuff, sample K2/4, depth 450.1 m, Kaczyce K2/07
A – large grain of embayed pyroclastic quartz with traces of mag matic cor ro sion, plagioclase and bi o tite, crossed po lar ized light (XPL); B – bi o tite plate (in the cen tre of pho to graph), XPL; C – os cil la tory zoned plagioclase grain (in the cen tre) be tween two large quartz grains, XPL;
D – coarse-grained tuff com posed of bro ken grains of plagioclase with polysynthetic twinning, pyroclastic quartz and sin gle grains of car bon - ates, XPL; E – large sanidine crys tal, sim ple twinned, in a groundmass of ma te rial re sult ing from devitrification of vol ca nic glass, XPL; F – vol - ca nic glass shards, pum ice type and the ob sid ian “Y” shape, or di nary light; G – large, bro ken al la nite grain with fine in clu sions of monazite and zir con, XPL; H – plagioclase grain (cen tre of pho to graph) with well-de vel oped twinning, XPL
Globigerinella obesa (Bolli), Globigerinoides bisphericus Todd, Gl. trilobus (Reuss), Orbulina suturalis Bronnimann, Praeorbulina glomerosa glomerosa (Blow), P. transistoria (Blow). Globorotalia bykovae dom i nate. The microfossil as - sem blage ex am ined also in cludes frag ments of sea-ur chin spines.
Ben thic foraminifera are rare and are mainly rep re sented by: Melonis pompilioides (Fichtel et Moll), Angulogerina esuriens Hornibrook, Bulimina inflata Sequenza and sin gle spec i mens of Cibicidoides conspiciendus Pishvanova (Fig. 7).
Spo radic ag glu ti nated foraminifers also oc cur but they most prob a bly were re de pos ited from the Carpatian flysch de pos its.
The sec ond sam ple is lo cated be low the tuffites (650.2 m) and yielded nu mer ous foraminifers both in a good pres er va tion state and in a de formed recrystallized or pyritised form (Fig. 7).
Ben thic foraminifers are dom i nated by Nonionella turgida (Wil - liam son) and Virgulinella pertusa (Reuss), and ac com pa nied by Chilostomella ovoidea Reuss, Allomorphina trigona Reuss and Globocassidulina subglobosa (Brady). Plank tonic foraminifers are dom i nated by small spe cies: Globigerinita glutinata and G.
tarchanensis, ac com pa nied by sin gle spec i mens of Globigerinella obesa, Globigerinoides trilobus, and Globorotalia bykovae (Ap pen dix 3).
The third (648.8 m) and fourth (648.5 m) sam ples are prac ti - cally de void of microfossils and are rep re sented only by de - formed foraminifers and sponge spicules.
DISCUSSION
BIOSTRATIGRAPHY AND ENVIRONMENT
Cal car e ous nannoplankton. The sam ples from the depths 684.0, 650.2 and 648.5 m, were as signed to the NN5 Zone based on the pres ence of H. carteri, C. pelagicus , R.
pseudoumbilica, and small Reticulofenestra spe cies.
Helicosphaera ampliaperta Bramlette et Wilcoxon, the last oc - cur rence (LO) of which de fined the bound ary be tween zones NN4 and NN5, was ab sent in the sam ples analysed. The stratigraphically im por tant spe cies for the NN5 Zone, S.
heteromorphus, was rep re sented as in di vid u als at the depths of 684.0 and 650.0 m.
The di ag nos tic spe cies for Lower Badenian strata of the Cen tral Paratethys, H. waltrans, oc curred in the sam ples from 684.0 and 648.5 m depth (i.e. Švábenická, 2002; Rögl et al., 2006; Tomanova-Petrová and Švábenická, 2007;
Melinte-Dobrinescu and Stoica, 2014). In the lo cal nannoplank - ton zonation of the west ern Cen tral Paratethys ac cord ing to Bartol (2008), the first oc cur rence (FO) of H. waltrans de fined the in ter val MuN5a that cor re lates with the low er most part of NN5 in the stan dard zonation of Mar tini (1971). The LO of this spe cies marks also the up per limit of the MuN5c in ter val which can be cor re lated with the MNN5b biozone of Di Stefano et al.
(2008) and with the up per bound ary of the Helicosphaera waltrans Subzone in Theodoridis’ zonation (1984) in the Med i - ter ra nean re gion. In the East ern Paratethys H. waltrans was re - corded in a short in ter val within the NN5 Zone (Tarkhanian Stage, lower Badenian) with H. carteri, H. intermedia Mar tini and S. heteromorphus (Andreyeva-Grigorovich and Savitskaya, 2000; Grigorovich, 2001). Ac cord ing to Švábenicka (2000), Æoriæ and Rögl (2004), Æoriæ et al. (2007) and Hohenegger et al. (2009), the FO of H. waltrans is diachronous in the east ern and west ern part of the Cen tral Paratethys, as well as in the Med i ter ra nean re gion (Fornaciari et al., 1996; Di Stefano et al., 2008). Fornaciari (in: Fornaciari et al., 1996) cor - re lated the range of H. waltrans with the up per part of the MNN5a and lower part of the MNN5b Subzones whereas Di Stefano et al. (2008) and Švábenicka (2002) men tioned that the ranges of H. waltrans and H. ampliaperta over lap. Ac cord ing to Theodoridis (1984) the com mon oc cur rence of this form was
Fig. 6. Summary of 40Ar/39Ar results of sanidine and biotite minerals of sample KAC (core sample K2/4)
In di vid ual ages are shown in ranked or der with 2s an a lyt i cal er ror bars. The three red ver ti cal bars mark the sanidine sam ples used to cal cu late the weighted mean age that is marked by the red hor i zon tal bar.
The pink shaded area in di cates the un cer tainty lim its fol low ing Kuiper et al. (2008). The blue ver ti cal bar in di cates the sanidine grain with the youn gest age. The youn gest gen er a tion bi o tite grains over lap with the ages de rived from the sanidines
Fig. 7. Foraminifera from Kaczyce K2/07 borehole
Depth 684.0 m A–H: A – Orbulina suturalis Bronnimann; B, C – Praeorbulina glomerosa glomerosa (Blow); D – Praeorbulina transistoria (Blow); E, F – Globigerinoides bisphericus Todd; G, H – Globorotalia bykovae (Aisenstat); I – Paragloborotalia mayeri (Cushman et Ellisor); J – Globigerinella obesa (Bolli); K–M – Globigerina glutinata (Egger); N, O – Globigerina tarchanensis Subbotina et Chutzieva; P, R – Cibicidoides conspiciendus Pishvanova; S – Angulogerina esuriens Hornibrook;
depth 650.2 m 19–22: T – Virgulinella pertusa (Reuss); U – Nonionella turgida (Wil liam son); W – Chilostomella ovoidea Reuss, Z – Allomorphina trigona Reuss
ob served only above the LO of H. ampliaperta. In con trast to the FOs the last com mon oc cur rence (LCO) of H. waltrans dated at 14.36 Ma (Ab dul Azizi et al., 2008) in the Med i ter ra - nean re gion can be used as a syn chro nous event and de fines the top of the MNN5a Subzone (Fornaciari and Rio, 1990) and also the top of the Cen tral Paratethyan Lagenidae Zone. In the Paratethys the LCO of this form was re corded at 14.39 Ma (the Styrian Ba sin: Hohenegger et al., 2009; Holcová, 2017) which agrees ap prox i mately with the dat ing in the Med i ter ra nean, with which the Cen tral Paratethys was con nected at that time.
Based on the oc cur rence of H. waltrans and small reticulofenestrids, C. premacintyrei, S. heteromorphus and P.
multipora, the part of the sec tion stud ied can be cor re lated with the lower part of the NN5 Zone sensu Švábenická (2002).
The re sults ob tained sup port pre vi ous cal car e ous nannoplankton stud ies from bore holes in the Cieszyn area (Garecka and Olszewska, 1995, 1998; Garecka et al., 1996;
Olszewska and Garecka, 1996; Moryc, 2005). In the bot tom part of the Skawina Beds in the Zebrzydowice 13 bore hole (~6 km E of the Kaczyce K2/07), the NN5 Zone was iden ti fied based on the oc cur rence of S. heteromorphus and lack of H.
ampliaperta (e.g., Mar tini and Müller, 1986).
Foraminifera. The foraminiferal as sem blage rec og nized in the first sam ple (684.0 m) cor re sponds to the Orbulina sutura - lis–Praeorbulina glomerosa Zone (ac cord ing to Cicha et al., 1975; Fig. 8) and can be cor re lated with the re gional IIA and IIB As sem blage Zone (Alexandrowicz, 1963b; Ta ble 1).
Orbulina suturalis Bronnimann has the best strati graphic value among the foraminifers which oc cur abun dantly in the first sam ple (684.0 m). In the oce anic realms, such as the At lan tic, the FO of O. suturalis is dated at 15.1 Ma (Wade et al., 2011). In the Med i ter ra nean bio-zonation its FO is as tro nom i cally dated at 14.56 Ma (Ab dul Aziz et al., 2008), and marks the base of the MMi5a subzone.
The foraminiferal as sem blage iden ti fied in the sam ple above 650.2 m does not con tain any in dex spe cies. The com - po si tion of the ben thic foraminiferal as sem blage, and, pri mar ily,
the pres ence and dom i na tion of the spe cies Nonionella turgida (Wil liam son), Virgulinella pertusa (Reuss), Chilostomella ovoidea Reuss, and Allomorphina trigona Reuss, in di cate dysoxic (cf. Peryt, 2013) con di tions, which is sup ported by very fre quent spec i men pyritisation. A sim i lar as sem blage was de - scribed from a nearby ex po sure at Stara Wieœ near Bielsko (Porêbska-Szotowa in Nowak, 1976). There, the base of the suc ces sion was cat e go rized as the Orbulina suturalis Zone (Cicha et al., 1975). There fore, the foraminiferal as sem blage of the 650.2 m sam ple prob a bly be longs to the same zone.
Ac cord ing to Hohenegger et al. (2009 with ref er ences therein) co-oc cur rence of the nannoplankton spe cies Helicosphaera waltrans and foraminiferal spe cies Praeorbulina glomerosa glomerosa cor re sponds to the re gional Cen tral Paratethyan Lower Lagenidae Zone (Grill, 1941) mean ing that the as sem blage from 684.0 m depth cor re sponds to this zone (Fig. 8). The Lower Lagenidae Zone (Grill, 1941) ends with the LCO (Last Com mon Oc cur rence) of H. waltrans (Hohenegger and Wagreich, 2012) dated at 14.357 ± 0.004 Ma (Ab dul Aziz et al., 2008). Ac cord ing to the ra dio-iso to pic data of the tuffitic ho ri - zon (14.27 ± 0.03 Ma) the low er most part of the Skawina For - ma tion rep re sents, most prob a bly, the Lower Lagenidae Zone – the low er most Up per Lagenidae Zone (Grill, 1941).
AGE OF THE BADENIAN FLOODING
Re gard less of the fol lowed biozonation, the biostratigraphic con straints for the basal Skawina For ma tion over lap with each other, and with the ra dio-iso to pic age de ter mined (Fig. 8). The
40Ar/39Ar tuff age (14.27 ± 0.03 Ma) from ~30 m above the base of the Skawina For ma tion is in agree ment with the NN5 and MNN5a nannofossil zones de ter mined (Fig. 8).
The oc cur rence of Orbulina suturalis, Praeorbulina glomerosa glomerosa, Pr. transitoria and Globorotalia bykovae in the Skawina For ma tion is known from other bore holes in the Carpathians (Garecka et al., 1996 and ref er ences therein;
Moryc, 2005 and ref er ences therein). This in di cates that the
Fig. 8. Correlation of Kaczyce K2/07 borehole to the time scale by biostratigraphic events and the radioisotopic age of the tuffite
Ranges of O. suturalis and P. glomerosa after Abdul Aziz et al. (2008) and Iaccarino et al. (2011)
max i mum age for the on set of deeper ma rine de po si tion in the study area is es ti mated at ~14.56 Ma (FO O. suturalis, Ab dul Aziz et al., 2008).
Ac cord ing to Kováè et al. (2007) there were two early Badenian trans gres sions in the Cen tral Paratethys. The first trans gres sion is doc u mented by plank tonic foraminiferal as - sem blages with Praeorbulina sicana and Pr. glomerosa within the cal car e ous nannoplankton NN4 Zone es ti mated at
~16.4-16.2 Ma (e.g., Hohenegger et al., 2009). The sec ond Badenian trans gres sion is char ac ter ized by plank tonic foraminiferal as so ci a tions with Praeorbulina circularis and Orbulina suturalis within the nannoplankton NN5 Zone, which should roughly cor re spond to the age range 14.9–14.6 Ma (Ab - dul Aziz et al., 2008; Iaccarino et al., 2011). Our re search on foraminifers and cal car e ous nannoplankton in di cates that the study area was af fected by the sec ond trans gres sion, sensu Kováè et al. (2007).
This trans gres sion was most likely forced by a com bi na tion of tec ton ics and eustasy; the Mi3b sea level rise (~14.9 Ma) might have as sisted the trans gres sion (Kominz et al., 2008;
John et al., 2011). Ar eas with a sim i lar age for the flood ing are re ported from many other re gions of the Cen tral Paratethys, in - clud ing the South Slo vak ba sin (Vass, 2002), North Cro atian bas ins (Æoriæ et al., 2009) and in ner Ukrai nian Carpathian Foredeep (e.g., Andreyeva-Grigorovich et al., 1997; Gozhyk et al., 2015).
CORRELATION OF VOLCANIC ASH LAYERS
Many Mio cene se quences of the Carpathian Foredeep con - tain pyroclastic interbeds (mainly tuffites). They are ob served in the Up per Silesia Ba sin, near Kraków and Wieliczka, as well as along the south ern mar gin of the Holy Cross Mts (e.g., Parachoniak, 1962; Dudek and Bukowski, 2004; Dudek et al., 2004; Bukowski et al., 2010; Bukowski, 2011, 2015). At least two of the pyroclastic lay ers have a char ac ter is tic min eral com - po si tion and oc cupy a sta ble strati graphic po si tion re gion ally.
These could be used as lithostratigraphic ho ri zons for the pur - pose of re gional cor re la tion. Alexandrowicz (1997) pro posed a
“bed” rank for them, re cog nis ing them as for mal lithostratigraphic units. The first pyroclastic layer oc curs in the lower part of the Skawina For ma tion and con tains char ac ter is tic foraminiferal as sem blages IIA or IIAB (Ta ble 1). The layer’s pres ence was con firmed by a num ber of pro files col lected in the Carpathian Foredeep, e.g. sev eral pro files from Che³mek and Che³m Wielki on the Przemsza River (Parachoniak, 1960;
Alexandrowicz and Pawlikowski, 1978) as well as ¯ory (Alexandrowicz, 1963b). This tuffite ho ri zon is called the Che³mek Tuffite Bed (Alexandrowicz, 1997).
The pe trog ra phy of the Che³mek Tuffite was de scribed in de tail by Parachoniak (1962) and Alexandrowicz and Pawlikowski (1978). The au thors iden ti fied a sim i lar ity with the tuffite col lected from bore hole Kaczyce K2/07. The spe cific sam ples dis played a char ac ter is tic high pro por tion of pyroclastic quartz (which was ei ther ab sent in other tuffite lev els or oc curred only in small pro por tions) and a sim i lar chem i cal com po si tion of vol ca nic glass (Ap pen dix 1).
The lithostratigraphic po si tion of the lay ers sit u ated in the lower part of the clayey de pos its of the Skawina For ma tion are very sim i lar to the pre vi ously ex am ined ones in the Brzezówka IG 1 pro file, lo cated in the vi cin ity of Kaczyce K2/07
(3 km SE; Alexandrowicz, 1963b). There, the tuffite layer oc - curs ~70 m above the Car bon if er ous base ment, within grey clays with sand in ter ca la tions (Schlier fa cies) and con tains a ben thic foraminifer as sem blage rep re sent ing the II AB Zone (Alexandrowicz, 1963b) cor re spond ing to the Orbulina suturalis–Praeorbulina glomerosa Zone (Cicha et al., 1975).
Con sid er ing the re spec tive re sults and close vi cin ity of the Kaczyce 2/07 and Brzezówka IG 1 bore holes, the tuffites oc cur - ring in both bore holes are most likely of a sim i lar age.
The re sults of our study al low us to cor re late the tuffite from the Kaczyce K2/07 bore hole at the level of the Che³mek Tuffite Bed (Alexandrowicz, 1997) and use it for re gional cor re la tion and dat ing. This vol ca nic ash fall (14.27 ± 0.03 Ma) co in cides in time with a pe riod of in ten sive ex tru sive vol ca nism in the Carpathian area. The on set of this ac tiv ity, af ter the first oc cur - rence (FO) of Orbulina suturalis, con firmed by 40Ar/39Ar dat ing, e.g. the Dej Tuff in Transylvanian Ba sin – 14.37±0.06 Ma (de Leeuw et al., 2013), or the tuff from Retznei Quarry in the Styrian Ba sin: 14.39±0.12 Ma – sanidine and 14.21±0.07 Ma bi o tite (Han dler et al., 2006). It is dif fi cult to clearly in di cate the lo ca tion of the erup tive cen tre. One po ten tial area is the Bükkalja vol ca nic field in north ern Hun gary (e.g., Lukács et al., 2009). The last ma jor vol ca nic event oc curred there at 14.1 ± 0.3 Ma (Harsány ignimbrite, Lukács et al., 2015). Cor re - la tion of the tuffite from the Kaczyce K2/07 with the Harsány ignimbrite erup tion event is sup ported also by a sim i lar min eral as sem blage in volv ing quartz, the com po si tion of the plagioclases, bi o tite, spo radic K-feld spar, zir con, al la nite and ap a tite (Lukács et al., 2009).
CONCLUSIONS
Our ra dio-iso to pic, petrographic and biostratigraphic data of the tuff-bear ing lower Skawina For ma tion from the Kaczyce K2/07 bore hole core has pro vided new in sights into the age and cor re la tion of the lower Badenian de pos its in the Pol ish Carpathian Foredeep.
Our biostratigraphic data with Orbulina suturalis and Praeorbulina glomerosa glomerosa show that the basal beds of the Skawina For ma tion up to the tuffites cover the re gional in - ter val of the Lower Lagenidae Zone – low er most Up per Lagenidae Zone (Grill, 1941). In the over ly ing tuff, the weighted mean 40Ar/39Ar age based on sanidine min er als is 14.27 ± 0.03 Ma.The mean age based on (par tially weath ered) bi o tite min er als from the same sam ple over laps with the sanidine age.
The 40Ar/39Ar tuff age is in agree ment with the NN5 and MNN5a Zones de ter mined with the cal car e ous nannofossil He lico - sphae ra waltrans. The volcanoclastic in ter val has a char ac ter - is tic pe trog ra phy (pyroclastic quartz-rich) and may be used as a lithostratigraphic marker ho ri zon in re gional cor re la tion, such as to the very sim i lar Che³mek Tuffite Bed (Alexandrowicz, 1997).
Ac knowl edge ments. We would like to spe cially thank I. Lipiarski and J. Misiak (Coal Ge ol ogy Re search Group, AGH Uni ver sity of Sci ence and Tech nol ogy) whose help dur ing col - lec tion of the sam ples was valu able, and R. Elsas (VU Uni ver - sity Am ster dam) for as sis tance in the min eral sep a ra tion lab.
This in ves ti ga tion was sup ported by the Neth er lands Geosciences Foun da tion (ALW) with fund ing from NWO through the VICI grant to WK and by pro jects AGH nos.
11.11.140.320 and 11.11.140.005.
REFERENCES
Ab dul Aziz, H., Di Stefano, A., Foresi, L.M., Hilgen, F.J., Iaccarino, S.M., Kuiper, K.F., Lirer, F., Salvatorini, G., Turco, E., 2008. In te grated stra tig ra phy and 40Ar/39Ar chro nol ogy of early Mid dle Mio cene sed i ments from DSDP Leg 42A, Site 372 (West ern Med i ter ra nean). Palaeo ge ogra phy, Palaeoclimato - logy, Palaeo ec ol ogy, 257: 123–138.
Alexandrowicz, S.W., 1957. Pyroclastic quartz from Tortonian sed i - ments in the Cra cow area (in Pol ish with Eng lish sum mary).
Biuletyn Instytutu Geologicznego, 115: 27–61.
Alexandrowicz, S.W., 1963a. Stra tig ra phy of the Mio cene de pos its in the Up per Silesian Ba sin (in Pol ish with Eng lish sum mary).
Prace Instytutu Geologicznego, 39: 1–147.
Alexandrowicz, S.W., 1963b. Sed i ments of the Lower Tortonian at Brzezówka, near Cieszyn (in Pol ish with Eng lish sum mary), Kwartalnik Geologiczny, 7 (2): 319–336.
Alexandrowicz, S.W., 1997. Lithostratigraphy of the Mio cene de - pos its in the Gliwice area (Up per Silesia, Po land). Bul le tin of the Pol ish Acad emy of Sci ence, Earth Sci ences, 45: 167–179.
Alexandrowicz, S.W., Pawlikowski, M., 1978. Mio cene tuffites from Che³m Wielki on Przemsza River (in Pol ish with Eng lish sum mary). Kwartalnik Geologiczny, 22 (1): 131–147.
Alexandrowicz, S.W., Garlicki, A., Rutkowski, J., 1982.
Podstawowe jednostki litostratygraficzne miocenu zapadliska przedkarpackiego (in Pol ish). Kwartalnik Geologiczny, 26 (2):
470–471.
Andreyeva-Grigoroviè, A.S., Savitskaya, N.A., 2000.
Nannoplankton of the Tarkhanian de pos its of the Kerch Pen in - sula (Cri mea). Geologica Carpathica, 51: 399–406.
Andreyeva-Grigorovich, A.S., Kulchytsky, Y.O., Gruzman, A.D., Lozynyak, P.Y., Petrashkevich, M.I., Portnyagina, L.O., Ivanina, A.V, Smirnov, S.E., Trofimovich, N., Savitskaya, N., Shvareva, N.J., 1997. Re gional strati graphic scheme of Neo - gene for ma tions of the Cen tral Paratethys in the Ukraine.
Geologica Carpathica, 48: 123–136.
Báldi-Beke, M., 1984. The nannoplankton of the Transdanubian Palaeogene for ma tions (in Hun gar ian with Eng lish sum mary).
Geologica Hungarica, Se ries Palaeontologica, 43: 3–307.
Bartol, M., 2008. Mid dle Mio cene cal car e ous nannoplankton of NE Slovenia (west ern Cen tral Paratethys). Paleontološki Inštitut Ivana Rahovca ZRC SAZU Ljublana: 5–136.
Bogacz, W., Kotarba, M., Krach, J., 1984. Struc tural fea tures of the coal-bear ing strata In the south ern part of the Rybnik Coal Dis trict (South ern Po land). Annales Societatis Geologorum Poloniae, 54: 361–377.
Bukowski, K., 2011. Badenian sa line sed i men ta tion be tween Rybnik and Dêbica based on geo chem i cal, iso to pic and ra dio - met ric re search (in Pol ish with Eng lish sum mary). Rozprawy i Monografie, 236.
Bukowski, K., 2015. Mio cene tuffite lev els from the Busko (M³yny) PIG-1 and Kazimierza Wielka (Donosy) PIG-1 bore holes (in Pol - ish with Eng lish sum mary). Biuletyn Pañstwowego Instytutu Geologicznego, 461: 79–94.
Bukowski, K., de Leeuw, A., Gonera, M., Kuiper, K.F., Krzywiec, P., Peryt, D., 2010. Badenian tuffite lev els within the Carpathian orogenic front (Gdów–Bochnia area, South ern Po land):
radioisotopic dat ing and strati graphic po si tion. Geo log i cal Quar - terly, 54 (4): 449–464.
Bu³a, Z., Jura, D., 1983. Litostratygrafia osadów rowu przedgórskiego Karpat w rejonie Œl¹ska Cieszyñskiego (in Pol - ish). Zeszyty Naukowe AGH, Geologia, 9: 5–27.
Cicha, I., Ètyroká, J., Zapletalová, I., Vanova, M., 1975. East Alps and West Carpathian bas ins: ma rine zones of ben thic foraminifera. In: Biozonal Sub di vi sion of the Up per Ter tiary Bas - ins of the East ern Alps and West Carpathians (ed. I. Cicha):
34–40. Pro ceed ings of the VIth Con gress RCMNS, Geol. Surv.
Prague.
Cicha, I., Rögl, F., Rupp, Ch., Ctyroka, J., 1998. Oligocene–Mio - cene foraminifera of the Cen tral Paratethys. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft, 549.
Æoriæ, S., Rögl, F., 2004. Roggendorf-1 bore hole, a key-sec tion for Lower Badenian trans gres sions and the strati graphic po si tion of
the Grund For ma tion (Molasse Ba sin, Lower Aus tria).
Geologica Carpathica, 55: 165–178.
Æoriæ, S., Švábenická, L., Rögl, F., Petrová, P., 2007. Strati graphi - cal po si tion of Helicosphaera waltrans nannoplankton Ho ri zon (NN5, Lower Badenian). Joannea – Geologie und Paläonto - logie, 9: 17–19.
Æoriæ, S., Paveliæ, D., Rögl, F., Mandic, O., Vrabac, S., 2009. Re - vised Mid dle Mio cene da tum for ini tial ma rine flood ing of North Cro atian Bas ins (Pannonian Ba sin Sys tem, Cen tral Paratethys).
Geologia Croatica, 62: 31–43.
De Leeuw, A., Filipescu, S., Maïenco, L., Krijgsman, W., Kuiper, K., Stoica, M., 2013. Paleomagnetic and chronostratigraphic con straints on the Mid dle to Late Mio cene evo lu tion of the Transylvanian Ba sin (Ro ma nia): im pli ca tions for Cen tral Paratethys stra tig ra phy and em place ment of the Tisza–Dacia plate. Global and Plan e tary Change, 103: 82–98.
Di Stefano, A., Foresi, L.M., Lirer, F., Iaccarino, S.M., Turco, E., Amore, F.O., Morabito, S., Salvatorini, G., Mazzei, R., Ab dul Aziz, H., 2008. Cal car e ous plank ton high res o lu tion bio-magnetostratigraphy for the Langhian of the Med i ter ra nean area. Rivista Italiana di Paleontologia e Stratigrafia, 114: 51–76.
Dudek, K., Bukowski, K., 2004. Badenian pyroclastic level from Gacki in Nida Val ley, Carpathian Foredeep, Po land. Special Pa - pers Min er al og i cal So ci ety of Po land, 24: 141–144.
Dudek, K., Bukowski, K., Heflik, W., 2004. Min er al og i cal char ac - ter is tics of the Bochnia Tuff from the Chodenice Beds (Carpathian Foredeep, S Po land). Mineralogia Polonica, 35:
63–78.
Dopita, M., Kumpera, O., 1993. Ge ol ogy of the Ostrava–Karvina coal-field, Up per Silesian ba sin, Czech Re pub lic and its in flu - ence on min ing. In ter na tional Jour nal of the Coal Ge ol ogy, 23:
291–321.
Doktor, M., 1992. Zró¿nicowanie gruboklastycznych osadów miocenu na obszarze Œl¹ska Cieszyñskiego (in Pol ish). Baseny sedymentacyjne: procesy, osady, architektura. II Krajowe Spotkanie Sedymentologów (Wroc³aw–Sudety, 4–7 IX 1993), Przewodnik: 151.
Doktor, M., 1994. Pozycja i cechy sedymentacyjne zlepieñca dêbowieckiego – trzeciorzêd zachodniej czêœci zapadliska przedkarpackiego (in Pol ish). Sedymentacja normalna, katastroficzna i wyj¹tkowa. Procesy i produkty. III Krajowe Spotkanie Sedymentologów (Sosnowiec, 12–15 IX 1994):
94–95.
Fodor, L., Jelen, B., Márton, E., Skaberne, D., Èar, J., Vrabec, M., 1998. Mio cene–Plio cene tec tonic evo lu tion of the Slovenian Periadriatic fault: im pli ca tions for Al pine-Carpathian ex tru sion mod els. Tec ton ics, 17: 690–709.
Fornaciari, E., Rio, D., 1996. Lat est Oligocene to early mid dle Mio - cene quan ti ta tive cal car e ous nannofossil biostratigraphy in the Med i ter ra nean re gion. Micropaleontology, 42: 1–36.
Fornaciari, E., Di Stefano, A., Rio, D., Negri, A., 1996. Mid dle Mio - cene quan ti ta tive cal car e ous nannofossils biostratigraphy in the Med i ter ra nean re gion. Micropaleontology, 42: 37–63.
Garecka, M., Olszewska, B., 1995. Próba korelacji utworów dolnej molasy na zachód od Krakowa na podstawie otwornic i nannoplanktonu wapiennego (in Pol ish). PIG-PIB OK; NAG OK/450: 1–19.
Garecka, M., Olszewska, B., 1998. Biostratigraphy of the early Mio - cene of the south ern Po land based on plank tonic foraminifera and cal car e ous nannoplankton. Przegl¹d Geologiczny, 46:
712–720.
Garecka, M., Marciniec, P., Olszewska, B., Wójcik, A., 1996. New biostratigraphical data and an at tempt of cor re la tion of Mio cene de pos its un der the overthrusted West ern Carpathians (in Pol ish with Eng lish sum mary). Przegl¹d Geologiczny, 44: 495–501.
Gonera, M., 1997. Mio cene foraminiferal as sem blage in the Gliwice area (Up per Silesia, Po land). Bul le tin of the Pol ish Acad emy of Sci ence. Earth Sci ences, 45: 97–105.
Gonera, M., 2000. Foraminiferida and palaeoenvironment of the Badenian for ma tions (Mid dle Mio cene) in Up per Silesia (Po - land) (in Pol ish with Eng lish sum mary). Studia Naturae, 48.
