GEOLOGICA CARPATHICA, 51, 3, BRATISLAVA, JUNE 2000
COUNTERCLOCKWISE ROTATIONS OF THE NEOGENE ROCKS
IN THE EAST SLOVAK BASIN
, DIONÝZ VASS
and IGOR TÚNYI
ELGI, Columbus u. 17-23, 1145 Budapest, Hungary
Technical University, Department of Environmental Studies, T.G. Masaryka 24, 960 53 Zvolen, Slovak Republic
Geophysical Institute of the SAS, Dúbravská cesta 9, 842 28 Bratislava, Slovak Republic
(Manuscript received March 17, 1999; accepted in revised form March 15, 2000)
Abstract: Paleomagnetic investigation of sedimentary and volcanic rocks of the East Slovak Basin gave information
about the counterclockwise (CCW) rotation of the Neogene units of Eggenburgian to Middle Sarmatian age. The
Eggenburgian sediments (1 loc. 20 spec.) show about 80° CCW rotation, the zeolitized rhyolite tuffs of Lower Badenian
age (2 loc. 19 spec.) show a 40°60° CCW rotation, the rhyolites (1 loc. 3 spec.) of Upper Badenian age about 50°
CCW rotation, the sediments of Lower-Middle Sarmatian age (1 loc. 6 spec.) gave CCW rotation of about 20° and the
youngest post-Sarmatian rhyolite (1 loc. 9 spec.) did not yield any rotation. The rotation was preceded by left lateral
penetration of the Tissia units into the West- and East-Carpathian boundary zone.
Key words: Western Carpathians, East Slovak Basin, Neogene sedimentary and volcanic rocks, paleomagnetism,
Recent communications, concerning paleomagnetism (Orlický
1996) and paleomagnetism plus isotope dating (Márton &
Pécskay 1995) of the north-eastern corner of the Inner Car-
pathians suggest that the counterclockwise declination rota-
tions observed on late Badenian-Sarmatian volcanics might be
of tectonic significance.
Orlický interpreted observations from the East Slovak Basin
(ESB) in terms of fault-related small-scale block movements,
while Márton and Pécskay envisage a kind of triangle, bor-
dered by the Hornád/Hernád-line, the Szolnok-Maramures fly-
sch belt and the NE Outer Carpathians, which could have ro-
tated as a unit in late Sarmatianearly Pannonian times. This
rotation would be about 45 Ma younger than the final coun-
terclockwise rotation of the central part of the Inner Western
Carpathians (Márton & Márton 1996; Márton et al. 1996).
The aim of the present study is to seek support for the coun-
terclockwise rotation in the East Slovak Basin also from sedi-
ments or volcano-sedimentary rocks and constrain the timing.
The sampling sites and localities of the present study are
shown on a schematic geological map in Fig. 1, and on a sche-
matic geological map of the pre-Tertiary basement (Fig. 2).
Geology and tectonics
The ESB started to open as a shear basin in the early Mi-
ocene (Eggenburgian, about 22 Ma B.P.). At the beginning, a
narrow furrow opened along the Pieniny Klippen Belt. The
marine transgression reached the basin from the remnant fly-
sch basins of the Outer Carpathians. At the end of the Eggen-
burgian, prograding deltas (Èelovce, Lada) entered the basin,
marking its temporary closure. Deposits of Ottnangian age
(1917.5 Ma B.P.) are missing (Fig. 3).
The ESB started to re-open in the early Karpatian (17.5 Ma
B.P.), by extension (Kováè et al. 1994a). Later, the character
of the paleostress field progressively changed, and shear be-
came the dominant factor in the evolution of the ESB. Shear
controlled basin evolution (Fig. 3) characterizes the late Kar-
patian through late Sarmatian period (1711.5 Ma B.P.). Dur-
ing this period, the basin had the features of a typical pull-
apart basin, including the migration of subsidence centres
(from NW to SE, in recent coordinates) and rapid subsidence
(Vass et al. 1988). The thickness of the deposits during this
period is more than a thousand metres and the whole basin
fill is 80009000 m thick in the centre. Other pull-apart fea-
tures of the basin are the en echelon arrangement of faults,
flower structures on major fault zones, and dismatch between
units of the basement.
The basement of the ESB is built of very different tectonic
units (Fig. 2). These are the Veporic Superunit represented
by the Krína Nappe, Humenné Mesozoic Horst and Veporic
Superunit of the Èierna Hora Mts. partly covered by Central
Carpathian Paleogene. The Kritchevo-Iòaèovce Unit formed
by metamorphic rocks, including slightly metamorphosed
Eocene marine deposits considered by Soták et al. (1993) to
be equivalent of the Vahic/Penninic Superunit. This supe-
runit may correspond to the Nádudvar Formation, or the
Szolnok-Maramures Flysch; the Zemplinic (Zemplén) Unit,
which probably belongs to the Tisza (Tissia) Superunit
(Körössy 1963; Grecula & Együd 1977); the Gemeric Supe-
runit, Bükk Unit and Meliatic Unit (which may represent the
NE promontory of the Pelsó Megaunit which escaped from
the Central Alpine and NW Dinarides area (Kázmér &
Kovács 1985; Haas et al. 1995).
By the end of the pull-apart evolution of the ESB, a strong
andesite volcanic activity started. This volcanic activity is
considered as subduction related and during the Sarmatian
the basin was in an interarc position (Vass et al. 1988).
160 MÁRTON, VASS
The recent geophysical evidence of the former pull-apart
character of the basin is the thin continental crust in the south
(including 89 km of basin fill deposits 27 km) which be-
comes thicker (32 km) in the North-Northwest (efara et al.
1987), the high heat flow (more than 110 Wm
) and the high
geothermal gradient (53 °C/km, Král et al. 1985).
The pull-apart history of the basin ended with the Sarma-
tian. During the Pannonian the subsidence significantly
slowed down and the Pannonian deposits are only a few hun-
dred metres thick.
During or after the Pontian, basin inversion took place.
Pliocene deposits are fluvio-lacustrinal and are restricted to
the SE corner of the basin.
Sampling and laboratory measurements
We drilled the Eggenburgian sediment at one, and the
zeolitized tuff of Badenian age at three localities. All these
are in well-controlled tectonic positions. Sarmatian volca-
nosedimentary rocks and andesite were collected at three
In addition to the sediments and sediment-like deposits,
two rhyolite domes were also sampled. At one of them,
which was earlier sampled by one of the authors (I. Túnyi)
hand samples were taken and subsequently drilled in the lab-
oratory, the other was drilled in the field. A total of 92 inde-
pendently and magnetically oriented samples were taken.
Standard-size cylinders were cut from the drill-cores, mea-
sured and stepwise demagnetized by the thermal and AF
methods or by combining the AF and thermal methods, IRM
and low susceptibility versus temperature experiments were
also carried out to help the identification of the magnetic
minerals. Stepwise thermal demagnetization was carried out
in Bratislava, the other experiments in Budapest.
Results and assessment of data
The samples from the two rhyolite domes yielded excellent
paleomagnetic directions. The NRMs are in both cases sin-
gle-component (Fig. 4), the carrier of the remanence is mag-
netite (Figs. 5a and 6a) and the site mean directions are sta-
tistically very well defined (Table 1).
Fig. 1. Simplified geological map of the East Slovak Basin and sampled sites. Explanation: 15: Neogene sedimentary basin fill and neo-
volcanics. 1 Pliocene; 2 Late Miocene, a sediments, b rhyolite; 3 neovolcanics Middle and Late Miocene in age, a pre-
dominantly andesites and andesite volcano-clastics, b rhyolite; 4 Middle Miocene, a sediments, b zeolitized tuff (Hrabovec
Tuff); 5 Early Miocene (Karpatian); 6 Central Carpathian Paleogene; 7 Outer Carpathian Flysch; 8 Klippen Belt; 9 Meso-
zoic of Krína Nappe Unit; 10 Paleozoic and Mesozoic of Zemplinic Unit; 11 Peleozoic and Mesozoic of Silicic Superunit, Meliat-
ic Unit and Veporic Superunit undivided; 12 Proterozoic of Zemplinic Unit; 13 sample sites, see Fig. 2 and Table 1.
COUNTERCLOCKWISE ROTATIONS OF THE NEOGENE ROCKS IN THE EAST SLOVAK BASIN 161
Fig. 2. Recent situation of the pre-Tertiary units in the East Slovak Basin basement and in its surroundings. 1 faults or unspecified
boundaries of tectonic unit; 2 overthrust lines; 3 state boundaries; 4 sample sites, loc. Nos. (see Table 1); H.F.B. Hornád/
Hernád fault belt.
Table 1: East Slovak Basin site and locality mean paleomagnetic directions of the present study.
n/no numbers used/collected samples; D°,I° (D
°) declination, inclination before (after) tilt correction; k and
° statistical parameters (Fisher 1953);
* statistics is based on number of speciment (n).
162 MÁRTON, VASS
Fig. 3. Schematic lithology, sedimentary cycles and paleostress diagrams of the East Slovak Basin (according to Kováè 1994a, modified).
The zeolitized rhyolite tuffs are weakly magnetic. This ex-
plaines that the demagnetization curves of the NRM are less
smooth than those of the rhyolites. Nevertheless, the compo-
nents of the NRM are well defined (Fig. 7). The IRM acqui-
sition curves suggest that the magnetic mineral is soft (Fig.
6b), and this combined with the stability (Fig. 5b) or moder-
ate increase (Fig. 7) of the susceptibility on heating, suggest
that the NRM is most likely residing in magnetite. The site
mean paleomagnetic directions are statistically fairly well
defined and depart significantly from that of the local direc-
tion of the present Earths magnetic field (Table 1).
The sediments are of different ages and of different litholo-
gies. The Eggenburgian locality, Lada, where several horizons
of the clay stone intercalations in the thick sandstone sequence
were sampled, yield a good paleomagnetic direction. The
Zijderveld diagrams reveal that the NRM is practically single-
component (Fig. 8), the main carrier of the magnetization is
magnetite (Fig 8a, Fig. 6b), though sometimes goethite may
also contribute to the NRM (Fig. 8b). At Lada, the majority of
the samples carry characteristic remanence, with direction sig-
nificantly different from that of the Earths present field at the
sampling area (Table 1). Of the sediments collected at other lo-
calities, Niná My¾a was unstable, while Svinica yielded a
mean direction which is interpreted as a recent overprint (Ta-
ble 1 and Fig. 9). At Slanèík, 6 samples of the collected 8 are
clustered away from the present field direction (Table 1 and
Fig. 10), while two are aligned with the present field (rejected
when computing the locality mean direction).
The East Slovak Basin is situated on the ALCAPA (and Tis-
sia) overriding plate of a subduction/collision zone, close to
the inner margin of the accretionary prism. The present (as-
sumed) configuration of the flysch accretionary prism (Outer
Carpathians and the arcuate shape of the Carpathians) suggests
that the collision between the subducting North European and
the overriding Carpathian-Pannonian plates was oblique. The
oblique collision, proceeded by oblique subduction resulted in
COUNTERCLOCKWISE ROTATIONS OF THE NEOGENE ROCKS IN THE EAST SLOVAK BASIN 163
Fig. 4. Typical behaviour of the rhyolites on thermal demagnetization. Modified Zijderveld diagrams and normalized intensity/suscepti-
bility (circles/dots) curves.
164 MÁRTON, VASS
Fig. 5. Low-field susceptibility versus temperature curves for
Lesné (upper diagram) and Niný Hrabovec (lower diagram).
Heating curves are of darker, cooling curves are of lighter colour.
Fig. 6. IRM acquisition curves. a Lada (SM1143A) and exam-
ples for zeolitized rhyolite tuffs; b rhyolite doms; c Sarma-
tian sediment Slanèík.
compression oblique to the convergence zone, and produced
shear stress along it. It is generally accepted that in the Car-
pathians the oblique convergence led to bending and final for-
mation of the accretionary prism, i.e. to the whole arcuate
shape of the Outer Carpathians. Along and near the convergent
margin, pull-apart or shear basins were generated. Such basins
connected to the Western Carpathians are the Vienna Basin,
the narrow furrows along the inner side of the Pieniny Klippen
Belt in NW Slovakia, the Transcarpathian Basin, including its
autonomous western part, the ESB.
The ESB was regarded as a pull-apart basin opened by a
major right-lateral strike-slip fault of NW-SE direction (Roy-
den & Báldi 1988; Vass et al. 1988). The lateral displacement
or wrench faulting caused the breaking up of the area into
elongated blocks by en echelon faults and the blocks
moved relative to each other along faults, corresponding to
Riedel Shears of the strain ellipsoid. The elongated blocks,
termed Riedel Flakes (Dewey 1982) when generated by
right lateral strike slip, are expected to suffer clockwise rota-
tion. Contrary to the prediction of the model by Royden &
Báldi (1988), the paleomagnetic results from the ESB sug-
gest counterclockwise rotation.
The oldest rock where we observed CCW rotation is Egg-
enburgian. The angle is about 80°. This locality (Lada) is in
the transition zone between the Central Carpathian flysch ba-
sin and the ESB (in fact, it is lying on the Central Carpathian
East of this locality, in the ESB proper, the angle of rota-
tions is smaller at the same time, the rocks studied here are
also younger. The oldest of them are the zeolitized rhyolite
tuff, which yields an overall mean direction of D = 297° I =
64°, k = 28,
= 24° (the statistics are based on the number
of sites, which is 3) when sites 3 and 4 are corrected, site 5 is
not corrected for the local tilts (in all other combinations the
tilt test is negative, tilt test by Watson & Enkin 1993).
Among the younger rocks, sampling points 2 and 8 are char-
acterized by moderate CCW declination deviation and point
1 shows no deviation from the present North (Fig. 10).
Orlický (1996) and Nairn (1967) observed similar rotations
on late Badenian-Sarmatian igneous rocks in the southern mar-
gin of the basin. Thus we can conclude that with the exception
of 1 site, i.e. the youngest one, all observations suggest that the
major part of the ESB basin (i.e. the part that started to open
after the Ottnangian, and subsided most intensively in the Sar-
matian) rotated in a CCW sense by an average angle of about
45°. The rotation observed at Lada seems to be larger and is
difficult to relate to the history of the major part of the ESB.
Perhaps it characterizes the movements of the Central Car-
pathian area more than that of the ESB.
COUNTERCLOCKWISE ROTATIONS OF THE NEOGENE ROCKS IN THE EAST SLOVAK BASIN 165
Fig. 7. Typical behaviour of the zeolitized rhyolite tuffs on combined thermal and AF demagnetization. Modified Zijderveld diagrams
and normalized intensity/susceptibility (circles/dots) curves.
166 MÁRTON, VASS
Fig. 8. Typical behaviour of samples from Lada on AF (upper diagram) and combined thermal and AF (lower diagram) demagnetization.
Modified Zijderveld diagrams and normalized intensity (circles) curves.
COUNTERCLOCKWISE ROTATIONS OF THE NEOGENE ROCKS IN THE EAST SLOVAK BASIN 167
Fig. 9. Svinica. Two examples showing the viscous character of the
remanence. Upper diagram: the Z component of the NRM on AF
demagnetization up to 50 mT (AF500), stored in the laboratory in a
vertical position for 3 weeks and measured again (AF500R). Lower
diagram: the Z component of the NRM on combined AF and ther-
mal demagnetization up to 300 °C, stored in the laboratory in a ver-
tical position for two months, demagnetized in an AF field of 20 mT
(AF200) measured and demagnetized up to 50 mT (AF500). Stored
for another 3 weeks in the lab with Z in the same vertical position
and remeasured (AF500R). It is important to note that when the
specimens are stored in the laboratory field between demagnetiza-
tion runs, the original NRM directions, which were close to the
present field, are not recovered during the new demagnetization run.
Fig. 10. Site and locality mean paleomagnetic direction with con-
fidence circles. The numbers refer to Table 1 (data in heavy print).
Stereographic projection. All inclinations are positive on the plot,
i.e. site mean directions with reversed polarity (1 and 5) are shown
as equivalent normal polarity directions.
However, the rotation of the ESB may be connected to that
of the Tokaj Mts., due to the similar angle and timing of the
rotation (Márton & Pécskay 1995). Concerning the exact
timing of the rotation, the CCW rotation of the mid-late Sar-
matian Slanèík, in addition to the previously existing indica-
tions obtained on igneous rocks of Sarmatian age, points to
the late Sarmatianearly Pannonian time. We cannot be more
precise, since the only reliable paleomagnetic result in our
data set, showing affinity to stable European directions, is
Hrádok at Michalovce, (rhyolite extrusion) with K/Ar ages
ranging from 10.9 to 14.3 Ma B.P. (Merlich & Spitkovskaya
1974; Vass et al. 1978)
Nevertheless, the constraint on timing is precise enough to
suggest that the major part of the ESB together with the
Tokaj area must have been emplaced 45 Ma later than the
Central Carpathian-North Hungarian block, with the North-
South running zone as the best candidate for a boundary be-
tween them in the area of the present Slánské vrchy Mts. in
the Hornád/Hernád fault zone. The structural unroofing of
the basement of the East Slovak Basin (in the sense of Soták
et al. 1993), when the Iòaèovce-Krichevo Unit was exhumed
during the Miocene extension can be corelated with the
above mentioned CCW rotation of the basin sedimentary fill
contemporaneus with volcanics.
The origin of the CCW rotation in the area of the East Slo-
vak Basin may also be explained in another way. At least two
basement units, the Zemplinic Unit and Iòaèovce-Kritchevo
Unit, have affinities to the Tissia Superunit. The Zemplinic
Unit was correlated with the Tissia and/or Mecsek Mts.
(Körössy 1963; Grecula & Együd 1977 and others). The
Iòaèovce-Kritchevo Unit and especially its Iòaèovce part, i.e.
the unit directly proved by wells as the ESB basement, ac-
cording to Vozár et al. (1993) may belong to the Szolnok-
Maramures Flysch and/or Nádudvar Formation. The Fig. 2
shows that both units could come to present position by left
lateral strike-slip from the SW. This left lateral motion pre-
ceded the left that is CCW rotation of the ESB. The relation
between sens of the strike-slip motion and the following
block rotation is documented by Torres & Slivester and Sen-
gör, Gorur & Saroglu (in Allen & Allen 1992).
Acknowledgement: This work was partially supported by
OTKA (Hungarian National Science Foundation) research
Grant No. T015988 and VEGA (Slovak Scientific Grant
Agency) research Grants No. 5136 and 5222. The authors
are thankful to M. Kalièiak for description of localities
Niná My¾a, Slanèík and Svinica as well as for fruitful re-
168 MÁRTON, VASS
Allen P.A., Allen J.R. 1992: Basin analysis, principles and applica-
tions. Blackwell, London, 1145.
Dewey J.F. 1982: Plate tectonics and the evolution of the British
Isles. J. Geol Soc. London 139, 371414.
Fisher R. 1953: Dispesion on a Sphere. Proc. of the RAS. A 217, 295.
Grecula P. & Együd K. 1977: Position of the Zemplin Inselberg in
the tectonic frame of the Carpathians. Miner. Slovaca 9, 6,
449462 (in Slovak, English summary).
Haas J., Kovács M., Krystyn L. & Lein R. 1995: Significance of Late
Permian-Triassic facies zones in terrane reconstructions in the
Alpine-North Pannonian domain. Tectonophysic 242, 1940.
Kázmér M. & Kovács S. 1985: Permian-Paleogene paleogeography
along the Eastern part of the Insubric-Periadriatic Lineament
system: Evidence for continental escape of the Bakony-Drau-
zug Unit. Acta Geol. Acad. Sci. Hung. 281, 2, 7184.
Kováè P., Vass D., Janoèko J., Karoli S. & Kalièiak M. 1994a: Tec-
tonic history of the East Slovak Basin during the Neogene.
ESRI Occassional Publication New Series No. 11 A-B, South
Carolina, U.S.A., 115.
Kováè M., Krá¾ J., Márton E., Plaienka D. & Uher P. 1994b: Alpine
uplift history of the Central Western Carpathians: geochrono-
logical, paleomagnetic, sedimantary and structural data. Geol.
Carpatica, 45, 2, 8396.
Körössy L. 1963: Comparison study of rock composition of the
Pannonian Basin. Földt. Közl. 93, 2, 153172 (in Hungarian).
Král M., Lizoò I. & Janèi J. 1985: Geotermal investigation in SSR.
Manuscript, Archív Geol. úst. D. túra, Bratislava (in Slovak).
Márton E. & Márton P. 1996: Large scale rotations in North Hunga-
ry during the Neogene as indicated by palaeomagnetic data. In:
Morris A. & Tarling D.H. (Eds): Palaeomagnetism and Tecton-
ics of the Mediterranean Region. Geological Society Special
Publication No. 105, 153173.
Márton E. & Pécskay Z. 1995: The Tokaj-Vihorlát-Oas-Ignis Trian-
gle: Complex Evaluation of Palemagnetic and Isotope Age
Data from Neogene Volcanics. IGCP Project 356 Plate Tec-
tonic Aspect of Alpine Metallogeny in the Carpatho-Balkan Re-
gion, 3rd Annual Meeting. Athens, 18-19 September 1995.
Volume of Abstract, 30.
Márton E., Vass D. & Túnyi I. 1996: Rotation of the North Hungari-
an Paleogene and Lower Miocene rocks indicated by paleo-
magnetic data (S. Slovakia, N-NE. Hungary). Geol. Carpathica
47, 1, 3141.
Merlich B.V. & Spitkovskaya S.M. 1974: Deep faults, Neogene
magnetism and mineralization of Zakarpatia. Lvov state Uni-
versity, 1175 (in Ukrainian).
Nairn A.E.M. 1967: Paleomagnetic investigations of the Tertiary
and Quarternary igneous rocks: III A paleomagnetic study of
the East Slovak Province. Geol. Rdsch., Band 56, 408419.
Royden L.H. & Báldi T. 1988: Early Cenozoic Tectonics and Paleo-
geography of the Pannonian and Surrounding regions. In: Roy-
den L.H. & Horváth F. (Eds.): The Pannonian basin a study in
Basin evolution. AAPC Memoir 45. Am. Ass. of Petroleum
Geol. Oclahoma, U.S.A., Budapest, 116.
Orlický O. 1996: Paleomagnetism of neovolcanics of the East-Slo-
vak Lowlands and Zemplínske Vrchy Mts.: A study of the tec-
tonics applying the paleomagnetic data (Western Carpathians).
Geol. Carpathica 47, 1, 1320.
Soták J., Rudinec R. & Spiiak J. 1993: The Penninic pull-apart
dome in the pre-Neogene basement of the Transcarpathian de-
pression (Eastern Slovakia). Geol. Carpathica 44, 1116.
efara J. et. al. 1987: Structural-tectonical map of the Inner Western
Carpathians for the purposes of depositional prognoses. Manu-
script, Archives Geofyzika, Bratislava (in Slovak).
Vass D., Tözsér J., Bagdasaryan G.P., Kalièiak M., Orlický O. & Ïu-
rica D. 1978: Chronology of vulcanic events in Eastern Slova-
kia on the grounds of isotopicalpaleomagnetical researches.
Geol. Práce, Spr. 71, 7788 (in Slovak, English summary).
Vass D., Began A., Kahan ., Köhler E., Krystek I., Lexa J. &
Repèok J. 1988: Regional geological break-up of the Western
Carpathians and northern headlands of Pannonian Basin on the
area of ÈSSR. GÚDGeofond Bratislava, Vojenský kar-
tografický ústav Harmanec (in Slovak).
Vass D., Kováè M., Koneèný V. & Lexa J. 1988: Molasse basins
and volcanic activity in Western Carpathian Neogene its
evolution and geodynamic character. Geol. Carpathica 39, 5,
Vozár J., Tomek È. & Vozárová R. 1993: Reinterpretation of pre-
Neogene basement of the East Slovak Basin. Miner. Slovaca
25, 6, Geovestník 12 (in Slovak).
Watson G.S. & Enkin R. 1993: The fold test in paleomagnetism as a
parameter estimation problem. Geophysical Research Letters
20, 19, 21353137.