www.geologicacarpathica.sk
Subsurface structure and tectonic style of the NE Outer
Carpathians (Poland) on the basis of integrated
2D interpretation of geological and geophysical images
JAN KUŚMIEREK
Faculty of Geology, Geophysics and Environment Protection, AGH University of Science and Technology, Al. Mickiewicza 30,
30-059 Kraków, Poland; kusm@geol.agh.edu.pl
(Manuscript received March 4, 2009; accepted in revised form October 2, 2009)
Abstract: Integration of the information from surface and subsurface geological exploration (maps and well sections) and
results of geological reinterpretation of more than ten archival seismic sections and several dozen magnetotelluric sound-
ings (MT; published and archival) implies a new structural picture of the Carpathian tectogene, interpreted to depths
exceeding 10 km. The tectonics of nappes and their basement is illustrated by four regional cross-sections (derived from
geological and petroleum-exploration traverses) and examples of detailed interpretation of zones with complicated struc-
ture, as well as results of testing the initial structural models with application of the balanced cross-section method and
gravimetric modelling. In the tectonics, a complicated system of overthrusts and detachments of sedimentary covers (from
their heterogeneous basement) represents a predominant feature. It induced, within particular nappes and tectonically
altered structural-facies units, specific systems of narrow folds with diversified geometries. Broad folds of the intermedi-
ate structural stage, which are gently sloping in the hinterland of the nappes, were interpreted on the basis of geophysics as
paraautochthonous elements. They cover deep-seated faults with large throws, which obliquely or subvertically dip to the
SW and were distinguished in the basement on the grounds of extreme contrasts at the resistivity boundaries. Zones of
dramatically low resistivities, which separate blocks of the uplifted basement, were interpreted as tectonic sutures with
geometry rebuilt in the stage of the Neogene lithosphere subduction. Therefore, the structural layout of the sedimentary
cover is characterized by more gently dipping nappe overthrusts of the sequential type and secondary, out-of-sequence
thrust slices, most frequently imbricate ones. The flysch covers resting over the tectonic sutures, particularly in margins of
inherited structural depressions, are characterized by more diversified tectonic style in comparison with peripheral, gently-
sloping covers thrust over the flexural platform slope, and with steep slices and imbricate thrusts having consequent NE
vergence. A specific type of dislocation is represented by flat inversional detachments (seismically documented) which are
accompanied by disharmonic folding of “thin-skinned” structural elements. In the eastern part of the foreland of the Dukla
overthrust, they form a developed system of backthrusts on the slope of a triangular structure superposed on a “shallower”
tectonic suture of the basement; the system replaces sets of fault-propagation folds developed in the eastern part of this zone.
Key words: Western Carpathians, subsurface mapping, tectonics of Alpides, fold and thrust belt, structural interpretation,
seismic sections, magnetotelluric soundings.
GEOLOGICA CARPATHICA, FEBRUARY 2010, 61, 1, 71—85 doi: 10.2478/v10096-010-0002-7
Introduction
The present state of growing knowledge of the tectonics and
evolution of the Outer Carpathians is characterized by an un-
usual diversity of views, dominated by overabundance of
new conceptions and interpretive schemes which sometimes
depart from profound analysis of the recognized subsurface
geological structure. In this context and in the light of
progress in methods and scope of investigations, dimen-
sioned cartographic images are an underestimated element
for justification of conceptual models and investigation
projects. One of the sources of evidence for this is the results
from deep wells drilled into the eastern part of the Polish
Carpathians, sections of which significantly depart from the
assumed ones.
The coherent relation of surface cartographic images and
well sections to geophysical models of subsurface tectonics
of structures, particularly to seismic images of the geometry
of folds in the cover, represents a fundamental problem in
the construction of acceptable images of the complicated
Carpathian tectonics. Interferential seismic records and their
low quality, as well as the lack of regionally continuous re-
flectors, have resulted in a sceptical attitude towards the
credibility of the seismic images from the Carpathian region,
acquired through standard methods of field-data processing
(e.g. Wdowiarz 1985).
Serious divergence is also found in the interpretation of the
depth of occurrence and tectonics of the basement of alloch-
thonous covers in the central zone of the fold and thrust belt.
Compared with seismic refraction profiles, which document
relatively regular and large-radius geometry of depressions in
the basement, the results of several hundred magnetotelluric
soundings (MT) carried out in this area have provided a much
more complicated structural image.
Against the background of the interpretive implications out-
lined above, relatively little attention has been given to the in-
fluence of the disharmonic tectonics of structures in the cover
and basement on the obtained geophysical images of the geo-
logical subsurface setting. This problem is crucial not only
from the scientific point of view, but also for the credibility of
72
KUŚMIEREK
Fig. 1. A – Location of the study area (framed) within the Polish segment of the Alpides; geostructural elements and units: I – Carpathian
Foredeep, II – Stebnik Unit, III – Boryslav-Pokuttya Unit, IV – Skole Unit, V – Sub-Silesian Unit, VI – Silesian Unit, VII – Dukla
Unit, VIII – group of Magura units, IX – Pieniny Klippen Belt, X – Podhale Trough, XI – Tatra Mts. B – Structural sketch of the
study area with location of presented 2D models and used profiles of magnetotelluric sounding. 1 – lines of regional cross-sections
(traverses); 2 – lines of detailed cross-sections (not in line with the traverses) and numbers of figures that illustrate them; 3 – line of the bal-
anced cross-section (Fig. 6); 4 – line of the seismic profile 34-15-96K tested through gravimetric modelling (Fig. 9); 5 – locations and numbers
of magnetotelluric profiles (a – recorded by older-generation instruments – after Stefaniuk 2001 and Stefaniuk et al. 2002); 6 – numbers of
magnetotelluric soundings (MT) which documented dramatic denivelations of the high-resistivity horizon (tectonic sutures of the base-
ment); 7 – location of deep-seated tectonic sutures; 8 – location of “shallower” tectonic sutures; 9 – subsurface traces and denotation of
probable transversal faults in the basement of the tectogene; 10 – extent of the zone of deep tectonic shears of the basement, a – interpolated
traces of the above zone and probable tectonic shears (unformed—initial?); 11 – locations of deep wells; 12 – deep wells penetrating the Pre-
cambrian basement – numbers in parentheses determine thickness [m] of Miocene deposits under the Skole Nappe overthrust and depth [m]
to the Precambrian basement; 13 – surface intersection traces of groups of structural-facies units; 14 – surface intersection traces of bound-
aries of particular nappes and units; 15 – surface intersection traces of faults which dislocate them.
73
2D INTERPRETATION OF SUBSURFACE STRUCTURE AND TECTONIC STYLE OF OUTER CARPATHIANS (POLAND)
petroleum-system modelling which requires as precise struc-
tural images as possible.
The aim of the paper is to present and to interpret two-di-
mensional images (mostly unpublished) of the subsurface
structure of the Outer Carpathians, worked out by the author
within the framework of the Polish-Ukrainian research
project DWN/1818-1/2M 2005 entitled “Transfrontier stud-
ies of deep-seated geological structures in the marginal zone
of the Carpathians from the point of view of the potential
discovery and development of new oil and gas fields” (Capik
et al. 2006). To reach the aim it was necessary to integrate
the previous state of geological recognition, reinterpreted
and supplemented by results of new investigations, with re-
sults of modelling of petroleum systems in the interfluve of
the San River (Poland) and Stryi River (western Ukraine).
Seven deep regional sections (so-called traverses) were the
objects of this modelling. Of them, four western ones have
been presented in this paper. The essential scope of the
present paper has been confined to structural images of the
eastern part of the Polish Carpathians (Fig. 1) and analysis of
their tectonic style.
The new models of the subsurface structure have been
constructed on the basis of the results of geological interpre-
tation carried out for reprocessed archival seismic sections
(Marecik et al. 2008) and MT soundings (Stefaniuk 2001,
2003; Stefaniuk et al. 2002), reinterpreted by the author. Com-
pared with previously published cross-sections (e.g. Poprawa
& Nemčok 1989; Kuśmierek 1990), the new interpretive op-
tions of the geological structure have been supported by
“segments” of geological-geophysical images (at larger
scales) and by testing of their correctness through the meth-
ods of balanced cross-sections and gravimetric modelling.
Geostructural background
The eastern segment of the Western Carpathians is charac-
terized by discrepant setting of structural covers, which man-
ifests itself by disappearance of the structural-facies units of
the Magura Group and increment of units of the Marginal
Group at the orogen front (Książkiewicz 1972; Oszczypko et
al. 2008). They encircle so-called Middle Group units that
attain the largest width in the borderland between Poland,
Slovakia and Ukraine. The Middle Group is characterized by
increased thickness of the youngest flysch members (Oligo-
cene—Early Miocene) distinguished as so-called Menilite—
Fig. 2. Synthetic structural-lithostratigraphic model of the eastern part of the Polish Carpathians. Geostructural elements and structural-facies
units: MG gr. – Magura Group of units, MD gr. – units and nappes of the Middle Group, Dk u. – Dukla, Sl n. – Silesian, Sub Sl u. – Sub-
Silesian, Sk n. – Skole, MR gr. – units of the Marginal Group, B-P u. – Boryslav-Pokuttya, St u. – Stebnik, Zg u. – Zgłobice; CFD – Car-
pathian Foredeep. Lithostratigraphic complexes. Carpathian Foredeep and units of the Marginal Group: 1 – autochthonous molasse (Late
Badenian—Sarmatian), 2 – postinversional cover (Late Sarmatian); folded deposits of the Early and Middle Miocene, 3 – of the Zgłobice Unit,
4 – of the Stebnik and Boryslav-Pokuttya units and patches of the transgressional cover that flatly overlies folded flysch deposits; flysch deposits
(locally in the form of patches under the Skole Nappe overthrust), 5 – erosional patches of the flysch cover on the platform slope (Late Eocene—
Oligocene), which were overthrust together with Stebnik molasses; Boryslav-Pokuttya Unit (Skole Series), 6 – Menilite Shales (Oligocene—Early
Miocene), 7 – Popeli Beds, Variegated Shales and Hieroglyphic Beds (Eocene), 8 – Inoceramian Beds (Ropianka Fm, Senonian—Paleocene).
Units of the Middle Group
: Skole Nappe: 7 and 8 – as above, 9 – Menilite-Krosno Series (Krosno Beds, Transition Beds and Menilite Beds,
Oligocene—Early Miocene), 10 – Siliceous Marls, Dołhe Shales, Spas Beds, Bełwin Mudstones (Hauterivian—Turonian); Sub-Silesian Unit:
11 – Menilite Beds and Krosno Beds (Oligocene), 12 – Variegated Shales, Węglówka Marls (Senonian—Eocene), 13 – Lgota (Gaize) Beds,
Veřovice Shales, Grodziszcze Sandstones and Cieszyn Beds (Valanginian—Cenomanian); Silesian Nappe: 13 – as above, 14 – Krosno Beds,
Transition Beds and Menilite Beds (Oligocene—Eggenburgian), 15 – Hieroglyphic Beds and Ciężkowice Sandstones (Eocene), 16 – Istebna
Beds, Godula Shales (Turonian—Paleocene); Dukla Unit: 17 – Krosno Beds, Transition Beds, Cergowa Beds and Menilite Shales (Oligocene),
18 – Variegated Shales, Przybyszów Sandstones, Hieroglyphic Beds (Eocene), 19 – Majdan Beds, Cisna Beds and Łupków Beds (Senonian—
Paleocene). Pre-Alpine basement of the Carpathian tectogene: 20 – deposits of the Early Mesozoic and Paleozoic (undifferentiated),
21 – Precambrian (Vendian—Early Cambrian?). Graphical symbols: 22 – overthrusts which distinguish groups of units, 23 – overthrusts of
particular nappes and units, 24 – faults in the basement, 25 – stratigraphic unconformities and sedimentary-erosional gaps.
74
KUŚMIEREK
Krosno Series (Jucha & Kotlarczyk 1958) that covers (to-
gether with older, Cretaceous—Oligocene flysch series) the
deep-seated basement of the tectogene (Fig. 2). Denivela-
tions of the basement are probably connected with the highest
gradients of the lithosphere thickness variations within the
Carpathian arc, between the Pannonian mantle diapir (approx-
imately 60 km) and the platform slope (up to 200 km), accord-
ing to seismological and magnetotelluric data (Konečný et al.
2002). These disproportions also become manifest in the
Earth’s crust thicknesses which are reflected in the Moho
discontinuity position (Kuśmierek & Ney 1988; Bielik 1999).
New and original results (Zeyen et al. 2002; Dérerová et al.
2006) confirm the above suggestions.
Probably the major part, if not the whole flysch cover, was
detached from its original basement along thrusts that sheared
bottom shale complexes of the Early Cretaceous, locally of the
Eocene. Against this background, nappe covers, formed of
thick turbidite sequences of the Late Cretaceous—Paleocene
and Oligocene, should be discerned from tectonically dis-
turbed structural-facies units with condensed thickness, which
originated from paleoelevations (Kuśmierek 1990).
According to Konečný et al. (2002), at the junction of the
Western and Eastern Carpathians, the slope of the subduct-
ing platform in the Karpatian—Early Badenian times was dis-
located by an oblique deep-seated fracture directed SW—NE.
The application of seismic tomography and thermal model-
ling, has enabled us to identify on the eastern side of this
fracture a steeply dipping detached slab of the continental
lithosphere, which was submerged in the asthenosphere un-
der the Outer Carpathian arc.
In the author’s opinion, geodynamic mobility of the litho-
sphere at the junction of the Western and Eastern Carpathians
becomes evident as early as in the sedimentary stage, in the
form of considerable facies and thickness variations of the
Cretaceous—Eocene sandstone series, which in the Marginal
Group were expressed most strongly in the Late Miocene. Un-
doubtedly, it had an effect in the form of the diversified tec-
tonic style of allochthonous covers and implied their
correlation in the transfrontier zone between Poland and
Ukraine. This refers especially to the flysch – molasse units
of the Marginal Group, which were formed in a late-geosyn-
clinal relict subbasin (Kuśmierek 1984; Konečný et al. 2002).
Thickness of molasses that filled the subbasin is dramatically
reduced in the zone of the meridional bend of frontal folds and
thrusts of the Middle Group, which is called the Przemyśl
Sigmoid, conventionally accepted as the border between the
Western and Eastern Carpathians (Świdziński 1971).
To NW of the Przemyśl Sigmoid only fragments of the
Stebnik cover were preserved at the front and at the base of the
Skole overthrust. Combining the tectogenesis of the Przemyśl
Sigmoid with the above mentioned deep-seated fracture and
taking into account the prominent discrepancy of the arrange-
ment of the marginal thrusts, as well as the subordinate tecton-
ic engagement of the Middle Miocene molasses in relation to
the Early Miocene ones and to the flysch deposits, one should
infer that the activity of this fracture did not reach the relict
subbasin or it ceased in the Late Sarmatian.
Transversal deep-seated faults of the strike-slip fracture
type, which dislocated zones of the buried basement and
were identified by interpretation of the geophysical surveys
and remote-sensing analyses (Kuśmierek 1990; Doktór et al.
1990), in the study area reveal a radial arrangement (Fig. 1)
and are not directly reflected in the tectonics of the alloch-
thonous covers, as the tectonics are dominated by ductile
continuous deformations and thrusts induced by centripetal
subduction of (rigid) blocks of the platform slope and their
subsurface wedging (Kuśmierek 1996).
Criteria of integration of the geological and
geophysical investigations
The recognition of the subsurface geological setting of the
study area is very irregular. The marginal part of the Car-
pathians is best documented by wells and seismic profiles,
which have been inspired by exploration for gas accumula-
tions in the underlying Miocene molasses and by searching for
a westward extension of deep-seated folds of the Boryslav-
Pokuttya Unit. On the contrary, the worst is the recognition
of the southeastern part where few deep wells have penetrat-
ed the thick cover of Oligocene deposits.
The study area is located in the central part of the “trans-
frontier” geological map of the Polish, Ukrainian and Slovak
Carpathians on the scale of 1 : 200,000 (Jankowski et al.
2004), accepted as the input source of surface information,
constrained in zones of complicated tectonics by cartograph-
ic images (published and archival) on larger scales.
The situations of the constructed cross-sections, oriented
perpendicularly to fold strikes, were controlled by locations of
deep wells and seismic profiles in such a way as to acquire a
possibly uniform image of the geological setting between the
Dukla Unit overthrust and the Carpathian Foredeep (Fig. 1).
Construction of the geological-seismic cross-sections (origi-
nally scaled to 1 : 50,000) was based on geological interpreta-
tion of several dozen reprocessed archival seismic sections
with digital recording, acquired by the “Geofizyka – Kraków
Company” in the years 1977—1996, and a few made by the
“Geophysical Exploration Company” (PBG) from Warsaw, as
well as on geological reinterpretation of earlier sections with
analog recording. Application of a modified procedure for
seismic data processing in the ProMAX system (Marecik et al.
2008) significantly improved the quality of the seismic sec-
tions in terms of their dynamics and resolution.
Well sections which were not located on traces of the
traverses or seismic sections were projected in accordance
with the strikes of outcrops of lithostratigraphic complexes. In
justified cases, tectonic interpretation of fragments of the well
sections was corrected in order to receive better relation to car-
tographic and seismic images, among others through recalcu-
lation of measured (true) dips into apparent dips when a trace
of a cross-section was oblique to the strikes of structures.
A fundamental criterion of construction of the geological-
seismic cross-sections was acknowledgement of factual data
in such a way as to secure consistence of the interpreted ge-
ometry of structures and dislocations with their intersection
traces and well sections, and the highest degree of consis-
tence with the pattern of reflectors. Lithostratigraphic identi-
fication of the reflectors could have been justified only by a
75
2D INTERPRETATION OF SUBSURFACE STRUCTURE AND TECTONIC STYLE OF OUTER CARPATHIANS (POLAND)
few synthetic seismograms (Kuśmierek & Baran 2008) that
could be generated for well sections possessing the neces-
sary sets of geophysical measurements.
Structural-lithostratigraphic criteria of classification of the
tectonostratigraphic units that form the eastern part of the
Polish Carpathians, as well as the structural sequence of the
covers, were compiled in Fig. 2, explanations of which as-
cribe sediments composing the covers to individual litho-
stratigraphic successions. During the construction of the
geological-seismic cross-sections and regional traverses,
characteristic thickness variation trends were ascribed to
lithostratigraphic members, in order to scale most reliably
the geometry of structures through using the available pro-
files and thickness maps (e.g. Kuśmierek et al. 1995). The
most rapid (sometimes dramatic) thickness changes are char-
acteristic of turbiditic deposits, as well as limbs of Oligocene
synsedimentary folds and lithosomas of coarse-clastic
Grodziszcze, Ciężkowice and Kliwa sandstones.
First-order objects of interpretation of the seismic sections
were represented by images of the subsurface geometry of
tectonic dislocations documented by surface mapping and/or
well sections, that means strike-slip faults and thrusts of var-
ious orders, subsurface traces of which were approximated
with the arc geometry. Tracing of them was not difficult,
particularly on seismic sections which were characterized by
good readability of reflectors. In this phase of interpretation,
numerous subsurface dislocations were detected, which do
not appear in the surface intersection image or have not been
documented by mapping. Identification of stratigraphic un-
conformities in the basement of the tectogene and contour-
ing of flysch elements (patches) within the Stebnik Unit
caused greater difficulty and uncertainty.
Afterwards, the structural arrangement of the lithostrati-
graphic boundaries was introduced into the obtained image
of the discontinuous tectonics, first of all on the basis of the
sistivity distribution in sediments that build the allochthonous
covers (Stefaniuk 2001, 2003; Stefaniuk et al. 2002).
In the first approximation, the lateral character of resistivity
changes in geoelectric cross-sections can be ascribed to three
hypsometric levels:
the shallow level with low and medium (sporadically
higher) values, strongly diversified and predominantly oblique
(vergent) resistivity boundaries; according to the depth criteri-
on, the level corresponds to the allochthonous covers;
the intermediate level with variable thickness (from 0 to a
few km), which is dominated by subhorizontal resistivity
boundaries; the level corresponds to the Miocene autochtho-
nous molasses and hypothetical paraautochthon of unidenti-
fied age;
the deep level with extreme resistivity contrasts in the
complexes which rest obliquely, often subvertically, with
maximal resistivity values correlated with the Precambrian
basement and with low values corresponding to younger (?)
altered rocks.
The position of the base of the intermediate level corre-
sponds to the hypsometry of refraction seismic horizons and it
probably reflects the morphology of the Mesozoic, Paleozoic,
and Precambrian basement. Identification of the top of this
level is evident in seismic sections within the marginal part of
the Carpathians as sharp boundaries of nappe thrusts over the
autochthonous molasses. It causes, however, difficulty in the
hinterland of the nappes (Lizoon & Zayats 1997) because of
weakly diversified seismic image over the subhorizontal re-
flection system; the system suggests the occurrence of second-
order detachments rather than hypothetical nappe overthrusts
and even “junction” of the covers (?).
The results of the MT sounding were interpreted in different
manners (e.g. Kuśmierek 1990; Ryłko & Tomaś 2005 and ref-
erences therein), often conservatively (e.g. fig. 4 in Stefaniuk
2006) in relation to the complicated structural arrangement of
Fig. 3. Interpretation of magnetotelluric soundings in the southern part of the geoelectric cross-
section No. 17 (see Fig. 1) Maniów—Przemyśl (adapted and supplemented after Stefaniuk 2003,
with permission). Identification of tectonic sutures in the consolidated basement (according to
the author): deep ones (x
1
, x
2
, x
3
) and shallower one (y
1
).
geological information from sec-
tions of outcrops and wells, and on
regional premises referring to par-
ticular zones or structural-facies
units. In the seismic sections, best
readable was the structural arrange-
ment of flat-lying fold limbs,
whereas zones of their hinges and
intense continuous deformations
were characterized by the interfer-
ential records of the wave field,
controlled by known properties of
the seismic imaging method.
The geological interpretation of
the morphology and structure of the
tectogene basement was based upon
the
results
of
magnetotelluric
sounding realized by PBG Warsaw
in the years 1975—1990 with the use
of analog instruments, and next in
the years 1997—2001 with the use of
new-generation high-frequency in-
struments that made it possible to
acquire information also on the re-
76
KUŚMIEREK
the resistivity boundaries of the deep level in the geoelectric
cross-sections (Stefaniuk 2001, 2003).
Figure 3 presents an example of a probable location of com-
pressional tectonic sutures, according to the author’s interpre-
tation, which are correlated with dramatic denivelations of the
high-resistivity horizons. Their geometry and hypsometric po-
sition justify distinguishing deep and shallower sutures, the
later (subordinate) are relatively “flatter” and most often occur
in the margins of the zone of the buried basement of the tecto-
gene (Fig. 1). Nevertheless, they are also contoured by high
resistivity contrasts (Fig. 4) which suggest the presence of
subhorizontal shears of the Precambrian basement separated
by fragments of the “wedged” sedimentary cover (?).
The geometry and subsurface intersection of the postulated
compressional sutures are undoubtedly disturbed by transver-
sal faults, probable traces of which (Fig. 1) were determined
on the basis of analysis of the geoelectric cross-sections, and
structural and resistivity-distribution maps of the top of the
basement (figs. 15 and 16 in Stefaniuk 2003). The idea of the
tectonic sutures in the basement of the tectogene refers to the
author’s earlier publications (Kuśmierek 1990, 1996) and to
the lithosphere model along the RP-X traverse (fig. 16 in
Bielik 1999) with the suggested position of the northern me-
gasuture located under the eastern part of the Polish Outer
Carpathians.
Characteristic features of the geological structure
and examples of its imaging
Integrated interpretation of the two-dimensional geological
and geophysical images according to the criteria described
above documents a new, more complicated picture of the tec-
tonics of the flysch series (Fig. 5), particularly in zones of
structural depressions which are characterized by the dishar-
monic style of surface (thin-skinned) and subsurface tectonic
deformations. The detachments found in numerous seismic
sections, among others in 31-19-94K (Fig. 5A), enabled the
author to carry out more profound interpretation of complicat-
ed folds recognized in well sections, which do not appear in
the surface cartographic image. The origin of these detach-
ments is probably connected with the advanced stage of the
tectonic compression, which is suggested by divergent direc-
tions of displacements (within their limbs). Some of these de-
tachments may represent reactivated compressive reverse
faults (Letouzey 1990); nevertheless, they belong to a younger
generation of tectonic shears when compared with steeply dip-
ping out-of-sequence overthrusts, traces of which they dislo-
cate. Thrusts of the sequential type are most weakly imaged in
their far hinterland, which is illustrated by an example of a hy-
pothetical detachment of the Skole Nappe from the paraau-
tochthon that occurs at depths exceeding 7000 m (Fig. 5A).
Complicated deformations are most frequently associated
with inherited structural depressions in which predominantly
thick series of the Krosno lithofacies deposits were preserved;
the deposits reveal anisopachous thickness distributions in
limbs of folds of the synsedimentary type. In order to date the
development of these deformations as potential hydrocarbon
traps, paleostructural models were constructed with applica-
tion of the balanced cross-sections (Kuśmierek et al. 2001),
among which one was oblique to the line of the traverse I
(Fig. 1) and imaged development of folds and thrusts within
the Silesian Nappe.
In the southern part of the nappe, the balancing results docu-
ment development of synsedimentary thrusts of the imbricate
type, which generated so-called fault-propagation folds,
whereas in the eastern part, at the nappe front, detachment
folds (Mitra 1986) were formed.
Unlike the widely used numerical options (e.g. Nemčok et
al. 2006), a manual procedure of balancing was applied. The
balancing was carried out for full thicknesses of the youngest
sediments, that means also their thicknesses removed by ero-
sion in the inversional stage (Fig. 6B, C), according to the
complicated procedures described by Kuśmierek et al. (1995).
The constructed models have proven that initial synsedimen-
tary deformations were formed before the time of sedimenta-
tion of the Jasło Limestone stratigraphic member (Fig. 6A)
and became intensified at the turn of Oligocene and Early
Miocene, that is before sedimentation of the transgressive
Middle Miocene molasses (Fig. 6C). They have also con-
Fig. 4. Resistivity contrasts in profiles of magnetotelluric soundings
in the Wetlina—Ustrzyki Dolne cross-section (after Stefaniuk et al.
2002, unpublished materials). According to the author’s interpreta-
tion, they document the “shallow” tectonic suture in its southern part
(Fig. 1, profile No. 18). 1 – magnetotelluric sounding (MT), 2 – re-
sistivity of complexes, 3 – location of the suture.
77
2D INTERPRETATION OF SUBSURFACE STRUCTURE AND TECTONIC STYLE OF OUTER CARPATHIANS (POLAND)
Fig. 5.
Traverse
I: Jaśliska—Husów.
1
– autochthonous molasses (Late Badenian—Sarmatian),
2
– folded molasses of the Stebnik and Zgłobice U
nits (Ottnangia
n—Early Sarmatian), undifferentiat-
ed;
deposits
of
Oligocene—Early
Miocene
(Ol—M
1
):
3
–
position
of
the
Jasło
Limestone
stratigraphic
member
(approx
imately 28 Ma),
a
–
Supra-Jasło
Complex
(Ol
2
—M
1nj
),
b
–
Sub-Jasło
Com-
plex
(Ol
1pj
),
4
–
O
li
g
o
ce
n
e
li
th
o
facies:
a
–
Krosno
(k
r
),
b
–
Menilite
and
Transition
(m
+
km),
5
–
Eocene
deposits
(E);
6
–
C
retaceous—Paleocene
deposits:
a
–
Paleocene—Senonian
(K
2
—P),
b
–
older
(Sub-Senonian,
K
1
),
7
–
subsurface
structural
elements
of
unidentified
age
(Paleogen
e—Late
Mesozoic,
pre-flysch?),
gently
sloping
under
nappe
overt
hrusts
(paraautochthon?),
8
–
d
e-
posits
of
Early
Mesozoic
(Jurassic—Triassic?)
and
Paleozoic
(un
differentiated),
9
–
high-resistivity
basement,
Precambrian
(Riphean—Vendian—Earl
y
Cambrian?),
according
to
magnetotelluric
sounding,
10
–
low-resistivity
lithostratigraphic
complexes
(recorded
by
ma
gnetotelluric
sounding)
which
separate
uplifts
of
basement
bloc
ks
–
interpreted
by
the
author
as
tectonic
sutures
(roots
of
nappes
of
the
Middle
and
Marginal
groups?),
11
–
stratigraphic
unconformities,
12
–
nappe
overthrusts,
13
–
lower-order
overthrusts
(tectonic
slices)
and
faults,
docume
nted
by
mapping,
drill-
ing
and/or
seismic,
14
–
probable
faults
in
the
basement,
with
geometry
interpreted
b
y
the
author
on
the
basis
of
magnetotelluric
sounding,
15
–
probable
subsurface
detachments
of
nappe
covers
from
paraautochthonous
elements,
16
–
location
and
denotatio
n
o
f
well
section,
17
–
well
section
projected
onto
the
traverse
plane,
18
–
number
of
seismic
section
.
A
–
seismic
image
of
su
b
surface
tectonics
in
the
axial
part
of
the
Central
Carpathia
n
Synclinorium.
19
–
Quaternary
(Q);
Silesian
Series,
lithostratigraphic
complexe
s:
Oligocene—Early
Miocene
deposits
(Ol—M
1
):
20
–
Middle
and
Upper
Krosno
Beds
(undifferentiated,
k
r
2—3
),
21
–
Lower
Krosno
Beds
(k
r
1
),
22
–
Transition
Beds
(km),
23
–
Menilite
Beds
(m);
older
deposits:
24
–
Eocene
(E),
25
–
S
e-
nonian—Paleocene
(P—K
2
),
26
–
Early
Cretaceous
(Sub-Senonian,
K
1
);
27
–
paraautochthon
(PA?),
28
–
seismic
reflectors.
78
KUŚMIEREK
Fig. 6. Image of development of synsedimentary tectonic deformations during Late Oligocene—Early Miocene times obtained through applica-
tion of the balanced cross-section method to the Silesian Nappe along the traverse I (Fig. 1) – according to unpublished materials (Kuśmierek,
Maćkowski et al. 1996). Paleostructural models: A – during sedimentation of the Jasło Limestone stratigraphic horizon (approximately
28 Ma); B – in the final stage of sedimentation of the Krosno Lithofacies (Egerian?); C – in the stage preceding the final inversion of the
Silesian Nappe (Late Karpatian—Early Badenian?). 1 – Dukla Unit, 2 – relative datum line of the paleostructural models, 3 – hypothetical
sea level and paleomorphological profile of the Jasło Limestone basin (model A), 4 – lithostratigraphic complexes – Menilite-Krosno Series:
a – Supra-Jasło Complex, b – Sub-Jasło Complex, 5 – Eocene deposits, 6 – Cretaceous—Paleocene deposits: a – younger (Senonian—
Paleocene), b – older (Sub-Senonian), 7 – transgressive Miocene deposits, 8 – hypothetical position of nappe overthrusts, 9 – secondary
overthrusts (tectonic slices) and synsedimentary faults.
firmed the correctness of tectonic interpretation of the
present-day subsurface cross-section as the input for the bal-
ancing method.
Figure 7 presents the geological structure along the
traverse II (Fig. 1). In its southern part, the seismic image doc-
uments common occurrence of typical fault- (thrust-) propaga-
tion folds, whereas its northern part is built up of structures
with highly diversified origin and geometry. Specific features
of tectonics at the front of the nappe overthrusts of the Middle
Group were depicted in Fig. 7A and B. In the zone of the over-
thrust covers of the Silesian Nappe and Subsilesian Unit, the
seismic image is weakly readable due to rapid changes of
thickness and lithology of interfingering flysch members (of
both the sequences) and their steep dips, which was recog-
nized, among others, in the Bykowce IG-1 well section
(Fig. 7A). These changes, in particular rapid wedging out of
thick series of Paleogene sandstones, undoubtedly influenced
the intensity of the tectonic deformations, typical also of the
outcrops of this zone (Malata 1997).
A distinctive character of tectonic deformations is typical
of the front of the Skole Nappe overthrust. At its base, tec-
tonically altered fragments of the Stebnik cover occur, and in
the zone of wedging out of the autochthonous Miocene mo-
lasses (encountered in the Bachórzec-1 well), flat tectonic
shears in the Precambrian basement also dislocate the nappe
base (Fig. 7B).
The northern part of the traverse III (Fig. 8) illustrates spe-
cific features of tectonics of the Marginal Group units and of
the Skole Nappe front in the Przemyśl Sigmoid zone (Fig. 1).
Long imbricated folds (“skybas”) and tectonic slices of the
Skole Nappe and wedging out Boryslav-Pokuttya Unit (Gluško
1968) are thrust over intensely folded older molasses of the
Stebnik Nappe, which are dislocated by flat thrusts (Fig. 8A).
The intensity of the tectonic deformations declines in the sec-
tion of younger members building up the Stebnik cover that is
locally overlain by transgressive conglomerates of the Late
Miocene. A specific feature of the Stebnik Nappe tectonics
in the borderland between Poland and Ukraine is represented
by erosional patches of the youngest members of the Skole
Series, encountered at the base of the nappe. The patches are
detached and overthrust together with the covering molasses
which rest with a sedimentary gap (Fig. 8A). Their extent was
contoured in more than ten seismic sections (Kuśmierek &
Baran 2008) on the basis of such criteria as continuity decline
and/or angular unconformities of seismic reflections in the
vicinity of the wells that encountered these patches.
The subsurface structure of the southern part of the
traverse III (to S of the Kuźmina-1 well) has been well recog-
79
2D INTERPRETATION OF SUBSURFACE STRUCTURE AND TECTONIC STYLE OF OUTER CARPATHIANS (POLAND)
Fig. 7.
Traverse
II:
Bukowsko—Łopuszka
Wielka
(Explanations
as
for
Fig. 5).
A
–
Tectonic
style
and
thickness
reduction
trends
of
flysch
covers
in
the
Silesian
overthrust
zone
–
position
of
the
cross-section
was
marked
A
(on
the
traverse)
and
its
line
w
as
marked
7A
(in
Fig. 1).
Lithostratigraphic
complexes – Menili
te-Krosno
Series:
1
–
Supra-Jasło
Complex,
2
–
Sub-Jasło
Complex;
3
– Eocene deposits,
4
– Senonian—Eocene deposits in the Sub-Silesian Unit (undiffere
ntiated),
5
– Senonian—Paleocene deposits,
6
– Early Cretaceous deposits (Sub-Senonian);
graphical
symbols:
7
–
lithostratigraphic
boundaries,
8
–
nappe
overthrusts,
9
–
lower-order
overthrusts
(tectonic
slices),
10
–
dips
of
beds,
11
–
well
section.
B
–
Seismic
image
of
geom-
etry
of
the
overthrusts
and
wedging
out
autochthonous
Miocene
m
olasses
in
the
marginal
zone
of
the
Carpathians.
Allochthonous
units;
Skole
Series
–
symbols
of
lithostratigraphic
complexes:
12
– Krosno Lithofacies (Ol
2
—M
1
kr
, undifferentiated); Stebnik Unit
and Zgłobice Unit:
13
– folded Miocene molasses (M
1—2
st
, Late Karpatian—Early Sarmatian,
undifferentiated); basement o
f
the tectogene:
14
– autochthonous Middle Miocene molasses (M
2
aut
, Late Badenian—Sarmatian, undifferentiated),
15
– Precambrian (Pr); explanation of the remaining lithostratigr
aphic sym-
bols (m, E, P—K
2
,
K
1
) – as for Fig. 5A.
80
KUŚMIEREK
Fig. 8.
Traverse
III:
Komańcza—Jaksmanice:
1
–
erosional
patches
of
the
flysch
cover
on
the
platform
slope
at
the
base
of
the
Stebnik
Unit
(F,
Late
Eocene—Oligocene),
2
–
deposits
of
the
Zgłobice
Unit
(M
2
Zg
);
remaining
explanations
as
for
Fig. 5
and
cross-section
A.
A
–
Geological-seismic
image
of
tectonics
of
the
Marginal
Group
of
allochthonous
units
and
their
basement
in
the
borderland
between
Poland
and
Ukraine
(after
Kuśmierek
&
Baran
2008,
repri
nted
with
permission).
Flysch
lithostratigraphic
complexes
(of
the
Skole
Nappe
and
Bor
yslav-Pokuttya
Unit):
3
–
Menilite
Beds
(Ol
m
),
4
–
Hieroglyphic
Beds
and
Variegated
Shales
(E
h
),
5
–
Inoceramian
Beds
(Ropianka
Fm,
Senonian—Paleocene,
K
2
in
-P),
6
–
Siliceous
M
arls
(Turonian,
K
2
mk
),
7
–
older
Cretaceous
de-
posits
(Turonian—Hauterivian);
folded
molasses
(Late
Ottnangian
—Early
Sarmatian):
8
–
Vorotyšča
Beds
(Saliferous
Clay,
M
1
W
),
9
–
Dubnik
Conglomerate
(M
1
D
),
10
–
Stebnik
Beds
(M
2
st
),
11
–
Balyč
Beds
(M
2
b
),
12
–
Przemyśl
Beds
(M
2
p
),
13
–
Radyč
Conglomerate
(M
2
R
)
–
postinversional
cover?
81
2D INTERPRETATION OF SUBSURFACE STRUCTURE AND TECTONIC STYLE OF OUTER CARPATHIANS (POLAND)
Fig. 9. Optimization of the density model along the traverse III (seismic profile 34-15-96K, its line is in Fig. 1) (after Ostrowski & Targosz
2006, unpublished materials of the Geophysical Exploration Company) on the basis of the author’s geological interpretation and density
data. Lithostratigraphic explanations as for Figs. 2, 5, 7; remaining explanations – see the figure.
nized by the seismic profile 34-15-96K and MT (profile 16 in
Fig. 1), running parallel to its line. In order to validate the MT
results, which document huge denivelations of the Precam-
brian basement, and to carry out preliminary, working inter-
pretation of the tectonics of the flysch cover, gravimetric
modelling was conducted along its line (Fig. 1). After rather
insignificant correction of rock densities, the modelling results
have confirmed correctness of the interpretation of the sub-
surface geological structure, as “errors” of matching of the
modelled gravitational effect with observed anomalies (mea-
surement data – Fig. 9) were insignificant.
Along the traverse IV, which was worst documented by
seismics (Fig. 10), the foreland of the Dukla Unit and Skole
Nappe is characterized by the most complicated tectonics. The
accepted interpretation of the specific tectonics in the so-
called Bieszczady facies subregion (Kuśmierek 1979), which
extends from the Dukla thrust up to the Otryt thrust (O—O in
Fig. 10), has been supported by seismic documentation of the
southern segment of the FII/I-74/75 profile (line 10A in
Fig. 1) that crosses the outcrops of the oldest (in this part of
the Carpathians) flysch formation members in the tectonic
element called the Bystre scale (Ślączka 1959). Detailed
mapping conducted by the author (Kuśmierek 1979) has docu-
mented that this element constitutes a frontal digitation of a
fold overturned to the NE (of the pseudosyncline type), which
is also revealed by the geometry of reflectors (Fig. 10A).
Occurrence of upturned rock series, combined with pres-
ence of tectonic windows and patches and backthrusts, was
also noted in the Ukrainian part of so-called Fore-Dukla Zone,
among others in the upper Uzh drainage basin (Danysh 1973).
Occurrence of backward thrust tectonic elements was also
identified in the Polanki IG-1 (Fig. 10) and Suche Rzeki IG-1
(Fig. 10B) well sections. The structural arrangement of reflec-
tions in both the seismic sections, which accentuates the diver-
gent, disharmonic structure of detached and tectonically
reactivated structural elements, indirectly reflects the mor-
phology of the basement.
The complicated tectonics of the internal synclinorium of
the Skole Nappe, before the front of the Silesian overthrust,
was recognized in the deep wells Jasień IG-1 and Brzegi
Dolne IG-1. Its deep-seated elements are also imaged by the
W00 70 276 seismic profile recorded by PBG (Fig. 10). The
Jasień IG-1 well section documented a complex system of
tectonic shears that do not appear in the surface structure.
They dislocate steep and locally backward inclined folds de-
void of the Lower Cretaceous deposits. The folds had been
82
KUŚMIEREK
Fig. 10.
Traverse
IV:
Cisna
(Poland)—Chidnovichi
(Ukraine);
the
Ukrainia
n
part
was
corrected
with
unpublished
materials
of
C.
Zayats
an
d
P.
Loziniak.
Early
Miocene
folded
molasses
of
the
Bo-
ryslav-Pokuttya Unit:
1
– Poljanica Beds,
2
– Vorotyšča Beds (Saliferous Clay); remaining explanations as
for Figs. 5, 8.
A
–
Interpretation of tectonics of structures in the foreland of th
e Dukla
Unit along the seismic section FII/I-74/75 (southern fragment;
see Fig. 1, line 10A) on the
basis of seismic documentation (Pe
pel, Bardadyn, Patryas – Geophysical Exploration Company, Warsa
w
1974/75,
unpublished
materials)
and
cartographic-structural
inv
estigations
(Kuśmierek
1979).
Menilite-Krosno
Series
(Oligocene):
3
–
Middle
Krosno
Beds
(Ol
k2
),
4
–
Lower
Krosno
Beds
(Ol
k1
),
5
– Transition Beds and Menilite Beds (undifferentiated, Ol
km+m
); older deposits:
6
– Eocene—Ciężkowice Sandstones, Variegated Shales and Hierogly
phic Beds (E
h
),
7
– Paleocene—Cretaceous
(undifferentiated
Istebna
Beds,
Lgota
Beds,
Grodziszcze
Sandsto
nes,
Cieszyn
Beds,
P-K),
8
–
overthrust
of
the
Dukla
Unit
(Dk
u.),
9
–
paraautochthon
(PA?),
1
0
–
overthrusts
of
lower
orders
and
faults,
11
–
erosional
outliers
of
the
thrust
upper
limb
of
the
Iwonicz—R
udawka
Rymanowska
Fold,
12
–
seismic
reflections,
13
–
well
location
and
symbol.
B
–
Interpretation
of
tectonics
of
structures
in
the
southeastern
part
of
the
seismic
section
15-I
-71K
(see
Fig. 1,
line 10B)
on
the
basis
of
seismic
documentati
on
(Shöppl
&
Bednarz
1972,
Polish
Oil
and
Gas
Company
Kraków,
u
n-
published
materials)
and
cartographic-structural
investigations
(Kuśmierek
1979).
Lower
Krosno
Beds
(divided):
14
–
sandstone
complex
(Ol
P
k1
),
15
–
sandstone-shale
complex
(Ol
Pł
k1
);
remain-
ing
explanations
as
for
Fig. 10A.
83
2D INTERPRETATION OF SUBSURFACE STRUCTURE AND TECTONIC STYLE OF OUTER CARPATHIANS (POLAND)
detached from the underlying deep-seated fold with the Lower
Oligocene sediments, 430 m thick, encountered at its top
(Żytko 2004). This gently sloping fold, with dips predomi-
nantly from 5 to 7°, was interpreted as a paraautochthonous
element documented by drilling (Fig. 10).
The northeastern part of the traverse IV – constructed on
the basis of the Ukrainian geological atlas (Shakin et al.
1976) and corrected by new, unpublished materials of C. Zayats
and P. Loziniak – illustrates, among others, developed
thickness of folded molasses of the Boryslav-Pokuttya Unit,
which overlie, with a sedimentary gap, deep-seated folds of
the unit.
Regional diversification of the tectonic style
Considerable differentiation of the feature of the subsurface
structures between southern and northern segments of particu-
lar traverses (Figs. 5, 7, 8, 10) justifies the usefulness of their
separate analyses. Internal segments of the traverses – lying
in the zone of compressional sutures in the tectogene base-
ment (Fig. 1) with diversified hypsometry of its individual
blocks and geometry and amplitudes of the deep-seated frac-
tures dislocating them – are characterized by more differenti-
ated types of structures in the cover. In their southern parts, at
least to the system of transversal deep-seated fractures C—D—E
(Fig. 1), sets of fault-propagation folds predominate; most fre-
quently they are represented by stacked slices with tectonical-
ly reduced northern limbs overlapping the internal margin of
the southern tectonic suture (Figs. 5, 7, 8). The system of
backthrusts that appears in the southern part of the traverse IV
(Fig. 10) is probably related to subsurface wedging of the up-
lifted basement blocks within the “shallower” tectonic suture,
above which so-called triangle zones of the eastern sector of
the Fore-Dukla Zone were formed (Roure et al. 1993). The or-
igin of interpretive controversies concerning this sector is con-
nected not only with the youngest phase of the compressional
inversion of the structures (during which backward-vergent
thrusts were formed; see Fig. 10A), but also with mutual rela-
tions between synsedimentary tectonic deformations and sedi-
mentary structures on the northern slope of the Fore-Dukla
uplift (Kuśmierek 1981).
The northern parts of the internal segment of the traverse IV
are characterized by common occurrence of detachment folds
with variable vergence, locally – backward vergence on
slopes of the thrust nappe covers, among others above broad
uplifts which can be interpreted as duplexes. Flat detachments
of the type of compressional inversion faults – identified in
seismic sections – are most often located in zones of structur-
al depressions of the flysch cover, which are superposed on
deep-seated compressional sutures. Sporadically they also oc-
cur in northern segments of the traverses I and II (up to the
subsurface trace of the fracture B; see Fig. 1) as associated
with disharmoniously folded structural elements (Figs. 5, 7).
The tectonic style of the external segments of the traverses,
dominated by the flexural slope of the subducted platform, is
characterized by a geometrically consequent system of thrusts
dipping toward the southwest. Their amplitudes increase to
the SE and they are intensified in the Przemyśl Sigmoid zone
behind the trace of the fracture B where – at the external side
of the zone of the compressional sutures – faults with smaller
throws appear, which dislocate the slope of the platform base-
ment (initial sutures? – Fig. 1). In the traverses I and II
(Figs. 5, 7), the gently sloping Skole Nappe cover is dislocat-
ed by flat-dipping overthrusts and tectonic slices, and some
synclinal structures are cut at the base by inversional detach-
ments. In the traverses III and IV (Figs. 8, 10), a system of im-
bricate thrusts is developed, which separate structural
elements of the “skyba” type and asymmetric geometry accen-
tuated by wedging out of the youngest lithostratigraphic mem-
bers of the Skole Series (preserved only in deeper synclines).
In the near-surface zone, they are characterized by steeper dips
and smaller amplitudes of displacements that sometimes de-
cline or are compensated by deformations of the continuous
type. From this it can be inferred that the early stage of their
propagation could have preceded sedimentation of the young-
est members of the Skole Nappe; the youngest members
wedge out on the slope of the platform margin, which is
shown by their thickness reduction combined with the tenden-
cy to change the lithofacies of the sediments toward succes-
sions of the platform type.
In the interpreted seismic sections, no deep-seated extension
of the Boryslav-Pokuttya Unit at the base of the Silesian
Nappe has been encountered. The prospects for discovering
oil fields (of the Boryslav type) under the Przemyśl Sigmoid
or in its southern margin had been linked with this conception
(e.g. Wdowiarz & Jucha 1981 and references therein). The
deepest well Kuźmina-1 (7541 m), drilled for this purpose, at
the base of the Stebnik Unit encountered a detached block of
flysch deposits (at the depth of 7062—7221 m) which were ad-
mitted to be olistoliths (Malata & Żytko 2006). However, in
the author’s opinion, it is a tectonically detached erosional
outlier of the flysch cover (Fig. 8), lying in a structural posi-
tion analogous to the previously described patches at the front
of the Skole overthrust.
The most distinct differentiation of the tectonic style of indi-
vidual structural-facies units along their strikes exists between
the traverses III and IV. It reveals tectonic mobility of the
transversal fractures (marked by letters from C to I in Fig. 1)
which dislocate the tectogene basement in the hinterland of
the Przemyśl Sigmoid and separate the northern and northeast-
ern segments of the Carpathian arc.
Summary
Cartographic imaging of the subsurface structure of the Outer
Carpathians tectogene is an underestimated element for recog-
nition of the tectogene structure. Such imaging is crucial for
profound interpretation of the complicated tectonics of the
allochthonous flysch covers and their basement, and for re-
construction of scaled paleostructural models. Integrated inter-
pretation of the two-dimensional cartographic and geophysical
images, combined with well sections, has documented a new,
more complicated picture of the subsurface structure in the east-
ern part of the Polish Carpathians, dominated by thrusts of the
cover and deep-seated faults of the basement, which induced
fold systems of various geometries and origins.
84
KUŚMIEREK
Acceptance of significant differentiation of the tectonic
style between surface and subsurface structural elements of
nappe covers and their heterogeneous basement has shaken
the sceptical attitude towards the credibility of the seismic im-
ages and results of the MT interpretation in the Carpathian do-
main. Application of the modified methodology of processing
of seismic data and their geological interpretation has speci-
fied subsurface traces of overthrusts and thrust faults, among
others documenting the geometry of flat inversional detach-
ments (that were previously unrecognized). Reinterpretation
of the MT results justifies relating the oblique and subvertical
resistivity boundaries with extreme contrasts to compressional
sutures of the tectogene. Overlying gently-sloping structural
elements in the nappe hinterland have been interpreted as
paraautochthonous covers, which should be admitted to be a
working hypothesis based upon geophysical premises and the
author’s interpretation of one of the deep well sections.
The interpretation of patches of the flysch cover at the base
of the Stebnik Nappe overthrust, which is different from the
commonly accepted, implies the advisability of revision of the
previously published stereotyped paleogeographic models.
Acknowledgments: Unpublished images of the subsurface
structure of the Carpathians were prepared within the frame-
work of the Polish-Ukrainian research Project (No. DWM/
1818-1/2N 2005) financed by the Ministry of Science and
Higher Education of the Republic of Poland. Their construc-
tion was possible owing to Polish Oil and Gas Company S.A.
and Polish Geological Institute, which made final documenta-
tions of wells and archival seismic sections available. Repro-
cessing of the seismic sections by a team managed by Tomasz
Maćkowski made it possible to carry out more profound geo-
logical interpretation conducted by the author, partly in coop-
eration with Urszula Baran. Their help is warmly appreciated.
The author wishes to thank his close collaborators for their
help in preparing this paper for printing: Julian Krach for the
translation into English and Grzegorz Machowski for the elec-
tronic version of figures.
References
Bielik M. 1999: Geophysical features of the Slovak Western Car-
pathians: a review. Geological Quarterly 43, 3, 251—262.
Capik M., Górecki W., Kuśmierek J., Maćkowski T., Karpach O.,
Karpenko A., Omelchenko V. & Machula Z. 2006: Polish-Ukrai-
nian cooperation in prospecting for petroleum in the transfrontier
zone of the Carpathians: purposes and perspectives. Technika
Poszukiwań Geologicznych, Geotermia, Zrównoważony Rozwój
2, 103—108 (in Polish).
Danysh V.V. 1973: Geology of the western part of the northern mar-
gin of the Ukrainian Carpathians. Naukova Dumka, Kiev, 1—117
(in Ukrainian).
Dérerová J., Zeyen H., Bielik M. & Salman K. 2006: Application of
integrated geophysical modeling for determination of the conti-
nental lithospheric thermal structure in the eastern Carpathians.
Tectonics 25, 3, Art. No. TC3009.
Doktór S., Graniczny M., Kucharski R., Mołek M. & Dąbrowska B.
1990: Subsurface geological structure of the Carpathians in the
light of complex remote-sensing and geophysical analyses.
Przegl. Geol. 11, 469—475 (in Polish).
Gluško W.W. 1968: Tectonics and oil/gas productivity of the Car-
pathians and adjacent depressions. Nedra, Moscow, 1—263 (in
Russian).
Jankowski L., Kopciowski R. & Ryłko W. 2004: Geological Map of
the Outer Carpathians: Borderlands of Poland, Ukraine and Slo-
vakia (1 : 200,000). Państwowy Instytut Geologiczny, Warszawa
(in Polish).
Jucha S. & Kotlarczyk J. 1958: Trial of new stratigraphics division of
Menilite Series and Krosno Beds. Nafta 8, 205—207 (in Polish).
Konečný V., Kováč M., Lexa J. & Šefara J. 2002: Carpatho-Pannon-
ian region: an interplay of subduction and back-arc diapiric up-
rise in the mantle. EGS Stephan Mueller, Spec. Publ. Ser. 1,
165—195.
Książkiewicz M. 1972: Geology of Poland. Vol. IV. Tectonics. Part 3:
Carpathians. Wydawnictwa Geologiczne, Warszawa, 1—228 (in
Polish).
Kuśmierek J. 1979: Gravitational deformations and backward over-
thrusts with reference to deep structures and petroleum pros-
pects of the Dukla Unit foreland in the Bieszczady Mountains.
Prace Geol., PAN 114, 1—68 (in Polish).
Kuśmierek J. 1981: Paleostructural analysis of the Otryt Series
(southeast part of the Central-Carpathian Depression). Zesz.
Nauk. AGH, Geol. 7, 3, 97—116 (in Polish).
Kuśmierek J. 1984: Justification of oil- and gas-productivity pros-
pects of the flysch formation in the eastern part of the Polish
Carpathians and proposals of resource documentation. Zagad-
nienia Surowców Energetycznych w Gospodarce Krajowej.
Materiały Konferencji Komitetu Gospodarki Surowcami Miner-
alnymi, PAN. Wydawnictwo AGH, Kraków,
27—49 (in Polish).
Kuśmierek J. 1990: Outline of geodynamics of Central Carpathian
Oil Basin. Prace Geol., PAN 135, 1—85 (in Polish).
Kuśmierek J. 1996: Evolution of the Central Carpathian Oil Basin –
quantitative interpretation. In: Roure F., Ellouz N., Shein V.S. &
Skvortsov I. (Eds.): Geodynamic evolution of sedimentary ba-
sins. International Symposium, Moscow, 281—303.
Kuśmierek J. & Baran U. 2008: Subsurface structure of the Car-
pathians in the zone of the Przemyśl Sigmoid: interpretation of
seismic sections and assessment of hydrocarbon prospects.
Kwartalnik AGH, Geologia 34, 3, 365—384 (in Polish).
Kuśmierek J. & Ney R. 1988: Problems of tectonics of the basement
and development of structures of the cover in the eastern part of
the Polish Carpathians. Przegl. Geol. 6, 318—325 (in Polish).
Kuśmierek J., Halat Z., Maćkowski T. & Papiernik B. 1995: Evolution
and hydrocarbon potential of the Polish Carpathians. Integrated
modelling interpretation in petroleum system of eastern part of al-
lochthonous units. Prace Geol., PAN 138, 1—92 (in Polish).
Kuśmierek J., Maćkowski T. & Łapinkiewicz A.P. 2001: Efects of
synsedimentary thrusts and folds on the results of two-dimen-
sional hydrocarbon generation modeling of the eastern Polish
Carpathians. Przegl. Geol. 49, 5, 412—417 (in Polish).
Letouzey J. 1990: Fault reactivation, inversion and fold-thrust belt.
In: Letouzey J. (Ed.): Petroleum and tectonics in mobile belts.
Editions Technip, Paris, 101—128.
Lizoon S.O. & Zayats C. 1997: New data on deep structure of the
Ukrainian Carpathians: geological reinterpretation of regional
seismic profiles. Przegl. Geol. 45, 11, 1144—1146 (in Polish).
Malata T. 1997: Tectonic style of the Węglówka zone of the Polish
Eastern Carpathians and its relationship to the Carpathian base-
ment. Biul. Państw. Inst. Geol. 376, 43—59 (in Polish).
Malata T. & Żytko K. 2006: Kuźmina 1. Profiles of deep wells of
the Polish Geological Institute 110, PIG, Warszawa, 1—65 (in
Polish).
Marecik T., Pieniądz K. & Smolarski L. 2008: Metholodogy of seis-
mic data processing in the Przemyśl Sigmoid – selected proce-
dures. Kwartalnik AGH, Geologia 34, 3, 527—540 (in Polish).
Mitra S. 1986: Duplex structures and imbricate thrust systems: geom-
85
2D INTERPRETATION OF SUBSURFACE STRUCTURE AND TECTONIC STYLE OF OUTER CARPATHIANS (POLAND)
etry, structural position and hydrocarbon potential. AAPG Bull.
70, 1087—1112.
Nemčok M., Krzywiec P., Wojtaszek M., Ludhová L., Klecker R.A.,
Sercombe W.J. & Coward M.P. 2006: Tertiary development of
the Polish and eastern Slovak parts of the Carpathian accretion-
ary wedge: insights from balanced cross-sections. Geol. Car-
pathica 57, 5, 355—370.
Oszczypko N., Ślączka A. & Żytko K. 2008: Tectonic subdivision of
Poland: Polish Outer Carpathians and their foredeep. Przegl.
Geol. 56, 10, 927—935 (in Polish).
Poprava D. & Nemčok J. 1989: Geological atlas of the Western Outer
Carpathians and their Foreland. PIG, Warszawa, GÚDŠ, Bra-
tislava, ÚÚG, Praha.
Roure F., Roca E. & Sassi W. 1993: The Neogene evolution of the
outer Carpathian flysch units (Poland, Ukraine and Romania):
kinematics of a foreland/fold-and-thrust belt system. Sed. Geol.
86, 177—201.
Ryłko W. & Tomaś A. 2005: Basement structure below the West
Carpathian—East Carpathian orogen junction (eastern Poland,
north-eastern Slovakia and western Ukraine). Geol. Carpathica
56, 1, 29—40.
Shakin V., Burov V.S., Vialov O.S., Glushko V.V., Kruglov S.S.,
Pietrashkiewich M.I. & Temniuk F.P. 1976: Geologic map of
the Ukrainian Carpathians and adjacent depressions. Scale
1 : 200,000. Ministry of Geology USSR, Kiev (in Russian).
Stefaniuk M. 2001: Main structural elements of the basement of east-
ern Polish Carpathians in the light of magnetotelluric investiga-
tions. Kwartalnik AGH, Geologia 27, 1, 127—159 (in Polish).
Stefaniuk M. 2003: Regional magnetotelluric investigations in the
Polish Eastern Carpathians. Kwartalnik AGH, Geologia 29, 3—4,
131—168 (in Polish).
Stefaniuk M. 2006: Some results of a new magnetotelluric survey in
the area of Polish Outer Carpathians. In: Golonka J. & Picha F.J.
(Eds.): The Carpathians and their foreland: Geology and hydro-
carbon resources. AAPG Mem. 84, 503—512.
Ślączka A. 1959: Stratigraphy of the Bystre scale (Middle Car-
pathians). Biul. Inst. Geol. 131, 203—251 (in Polish).
Świdziński H. 1971: The extent of horizontal displacements in the
Northern Flysch Carpathians. Rocz. Pol. Tow. Geol. XLI, 1,
181—211 (in Polish).
Wdowiarz S. 1985: Some problems of the geological structure and
oil/gas productivity of the Central Carpathian Synclinorium in
Poland. Biul. Inst. Geol. 350, 5—45 (in Polish).
Wdowiarz S. & Jucha S. 1981: North-western extension of the
Borislav-Pokutse zone of deep-seated folds in the Polish Car-
pathians. Biul. Inst. Geol. 335, 7—22.
Zeyen H., Dérerová J. & Bielik M. 2002: Determination of the conti-
nental lithospheric thermal structure in the Western Carpathians:
integrated modelling of surface heat flow, gravity anomalies and
topography. Phys. Earth Planet. Inter. 134, 1—2, 89—104.
Żytko K. 2004: Jasień IG-1. Profiles of deep wells of the Polish Geo-
logical Institute 103, PIG, Warszawa, 1—67 (in Polish).