GEOLOGICA CARPATHICA, FEBRUARY 2005, 56, 1, 1728
Deformation phases in the selected shear zones within the
Tatra Mountains granitoid core
EDYTA JUREWICZ
1
and
BOGUS£AW BAGIÑSKI
2
1
Laboratory of Tectonics and Geological Mapping, Faculty of Geology, Warsaw University, al. ¯wirki i Wigury 93, 02-089 Warszawa,
Poland; edytaj@geo.uw.edu.pl
2
Institute of Geochemistry, Mineralogy and Petrology, Faculty of Geology, Warsaw University, al. ¯wirki i Wigury 93, 02-089 Warszawa,
Poland; b.baginski1@uw.edu.pl
(Manuscript received June 25, 2003; accepted in revised form March 16, 2004)
Abstract: The paper presents the complex geological structure and microstructure of four selected polydeformed shear
zones within the granitoid core of the High Tatra Mountains. Sequences of deformation and mineralization were deter-
mined for each zone. In order to determine the deformation conditions, petrotectonic analysis and the chlorite
geothermometer were applied. The obtained data were correlated with earlier published fluid inclusions investigations.
Next, the results were supported by petrotectonic and structural analyses, and on the basis of the whole set of data three
groups of structures were distinguished: 1 pre-Alpine (connected with late Variscan extension or Early Jurassic
rifting, brittle-plastic in character); 2 Alpine (formed during the Late Cretaceous thrusting, marked by the presence of
flat-dipping slickensided faults); 3 late Tertiary (linked with the uplift of the Tatra massif and the accompanying
extension and sinistral oblique-normal-slip faults). On the basis of the pressure 1.451.70 kba (145170 MPa) and
temperatures (212254 °C) estimated from fluid inclusion analysis, as well as temperatures range of 205250 °C ob-
tained from the Cathelineau geothermometer, the depth of the granitoid massif position during the Late Cretaceous
Alpine thrust folding was determined at 67 km and the geothermal gradient at ca. 30 °C.
Key words: Western Carpathians, High Tatra Mountains, tectonic evolution, shear zones, granitoid rocks, cataclasites,
mylonites.
Introduction
The Tatra Mountains represent the northernmost basement
massif of the Inner Western Carpathians. The younger part of
the crystalline core comprises granitoid rocks considered to be
products of the Variscan Orogeny (Petrík et al. 1994). The iso-
topic ages of the granitoid intrusion of the Tatra Mountains
range between 300330 Ma according to the
40
Ar/
39
Ar and
Rb/Sr methods (Burchart 1968; Maluski et al. 1993; Janák
1994; Kohút & Sherlock 2003) and 340310 Ma according to
zircon dating (Poller et al. 2000; Poller & Todd 2000). The
depth of the magma intrusion was estimated at 1822 km,
which corresponds to 56 kbar (500600 MPa) and 450
550 °C (Kohút & Janák 1994). During the Variscan Orogeny,
the first deformation stage is related to the south-eastward
ductile thrusting of the upper unit composed of granites and
migmatites over the footwall metasediments of the Western
Tatra Mountains (Fritz et al. 1992; Janák 1994). The second
Variscan extensional deformation was characterized by W-E
stretching (Kohút & Janák 1994). After the Permian, the Tatric
pre-Alpine complexes were buried not deeper than 12 km (ca.
250 °C Kováè et al. 1994). Structural studies of Puti
(1992), Kohút & Janák (1996) and Janák & Kahan (1996) sug-
gest the brittle character of the deformation during the Alpine
stage occurring in low P-T conditions. The Tertiary uplift of
the Tatra Mountains took place 1510 Ma ago, as shown by
apatite fission track dating (Burchart 1972; Krá¾ 1977; Kováè
et al. 1994).
This paper is focused on the presentation of selected shear
zones within the High Tatra Mountains granitoid core
(Fig. 1A) in relation to their multistage tectonic evolution doc-
umented by several phases of deformation and mineralization.
Despite the polydeformed character of these zones, it is possi-
ble to determine the chronology of events, conditions of defor-
mation in each stage of tectonic evolution, as well as to relate
them to regional events.
Classification of shear zones
The granitoid core of the High Tatra Mountains is cut by
several-meters thick tectonic zones, clearly visible in the mor-
phology as cols. According to Grochocka-Piotrowska (1970)
these zones can be subdivided into:
a so-called uniform slip zones, comprising numerous
slickensides with closely adherent fault-walls;
b debris zones cataclasites, mylonites and tectonic
breccia;
c fault zones with ductile deformation.
Jurewicz (2000a, 2002) presented a slightly different view
for distinguishing particular dislocations within the granitoid
core of the High Tatra Mountains, based on their geometry.
The dislocations were initially sub-divided into two groups:
flat-dipping faults with dips <45° (Fig. 1D) and steep singular
faults and faults zones (Fig. 1C,E) with dips >45°. The flat-
dipping faults are characterized by most commonly 2080°
www.geologicacarpathica.sk
18 JUREWICZ and BAGIÑSKI
Fig. 1. A Sketch-map of the Polish part of the High Tatra Mountains and location of the four studied mylonitic zones: a Galeria Cu-
bryñska Ridge; b Miêguszowiecka Pass; c Miedziane Ridge; d Poredni Granat Mountain. BH stereoplot of the shear zones,
projection on the lower hemisphere: B orientation of the investigated shear planes; arrow points orientation of striae; C pole to the (a)
and (b) shear planes in relation to the contour plot of the pre-Alpine mylonitic zones; D pole to the (c) shear plane in relation to the con-
tour plot of the flat dipping fault planes of Alpine ages; E pole to the (d) shear plane in relation to the contour plot of the steep-dipping
shear zones (normal-oblique-slip faults) of late Tertiary age; F,G,H after rotation of the Tatra Mountains block to the position prior to the
late Tertiary rotational uplift (40° southwards around the 90/0 axis; see for detail: Jurewicz 2000a, 2002); Note that the orientation of the
d-plane after rotation (F, G) and without rotation is correlated with the maximum of steep faults (E) connected with Neogene extension. I
scheme of rotation along horizontal axis to position prior to the late Tertiary uplift.
DEFORMATION PHASES IN THE SHEAR ZONES WITHIN TATRA MTS GRANITOID CORE 19
oriented, smooth planes and the presence of tectonic striations
on mineralized surfaces (most commonly epidote-quartz or
chlorite-quartz). They are linked with the Alpine thrust fold-
ing, and the striae allowed reconstruction of the stress field re-
sponsible for the thrust formation in the Tatra Mountains (Ju-
rewicz 2000a,b). Steep faults, in turn, do not comprise a
uniform group in relation to their orientation, character of ac-
companying structures, as well as their origin and age. In Ju-
rewicz (2002) they were tentatively sub-divided into:
a steep dislocations comprising mylonites and/or catacla-
sites, several tens of cm to approximately 23 m wide, or com-
prising a series of narrow zones from several to several tens of
cm wide, with strikes about 40° or 110° (Fig. 1C);
b steep dislocations comprising singular planes or sys-
tems of several parallel planes with strikes about 35°
(Fig. 1E).
The geometric analysis of singular steep fault planes al-
lowed us to identify them as sinistral strike-slip faults or ob-
lique-normal-slip faults, and to link them with the Middle Mi-
ocene 106120° (Jurewicz 2002) extension, which took place
after the rotational uplift of the Tatra Mountains (Piotrowski
1978; Kováè et al. 1994; Sperner 1996; ¯elaniewicz 1996;
Jurewicz 2000a). Dislocations comprising cataclasites and
mylonites are most probably older that the flat-dipping slick-
ensides, as well as the steep singular slickenside fault planes.
However, dislocations with orientations similar to those of
steep faults could be reactivated during the late Tertiary uplift
of the Tatra massif. Some of the fault planes could be geomet-
rically connected with magmatic-tectonic jointing described
by Jaroszewski (1985). During the Alpine thrust movements
the presently steep dislocation zones did not lie in orientations
close to the planes of maximum shearing, therefore they were
not reactivated.
In the Polish part of the High Tatra Mountains, low dips of
the cataclastic and mylonitic zones are rather uncommon. One
such zone was identified in the vicinity of Czarna £awka in
Liptowskie Mury, where it is ca. 40 cm thick and is oriented at
340/35; the second one described below occurs on the Miedziane
Ridge, where ca. 1020 cm thick mylonitic epidote occurs.
Methodology
Observations of structures and textures were carried out di-
rectly in the field, on polished surfaces, in an optical micro-
scope and a microprobe (BSE images). The minerals were rec-
ognized under an optical microscope, and the chemical
composition was determined by microprobe analysis. To de-
termine the temperature conditions of the deformation and
mineralization processes, the chlorite geothermometers
(Cathelineau & Nieva 1985; Cathelineau 1988) were applied.
There is a certain problem in contemporary literature with
the precise application of the terms mylonites and catacla-
sites. The existing criteria are not clear. Some authors when
describing rocks from shear zones use the term tectonites.
Cataclastic zones are difficult to distinguish from mylonitic
zones in the field. Cataclasites are considered to be rocks com-
prising sharp-edged rock and mineral fragments, crushed dur-
ing the process of brittle fracturing, however without melting
(Passchier & Trouw 1997). Mylonites are defined as strongly
deformed rocks occurring in ductile shear zones, commonly
with planar foliation and stretching lineation (Passchier &
Trouw 1997; Bucher & Frey 2002). Lapworth (1885) linked
mylonites with brittle faults; presently, however, they are con-
sidered to be formed under the influence of crystal-plastic ma-
trix flow, despite the fact that brittle deformation is observed
in isolated rock lenses and individual mineral grains (some
minerals reveal brittle fractures). According to Yardley (1991)
the presence of neoformed minerals is a prerequisite to assign
rocks from shear zones to mylonites.
The internal fabric of mylonitic zones in the Tatra Moun-
tains differs in the degree of the mylonitization process and
number of deformation and mineralization phases. The varia-
tion of the mylonitic structures is also observed within particu-
lar zones and is linked with the degree of structural reworking
changing along each zone. The zones reveal traces of reactiva-
tion, for example, in the form of deformation of mylonitic fab-
rics formed during earlier shearing, or mineral veins formed
during progressive deformation and in relaxation stages. This
paper shows the complex and variable structure of the shear
zones in the Tatra Mountains and the poly-phase process lead-
ing to their formation based on selected dislocation zones: in
the Galeria Cubryñska Ridge, on Poredni Granat in the
Granaty Ridge, in the Miêguszowiecka Prze³êcz pod
Ch³opkiem Pass, further referred to as the Miêguszowiecka
Pass, as well as on the Miedziane Ridge (Fig. 1A). On the ba-
sis of the succession and condition of deformation, the phases
of development were correlated with stages of tectonic evolu-
tion of the High Tatra Mountains.
Characteristics of the selected shear zones
Galeria Cubryñska Ridge
This 205/80 oriented zone (Fig. 1A,B-a,C-a) transects the
north-western slopes of the Cubryna Mountain the so-
called Galeria Cubryñska, and is one of the widest and most
complex zones in the series of three parallel tectonic zones in
this area. It is ca. 1.52 m wide and represents a fissure cutting
several tens of meters into the massif, with a clearly-visible
debris fan beneath it. After reversing to the position prior to
the post-Paleogene rotational uplift this zone attains the dip of
ca. 75° (Fig. 1F-a,G-a). Its internal structure is very complex.
It is delimited from the wall rocks (Fig. 2A-1) by distinct
slickenside surfaces (Fig. 2A-5) coated with ca. 0.52 cm
thick mylonitic epidote with clear 292/35 shear striae indicat-
ing a dextral dip-slip movement. The slickensides document
the last phase of movement, which took place along the
boundary of rock media with different reological properties
(mylonite and granitoid). The filling of fractures (quartz-filled
gashes Fig. 2A-6) with orientations parallel to the margins
of the mylonitic zone and developed along the boundary of the
earlier vein of green quartz (Fig. 2A-4) are younger than the
movement phase. The quartz vughs developed along the
northern margin of the mylonitic zone, probably grew in an
extensional fissure but did not fill it entirely; the space be-
tween the crystals is filled with younger white milky calcite
20 JUREWICZ and BAGIÑSKI
(Fig. 2A-7). Calcite in this zone also occurs in lens-shaped drus-
es within the moderately deformed granitoid (Fig. 3A). This
calcite, as well as other carbonates in other places has a char-
acteristic ferricrust. Earlier than the green quartz (Fig. 2A-4),
the colour of which comes from chlorite, are veins of milky
quartz (Fig. 2A-3), which underwent boudinage and slight de-
formation. The oldest tectonic phase is linked with a shear
process, which resulted in mylonitization, dynamic recrystalli-
zation and textural reworking (Fig. 2A-2). The effects of this
process can be seen directly in the field in the form of the S-C
structures indicating the downward displacement of the south-
ern limb. The S-surfaces are wavy-shaped foliations cut by the
C-planes surfaces defined by microshears parallel to the shear-
zone boundary (see Shimamoto 1989; Lin 1999). Porphyro-
clasts of magmatic quartz, several-mm in diameter, which bear
traces of brittle deformation (cataclastic fracturing), can be ob-
served on a polished surface (Fig. 3C). Under the microscope
the quartz porphyroclasts show undulose extinction and fab-
rics of dynamic recrystallization.
The S-C fabrics have also been recognized under the micro-
scope (Fig. 4A). Along the S-C surfaces elongated grains of
neoformed quartz in the pattern of an anastomosing network
occur. This quartz is also characterized by undulose extinc-
tion. According to Lin (1999) one of the most significant mi-
crostructural differences between the S-C cohesive catacla-
sites and the S-C mylonites is the absence of dynamically
recrystallized grains in S-C cataclasites, what unequivocally
points to the Galeria Cubryñska shear zone as mylonites. The
rock has a green colour from chlorites developed after primary
biotite, the presence of which has been registered under the
microscope as well as in BSE images (Fig. 5A). Undulose ex-
tinction, deformation bands and kink bands are clearly visible
in plagioclase porphyroclasts (Fig. 4D), pointing to the low-
grade condition of deformation taking place typically in tem-
peratures 300400 °C (Pryer 1993; Passchier & Trouw 1996).
Furthermore, internal fracturing, occasionally filled by epidote
and quartz (Fig. 4E) also occurs. Nucleation and growth of
new minerals such as white mica porphyroblasts overgrowing
sericite-rich matrix is also observed in the thin section
(Fig. 4B). Later than the newly grown mica flakes are veins of
calcite fibres (Fig. 4C).
Fluid inclusions analyses from the milky quartz vein (Ju-
rewicz & Koz³owski 2003) point to the temperature 264 °C
and pressure 1.6 kbar (160 MPa), and the observation of the
deformation character indicate that the temperature could
reach beyond 300 °C. The data, obtained in studies of fluid in-
clusions from vein quartz in other mylonitic zones indicate the
pressures of ca. 1.31.63 kbar (130160 MPa) and tempera-
ture of ca. 264316 °C (Koz³owski & Jurewicz 2001; Ju-
rewicz & Koz³owski 2003). For neomorphic quartz from shear
surfaces in mylonites the respective values obtained by
Koz³owski are: 1.3 kbar (130 MPa) and 216 °C (in Korna-
towski 2002).
Miêguszowiecka Pass
This is one of the several almost parallel mylonitic zones
occurring in the vicinity of the Kocio³ Miêguszowiecki cirque.
Fig. 2. Sketch of the shear zones of the Galeria Cubryñska Ridge. A view from the south, and the Poredni Granat Mountain. B view
from above. Numbers indicate the order of the deformation and mineralization phases: 1 granitiod wall rock, 2 zone of mylonitization,
dynamic recrystallization and texture reworking, 3 veins filled with milky quartz and barite, 4 veins filled with green quartz, 5
slickenside surfaces coated with mylonitic epidote, 6 quartz-filled gashes, 7 younger milky calcite druses and Fe dolomite. Gr
granitoid, S-Cmyl S-C mylonites, S foliation, C shear surface, Cat cataclasites, Qtz quartz, m milky, g green, dr
druse, Cal calcite, Ep epidote, Brt barite, Fp fault plane, St striae, Fe-dol ferrous dolomite, T tension fractures of
Riedel-type shear system, filled with quartz, with later antithetic movement.
DEFORMATION PHASES IN THE SHEAR ZONES WITHIN TATRA MTS GRANITOID CORE 21
Fig. 3. A calcite druse with core of iron oxides and hydroxides, Galeria Cubryñska Ridge (correlated with 7 on Fig. 2A). B vein of
quartz (dark) transecting a barite vein (light), Poredni Granat Mountain (view from above; details on the Fig. 2B). CE polished surfac-
es: C S-C mylonites from Galeria Cubryñska Ridge with the neoformed quartz along the shear bands; D microfaults (f) transecting
porphyroclasts of quartz; relicts of S-C fabrics, Miêguszowiecka Pass; E asymmetric microfolds of mylonitic foliation with elongated and
boudinaged porphyroclasts of quartz, Miêguszowiecka Pass.
22 JUREWICZ and BAGIÑSKI
Fig. 4. Thin sections in crossed polarizers: AE Galeria Cubryñska Ridge, FH Miêguszowiecka Pass. A polymineralic foliation
composed of quartz/mica/sericite/feldspar layers in S-C mylonites; arrows indicate sense of shear. B nucleation of mica porphyroblast
grown on sericite. C veins of calcite fibres between mica flakes. D deformation of twins in plagioclase. E vein (rims marked white)
of euhedral epidote grown along the vein-wall, filled with quartz. F porphyroclast of quartz with fine-grained calcite in strain shadows;
quartz crystal shows deformation lamellae and undulose extinction; tension gashes filled with calcite. G microshears associated with mi-
crofolds; arrows indicate sense of shear. H porphyroclasts of quartz with elongated crystals of calcite in strain shadows; arrows indicate
sense of shear.
DEFORMATION PHASES IN THE SHEAR ZONES WITHIN TATRA MTS GRANITOID CORE 23
This zone (Fig. 1A,B-b,C-b), ca. 12 m wide and oriented
150/60, cuts the massif of Miêguszowiecki Szczyt Czarny
Mountain on its northern slope. After reversing to the position
prior to the post-Paleogene rotational uplift this zone attains a
sub-vertical position (Fig. 1F-b,G-b). Due to the fact that it is
well exposed for a distance of ca. 300 m, from Kazalnica to
the Miêguszowiecka Pass, the variation of microstructures and
deformation gradient can be observed along its strike. In the
lower, more eastern parts in the vicinity of Kazalnica, charac-
teristic deformation textures such as folding (Fig. 3E) and mi-
crofaulting (Fig. 3D) of pre-existing foliation can be observed.
The folds within this zone are not indicators of the shear
sense, because fold axial planes do not show specific orienta-
tion and can have the same or the opposite sense of asymmetry
to the bulk displacement. This fact may be linked with the
back rotation between the shear zone during progressive de-
formation (see Harris 2003) or change in the direction of
movement (Hippertt & Tohver 1999). Brittle deformation
(Fig. 3D), that is cataclastic fracturing, shearing of grains
showing domino-like microstructures can be observed in
Fig. 5. BSE-images: AB Galeria Cubryñska; C,D,E Miêguszowiecka Pass; F Miedziane Ridge. A metamorphic and neomor-
phic minerals and mylonitic fabrics. B ductile folded, kinked and disrupted crystals of Ti-rich biotite. C rotated porphyroclast of
fractured quartz with calcite in strain shadows; intercrystalline slip within mica-bar porphyroclast (like mica fish structure). D
calcite in strain shadows adjacent to quartz porphyroclast, partially newly recrystallized (σ-type object); note undulose extinction and
brittle fractures filled with calcite in the quartz porphyroclast. E bright parts of epidote blast (Fe-rich) grown on darker (Fe-poor), earlier
formed and crushed ones. F zoned K-feldspar with Ba-rich rims (the bright parts of the feldspars); arrows indicate sense of shear;
symbol of minerals after Kretz (1983).
24 JUREWICZ and BAGIÑSKI
porphyroclasts of magmatic quartz (see Needham 1995; Hip-
pert & Hong 1998). Strain shadows usually composed of cal-
cite or neoformed SiO
2
may occur adjacent to quartz porphy-
roclasts (Figs. 4F,H, 5C,D). Closer to the Miêguszowiecka
Pass the shear zone is filled with tectonic gouge. It is likely
that the minor folding of mylonitic fabric is linked with the
older deformation phase, whereas the tectonic gouge and un-
cohesive cataclasites developed in a later deformation phase
due to the reactivation of an existing mylonitic zone. There are
also fragments of crushed and deformed quartz veins in some
parts of the mylonitic zone. Analyses of fluid inclusions made
by Koz³owski (in Kornatowski 2002) indicated temperatures
of 262 °C and pressures of 1.6 kbar (160 MPa), which are val-
ues similar to those obtained for the Galeria Cubryñska Ridge.
In the younger quartz veins developed along the walls of the
mylonitic zone, euhedral grains are observed, with spaces be-
tween them filled with later ferrous carbonates (Fe-dolomite
and ankerite). These carbonates are typically poorly preserved
and empty voids with walls built of quartz crystals coated with
Fe-hydroxides, being the remains after weathering of Fe-rich
carbonates, are often observed. According to Michalík (1952),
carbonate veins in granitoids of the High Tatra Mountains re-
veal a zonal composition: the middle part consists of calcite,
whereas dolomite, followed by ankerite and siderite occur to-
wards the margins. The variability within the mineral compo-
sition is observed in single dolomite crystals, which also have
a zonal composition, where their rim is composed of ankerite
(Kornatowski 2002). Such composition of the carbonate veins
may be a result of Fe-ions migration and their gradual disap-
pearance from hydrothermal solutions, which in the terminal
phase contained pure calcite.
In the vicinity of the Kocio³ Miêguszowiecki cirque lie sev-
eral parallel mylonitic zones, which are linked with the pres-
ence of the so-called violet, or titanous-violet veins (Jaczy-
nowska 1980) of controversial origin. Their first chemical
analysis was presented by Kreutz (1924), whereas their origin
was given by Koisar & Zawidzki (1972). The authors deter-
mined the geochemical transformations taking place in mylo-
nitic zones leading to the increase of hematite contents respon-
sible for the specific colour of the veins. By analogy to the site
from Gerlach described by Petrík & Reichwalder (1996; see
also Petrík et al. 2003 and Kohút & Sherlock 2003), Gawêda
& Piwkowski (2000) considered the violet veins from Koñ-
czysta Turnia Mountain, and Pasternakowe Czuby Mountain
as pseudotachilites, also postulating a similar origin for the vi-
olet veins in the entire Tatra Mountains, including those from
Kocio³ Miêguszowiecki cirque. We suggest that violet veins
from the vicinity of Kocio³ Miêguszowiecki cirque and the
role of hematite and titanite require a separate analysis.
Miedziane Ridge
On the Miedziane Ridge running towards the Marchwiczna
Pass (Fig. 1A) a flat-dipping, smooth tectonic surface, orient-
ed 15/35, can be observed (Fig. 1B-c,D-c). The shear plane is
coated with mylonitic epidote and slickensided. The striae are
semiparallel to the strike of the plane (Fig. 1B-c). The orienta-
tion and character of this surface does not match the described
above mylonitic zones (Fig. 1B-c,D-c). It shows a geometric
coincidence with the sloping slickensides linked with Alpine
thrusting (Burchart 1963; Jurewicz 2000a). After rotation of
the fault plane to the position prior to the late Tertiary uplift of
the Tatra massif it attains a near horizontal position (Fig. 1F-c,
H-c). It differs from other similarly oriented planes by the
presence of a ca. 15-cm-thick mylonitic epidote-quartz mass,
occurring instead of a thin, typically not exceeding ca. 2 cm
mineralization comprising of synkinematicaly grown epidote
and quartz. SEM photographs of epidote (Fig. 5E) show a
clear mosaic-like composition of that mineral (angular shape
of previously mylonitized grains). This could be a result of
multiple activity of this shear zone where crystals were
crushed and then recrystallized.
The composition of some minerals found in the Miedziane
Ridge and Miêguszowiecka Pass shear zones are presented in
Table 1. Their position in the rock texture is shown on
Fig. 5E,F. The high Ba contents in K-feldspar, characteristic
of such conditions and the zonation in epidote, which indi-
cates the decrease in temperature during mineral crystalliza-
tion is notable (see higher Fe contents in the rim area than in
the previously grown and crushed blasts on Fig. 5E with
higher Fe content the colour of the epidote crystal is brighter).
The results of fluid inclusion investigations from the epi-
dote-quartz assemblage on similarly oriented slickenside fault-
planes indicated the temperature interval from 212 to 254 °C
and pressures ranging from 1.45 to 1.73 kbar (145173 MPa)
(Jurewicz & Koz³owski 2003).
Poredni Granat MountainGranaty Ridge
The tectonic zone occurring in the Granaty Ridge (Fig. 1A)
is unique due to the fact that it transects the peak of Poredni
Granat Mountain (2235 m), and does not as usually
form a pass. The reason for such preferential erosion is the
presence of the largest barite vein in the entire Tatra Moun-
tains (Figs. 2B, 3B). Besides the Granaty area, barite in lens-
like form was found in the couloir below the Rohatka Pass in
the Polski Grzebieñ massif (Paulo 1997). The 20-cm-thick
barite vein from Poredni Granat Mountain (Figs. 2B-3, 3B)
occurs within a ca. 11.5 m thick cataclastic zone oriented
305/85 (Figs. 1B-d,E-d, 2B-2). It is relatively older than the
vein of green quartz (Fig. 2B-4), which fills the space between
the barite and the wall rock, cuts the barite vein along a ten-
sion fracture (T-type of the Riedel shear zone) and runs to its
other side. Younger than the barite, and the quartz mineraliza-
tion, is the several-cm-thick shear zone running inside the bar-
ite vein (Fig. 2B-5). During shearing and quartz mineraliza-
tion the remobilization of barite took place (Fig. 2-5,6). Under
the microscope this area is reflected by the co-occurrence of
fine-grained barite and quartz filling the spaces between large
crystals of tabular habit. Translations along the earlier origi-
nated tension fractures (T-type), with the opposite sense with
respect to the shear zone of the Poredni Granat Mountain are
connected with the next stage of tectonic activity (see Ahlgren
2001).
At the boundary between the barite vein and the wall rock
beyond the shear zone the break off took place in further stag-
es. The resulting space was subsequently filled with quartz
DEFORMATION PHASES IN THE SHEAR ZONES WITHIN TATRA MTS GRANITOID CORE 25
Miedziane Ridge
Miêguszowiecka Pass
Epidote
1
Epidote
1
K-feldspar
2
K-feldspar
2
Chlorite
3
Chlorite
3
Chlorite
3
Muscovite/
Sericite
4
Muscovite/
Sericite
4
SiO
2
37.90
37.48
64.57
63.36
30.02
27.74
30.86
45.36
45.41
TiO
2
0.13
0.44
0.49
1.30
0.93
0.85
Al
2
O
3
25.81
21.86
18.72
18.59
23.79
20.70
20.25
31.57
31.95
Fe
2
O
3
10.26
15.65
Mn
2
O
3
0.30
0.19
0.07
0.06
0.10
0.00
0.00
FeO
19.34
23.48
20.17
4.60
4.33
MgO
13.47
15.55
14.60
0.97
0.89
CaO
23.26
22.68
0.01
0.00
0.03
0.02
0.00
BaO
0.35
1.24
Na
2
O
0.67
0.24
0.04
0.02
0.03
0.30
0.31
K
2
O
15.67
15.71
1.72
0.16
0.79
10.61
10.64
H
2
O+
1.85
1.80
12.01
11.63
11.88
4.37
4.38
Total
99.38
99.80
99.97
99.14
100.91
99.83
99.99
98.71
98.75
Si
3.00
3.01
2.99
2.98
6.05
5.73
6.26
6.23
6.22
Ti
0.01
0.07
0.08
0.20
0.10
0.09
Al
2.40
2.07
1.02
1.03
5.65
5.03
4.84
5.11
5.16
Fe
3+
tot
0.61
0.94
Mn
3+
0.01
0.01
0.01
0.01
0.01
0.00
0.00
Fe
2+
3.26
4.05
3.42
0.53
0.50
Mg
4.03
4.78
4.41
0.20
0.18
Ca
1.97
1.95
0.00
0.00
Ba
0.01
0.02
Na
0.06
0.02
0.44
0.04
0.20
0.08
0.08
K
0.92
0.94
0.02
0.01
0.01
1.86
1.86
Total
7.99
7.98
5.00
4.99
19.52
19.73
19.34
14.09
14.08
Al+Fe
3+
tot
3.02
3.02
Al
IV
in
chlorite
0.98
1.14
0.87
pie
0.29
0.19
T (
o
C)
253.00
304.00
219.00
pist
20.18
31.31
zo
79.52
68.50
Table 1: Composition of the main minerals occurring in selected shear zones from the Tatra Mountains.
(Fig. 2B-6). On the boundary between the quartz and the bar-
ite vein as well as along the shear zone lenses of later Fe-car-
bonate mineralization occur (Fig. 2B7). Along this zone bar-
ite attains a pink colour, which according to Paulo (1997) is
linked with dispersed hematite pigment.
The green quartz vein was investigated using inclusion
analyses (Jurewicz & Koz³owski 2003), which indicated the
crystallization temperature of 210 °C and pressure of
0.85 kbar (85 MPa). This pressure value is much lower than
that obtained from quartz in other shear zones of the High
Tatra Mountains area and can be correlated with extension
connected with the late Tertiary uplift of the Tatra Mountains
(Kováè et al. 1994; Birkenmajer 1999). The orientation of this
zone (Fig. 1B-d,E-d) also allows us to link this zone with oth-
er steep dislocations (oblique-normal-slip faults) connected
with Miocene extension (Jurewicz 2002).
Discussion and conclusions
The structural analysis of the selected shear zones in con-
nection with the determination of the deformation microstruc-
tures and chronology of events allowed a tentative correlation
1
all Fe computed as Fe
3+
, analyses normalized to 12O+OH.
2
analyses normalized to 8O.
3
all Fe computed as Fe
2+
, analyses nor-
malized to 20O+16OH.
4
all Fe computed as Fe
2+
, analyses normalized to 20O+4OH. Temperatures calculation according to Catheli-
neau & Nieva (1985) and Cathelineau (1988).
with stages of the Tatra Mountains tectonic evolution present-
ed in Fig. 6. Three groups of structures can be distinguished
corresponding to three distinct tectonic stages:
1 The pre-Alpine stage sensu lato, with relicts of struc-
tures linked with the late Variscan extension distinguished by
Kohút & Janák (1994), as well as those developed during the
Early Jurassic rifting of the Variscan continental crust
(Plaienka 1991, 2003a; Plaienka & Prokeová 1996). Defor-
mation in these zones is of brittle-plastic character. The dips of
their planes (Fig. 1C), with regard to the late Tertiary rotation
(Fig. 1F,I) are steep (ca. 60°) and thus typical rather for nor-
mal faults than for flat-dipping thrusts (Davis & Reynolds
1996), whereas the sense of movement determined in the
Galeria Cubryñska Ridge on the basis of the S-C fabrics indi-
cates a reverse fault, which testifies to its multiple reactiva-
tion. Zones of this type were also reactivated in presence of
the Neogene stress field as sinistral normal-oblique-slip faults,
which resulted in striations on the slickensided, epidote-coat-
ed wallrocks.
2 The Alpine stage is linked with horizontal NW and N
compression and the resulting thrusting and folding, which are
marked in the granitoid massif by the presence of flat-dipping
thrust-faults with smooth slickensided surfaces coated with
26 JUREWICZ and BAGIÑSKI
quartz and epidote (Fig. 1D). The primary dips of these planes
obtained from rotation (Fig. 1I) to positions prior to the Neo-
gene uplift were southwards (Fig. 1H). These faults do not
bear traces of activation during younger tectonic phases.
3 The late Tertiary stage is linked with the uplift of the
Tatra block and the accompanying extension and sinistral ob-
lique-normal-slip faults. During this stage several new normal
faults were formed and the reactivation of older mylonitic
zones took place, where break off along the walls and an ob-
lique-slip movement took place. These faults were formed in
the present position of the Tatra block and do not require rota-
tion. The convergence of the orientation of some mylonitic
Fig. 6. Chronology and condition of deformation within the selected shear zones. Numbers in the circles correspond to Fig. 2.
DEFORMATION PHASES IN THE SHEAR ZONES WITHIN TATRA MTS GRANITOID CORE 27
zones in the present position of the Tatra block (Fig. 1C) with
the position of faults developed in the late Tertiary (Fig. 1E),
which led to the reactivation of older zones, is observed.
The particular tectonic stages were best registered in the
shear zone on Galeria Cubryñska Ridge (Figs. 2, 6), whereas
the Miêguszowiecka Pass mylonitic zone although similar
in the deformation character underwent reactivation in brit-
tle conditions in later tectonic stages, which led to the com-
plete destruction of older structures and the formation of loose
cataclasites and tectonic gouge. The reactivation process took
place in the late Tertiary during the uplift of the Tatra block
(Burchart 1972; Kováè et al. 1994), when the existing discon-
tinuity plane was reactivated. According to Sibson (1977) and
Lin (1999) incohesive cataclasites are generally produced at
shallow depths (<4 km), whereas mylonites may be formed at
depths of 715 km in the brittle-ductile transition zone of pre-
dominantly crystal-plastic deformation. Guermani & Pennac-
chionis (1998) observations in the Mont Blanc massif sug-
gest that mylonites progressively develop by the plastic
reactivation of cataclastic shear zones during greenschist fa-
cies metamorphic conditions. Thus, plastic deformation ap-
pears as second in brittle discontinuities with fine-grained ma-
trix of cataclasites, which suggests that depth is not a factor
necessary for the development of mylonites. In the case of the
Miêguszowiecka Pass a reverse process can be observed: duc-
tile deformation underwent brittle destruction (mylonites
overprinted by brittle fracturing, see Scholz 1988) in a young-
er tectonic phase.
On the basis of the values of temperature and pressure ob-
tained from fluid inclusion study and from observations of the
deformation microstructures, the conditions, in which tectonic
zones were developed in a particular stage, can be compared.
The data obtained from the fluid inclusions studies proved
that synkinematic quartz slickenfibres on fault surfaces (con-
nected with Alpine thrusting) crystallized at higher pressure
and lower temperature (1.451.7 kbar (145170 MPa), 212
254 °C) than vein quartz in mylonitic zones (1.31.63 kbar
(130163 MPa), 264316 °C). The pressure values 1.45
1.7 kbar (145170 MPa) for structures linked with Alpine
thrusting allows us to estimate the depth of the deformation
processes at 67 km. Higher pressure values for flat-dipping
fault-thrusts may be a result of horizontal compression ex-
ceeding the values of lithostatic pressure as well as of loading
by the thrusting nappe units, whereas the lower values of pres-
sure for mylonitic zones may be linked with the component of
extension parallel to the shear zones reducing the stress as
well as the shallower position of the granitoid massif during
the rifting of the Variscan continental crust (see Plaienka
2003a). The temperature values are not only the result of the
geothermal gradient, but also of hydrothermal solutions activ-
ity and dynamometamorphic processes. In spite of this, it
should be assumed that the value of the geothermal gradient
~20 °C/km accepted after Kováè et al. (1994) is too low,
therefore the position of the granitoid massif of the Tatra
Mountains assumed at ca. 1011 km (200225 °C) about 70
50 Ma ago seems to be too deep. The comparison of data re-
lating to the temperature obtained from fission track geochro-
nological dates by Kováè et al. (1994) as well as pressure and
temperature obtained from fluid inclusions analyses, con-
firmed by the Cathelineau & Nieva (1985) and Cathelineau
(1988) chlorite geothermometer, allows to estimate the geo-
thermal gradient for the Late Cretaceous nappe folding at ca.
30 °C/km. Such high values of the geothermal gradient at that
time could be connected with crustal heating due to the up-
welling of the upper mantle at the base of the nearby Vahic
ocean (Plaienka 2003b).
Acknowledgment: This research was supported by an indi-
vidual BW Grant No. 1527/2 for E. Jurewicz and No.1567/16
for B. Bagiñski. We are grateful to Prof. K. Schulmann, Assoc.
Prof. D. Plaienka and Dr. M. Kohút for critical reading of the
manuscript and fruitful discussion. Thanks are also extended to
the Direction of the Tatra National Park for permission to con-
duct fieldwork, Dr. P. Dzier¿anowski for help with the micro-
probe analysis and Dr. A. ¯yliñska for linguistic advice.
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