GeolCarp_Vol59_No1_3

GEOLOGICA CARPATHICA, FEBRUARY 2008, 59, 1, 3—18

www.geologicacarpathica.sk

1. Introduction

The pre-Mesozoic basement of the Slovak Western Car-
pathians is supposed to derive from the south-eastern-Eu-
ropean Variscides (Matte 1991), which were in part incor-
porated into the Alpine orogenic belt (Fig. 1). The
basement complexes of the Central Western Carpathians
(Figs. 2, 3) are part of the Cretaceous Tatric, Veporic and
Gemeric structural Superunits (Plašienka et al. 1997), anal-
ogous to the Austroalpine realm in the Eastern Alps (Putiš
1992, 2002; Gebauer 1993; von Raumer & Neubauer
1993; Dallmeyer et al. 1996, 2005).

The Variscan nappe-stack is southeast-vergent (Fig. 3

after Putiš 1992; Bezák 1994; Putiš et al. 2003, and cita-
tions therein) and despite Alpine tectonics, is still recog-
nizable in domains outside the Cretaceous shear zones.
The tectono-stratigraphically Upper Variscan structural

Cambrian-Ordovician metaigneous rocks associated with

Cadomian fragments in the West-Carpathian basement

dated by SHRIMP on zircons: a record from the Gondwana

active margin setting

MARIÁN PUTIŠ

, SERGEY SERGEEV

, MARTIN ONDREJKA

, ALEXANDER LARIONOV

PAVOL SIMAN

, JÁN SPIŠIAK

3,4

, PAVEL UHER

and ILJA PADERIN

Comenius University Bratislava, Faculty of Natural Sciences, Department of Mineralogy and Petrology, Mlynská dolina G,

842 15 Bratislava, Slovak Republic; putis@fns.uniba.sk

All-Russian Geological Research Institute (VSEGEI), Sredny Prospekt 74, 199106 St.-Petersburg, Russia; sergey_sergeev@vsegei.ru

Slovak Academy of Sciences, Geological Institute, Dúbravská cesta 9, 840 05 Bratislava, Slovak Republic;

geolsima@savba.sk; spisiak@savbb.sk

Faculty of Natural Sciences, Matej Bel University, Tajovského 40, 974 01 Banská Bystrica, Slovak Republic; spisiak@fpv.umb.sk

(Manuscript received January 31, 2007; accepted in revised form June 13, 2007)

Abstract: The Central West-Carpathian basement, included in Cretaceous-Early Tertiary structures, shows remnants of
pre-Alpine, mainly Variscan tectonics. The paper documents in-situ U-Pb zircon (SHRIMP) ages of a major Cambrian to
Ordovician magmatic event, recorded in the West-Carpathian basement. Cambrian to Ordovician, less Early Silurian
concordia magmatic ages, with older 525—470 Ma and younger 480—440 Ma age intervals were dated in layered
amphibolites and granitic orthogneisses of the tectono-stratigraphically Upper Variscan structural Unit. The zircon cores,
especially in orthogneisses, often show Cadomian, mainly magmatic source (protolith) ages, spanning 638—549 Ma,
with a concordia age at 617 ± 11 Ma. Older Proterozoic to Archean protolith ages (2000 up to 3400 Ma) are much less
common. Cadomian ages highly predominate in kyanite-garnet orthogneisses, tectonically incorporated into the me-
dium-grade metasediments of the Middle Variscan structural Unit. Kyanite-garnet orthogneisses show idiomorphic,
magmatically zoned zircons with ages spanning 649—554 Ma, with concordia ages at 607 ± 10 and 558 ± 7 Ma, and
metamorphic ages between 540—530 Ma. These ages corroborate the protolith ages of hosting metasediments with a
lower intercept around 500 Ma. Early Ordovician ages were also found from the calc-alkaline metavolcanics (482 ± 6 Ma,
metarhyolite, or 476 ± 7 Ma, metadacite) of low-grade volcano-sedimentary complexes in the Lower Variscan structural
Unit. Long-term magmatic/volcanic activity due to melting of the crust and subcrustal lithosphere is coeval with the
rifting of Cadomian crust and evolution of the Gondwana northern active continental margin. The ages of 430—380 Ma
of layered amphibolites and orthogneisses reflect the Eo-Variscan subduction/collision metamorphic event in the
Prototethyan realm, coeval with the collision of the eastern Avalonian-Cadomian/western Hunic terranes, as part of the
Armorican microplate, with Laurussia/Avalonia. The collapse of the Eo-Variscan collisionally thickened crust led to partial
melting within the Upper Variscan structural Unit, generating 370—340 Ma old zircons in dated metaigneous rocks.

Key words: Proterozoic/Archean, Paleozoic, Cadomian, Gondwana, West-Carpathian basement, SHRIMP zircon dating.

Unit, or the Tatra Nappe, includes the mid-crustal Jarabá
complex (para- and orthogneisses, amphibolites, scarce
calc-silicate marbles, migmatites, intruded by granitic plu-
tons) and a lower-crustal layered amphibolite complex
(with rare lenses of garnet-clinopyroxene amphibolites as
relic eclogites and granulites, antigorite serpentinites, gar-
net-kyanite ortho- and paragneisses). These overlie the
Middle Variscan structural Unit or the Hron Nappe (stau-
rolite-garnet, or kyanite/andalusite, sillimanite-garnet mi-
caschists to gneisses, subordinate amphibolites). The col-
lisionally accreted Lower Variscan structural Unit is
composed of the Paleotethyan ophiolitic (Zlatník/Ra-
kovec) complexes and the continental margin related
(Gelnica, Hladomorná Dolina, Harmónia, Pezinok and oth-
ers) complexes. The time of thrusting of the Tatra Nappe
over the Hron Nappe is constrained by

Ar/

Ar amphib-

ole ages of mylonitized layered amphibolites at ca.

CAMBRIAN-ORDOVICIAN METAIGNEOUS ROCKS IN THE WEST-CARPATHIAN BASEMENT DATED BY SHRIMP

356 Ma (Dallmeyer et al. 1993, 1996). The collision-ac-
cretion of the Lower Variscan structural Unit is estimated
to have occurred between late early Carboniferous and
early Permian, based on different geological criteria. The
West-Carpathian basement is included in Cretaceous to
Early Tertiary tectonic structures within the Tatric, Ve-
poric and Gemeric zones.

Published isotopic ages from the West-Carpathian base-

ment complexes are usually not older than Early Paleozo-
ic (Cambel et al. 1990; Krist et al. 1992). A meta-leucoto-
nalite layer of the layered amphibolites from the
North-Veporic basement Hlôžková (Hoškova) Valley yields
U-Pb zircon ages of 514 ± 24 and 348 ± 31 Ma (upper and
lower discordia intercept ages, Putiš et al. 2001). A dioritic
gneiss layer from the North-Veporic Ve ký Zelený Potok
Valley, dated at 346 ± 1 Ma (the lower intercept age, Putiš
et al. l.c.) was interpreted as a remelting product of the
layered amphibolites (Putiš 2002). Gaab et al. (2005)
published possible metamorphic ages (360—330 Ma) of
the felsic layers from the North-Veporic Hlôžková (Hoško-
va) Valley and from Drotačka. Three North-Veporic or-
thogneisses (from the Koleso and Úplaz Valleys as well as
from Mihálikovo) yielded Ordovician ages (470—460 Ma
and 440 Ma, respectively) and are identical to ages ob-
tained by CHIME from the North-Veporic Koleso Valley
orthogneiss (490—450 Ma, Janák et al. 2002). The South-
Veporic Muráň granitic orthogneiss showed a convention-
al multigrain zircon U-Pb age of ca. 500 Ma (Putiš et al.
2003; Kováčik et al. submitted; A. Kotov, pers. comm.).
Gaab et al. (2006) constrained an Ordovician age for the

Muráň orthogneiss (464 ± 40 Ma). Kováčik et al. (2005)
dated a thermal overprint of the Muráň orthogneiss at
312 ± 15 Ma by CHIME. The granitic orthogneisses from
the Jarabá complex in the Tatric basement yield U-Pb zir-
con ages spanning from ca. 405 to 380 Ma (Poller et al.
2000; Putiš et al. 2003). Late Proterozoic to Cambrian pro-
tolith ages (ca. 650 to 500 Ma) were obtained from
metasedimentary rocks from the Middle Variscan structur-
al Unit (Kohút et al. 2007). Calc-alkaline (Vozárová &
Ivanička 1996; Hovorka & Méres 1997) metavolcanics of
the Lower Variscan structural Unit were dated in a wider
age interval of 500—400 Ma (Shcherbak et al. 1988).

The obtained multi- and single-grain zircon U-Pb or

CHIME ages are quite variable, many of them spreading
± 30—40 Ma, which was also a reason for the application of
the “in situ SIMS” or SHRIMP dating method. Until now,
only two West-Carpathian granitoids, which experienced
Cretaceous mylonitization (from Krá ova Ho a Massif in
the Nízke Tatry Mountains), were dated by the SHRIMP
method (359—345 Ma, Gaab et al. 2005).

Considering the different ages known from the West-

Carpathian basement, the following questions arise: 1. Is
there a clear cut limit between Neoproterozoic magmatic/
metamorphic events and the Early Paleozoic break-up in
the Gondwana northern margin, recorded in the West-Car-
pathian basement? 2. What type of (Cadomian?) basement
was rifted in Early Paleozoic times? 3. Which are the rift
and/or active margin-settings preserved within the rem-
nants of the Variscan tectonic structure in the alpidic
West-Carpathian orogenic belt? It is the goal of this paper

Fig. 3. Generalized cross-section of the pre-Alpine West-Carpathian basement (modified after Putiš et al. 2003) showing principal
Variscan structural units with south-east vergent thrusting. Top of the figure indicates an opposite north-west vergent Cretaceous nappe
thrusting. The figure is provided with chosen SHRIMP ages (explanation in text).

PUTIŠ, SERGEEV, ONDREJKA, LARIONOV, SIMAN, SPIŠIAK, UHER and PADERIN

to present the first SHRIMP zircon age data constraining
the evolution of Early Paleozoic magmatic rocks in some
West-Carpathian basement complexes interpreted as repre-
senting an active continental margin setting at the northern
Gondwana margin. These ages are compared to published
basement ages from the south-eastern European Variscides,
which are considered to be of Gondwanan origin too.

2. Analytical technique

Zircons have been extracted applying standard heavy

liquid and magnetic separation. Half-sectioned zircons
mounted in epoxy puck were first imaged by cathodolu-
minescence (CL) and BSE in order to reveal internal struc-
ture and surface features for analytical spot positioning.
In-situ U-Pb analyses were performed on a SHRIMP-II in
the Center of Isotopic Research (CIR) at VSEGEI during
three analytical sessions.

The results are acquired with a secondary electron mul-

tiplier in peak-jumping mode following the standard pro-
cedure (e.g. Williams 1998; Larionov et al. 2004). Primary
O

-beam with ion current —2 to —3 nA produced elliptic

ca. 25 20 m size analytical crater. Typical mass-resolu-
tion at 254 AMU (

238

UO) was M/ M > 5000 (1 % valley),

allows resolution of possible isobaric interferences. One-
minute rastering over a rectangular area of ca. 65 50 m
is employed before each analysis in order to remove the
gold coating and possible surface Pb contamination.

The following ion species are measured in sequence:

196(Zr

O)—

204

Pb—background (ca. 204 AMU)—

206

Pb—

207

Pb—

208

Pb—

238

U—

248

ThO—

254

UO with integration times ranging

from 2 to 30 seconds. Four cycles for each analysed spot
were acquired. Each fourth measurement is carried out on
the standard zircon TEMORA (Black et al. 2003) or
91500 (Wiedenbeck et al. 1995). The latter was used as
“U-concentration” standard.

The raw data were then processed with the SQUID

v1.13a (Ludwig 2005a) and ISOPLOT/Ex 3.22 (Ludwig
2005b) software, with decay constants of Steiger & Jäger
(1977). The common lead correction is done using mea-
sured

204

Pb/

206

Pb following the model of Stacey & Kram-

ers (1975). The age data from samples of complicated multi-
stage evolution are processed by the “Unmix Ages” tool of
the ISOPLOT, in order to distinguish the main age groups.

Almost all the measured spots gave concordant ages,

shown in concordia diagrams. Discordant results of multi-
ple analyses from the same crystal were used to construct a
discordia line. On average, analyses of 10 zircon grains
have been performed on each rock-sample. The resulting
ages have a 2 error.

3. Description of investigated rocks

A major Early Paleozoic magmatic event seems to be re-

flected by both, the lower-crustal layered amphibolites
and associating granitic orthogneisses of the Upper
Variscan structural Unit (the Tatra Nappe), and the upper-

crustal volcano-sedimentary complexes of the Lower
Variscan structural Unit. Candidates for the rifted pre-Pale-
ozoic type of basement appear to be the kyanite-garnet-
rutile or garnet orthogneiss fragments, tectonically em-
placed into the micaschist-gneisses of the Middle Variscan
structural Unit, having an origin in the northern Gondwana
margin. These rocks were dated by SHRIMP. The geologi-
cal time scale of Gradstein & Ogg (2004) is used.

3.1 Layered amphibolites

Layered amphibolites (or banded amphibolites after

Spišiak & Pitoňák 1992, or leptyno-amphibolite complex
after Putiš 1992; Hovorka & Méres 1993) show structures
of pre-metamorphic compositional layering (D0), with
(meta)tonalitic to (meta)leucotonalitic layers of relatively
felsic mineral composition a few decimeters thick, alter-
nating with amphibole-rich dark layers of (meta)gabbro-
dioritic to (meta)gabbroic and Pl-free Cpx-bearing horn-
blenditic (meta)cumulate-like layers. These layers have
typical metamorphic (D1) – granoblastic to nemato-gra-
noblastic textures. Preserved primary magmatic structures
such as compositional layering are seen in straight, more
or less sharp boundaries between the layers.

A younger generation of layering (D2) formed in a few

decimeters wide zones of layer-parallel shear. Synmeta-
morphic, stretched interlayer folds are often separated, or
sheared off, and their cores are filled by pale fine- to medi-
um-grained quartz-plagioclase leucosomatic seggregates.
Aplitic to pegmatitic leucosomes, with leucotonalitic min-
eral composition and magmatic microstructures are
rimmed by typical amphibole-, rarely amphibole-diopside
rich melanosome. The mesoscopic/textural relationships
suggest that meta-tonalite and meta-leucotonalite layers
outside the melting zones could be older than the leuco-
some layers, the latter being a product of partial melting.
The most conspicuous newly-formed layers are plagio-
clase-rich dioritic gneisses, product of partial melting of
metagabbroic layers. They are often crosscut by exten-
sional shear bands filled by leucotonalitic pegmatitoids.

The development of ductile straight bands (D3) is in-

ferred to be connected with the formation of low-angle ex-
tensional normal faulting during the exhumation. The
whole complex, after ductile deformation, varies in thick-
ness of the first hundreds of meters. The latest generation
of layers is composed of clinozoisite, chlorite, albite and
quartz, and could represent the closure of the D3 stage or
Alpine-type veins. The D1 to D3 structures are crosscut by
veins of aplites, pegmatites, as well as volcanic dikes, dat-
ed as Permian to Early Triassic (Kotov et al. 1996; Putiš et
al. 2000, 2001).

Some antigorite serpentinite lens-shaped bodies ob-

served in the footwall of the Upper Variscan structural
Unit are interpreted as tectonic slices of upper mantle ori-
gin hosted by micaschist-gneisses of the Middle Variscan
structural Unit (Korikovsky & Putiš 2002).

The pre-Alpine metamorphic conditions of the layered

amphibolite complex of the Upper Variscan structural
Unit was estimated at a temperature of ca. 610

°C and

CAMBRIAN-ORDOVICIAN METAIGNEOUS ROCKS IN THE WEST-CARPATHIAN BASEMENT DATED BY SHRIMP

600—700 MPa of pressure on the southern margin of the
North-Veporic area, or 630

°C at 700—800 MPa in the

northern part of the North-Veporic area. The P-T condi-
tions of the superimposed Alpine deformation and recrys-
tallization in the North-Veporic area did not exceed medi-
um-pressure greenschist-facies conditions (T

max

400

°C at

max

= 600—700 MPa) (Putiš et al. 1997; Korikovsky et al.

1997). However, temperatures slightly over 500

°C at

max

= 800—900 MPa were found along the Cretaceous Po-

horelá tectonic line. This evolution is compatible with the
resetting of the K-Ar system in amphiboles (Krá et al.
1996; Kováčik et al. 1996). The estimated metamorphic
conditions of the Alpine basement reactivation in the Ve-
poric area could not reset the pre-Alpine zircon ages.

Typical members of layered amphibolites from the Tat-

ric and Veporic basement were chosen for SHRIMP dating
(Figs. 2 and 3).

3.2 Granitic orthogneisses

They are characteristic of the high-grade crystalline

complexes of the Upper Variscan structural Unit, forming
several kilometers long and hundreds of meters wide lens-
shaped bodies hosted by paragneisses and migmatites.
The Jarabá structural complex in the Tatric basement, or

ubietová and Čierny Balog structural complexes in the

Veporic basement contain the largest granitic to tonalitic
orthogneiss bodies (Putiš et al. 2003, and citations there-
in). These orthogneisses often show well preserved mag-
matic fabrics, defined by oriented feldspars and micas,
forming domains almost free from a ductile overprint. The
original rock was a porphyric granite or granodiorite to to-
nalite with aligned prismatic K-feldspars and plagioclase
crystals, surrounded by oriented muscovite and biotite
flakes, giving evidence of syntectonic magmatic flow at
subsolidus to solidus temperatures (

~700—600 °C). In oth-

er domains, larger quartz crystals are weakly elongate, par-
allel to foliation. The remaining quartz grains keep their
interstitial location. Abundant strain-induced myrmekites
are developed parallel to the foliation along the K-feld-
spars megacrysts. Large, plastically strained domains have
macroscopically recognizable - and -type rotated feld-
spar porphyroclasts enclosed in a dynamically recrystal-
lized quartz-feldspar-mica mylonitic matrix. Shape asym-
metries around porphyroclasts point to a top-to-the-SE
ductile thrusting of the Upper Variscan structural Unit
(the Tatra Nappe) over the Middle Variscan structural
Unit (the Hron Nappe), in present-day geographical
coordinates (Putiš 1992; Fritz et al. 1992; Madarás et al.
1999; Putiš et al. 2003).

Some orthogneisses occur in close neighbourhood to

the layered amphibolite complex, showing common defor-
mation-recrystallization stages, for example garnet orthog-
neiss at the base of this complex in the Ve ký Zelený
Potok Valley (southern part of the North-Veporic base-
ment).

Orthogneisses are present as rare tectonic fragments in

the footwall micaschists and gneisses of the Middle
Variscan structural Unit. Kyanite-garnet-rutile ortho- and

paragneisses, locally with migmatitic layering, are partly
re-equilibrated (e.g. kyanite is locally replaced by an-
dalusite) with the hosting MP-MT metamorphics in the
area north of He pa. The peculiar features are lenses of ma-
fic eclogites (Janák et al. 2003, 2007) or HP granulites
(Putiš et al. 2006a) enclosed in this type of orthogneiss.
Orthogneisses from all three domains were chosen for
SHRIMP dating (Figs. 2, 3).

3.3 Metavolcanic rocks

We dated two metavolcanic rocks from the Lower

Variscan structural Unit Gemeric basement (Figs. 2, 3). A
metarhyolite or porphyroid was sampled from the volca-
no-sedimentary sequence overlying the flyschoid
metasediments of the Gelnica complex. Metadacite occurs
at the base of the Rakovec greenschist complex. They pre-
serve magmatic structures – relics of feldspar and quartz
phenocrysts, partly recrystallized, surrounded by green-
schist-facies metamorphic matrix minerals.

4. SHRIMP ages

Besides rare data indicating Cadomian magmatic or

metamorphic events, mainly Cambrian to Ordovician and
few Early Silurian age data were encountered. These will
be presented in the following subchapters.

4.1 Layered amphibolites

Different lithologies from the layered amphibolite com-

plex in the Tatric, Veporic and Gemeric basement were
dated.

Decimeter-thick amphibolitic and metaleucotonalitic

layers were sampled in the Tatric basement in a gallery ca.
6 km north of Jasenie in the western part of the Nízke
Tatry  Mountains (Figs. 2, 3). Euhedral zircons with fine
oscillatory zoning, typical of magmatic origin, were dated
from both major lithotypes (samples NTJ-T1 and NTJ-S1)
and gave concordia ages of 481 ± 4 Ma  (Th/U = 0.2—0.47;
Fig. 4) and  480 ± 5 Ma  (Th/U = 0.24—0.42; Figs. 5, 6),  re-
spectively. Outer discordant zircon zones rarely indi-
cate ages of 428  and  411 Ma (a metamorphic event?;
Th/U = 0.12—0.15), or 338 ± 6 Ma (extensional collapse?).

Fig. 4. CL images of dated zircons from a dark NTJ-T1 layer.
Nízke Tatry Mountains, Jasenie, Tatric basement.

PUTIŠ, SERGEEV, ONDREJKA, LARIONOV, SIMAN, SPIŠIAK, UHER and PADERIN

Fig. 5. CL images of dated zircons from a pale NTJ-S1 layer.
Nízke Tatry Mountains, Jasenie, Tatric basement.

Fig. 6. Concordia diagram of dated zircons from a pale NTJ-S1
layer. Nízke Tatry Mountains, Jasenie, Tatric basement.

Fig. 7. CL images of dated zircons from a metatonalite HLO-1
layer from the layered amphibolite complex. Nízke Tatry
Mountains, Hlôžková Valley, North-Veporic basement.

Fig. 8. Concordia diagram of dated zircons from a metatonalite
HLO-1 layer from the layered amphibolite complex. Nízke Tatry
Mountains, Hlôžková Valley, North-Veporic basement.

Layered amphibolites from the Veporic basement were

dated in the eastern part of the Nízke Tatry Mountains, in
Hlôžková (Hoškova) Valley, and in the Vepor Mountains
(Ve ký Zelený Potok Valley), both areas representing the
North-Veporic basement (Figs. 2, 3). The partly resorbed
anhedral zircon crystals with lobate outlines still have well
preserved inner “wide mono-” or “sector-zoned” parts, typi-
cal of magmatic origin. The zircon resorption occurred dur-
ing partial melting of metaigneous layers. Both dated meta-
tonalite and metaleucotonalite layers (samples HLO-1, 2)
give U-Pb ages ranging from 508 to 480 Ma, with concor-
dia ages at 502 ± 3 Ma (Th/U = 0.26—0.46; Figs. 7, 8) and
492 ± 4 Ma (Th/U = 0.26—0.45), respectively. The outer dis-
cordant zircon zones of 398 and 389 Ma (Th/U = 0.12)
could be related to the evolution of HP-HT rare boudins of
clinopyroxene-garnet rocks in layered amphibolites.

The hanging wall of the Upper Variscan structural Unit

(Tatra Nappe, Fig. 3) in the Ve ký Zelený Potok Valley,
the Vepor Mts (samples VZP-2, 5) was subjected to a high-
er degree of partial melting and provides newly-formed
migmatitic layers of different petrographical composition.
The concordia age of the dioritic gneiss layer (sample
VZP-5) is 363 ± 3 Ma (Th/U = 0.38—0.59; Figs. 9, 10). On
the other hand, an inherited zircon core of 2400 Ma indi-
cates older sources. An age of 549 ± 18 Ma obtained again

from a zircon core, could represent the protolith age of the
partially melted metagabbro. Younger age-data ranging
from 349 to 287 Ma are interpretable as disturbance of the
U-Pb system due to a post-orogenic extension collapse/
melting event, synchronous with the intrusion of the Ve-
por granitoids (Bibikova et al. 1990; Gaab et al. 2005). A
leucotonalitic leucosome (sample VZP-2) was dated at
373 ± 6 Ma (Th/U = 0.16—0.45). Zircons 609—550 Ma old
might represent contamination of a gabbroic melt by Ca-
domian crust or the protolith age of partially melted met-
agabbro. The ages of 504—467 Ma fit the time of a gabbro-
ic intrusion well. An age of 430 Ma (Th/U = 0.03) probably
indicates an early collision metamorphic event. One zir-
con records an age of 308 Ma.

A metaleucotonalite (sample GR-1) of the Gemeric base-

ment comes from decimeter-size pebbles of the Pennsyl-
vanian metaconglomerates (locality of Grajnár). Only

CAMBRIAN-ORDOVICIAN METAIGNEOUS ROCKS IN THE WEST-CARPATHIAN BASEMENT DATED BY SHRIMP

matic zircon was dated to 516 ± 7 Ma (Th/U = 0.2—0.6;
Fig. 11). Two outer zones and one newly-formed zoned
crystal document the age of superimposed partial melting
as 359 ± 5 Ma. An inherited zircon core gave a Late Pro-
terozoic protolith age of 577 Ma. In one case, a relic
Archean zircon core, a ca. 3400 Ma old (upper intercept
age; Fig. 12), was detected within an approximately
351 Ma old zircon (Fig. 13). A granitic orthogneiss (sam-
ple SAM-18) from the Čertova Svadba Hill (close to the
Čertovica thrust-fault zone, dividing the Tatric and North-
Veporic nappes) was dated 485 ± 6 Ma. The analyses were
performed from euhedral, oscillatorily zoned magmatic
zircons in an age interval from 513 to 472 Ma. Two inher-
ited zircons gave Neoproterozoic protolith ages of 659
and 581 Ma. A granitic orthogneiss (sample SAM-13) near
Podbrezová was dated to 462 ± 6 Ma.

Magmatically zoned zircons from the tonalitic orthog-

neiss (sample SAM-12) from the Čierna Valley near Rat-
kovské Bystré, South-Veporic basement, gave a concordia
magmatic age of 507 ± 4 Ma (Th/U = 0.1—0.4; Figs. 14, 15).
The sample contains grains with Neoproterozoic magmatic
type zoning with a concordia age of 577 ± 8 Ma. A similar
magmatic concordia age of 497 ± 4 Ma was found in a gra-
nitic orthogneiss (sample SAM-6) from the Chorepa pass.

For comparison, we dated granitic orthogneisses from the

Tatric basement. Granitic orthogneiss from the Lomnistá
Valley in the Nízke Tatry Mountains (sample SAM-15)
gave a concordia age of 472 ± 6 Ma (Th/U = 0.15—0.53;
Figs. 16, 17). However, a morphologically different zircon
indicates a younger thermal overprint at 407—388 Ma
(Th/U = 0.1—0.3). A granitic orthogneiss from the Vajsková
Valley in the Nízke Tatry Mountains (sample SAM-16) gave
a concordia magmatic age of 470 ± 6 Ma (Th/U = 0.1—0.35;
Figs. 18, 19). It contains many magmatically zoned zircons
with a concordia age at 617 ± 11 Ma (Th/U = 0.85—1.45)
and lower intercept age at 531 ± 29 Ma. A concordant age
of 497 ± 6 Ma was found in the sample MF-1 from the Malá
Fatra Mountains.

Fig. 9. CL images of dated zircons from a gneissic dioritic VZP-5
layer from partially melted layered amphibolite complex. Vepor
Mountains, Ve ký Zelený Potok Valley, North-Veporic basement.

Fig. 10. Concordia diagram of dated zircons from a gneissic dioritic
VZP-5 layer from partially melted layered amphibolite complex. Ve-
por Mountains, Ve ký Zelený Potok Valley, North-Veporic basement.

Fig. 11. CL images of dated zircons from a granitic VZP-6
orthogneiss at the base of the layered amphibolite complex Vepor
Mountains, Ve ký Zelený Potok Valley, North-Veporic basement.

one regularly zoned zircon grain yields a magmatic age of
ca. 457 Ma. Most of the ages cluster around 398 ± 4 Ma.
They have wider, less regular (metamorphic?) oscillatory
zoning in comparison to those of magmatic origin, with
Th/U

~0.1. Equally, three spots in outer zones give ages of

386—372 Ma. An inherited zircon core shows a Late Pro-
terozoic protolith age of 634 Ma.

4.2 Granitic to tonalitic orthogneisses

Kyanite-garnet-rutile orthogneisses and garnet granitic

orthogneisses often occur at the base of the layered am-
phibolite complex (Fig. 2). Granitic orthogneisses, associ-
ated with the layered amphibolites, were dated in the
North-Veporic basement. One body of them (sample VZP-6)
occurs in the Ve ký Zelený Potok Valley (southern part of
the North-Veporic basement). Oscillatorily zoned mag-

CAMBRIAN-ORDOVICIAN METAIGNEOUS ROCKS IN THE WEST-CARPATHIAN BASEMENT DATED BY SHRIMP

dia age at 607 ± 10 Ma and/or metamorphic ages between
540—530 Ma measured from wide non-oscillatory zones
(Th/U = 0.11—0.14). The lower intercept at 326 ± 10 Ma (be-
sides the upper one at 607±10 Ma) indicates a Variscan
thermal overprint. Oscillatorily zoned zircons in garnet-
rutile orthogneiss (sample VV33Bo-1; Th/U = 0.37—1.55;
Figs. 22, 23) show magmatic ages spanning 649—554 Ma,
with the concordia age at 558 ± 7 Ma. It is important to no-
tice that medium- to coarse-grained sample VV33Bo-1 rep-
resents melting (sillimanite-bearing) domains in tiny- to
fine-grained laminated kyanite-garnet-rutile or garnet-
rutile K-feldspar-bearing orthogneisses. Older Proterozoic
to Late Archean protolith ages (1300 up to 2700 Ma) are
much less common. For the age statistics and interpreta-
tion see discussion.

4.3 Metavolcanics

Early Ordovician magmatic concordia ages were also

found in the calc-alkaline metavolcanics (482 ± 6 Ma,
metarhyolite, sample HE-1, or 476 ± 7 Ma, metadacite,
sample ZA-1) of low-grade volcano-sedimentary complex-
es in the Lower Variscan structural Unit of the Gemeric
basement.

5. Results and discussion

The new U-Pb zircon ages improve our knowledge on

the age and evolution of the West-Carpathian pre-Mesozoic
basement, hitherto based mainly on conventional U-Pb
zircon, Rb-Sr isochrone, CHIME and

Ar/

Ar dating

methods. Considering the above presented new SHRIMP
data, different age groups can be distinguished (Fig. 2).
Metaigneous rocks were preferably dated. Magmatic zir-
cons, besides nearly idiomorphic form and fine oscillatory
growth zoning usually have relatively higher Th/U values
(usually > 2; § 4) in comparison to measured metamorphic
zircon zones or newly-formed metamorphic zircons. The
obtained age groups are reviewed, interpreted and dis-
cussed in chronologic order.

U-Pb ages of zircons from investigated rocks are given

in Tables 1—20 as an Appendix of this paper in web ver-
sion at www.geologicacarpathica.sk.

The oldest (mid-Proterozoic-Archean) group, preserved

as relics in zircon cores, is probably of detrital origin from
an older hinterland. For example, one zircon core from the
North-Veporic granitic orthogneiss, at the base of the lay-
ered amphibolite complex, closely associating with the
kyanite-garnet paragneisses (Ve ký Zelený Potok Valley),
gave a Middle/Early Archean age of 3400 Ma (Putiš et al.
2006b, 2007a—c) thus representing the oldest geological/
geochronological record described in the Western Car-
pathians (Figs. 12, 13). Such a rare Archean age resembles
the oldest parts of the Central European continental crust
(Gebauer et al. 1989, 3840 Ma).

Neoproterozoic—Cadomian ages in the time span of ca.

640—530 Ma are found in zircons from different types of
orthogneisses.

Fig. 17. Concordia diagram of dated zircons from a granitic SAM-15
orthogneiss from the Lomnistá Valley in the Nízke Tatry Moun-
tains, Tatric basement.

Fig. 18. CL images of dated zircons from a granitic SAM-16
orthogneiss from the Vajsková Valley in the Nízke Tatry
Mountains, Tatric basement.

Fig. 19. Concordia diagram of dated zircons from a granitic SAM-16
orthogneiss from the Vajsková Valley in the Nízke Tatry Moun-
tains, Tatric basement.

PUTIŠ, SERGEEV, ONDREJKA, LARIONOV, SIMAN, SPIŠIAK, UHER and PADERIN

Zircon cores of Cambrian-Ordovician orthogneisses of-

ten show magmatic protolith ages spanning 638—549 Ma
(Figs. 9, 11, 14, 18), with the concordia age at 617 ± 1
(sample SAM-16, Fig. 18). Therefore the measured age in-
terval probably includes two different age groups (ca.
650—600 Ma and/or ca. 600—550 Ma).

The orthogneisses of the North-Veporic basement for-

merly interpreted as Ordovician (Gaab et al. 2005) were
found to contain almost exclusively zircons of Neopro-
terozoic (Cadomian) magmatic ages spanning 608—586 Ma
(sample KO-1, Figs. 20, 21), or 649—554 Ma (sample
VV33Bo-1, Figs. 22, 23), with concordia age of
607 ± 10 Ma (sample KO-1, Fig. 21), or 558 ± 7 Ma (sample

VV33Bo-1, Fig. 23). The ages between 540—530 Ma
(sample KO-1, Fig. 20) are interpreted as Cadomian meta-
morphic overprint. From the 31(10 + 21) measured spots
in both samples, 23(4 + 19) spots gave Cadomian mag-
matic ages, 3(1 + 2) spots – older Proterozoic to Late
Archean ages, 2(2 + 0) spots – Cadomian metamorphic
ages, and only 3(3 + 0) spots, located on outer zircon zones,
gave Cambrian-Ordovician ages. Thus, Cadomian mag-
matic zircon ages suffered from a late-Cadomian metamor-
phic and a Cambrian-Ordovician thermal rejuvenation
(Figs. 20, 22).

The sample VV33Bo-1 although formed by melting of

kyanite-garnet-rutile orthogneiss (sample KO-1), shows

Fig. 20. CL images of dated zircons from KO-1 orthogneiss from
the Koleso Valley in the Nízke Tatry Mountains, North-Veporic
basement.

Fig. 21. Concordia diagram of dated zircons from KO-1
orthogneiss from the Koleso Valley in the Nízke Tatry Mountains,
North-Veporic basement.

Fig. 22. CL images of dated zircons from VV33Bo-1 orthogneiss
from the Jaškovec (Krivu a) Valley in the Nízke Tatry Mountains,
North-Veporic basement.

Fig. 23. Concordia diagram of dated zircons from VV33Bo-1
orthogneiss from the Jaškovec (Krivu a) Valley in the Nízke Tatry
Mountains, North-Veporic basement.

CAMBRIAN-ORDOVICIAN METAIGNEOUS ROCKS IN THE WEST-CARPATHIAN BASEMENT DATED BY SHRIMP

nearly the same zircon magmatic ages. Supposed melting
temperatures between 600—700

°C were probably not suf-

ficient for the zircon resolution in the orthogneiss. The
age of lenses of HP eclogites and granulites (Janák et al.
2003, 2007; Putiš et al. 2006a), enclosed in partially melt-
ed orthogneiss, is unknown.

Similar Neoproterozoic magmatic ages were found in

the Austroalpine basement to the south of the Tauern Win-
dow in the Eastern Alps (Schulz et al. 2004; Dekant et al.
2005, and submitted).

Metamorphic ages (540—530 Ma) fit a hiatus in sedi-

mentation on Cadomian terranes (Cadomian unconformi-
ty), related to the Cadomian orogeny. Magmatic ages,
around younger concordia age of ca. 558 Ma, are coeval
with magmatism in the Avalonian-Cadomian arc, recon-
structed between 570 and 540 Ma in Saxo-Thuringia (Lin-
nemann & Romer 2002). Magmatic ages, around the older
concordia age of ca. 607 Ma, are consistent with an older
magmatic phase in the Avalonian-Cadomian arc, recon-
structed before 607 Ma, the cooling age from

Ar/

Ar dat-

ing of magmatic hornblendes in the Cadomian orogen ex-
posed in NW France and the Channel Islands (Dallmeyer et
al. 1991). D’Lemos et al. (2001) confirmed both age groups
by dating magmatic zircons to 610 ± 2 Ma and 572 ± 1 Ma.

The orthogneisses from the West-Carpathian Middle

Variscan structural Unit could therefore represent remnants
of the Cadomian crust detached from the continental
margin of Gondwana and tectonically emplaced into
MT-MP micaschist gneisses, derived from Neoproterozo-
ic/Early Cambrian Gondwana margin flyschoid sediments.
Although the time of tectonic emplacement of the orthog-
neisses, hosting rare boudins of HP-HT metamafics, is not
well constrained, the orthogneiss ages corroborate well the
Neoproterozoic to Cambrian source ages (ca. 650 to
500 Ma, Kohút et al. 2007, and in press) of the hosting
metasedimentary rocks.

The measured Cadomian ages thus indicate that some of

the West-Carpathian (Tatric-Veporic) basement fragments
shared a common geological history with the eastern Ava-
lonian-Cadomian/western Hunic terranes throughout the
Neoproterozoic and Early Cambrian.

Cambrian to Ordovician ages spanning 525—440 Ma

are characteristic for the dated layered amphibolites, gra-
nitic orthogneisses and acid metavolcanics.

Layered amphibolites: The layered amphibolites for-

merly interpreted as Ordovician (Gaab et al. 2005), or
Cambrian (Putiš et al. 2001) yielded Ordovician SHRIMP
ages (482—450 Ma, Figs. 4—6) in the Tatric (Nízke Tatry
Mountains) basement, but Cambrian to Ordovician (508—
467 Ma, Figs. 7, 8) in the North-Veporic (Vepor Moun-
tains) basement, with concordia ages of 480 ± 5 Ma or
503 ± 4 Ma, respectively (Figs. 6, 8). They may represent
two magmatic (Cambrian/Early Ordovician and/or Ordov-
ician/Early Silurian) phases of a gabbroic(-dioritic) intru-
sion into the continental lower crust. Preliminary
geochemical data infer a fractionated gabbroic to dioritic
origin for the layered amphibolites (Putiš et al. 2006a).

Granitoid orthogneisses: The hitherto known conven-

tional U-Pb data distinguished two granitic orthogneiss

generations – one Ordovician (Gaab et al. 2005), and the
other Early Devonian (Poller et al. 2000; Putiš et al. 2003).
SHRIMP dating confirmed a wider, but still single princi-
pal Cambrian-Ordovician age interval in both the Tatric
and Veporic domains. As in the layered amphibolites, two
main age intervals are distinguishable: a highly predomi-
nating Cambrian/Early Ordovician (Figs. 11, 14—17), and
Ordovician/Early Silurian (Figs. 18, 19 and sample SAM-13
in Fig. 2) in S- and I-type (Putiš et al. 2003 and citations
therein) granitic/tonalitic orthogneisses.

The Early Ordovician ages of two dated samples of calc-

alkaline acid metavolcanics (482 ± 6 Ma and 476 ± 7 Ma)
fit in well with the first magmatic phase of a gabbroic in-
trusion found in layered amphibolites, or to the first gener-
ation of orthogneisses. Acid volcanism could have been
triggered by partial melting at the base of the extensional-
ly thinning continental crust due to injection of basic
magmas of a gabbro-basalt composition.

Major Cambrian-Ordovician magmatism/volcanism, de-

tected in the West-Carpathian basement, could be related
to rifting, followed by more recent magmatic/volcanic ac-
tivity above the southward subducting Panthalassa Ocean
slab in the Gondwana active continental margin. Gabbroic
to dioritic intrusions, generated by suprasubduction melt-
ing of the subcrustal lithosphere, were emplaced and dif-
ferentiated in the continental lower crust as a precursor of
the dated layered amphibolites. Contemporaneous melt-
ing of the lower crustal rocks enabled formation of granit-
ic to tonalic bodies, precursors of the dated orthogneisses.
The Early Ordovician acid calc-alkaline metavolcanics of
the low-grade volcano-sedimentary complexes in the
Lower Variscan structural Unit also fit in well with this
scenario. They might be related to break-up of the Gond-
wana northern active continental margin by splitting it
into microplates like Avalonia (by the opening of the Pro-
totethyan Rheic Ocean at ca. 480—470 Ma) and Armorica
(by the opening of the Prototethyan (2) Massif Central-
Galicia Ocean at ca. 450—440 Ma), as suggested by the
two main age intervals measured of 525—470 Ma and
480—440 Ma, respectively. From this point of view, a time
boundary between the Neoproterozoic, or Cadomian mag-
matic-metamorphic event (from ca. 650 to 530 Ma) and
the Early Paleozoic rifting/active margin setting (starting
at ca. 525 Ma), recorded in the West-Carpathian basement,
should be the Early Cambrian. Detrital white mica from
the Early Paleozoic low-grade metamorphosed flyschoid
sediments of the Lower Variscan structural Unit of the Ge-
meric basement (Ochtiná Carboniferous complex) was dat-
ed by the

Ar/

Ar method to ca. 508 Ma (Cambrian;

Dallmeyer et al. 1996). Vozárová et al. (2005) found detri-
tal mica of Ordovician age (ca. 465 Ma) in the Late Paleo-
zoic sandstones of the North-Gemeric unit, and both these
ages fit in well with the Cambrian-Ordovician magmatic
ages preserved in the Upper/Middle Variscan structural
Unit of the Tatric-Veporic basement.

The Cambrian to Early Ordovician age interval is co-

eval with the separation of the Avalonian microplate from
the northern Gondwana margin (Pin & Marini 1993) and
opening of the Prototethyan Rheic Ocean at ca. 470 Ma

PUTIŠ, SERGEEV, ONDREJKA, LARIONOV, SIMAN, SPIŠIAK, UHER and PADERIN

(e.g. Banka et al. 2002; Winchester et al. 2002). The end
of the younger interval at ca. 440 Ma is usually interpret-
ed as separation of the Armorican microplate from
northern Gondwana by the opening of the Paleotethys
Ocean (l.c.). However, fauna analysis (Robardet 2003)
proves, for example, very high values of the coefficients
of similarity (CS=0.90) for Early Devonian (Lochkovian)
chitinozoan assemblages, precluding any important
difference in latitude and also the existence of a wide
ocean between the Armorican Massif (Armorica) and the
Algerian Sahara (Gondwana). Conversely, these
coefficients are much weaker (CS = 0.37—0.48) between
these regions and northern Europe (Podolia and Poland)
situated on the southern margin of Laurussia (Paris 1993).
This suggests that there was a noticeable difference of
latitude for North Gondwana and northern Europe. The
above mentioned fauna analysis is, however, not in
contradiction to a later opening of the Paleotethyan Ocean
(or a system of basins) – in the Midle/Late Devonian, as
suggested by the ages of the dated incomplete Paleotethyan
ophiolitic complexes in the Western Carpathians (ca. 385—
350 Ma, Putiš et al. 2006b, 2007a—c). Therefore the
younger magmatic phase (480—440 Ma) we relate to the
opening of the Prototethyan (2) Massif Central-Galicia
Ocean dividing the Armorica from the Gondwana. This oce-
anic basin was eastward reducing to an extensionally
thinned continental crust, including the West-Carpathian
basement. Northward directed subduction/collision under
thrusting (430—380 Ma) below the Armorican microplate
initiated formation of a back-arc basin (Pernek oceanic
back-arc basin in the Western Carpathians; Putiš 1992 –
Fig. 5, top) on the southern Armorican margin. Contemp-
oraneous and continuing extension of the northern
Gondwana (passive) continental margin led to opening
of the Paleotethys Ocean in Middle/Late Devonian times
(385—350 Ma, Putiš et al. 2006b, 2007a—c).

The two distinguished magmatic phases overlap with

the whole period of the Cambrian-Ordovician extension in
the eastern Avalonian-Cadomian/western Hunic terranes,
the fragments of which were identified in the Upper
Variscan structural Unit (Tatric and Veporic basement) of
the Western Carpathians. This evolution confirms the
mentioned terranes as an integrated part of the Armorican
microplate (s.l.) before the opening the Paleotethys Ocean.

Silurian to Middle Devonian ages (ca. 430—390 Ma) are

well preserved in outer, often discordantly grown zircon
zones, or in newly crystallized zircons of layered amphib-
olites and orthogneisses (Figs. 4—8, 16, and samples GR-1,
VZP-2, 3, SAM-13 and MF-1 in Fig. 2). They have de-
creased Th/U values, typical of a metamorphic overprint,
in comparison to magmatic zircons. Although both princi-
pal Cambrian-Ordovician extension intervals are recorded
in the Upper Variscan structural Unit (the Tatra Nappe) of
the Tatric-Veporic basement, the latter also indicates an
important Eo-Variscan northward dipping subduction/col-
lision suture zone (Fig. 3) observable as a nappe surface
between the Upper and Middle Variscan structural Units
(Putiš 1992; Putiš & Grecula in Plašienka et al. 1997;
Fig. 6). The ages of 430—390 Ma are consistent with the

closure of the Prototethyan (2) Massif Central-Galicia
Ocean (Matte 1991, 2001; or Galicia ± Southern Brittany,
Massif Central ± Moldanubian Ocean after Tait et al. 1997),
subduction (a HP metamorphic event; e.g. von Quadt et al.
1997) and collisional suture formation at the southern Ar-
morica margin, contemporaneous with the rifting and a
more recent opening of the Paleotethys Ocean along the
northern Gondwana margin.

Late Devonian to Mississippian ages (385—340 Ma)

are well preserved in outer zircon zones, or in newly crys-
tallized zircons of layered amphibolites and orthogneisses
(Figs. 9, 11—13, 21). These ages, found from the south-
east-vergent collision nappe stack in the Tatric and Ve-
poric basement (Fig. 3), clearly indicate a superimposed
metamorphic/melting event due to extensional collapse
of the thickened Variscan crust, producing large granitic-
tonalitic plutons mostly 360—320 Ma old (Petrík & Ko-
hút 1997).

The ages corroborate collision of the Armorican micro-

plate (with included eastern Avalonian-Cadomian/western
Hunic terranes fragments) with Laurussia/Avalonia, fol-
lowing the closure of both Prototethyan Oceans limiting
the Armorican microplate. The West-Carpathian base-
ment, however preserves only the southern side of this
microplate.

The newly identified age groups enable a general corre-

lation of the West-Carpathian Paleozoic complexes with
other fragments of the European(/African) Variscides, like-
ly derived from the northern Gondwana continental mar-
gin (Piqué et al. 1993; von Raumer 1998; Franke 2000;
Shelley & Bossi

ère 2000; Matte 2001, 2007; Cartier et al.

2001; von Raumer & Stampfli 2007). For example, similar
Cambrian-Ordovician magmatic ages of metaigneous rocks
from the Saxothuringian and Moldanubian zones indicate
that the European Variscides share the evolution of the
northern Gondwana margin (Linnemann et al. 2000; Ban-
ka et al. 2002). This major Cambrian-Ordovician magmat-
ic event, reconstructed from orthogneisses, was dated by
the Pb-Pb and U-Pb methods in eastern Bohemia (Kröner
et al. 1994, 2000, 2001) or in the Polish Sudetes (Kryza &
Pin 1997; Štípská et al. 2001; Ż

elaźniewicz et al. 2006).

Cambrian plutonism is known within the Bohemian Mas-
sif from U-Pb zircon ages and structural development of
metagranitoids of the Teplá crystalline complex (Dörr et
al. 1998) and the Moldanubian domain (Friedl et al. 2004;
Schulmann et al. 2005). Dörr et al. (2002) proposed a ten-
tative model for the evolution of the Avalonian-Cadomian
terranes, which is compatible with the oldest history of the
West-Carpathian basement.

Despite this paper is far from a comparitive study, it is

remarkable, how distant European Variscan areas can
show very close analogies. For example, the Upper
Variscan structural Unit (the Tatra Nappe) of the Tatric
and North-Veporic basement shows analogies to the Upper
Gneiss Unit of the French Massif Central, including a HP
Eo-Variscan event ca. 415 Ma old registered in eclogitic
and HP granulitic boudins in the layered amphibolite
complex, and later 370—340 Ma migmatitization. The
North-Veporic ( ubietová) and South-Veporic (Čierny Ba-

CAMBRIAN-ORDOVICIAN METAIGNEOUS ROCKS IN THE WEST-CARPATHIAN BASEMENT DATED BY SHRIMP

log) structural complexes with MP/MT paragneisses and
large bodies of Cambrian-Ordovician granitic-tonalitic or-
thogneisses resemble the Lower Gneiss Unit of the French
Massif Central (Faure et al. 1997). The Middle Variscan
structural Unit (the Hron Nappe) seems to be analogous to
the Paraautochthonous Unit of the French Massif Central,
both with predominating MP-MT micaschists to parag-
neisses. The Lower Variscan structural Unit could be anal-
ogous to the Southern Paleozoic Fold and Thrust Belt
(Montagne Noire, Cévennes) including the Southern Fore-
land Carboniferous cover (Faure et al. 2005). The Devo-
nian metaophiolitic complexes occur in both regions. The
Devonian Brévenne metaophiolitic complex resembles
the Pernek complex in the Western Carpathians. The
southward directed sequence of thrusting is roughly com-
patible too. Similar analogies can be seen in the south-ver-
gent Moldanubian Unit of the Bohemian Massif, at least
concerning the positioning of the “Upper Variscan” Gföhl
structural Unit (with layered amphibolites and HP
metamafics) thrust over the “Middle Variscan” Drosendorf
structural Unit (micaschists to gneisses). All the regions
compared above have many similarities pointing to a
Gondwana/Armorica origin.

6. Evolution and origin of the West-Carpathian

basement – conclusion

In conclusion, we would like to summarize the results

and new aspects of the West-Carpathian basement evolu-
tion.

They include relics of Cadomian basement, character-

ized by orthogneisses yielding magmatic concordia ages
at 617 ± 1, 607 ± 10 and 558 ± 7 Ma (from a Cadomian mag-
matic arc?) and metamorphic ages between 540—530 Ma.
The corresponding zircons contain cores of 700—3400 Ma,
testifying a Proterozoic to Archean hinterland.

During the Early Paleozoic times, two main magmatic

phases become evident, a Cambrian/Early Ordovician
phase, interpreted as representing a Middle Cambrian rift-
ing event, followed by magmatic rocks of a Late Cambrian
to Early Ordovician first magmatic phase (525—470 Ma),
or Ordovician to Early Silurian as the second magmatic
phase (480—440 Ma), representing a more recent crustal
extension in active continental margin setting. Magmati-
cally layered upper mantle gabbroic(-dioritic) intrusions
were emplaced in the vicinity of granitic rocks in partially
melted domains of the extensionally thinned continental
lower crust. These magmatic phases, found in layered am-
phibolites and orthogneisses of the Upper Variscan struc-
tural Unit were accompanied by the formation of volcano-
sedimentary complexes, the latter mainly present in the
Lower Variscan structural Unit. The metasediments of the
Middle Variscan structural Unit appear to be a remnant
of the Proterozoic-Early Cambrian northern Gondwana
margin.

Evidently, the area, represented now by the Tatric and

Veporic medium- to high-grade complexes (the Upper and
Middle Variscan structural Units), underwent the large-

scale transformations of the Variscan age, including an
Eo-Variscan northward subduction (430—390 Ma), south-
vergent syncollisional nappe stacking (385—360 Ma) and
collapse (360—340 Ma), resembling the evolution of the
eastern Avalonian-Cadomian/western Hunic terranes, or
Armorica (s.l.) in the Prototethyan realm. The Eo-Variscan
continental subduction/collision (430—370 Ma), running
along the southern margin of the Armorican microplate
(no Prototethyan Ordovician-Silurian ophiolites have
been found in the West-Carpathian basement), initiated
rifting and a more recent extensional magmatism/volcan-
ism in the active south-Armorican  and the passive north-
ern Gondwana margin (385—350 Ma), the latter transform-
ing into a system of Paleotethyan basins in the Late
Devonian to Mississippian.  This evolutionary stage is in
good agreement with the ages of the Lahn-Dill type volca-
no-sedimentary as well as those of the incomplete ophi-
olitic complexes in the Western Carpathians (385—
350 Ma, Putiš et al. 2006b, 2007a—c). The latter had been
subducted northward (350—330 Ma) in front of the accret-
ed (330—300 Ma) Upper Devonian/Mississippian  volca-
no-sedimentary complexes of the northern Gondwana
margin to Armorica, before the late Variscan post-colli-
sional collapse (300—270 Ma). The Paleotethyan subduc-
tion/accretion complexes, exposed in the Gemeric base-
ment, developed to the north of the passive northern
Gondwana margin Noric terrane. Therefore the West-Car-
pathian basement shows a strong Gondwana/Armorica af-
finity.

Acknowledgments: Support from Slovak Research and
Development Agency (No. APVT 20-016104; APVV
12504, 0557-06) and VEGA Agency (No. 1/4038/07) is
greatly acknowledged. Fruitful discussions and a con-
structive review by Prof. Dr. J.F. von Raumer contributed
to decisive improvement of the original manuscript. The
suggestions of Prof. Dr. W. Siebel and Prof. Dr. W. Frisch
as the reviewers are appreciated very much.

References

Banka D., Pharaoh T.C. & Williamson J.P. 2002: Potential field im-

aging of Paleozoic orogenic structure in northern and central
Europe. Tectonophysics 360, 23—45.

Bezák V. 1994: Proposal of the new division of the West Car-

pathian crystalline based on the Hercynian tectonic building
reconstruction. Miner. Slovaca 26, 1—6 (in Slovak with En-
glish summary).

Bibikova E.V., Korikovsky S.P., Putiš M., Broska I., Golzman Y.V.

& Arakeliants M.M. 1990: U/Pb, Rb/Sr and K/Ar dating of
Sihla tonalites of Vepor pluton (Western Carpathians). Geol.
Zbor. Geol. Carpath. 41, 427—436.

Biely A. (Ed.), Bezák V., Elečko M., Gross P., Kaličiak M.,

Konečný V., Lexa J., Mello J., Nemčok J., Potfaj M., Rakús
M., Vass D., Vozár J. & Vozárová A. 1996: Geological Map
of Slovakia 1: 500,000. D. Štúr Inst. Geol. Publ., Bratislava.

Black L.P., Kamo S.L., Allen C.M., Aleinikoff J.N., Davis D.W.,

Korsch R.J. & Foudoulis C. 2003: TEMORA 1: a new zircon
standard for Phanerozoic U-Pb geochronology. Chem. Geol.
200, 155—170.

PUTIŠ, SERGEEV, ONDREJKA, LARIONOV, SIMAN, SPIŠIAK, UHER and PADERIN

Cambel B., Krá J. & Burchart J. 1990: Isotopic geochronology of

the Western Carpathian Crystalline Complex with catalogue of
data. VEDA, Bratislava, 1—183 (in Slovak with English sum-
mary).

Cartier C., Faure M. & Lardeux H. 2001: The Hercynian orogeny

in the South Armorican Massif (Saint-Georges-sur-Loire Unit,
Ligerian Domain, France): rifting and welding of continental
stripes. Terra Nova 13, 143—149.

Dallmeyer R.D., D’Lemos R.S., Strachan R.A. & Müller P.A. 1991:

Tectonothermal chronology of early Cadomian arc develop-
ment in Guernsey and Sark, Channel Islands. J. Geol. Soc.
148, 691—702.

Dallmeyer R.D., Neubauer F. & Putiš M. 1993:

Ar/

Ar mineral

age controls for the Pre-Alpine and Alpine tectonic evolution
of nappe complexes in the Western Carpathians. PAEWCR
Conference, Excursion guide, Stará Lesná, 11—20.

Dallmeyer R.D., Neubauer F., Handler R., Fritz H., Müller W., Pana

D. & Putiš M. 1996: Tectonothermal evolution of the internal
Alps and Carpathians: Evidence from

Ar/

Ar mineral and

whole-rock data. Eclogae Geol. Helv. 89, 203—227.

Dallmeyer R.D., Németh Z. & Putiš M. 2005: Regional tectonother-

mal events in Gemericum and adjacent units (Western Car-
pathians, Slovakia): Contribution by the

Ar/

Ar dating.

Slovak Geol. Mag. 11, 155—163.

Dekant Ch., Wölfler A., Siebel W., Putiš M., Markl G. & Frisch W.

2005: New U-Pb investigations in the Austroalpine of the
Kreuzeck Massif, Karinthia (Eastern Alps). Geophys. Res. Ab-
str., Vol. 7, 04857, 2005 SRef-ID: 1607—7962/gra/EGU05-A-
04857© European Geosciences Union 2005.

Dekant Ch., Wölfler A., Siebel W., Putiš M., Frank W. & Frisch W.

submitted: Geochronological constraints on the evolution of
the Kreuzeck Massif, Austria: a U/Pb and

Ar/

Ar study. Int.

J. Earth Sci. (Geol. Rdsch.).

D’Lemos R.S., Miller B.V. & Samson S.D. 2001: Precise U-Pb zir-

con ages from Alderney, Channel Islands: growing evidence
for discrete Neoproterozoic magmatic episodes in northern Ca-
domia. Geol. Mag. 138, 719—726.

Dörr W., Fiala J., Vejnar Z. & Zulauf G. 1998: U-Pb zircon ages

and structural development of metagranitoids of the Teplá
crystalline complex: evidence for pervasive Cambrian plu-
tonism within the Bohemian massif (Czech Republic). Geol.
Rdsch. 87, 135—149.

Dörr W., Zulauf G., Fiala J., Franke W. & Vejnar Z. 2002: Neopro-

terozoic to Early Cambrian history of an active plate margin in
the Teplá-Barrandian unit – a correlation of U-Pb isotopic-di-
lution-TIMS ages (Bohemia, Czech Republic). Tectonophysics
352, 65—85.

Faure M., Leloix Ch. & Roig J.-Y. 1997: Polycyclic evolution of

the Hercynian Belt. Bull. Soc. Géol. France 168, 695—705.

Faure M., Méz

ème E.B., Duguet M., Cartier C. & Talbot J.-Y.

2005: Paleozoic tectonic evolution of medio-europa from the
example of the French Massif Central and Massif Armorican.
J. Virt. Expl. 5, 19.

Franke W. 2000: The mid-European segment of the Variscides: tec-

tonostratigraphic units, terrane boundaries and plate tectonic
extension. In: Franke W., Altherr R., Haak V., Oncken O. &
Tanner D. (Eds.): Orogenic processes: Quantification and
modelling in the Variscan Belt. Geol. Soc. London, Spec.
Publ. 179, 35—61.

Friedl G., Finger F., Paquette J.L., von Quadt A., McNaughton N.J.

& Fletcher I.R. 2004: Pre-Variscan geological events in the
Austrian part of the Bohemian Massif deduced from U-Pb zir-
con ages. Int. J. Earth Sci. 93, 802—823.

Fritz H., Neubauer F., Janák M. & Putiš M. 1992: Variscan mid-

crustal thrusting in the Carpathians II: Kinematics and fabric
evolution of the Western Tatra basement. Terra Nova 4, 2.

Gaab A.S., Poller U., Janák M., Kohút M. & Todt W. 2005: Zircon

U-Pb geochronology and isotopic characterization for the pre-
Mesozoic basement of the Northern Veporic Unit (Central
Western Carpathians, Slovakia). Schweiz. Mineral. Petrol. Mitt.
85, 69—88.

Gaab A.S., Janák M., Poller U. & Todt W. 2006: Alpine reworking

of Ordovician protoliths in the Western Carpathians: Geochro-
nological and geochemical data on the Muráň Gneiss complex.
Lithos 87, 261—275.

Gebauer D. 1993: The pre-Alpine evolution of the continental crust

of the Central Alps: an overview. In: Raumer J. von & Neu-
bauer F. (Eds.): The pre-Mesozoic geology in the Alps.
Springer, Berlin, Heidelberg, New York, 93—117.

Gebauer D., Williams I.S., Compston W. & Grünenfelder M. 1989:

The development of the Central European continental crust
since the early Archean based on conventional and ion-micro-
probe dating of detrital zircons up to 3.84 billion years old.
Tectonophysics 157, 81—96.

Gradstein J.G. & Ogg A.G. (Eds.) 2004: A geologic time scale

2004: Cambridge University Press, and the official website of
the International Commission on Stratigraphy (ICS) under
www. stratigraphy.org.

Haas J., Kovács S., Krystyn L. & Lein R. 1995: Significance of

Late Permian—Triassic facies zones in terrane reconstructions
in the Alpine—North Pannonian domain. Tectonophysics 242,
19—40.

Hovorka D. & Méres Š. 1993: Leptyno-amphibolite complex of the

Western Carpathians: occurrences and lithology. Miner. Slova-
ca 25, 1—9 (in Slovak with English abstract).

Hovorka D. & Méres Š. 1997: Geochemistry of the Early Paleozoic

felsic metavolcanics of the Gemeric unit (Western Car-
pathians). In: Grecula P., Hovorka D. & Putiš M. (Eds.): Geo-
logical evolution of the Western Carpathians. Miner. Slovaca,
Monograph, Bratislava, 289—300.

Janák M., Finger F., Plašienka D., Petrík I., Humer B., Méres Š. &

Lupták B. 2002: Variscan high P-T recrystallization of Ordov-
ician granitoids in the Veporic unit (Nízke Tatry Mountains,
Western Carpathians): New petrological and geochronological
data. Geolines 14, 38—39.

Janák M., Méres Š. & Ivan P. 2003: First evidence for omphacite

and eclogite facies metamorphism in the Veporic unit of the
Western Carpathians. J. Czech Geol. Soc. 48, 1—2, 69.

Janák M., Méres Š. & Ivan P. 2007: Petrology and metamorphic P-T

conditions of eclogites from the northern Veporic unit, Western
Carpathians, Slovakia. Geol. Carpathica 58, 121—131.

Kohút M., Poller U., Todt W. & Konečný P. 2007: Detrital zircon

and monazite dating: useful tool for tracking Pan-African
orogeny remnants in the Western Carpathians. CzechTec 07
Meeting, Abstr. 42—44.

Kohút M., Poller U., Gurk Ch. & Todt W. in press: Geochemical

composition, isotopic signature and U-Pb zircon ages of
metasedimentary rocks: Implications for the evolution of the
pre-Variscan basement at the eastern border of Central Europe.
Swiss J. Geosci.

Korikovsky S.P., Putiš M. & Plašienka D. 1997: Cretaceous low-

grade metamorphism of the Veporic and North-Gemeric
Zones: a result of collisional tectonics in the central Western
Carpathians. In: Grecula P., Hovorka D. & Putiš M. (Eds.):
Geological evolution of the Western Carpathians. Miner. Slo-
vaca, Monograph, Bratislava, 107—130.

Korikovsky S.P. & Putiš M. 2002: Olivine-orthopyroxene-amphib-

ole-talc-chlorite meta-serpentinites in the medium-temperature
metamorphic complex of Northern Veporic, Western Car-
pathians: phase equilibria, metamorphic parameters, compari-
son with gneiss and amphibolite associations. Petrology 10,
3—29.

CAMBRIAN-ORDOVICIAN METAIGNEOUS ROCKS IN THE WEST-CARPATHIAN BASEMENT DATED BY SHRIMP

Kotov A.B., Miko O., Putiš M., Korikovsky S.P., Salnikova E.B.,

Kovach V.P., Yakovleva S., Bereznaya N.G., Krá J. & Krist
E. 1996: U/Pb dating of zircons of postorogenic acid metavol-
canics and metasubvolcanics: A record of Permian-Triassic
taphrogeny of the West-Carpathian basement. Geol. Carpathi-
ca 47, 73—79.

Kováčik M., Krá J. & Maluski H. 1996: Metamorphic rocks in

the southern Veporicum basement: their Alpine metamor-
phism and thermochronologic evolution. Miner. Slovaca 28,
185—202.

Kováčik M., Konečný P., Kollárová V., Holický I. & Siman P.

2005: Electron microprobe dating of monazite in basement
metamorphites from the Kohút zone of Veporicum and case
correlation aspects (Western Carpathians). Slovak Geol. Mag.
11, 91—105.

Kováčik M., Kotov A.B. & Salnikova E.B. submitted: Concordia

U-Pb zircon ages from the south-Veporic Muráň orthogneiss
(Western Carpathians): evidence for Cambrian granitic mag-
matism. Miner. Slovaca.

Krá J., Frank W. & Bezák V. 1996:

Ar—

Ar spectra from am-

phibole of Veporic amphibolic rocks. Miner. Slovaca 28,
501—513 (in Slovak, English summary).

Krist E., Korikovsky S.P., Putiš M., Janák M. & Faryad S.W. 1992:

Geology and petrology of metamorphic rocks of the Western
Carpathian crystalline complexes. Comenius University Press,
Bratislava, 1—324.

Kröner A., Jaeckel P. & Opletal M. 1994: Pb-Pb and U-Pb zircon

ages for orthogneisses from eastern Bohemia: further evidence
for a major Cambro-Ordovician magmatic event. J. Czech
Geol. Soc. 39, 61.

Kröner A., Štípská P., Schulmann K. & Jaeckel P. 2000: Geochrono-

logical constraints on the pre-Variscan evolution of the north-
eastern margin of the Bohemian Massif, Czech Republic. In:
Franke W., Altherr R., Haak V., Oncken O. & Tanner D. (Eds.):
Orogenic processes: quantification and modelling in the
Variscan Belt. Geol. Soc. London, Spec. Publ. 179, 175—197.

Kröner A., Jaeckel P., Hegner E. & Opletal M. 2001: Single zircon

ages and whole-rock Nd isotopic systematics of early palaeo-
zoic granitoid gneissess from the Czech and Polish Sudetes
(Jizerské Hory, Krkonoše Mountains and Orlice-Sněžník com-
plex). Int. J. Earth Sci. 90, 304—324.

Kryza R. & Pin C. 1997: Cambrian/Ordovician magmatism in the

Polish Sudetes: no evidence for subduction-related setting.
EUG9 Meeting, Strasbourg, Terra Abstracts. Cambridge Pub-
lications, Cambridge, UK, 144.

Larionov A.N., Andreichev V.A. & Gee D.G. 2004: The Vendian

alkaline igneous suite of northern Timan: ion microprobe U-Pb
zircon ages of gabbros and syenite. In: Gee D.G. & Pease
V.L. (Eds.): The Neoproterozoic timanide orogen of Eastern
Baltica. Geol. Soc., London, Mem. 30, 69—74.

Linnemann U., Gehmlich M., Tichomirowa M., Buschmann L.,

Nasdala L., Jonas P., Lutzner H. & Bombach K. 2000: From
Cadomian subduction to Early Paleozoic rifting: the evolution
of Saxo-Thuringia at the margin of Gondwana in the light of
single zircon geochronology and basin development (central
European Variscides). In: Franke W., Altherr R., Haak V., On-
cken O. & Tanner D. (Eds.): Orogenic processes: Quantifica-
tion and modelling in the Variscan Belt. Geol. Soc. London,
Spec. Publ. 179, 131—154.

Linnemann U. & Romer R.L. 2002: The Cadomian Orogeny in

Saxo-Thuringia, Germany: geochemical and Nd-Sr-Pb isoto-
pic characterization of marginal basins with constraints to geo-
tectonic setting and provenance. Tectonophysics 352, 33—64.

Ludwig K.R. 2005a: SQUID 1.12 A User’s Manual. A Geochrono-

logical Toolkit for Microsoft Excel. Berkeley Geochronology
Center Spec. Publ., 1—22.

Ludwig K.R. 2005b: User’s Manual for ISOPLOT/Ex 3.22. A geo-

chronological toolkit for Microsoft Excel. Berkeley Geochro-
nology Center Spec. Publ., 1—71.

Madarás J., Putiš M. & Hók J. 1999: Structural features of the Her-

cynian tectonics in the southern part of the Ďumbier crystalline
complex (Low Tatra Mts., Western Carpathians). Miner. Slova-
ca 31, 17—30.

Matte P. 1991: Accretionary history and crustal evolution of the

Variscan belt in Western Europe. Tectonophysics 196, 309—337.

Matte P. 2001: The Variscan collage and orogeny (480—290 Ma)

and the tectonic definition of the Armorica microplate: a re-
view. Terra Nova 13, 122—128.

Matte Ph. 2007: Variscan thrust nappes, detachments, and strike-

slip faults in the French Massif Central: interpretation of the
lineations. Geol. Soc. Amer. Mem. 200, 1—12.

Paris F. 1993: Evolution paléogéographique de l’Europe au Paléo-

zoique inferieur: le test des Chitinozoaires. C.R. Acad. Sci.
Paris 316, 273—280.

Petrík I. & Kohút M. 1997: The evolution of granitoid magmatism

during the Hercynian orogen in the Western Carpathians. In:
Grecula P., Hovorka D. & Putiš M. (Eds.): Geological evolu-
tion of the Western Carpathians. Miner. Slovaca, Monograph,
Bratislava, 235—252.

Pin C. & Marini F. 1993: Early Ordovician continental break-up in

Variscan Europe: Nd-Sr isotope and trace element evidence
from bimodal igneous associations of the southern Massif Cen-
tral, France. Lithos 29, 177—196.

Piqué A., Bossi

ère G., Bouillin J.P., Chalouan A. & Hoepffner Ch.

1993: Southern margin of the Variscan belt: the northwestern
Gondwana mobile zone (eastern Morocco and northern Alge-
ria). Geol. Rdsch. 82, 432—439.

Plašienka D., Grecula P., Putiš M., Kováč M. & Hovorka D. 1997:

Evolution and structure of the Western Carpathians: an over-
view. In: Grecula P., Hovorka D. & Putiš M. (Eds.): Geologi-
cal evolution of the Western Carpathians. Miner. Slovaca,
Monograph, Bratislava, 1—24.

Poller U., Janák M., Kohút M. & Todt W. 2000: Early Variscan

magmatism in the Western Carpathians: U-Pb zircon data from
granitoids and orthogneisses of the Tatra Mountains (Slova-
kia). Int. J. Earth Sci. 89, 336—349.

Putiš M. 1992: Variscan and Alpidic nappe structures of the West-

ern Carpathian crystalline basement. Geol. Carpathica 43,
369—380.

Putiš M. 2002: Tectonothermal evolution of the Austro-Alpine—

Centro-Carpathian Microplate: microstructural-P-T-t-d trends
– a correlation. Geol. Carpathica, Spec. Issue 53, 151—155.

Putiš M., Filová I., Korikovsky S.P., Kotov A.B. & Madarás J.

1997: Layered metaigneous complex of the Veporic basement
with features of the Variscan and Alpine thrust tectonics (the
Western Carpathians). In: Grecula P., Hovorka D. & Putiš M.
(Eds.): Geological evolution of the Western Carpathians. Min-
er. Slovaca, Monograph, Bratislava, 175—196.

Putiš M., Kotov A.B., Uher P., Korikovsky S.P. & Salnikova E.B.

2000: Triassic age of the Hrončok pre-orogenic A-type granite
related to continental rifting: a new result of U-Pb isotope dat-
ing (Western Carpathians). Geol. Carpathica 51, 59—66.

Putiš M., Kotov A.B., Korikovsky S.P., Salnikova E.B., Yakovleva

S.Z., Berezhnaya N.G., Kovach V.P. & Plotkina J.V. 2001: U-Pb
zircon ages of dioritic and trondhjemitic rocks from a layered
amphibolitic complex crosscut by granite vein (Veporic
basement, Western Carpathians). Geol. Carpathica 52, 49—60.

Putiš M., Kotov A.B., Petrík I., Korikovsky S.P., Madarás J., Salni-

kova E.B., Yakovleva S.Z., Berezhnaya N.G., Plotkina Y.V.,
Kovach V.P., Lupták B. & Majdán M. 2003: Early- vs. Late
orogenic granitoids relationships in the Variscan basement of
the Western Carpathians. Geol. Carpathica 54, 163—174.

PUTIŠ, SERGEEV, ONDREJKA, LARIONOV, SIMAN, SPIŠIAK, UHER and PADERIN

Putiš M., Demko R., Kromel J. & Filová I. 2006a: Geochemical

trends and metamorphic conditions of the LAC meta-igneous
rocks in the North-Veporic zone (Western Carpathians). Con-
ferences, Symposia, Seminars, D. Štúr State Geological Insti-
tute Press, Bratislava, Conf. Geochemistry 2006 (Ďurža O. &
Rapant S. Eds.), 91—93 (in Slovak).

Putiš M., Ondrejka M., Siman P., Spišiak J., Uher P., Larionov A.

& Paderin I. 2006b: The first SHRIMP age-data on magmatic-
metamorphic events in the Western Carpathians basement.
Conferences, Symposia, Seminars, D. Štúr State Geological In-
stitute Press, Bratislava, Conf. Geochemistry 2006 (Ďurža O.
& Rapant S. Eds.), 91—93 (in Slovak with English abstract).

Putiš M., Ondrejka M., Sergeev S., Larionov A., Radvanec M., Si-

man P., Spišiak J., Kohút M., Uher P. & Paderin I. 2007a: In-
situ U-Pb (SHRIMP) zircon dating of the West-Carpathian
pre-Mesozoic basement rocks. Symposium on Petrology and
Dating. Comenius University, May 2007, Abstr., 16—20.

Putiš M., Sergeev S., Chovan M., Radvanec M., Kohút M., Larionov

A., Ondrejka M., Siman P., Spišiak J., Uher P. & Paderin I.
2007b: The pre-Mesozoic basement of the Western Carpathians,
Slovakia: SHRIMP ages and mineralizations of a Gondwana/
Armorica fragment in Variscan-Alpine orogenic structure.
International Symposium on Crust-Mantle Evolution and
Mineralization. Nanjing University, March 2007, Abstr., 44—46.

Putiš M., Sergeev S., Larionov A., Radvanec M., Siman P., Spišiak

J., Kohút M., Uher P., Ondrejka M., Filová I. & Paderin I.
2007c: Evolution and origin of the West-Carpathian pre-Me-
sozoic basement, dated by SHRIMP. International Symposium
on Mechanics of Variscan Orogeny: a modern view on oro-
genic research. Orleans, September 2007, Abstr., 147.

Quadt A. von, Günther D., Frischknecht R., Zimmermann R. &

Franz G. 1997: The evolution of pre-Variscan eclogites of the
Tauern window (eastern Alps): a Sm/Nd conventional and la-
ser ICP-MS zircon U-Pb study. Schweiz. Mineral. Petrogr.
Mitt. 77, 265—273.

Raumer J.F. von 1998: The Paleozoic evolution in the Alps: from

Gondwana to Pangea. Geol. Rdsch. 87, 407—435.

Raumer J.F. von & Neubauer F. 1993: Late Precambrian and Paleo-

zoic evolution of the Alpine basement: an overview. In:
Raumer J.F. von & Neubauer F. (Eds.): The Pre-Mesozoic ge-
ology in the Alps. Springer, Berlin, Heidelberg, New York,
625—640.

Raumer J.F. von & Stampfli G.M. 2007: Paleozoic Oceans at the

Gondwana margin – a discussion. La Coruńa: IGCP 497 An-
nual Meeting Abstract. In: Arenas R., Martinez Catalan J.R.,
Abati J. & Sanchez Martinez S. (Eds.): The rootless Variscan
suture of NW Iberia (Galicia, Spain). Publicaciones del Insti-
tuto Geologico y Minero de Espa

ña, 131—133.

Robardet M. 2003: The Armorica ‘microplate’: fact or fiction? Crit-

ical review of the concept and contradictory palaeobiogeo-
graphical data. Palaeogeogr. Palaeoclimatol. Palaeoecol.
3076, 1—24.

Schulz B., Bombach K., Pawlig S. & Brätz H. 2004: Neoproterozo-

ic to Early-Paleozoic magmatic evolution in the Gondwana-

derived Austroalpine basement to the south of the Tauern
Window (Eastern Alps). Int. J. Earth Sci. 93, 824—843.

Shcherbak N.P., Bartnitsky E.N., Mitskievich N.Y., Stepanyuk

L.M., Cambel B. & Grecula P. 1988: U-Pb radiometric deter-
mination of the age of zircons from Modra granodiorite, Malé
Karpaty Mts., and porphyroid from Spiš-Gemer Ore Mts.,
Lower Paleozoic (Western Carpathians). Geol. Zbor. Geol.
Carpath. 39, 427—436 (in Russian, English abstract).

Shelley D. & Bossi

ère G. 2000: A new model for the Hercynian

orogen of Gondwanan France and Iberia. J. Struct. Geol. 22,
757—776.

Spišiak J. & Pitoňák P. 1992: Banded amphibolitic rocks – pre-

Variscan basement of the Western Carpathians? Terra Abstr. to
Terra Abstr. Suppl. 4, 2, 63.

Stacey J.S. & Kramers J.D. 1975: Approximation of terrestrial lead

isotope evolution by a two-stage model. Earth Planet. Sci.
Lett. 26, 207—221.

Stampfli G.M. & Borel G.D. 2002: A plate tectonic model for the

Paleozoic and Mesozoic constrained by dynamic plate bound-
aries and restored synthetic oceanic isochrons. Earth Planet.
Sci. Lett. 196, 17—33.

Steiger R.H. & Jäger E. 1977: Subcommission on geochronology:

convention on the use of decay constants in geo- and cosmo-
chronology. Earth Planet. Sci. Lett. 36, 359—362.

Štípská P., Schulmann K., Thompson A.B., Ježek J. & Kröner A.

2001: Thermo-mechanical role of a Cambro-Ordovician pale-
orift during the Variscan collision: The NE margin of the Bo-
hemian Massif. Tectonophysics 332, 239—253.

Tait J.A., Bachtadse V., Franke W. & Soffel H.C. 1997: Geodynam-

ic evolution of the European Variscan fold belt: paleomagnetic
and geological constraints. Geol. Rdsch. 86, 585—598.

Vozárová A., Frank W., Krá J. & Vozár J. 2005:

Ar/

Ar dating

of detrital mica from the Upper Paleozoic sandstones in the
Western Carpathians (Slovakia). Geol. Carpathica 56, 463—472.

Vozárová A. & Ivanička J. 1996: Geodynamic position of acid vol-

canism of the Gelnica Group (Early Paleozoic, Southern Ge-
mericum; Inner Western Carpathians). Slovak Geol. Mag. 3—4,
96, 245—250.

Wiedenbeck M., Allé P., Corfu F., Griffin W.L., Meier M., Oberli

F., Von Quadt A., Roddick J.C. & Spiegel W. 1995: Three nat-
ural zircon standards for U-Th-Pb, Lu-Hf, trace element and
REE analyses. Geostandards Newsletter 19, 1—23.

Williams I.S. 1998: U-Th-Pb geochronology by ion microprobe. In:

Applications in microanalytical techniques to understanding
mineralizing processes. Reviews in Economic Geology 7, 1—35.

Winchester J.A. The PACE TMR Network Team 2002: Paleozoic

amalgamation of Central Europe: new results from recent
geological and geophysical investigations. Tectonophysics
360, 5—21.

Żelaźniewicz A., Nowak I., Larionov A. & Presnyakov S. 2006:

Lower Ordovician migmatite and post-tectonic Upper Viséan
syenite in the western limb of the Orlica-Śnieżnik Dome, West
Sudetes: U-Pb SHRIMP data from zircons. Geol. Sudetica 38,
63—80.