GEOLOGICA CARPATHICA, 51, 3, BRATISLAVA, JUNE 2000
145158
MULTIPLE SOURCES OF THE WEST-CARPATHIAN VARISCAN
GRANITOIDS: A REVIEW OF Rb/Sr AND Sm/Nd DATA
IGOR PETRÍK
Geological Institute, Slovak Academy of Sciences, Dúbravská 9, 842 26 Bratislava, Slovak Republic; geolpetr@savba.savba.sk
(Manuscript received December 6, 1999; accepted in revised form May 16, 2000)
Abstract: Detailed reviewing of several existing Rb/Sr datings from the West-Carpathian granitic massifs shows that
the Rb/Sr dates older than U/Pb zircon data are possibly caused by inclusion of high Rb/Sr samples in the sample
collections. Such samples, usually occurring as leucocratic veins in metamorphic complexes, usually have higher
initial
87
Sr/
86
Sr ratios which results in generating pseudo-isochrons. Therefore, there is no need for an initial mixing
line as suggested earlier. Some samples outlying both above and below isochrons may be interpreted in terms of
system opening at a time different from the initial closure. Depending on reconstructed Rb/Sr ratios late Variscan to
Early Alpine ages are obtained for the opening. In contrast to Rb/Sr, previously published Sm/Nd data show that the
initial
143
Nd/
144
Nd ratios were not homogenized making it possible to suggest end-members responsible for the ob-
served variation. Such end-members are sought in (1) the peraluminous (leuco)granites that originated through dehy-
dration melting of gneisses with fairly high I
Sr
and (2) gabbro/dioritic rocks occurring within granite massifs or as
mafic enclaves. Assimilation of supracrustal rocks by the mafic magma could have produced either sub- to metaluminous
I-type granitoids or peraluminous S-type granites depending on proportions of the end-members. The varying propor-
tions may also have been responsible for the mineralogical and petrological differences observed between the two
groups. Seven different sources are suggested for all the Variscan granitoids in the Western Carpathians.
Key words: Western Carpathians, open system, source rock, end-member, granitoids, leucogranite, diorite, assimilation,
Rb/Sr, Sm/Nd, pseudoisochron.
Introduction
The problem of the source rocks of the West-Carpathian
Variscan granitoids (Fig. 1) has been addressed several times
mainly on isotopic grounds discussing the possible role of a
mantle component. Less frequently, the probable protolith
was characterized by petrological considerations. While ear-
ly researchers preferred a metasedimentary source and palin-
genetic origin of granitoids (Cambel 1980; Hovorka 1980),
later, mainly due to accumulating Rb/Sr data, the role of
mantle component has been increasingly emphasized
(Cambel & Petrík 1982; Krá¾ 1994). The recognition of S-, I-
and A-type features borne by these granitoids enabled differ-
ent source lithologies to be assumed (Cambel & Vilinoviè
1987; Petrík et al. 1994; Uher & Broska 1996; Petrík & Ko-
hút 1997).
Recently, the existing body of Rb/Sr data was comple-
mented by new Sm/Nd determinations (Kohút et al. 1999).
The authors found in contrast to the Rb/Sr system, that the
Sm/Nd system was not homogenized and samples do not
generate isochrons. To explain the heterogeneity in
143
Nd/
144
Nd ratios they also invoked processes of contamination
and/or magma mixing. Based on depleted mantle Nd model
ages, the role of a Middle Proterozoic component recycling
was stressed (l.c.).
All the isotopic data clearly preclude a single source for
the West-Carpathian granitoids. Although this was conclud-
ed by all authors, the lithological character of possible pre-
cursors was mentioned only in a general way, mainly in the
isotopic context. The aim of the present work is to confront
the available data with actual, granite-related rocks found in
outcrops, and to suggest probable protoliths.
Geological setting
The West-Carpathian Variscan granitoids comprise consid-
erable parts of the Variscan crystalline terranes imbricated in
the Alpine structural edifice (Fig. 1). The edifice was formed
by contraction of the Variscan continental crust disintegrated
by Early Jurassic rifting and Early Cretaceous extension.
Three main megaunits were thrust one over another during
the Late Cretaceous: the Tatric Superunit, Veporic Superunit
and Gemeric Superunit (Plaienka et al. 1997). The bulk of
granitoids were emplaced during the Carboniferous (350
300 Ma B.P.) when they intruded the thickened Early Paleo-
zoic basement, and after initial uplift and erosion in the Early
Triassic, they were submerged and remained buried until the
Tertiary. Then, in the Paleogene, first the Vepor pluton was
exhumed along normal faults, followed in the Neogene by
Tatric plutons (Kováè et al. 1994) to form the characteristic
present day core-and-cover structure. The granitoids in the
Tatric Superunit crop out in eleven core mountains. In the
Veporic Superunit the largest and most complex Vepor plu-
ton has been uncovered. All the Tatric and Veporic granitoid
plutons intruded high-grade metamorphic rocks: migmatites,
gneisses and amphibolites. By contrast, in the Gemeric Supe-
runit small bodies of Permian Gemeric granites intruded low
146 PETRÍK
grade metapelites and now occur in the form of tectonic slic-
es. While Tatric granitoids bear mostly primary, Variscan
features, the Veporic and Gemeric granitoids are often
sheared and strongly reworked due to the Alpine burial reset-
ting their K/Ar and
40
Ar/
39
Ar ages (Dallmayer et al. 1996;
Kováèik et al. 1996).
The isotopic evidence
A major part of the granitoids with a peraluminous, com-
monly leucocratic, character and a more or less obvious rela-
tionship to metasedimentary wall rocks (migmatite belts,
paragneiss xenoliths) was included in the S-type group. Some
of them have slightly increased initial Sr isotope ratios (Rima-
vica Granite in the Veporic Superunit or Malé Karpaty grani-
toids), or very high ratios (Kralièka Granite of the Nízke Tatry
Mts., Gemeric granites), while others do not (Stráovské vrchy
or Vysoké Tatry Mts.), Table 1. A minor part of the biotite-rich
granitoids (granodiorites and tonalites), showing sub- to meta-
luminous natures, and scattered mafic microgranular enclaves
(MME) form the I-type group. They mostly have low Sr initial
ratios around 0.705 (Tribeè Mts., Sihla tonalite) however, a
significant exception is represented by the Praivá/Ïumbier
granodiorite of the Nízke Tatry Mts. with I
Sr
= 0.7078, Table 1.
The A-type group represented by the Hronèok Granite also
shows a high I
Sr
(0.7114). Based on detailed discussion of the
Rb/Sr data, Krá¾ (1994) distinguished two groups of granitoids
with I
Sr
> 0.707 and = 0.706 (approximating the S- and I-type
group) and suggested wall rock assimilation to explain the
higher I
Sr
values.
Rb/Sr systematics
The accumulated Rb/Sr whole rock and U/Pb zircon data
showed that a discordancy exists between them, the former
giving higher dates. Krá¾ (1994) and Petrík et al. (1994) dis-
cussed the discordancy, speculated about a possible lack of
homogenization and postulated an inherited
87
Sr/
86
Sr mixing
line of the source rock. If so, the Rb/Sr data should help to
identify possible end-members. However, a closer inspection
of several published Rb/Sr data sets shows that at least some
of the published dates are based on pseudoisochrons con-
structed using unrelated or altered rocks. [All the following
age calculations were performed by Isoplot (Ludwig 1994),
using the errors given by authors, and results are at 95%
probability level (2
σ
), see Table 1].
Stráovské vrchy Mts. (Suchý granitic core)
The original Rb/Sr age (Krá¾ et al. 1987, recalculated as
392 ± 17 Ma, Table 1), based on four selected samples (SR-
3, 4, 5, 6), exceeds the zircon age (356 ± 9 Ma, Krá¾ et al.
1997) by 36 Ma. The original slope is rather steep owing to
the exclusion of a low Sr sample SR-2, and accepting a high
Rb/Sr sample SR-6 (Fig. 2A). The latter sample is a leuco-
cratic sill (one of several) alternating with paragneisses in
the Suchý core. The sills occur within a gneiss belt 500 m
wide steeply dipping into the main granitic body and show-
ing no transition to it. The sample was included because of
its high Rb/Sr ratio, being considered a leucocratic off-spring
of the main body. A view that such aplitic leucocratic veins
are products of the dehydration melting of the metapelitic
Fig. 1. Crystalline basement outcrops in the Western Carpathians showing main granitoid types and mountain ranges.
Ge
mer
ic
S
upe
runi
t
Mainly I-type tonalites
Metamorphic rocks
Orthogneisses
S- and I-type granitoids
(undivided)
Porphyritic and S-type
granitoids
10 20 30
0
km
H
Koice
Tatra Mts.
Malá
Fatra Mts.
Tribeè Mts.
Stráovské
vrchy Mts.
iar Mts.
Ve¾ká Fatra Mts.
Nízke Tatry Mts.
Malé
Karpaty Mts.
Povaský
Inovec Mts.
Slovenské rudohorie Mts.
Èierna
hora Mts.
Bratislava
Tat
ric
Su
per
un
it
Ve
po
ric
S
up
er
un
it
S-type granitoids and
orthogneisses
%
o
&
o
'
o
o
o
"&
o
"'
o
S MM
ZT
S - Suchý core
MM - Malá Magura core
Bm
Mm
Bm - Bratislava massif
Mm - Modra massif
H - Hronèok A-type granite
ZT Západné Tatry Mts.
G
G - Gemeric granites
R
R - Rimavica granite
MULTIPLE SOURCES OF THE WEST-CARPATHIAN VARISCAN GRANITOIDS 147
source (paragneisses) rather than late differentiates of the
main body is now considered more probable. The SR-2 sam-
ple with no signs of postmagmatic alteration or contamina-
tion was reconsidered and included into a new set. The new
arrray including five samples gives 353 ± 34 Ma, a value
concordant with the zircon dating, although with larger error
and MSWD = 19.4 (Table 1).
Rb and Sr mobility. For one of the originally excluded
samples (SR-1) Krá¾ et al. (1987) suggested a possible Rb
mobility. The sample with the lowest Rb (40 ppm, compared
to the typical range of 70100 ppm) contains abundant late
sillimanite (3.5 vol. %) accompanied by minor muscovite
(3.7 %). Various sillimanite-bearing granitoids were found
along a belt at least 5 km long containing up to 7 % silliman-
ite and 6 % muscovite. The assemblage is thought to have
formed at a high-temperature subsolidus stage in a low pH
environment (acid leaching, Korikovsky et al. 1987; Burn-
ham 1979). The decrease of the Rb/Sr ratio at a time signifi-
cantly different from that of the initial system closure may
result in an outlying position of the altered sample above
the isochron, and vice versa. The distance from the isochron
(defined by non-altered samples) will be proportional to the
Rb/Sr decrease and the time elapsed since the initial closure
(i.e. the greater and younger the Rb escape, the greater the
deviation). Provided that we are able to reconstruct the origi-
nal Rb/Sr ratio, the time elapsed between the initial closure
and system opening can be calculated [see Fig. A1 and equa-
tions (A1, A2) in Appendix].
Hradetzky & Lippolt (1993) discussed in detail the Rb/Sr
system and concluded that in superficial conditions it is the
Sr mobility which causes the system opening. The example
of Suchý sillimanite granitoids suggests that in high-temper-
ature, acid hydrothermal solutions, Rb may become more
mobile than Sr. Marquer & Peuqat (1994) found that in gran-
ites deformed in ductile shear zones the Rb/Sr ratio increases
in greenschist facies and decreases in amphibolite facies con-
ditions. Moreover, the greenschist facies mylonites fall be-
low and the amphibolite facies mylonites above the intrusive
Rb/Sr isochron.
In the given example, the Rb/Sr values prior to alteration
were derived assuming various degrees of the Rb escape (Ta-
ble 2). For the Suchý sillimanite granitoids, t
1
=
51102 Ma
and t
c
= 302 251 Ma [eq. (A1), (A2), Appendix], assuming
the intrusive age of 353 Ma (Table 2).
It is realized that the derived ages depend on the method of
Rb and Sr reconstructions (by inspection of outliers in varia-
tions diagrams, Fig. 2B,C,D) and are based on one sample.
Therefore, special research is needed to confirm the open sys-
tem interpretation of anomalous areas in granitic massifs.
However, if real, the obtained Permian age data would coin-
cide with the Permian to Lower Triassic post-collisional tran-
stension and rifting in the West-Carpathian basement. In-
creased heat flow could have initiated circulation of high
temperature fluids along weakened zones of the northern Tatra
basement complex (Tatra Fatra Belt, Plaienka et al. 1997).
A parallel, much more pronounced process, is recorded in the
southern Vepor Belt where significant Permian to Lower Tri-
assic magmatism and volcanism occurred (Uher & Broska
1996; Kotov et al. 1996; Puti et al 2000). Two additional cas-
es are shown below where outliers below the isochron corre-
late well with apparent Rb/Sr increases (Table 2).
Tribeè Mts.
The Tribeè tonalites dated by the Rb/Sr method (Bag-
dasaryan et al. 1990) yielded 362 ± 27 Ma (recalculated at
Table 1: Rb/Sr isochron ages of selected West-Carpathian granite cores recalculated at 95% probability level (Isoplot & Ludwig 1994).
Notes: Errors are those given by authors (
87
Rb/
86
Sr,
87
Sr/
86
Sr): 2 %, 0.02 % (1
σ
) by Bagdasaryan, Cambel and co-workers; 0.25 %, 0.005 %
(1
σ
) by Krá¾ and co-workers; 1%, 0.03% (2
σ
) by Kohút and co-workers. For samples with MSWD>1 also magnified errors 2
σ
*
√
MSWD are
given. n
116
refer to the following samples: n
1
SR-3A, 3B, 4, 5, 6; n
2
as for n
1
with SR-2, without SR-6; n
3
T-18, 50, 25, 87, 27; n
4
as
for n
3
without T-27; n
5
T-22, 36, 37, 62, 63, 70; n
6
: as for n
5
without T-37; n
7
ZK-14, 24, 92, 117, 120, J-3, 5, 16; n
8
ZK-68, Kr-1, 2, 3,
2/83, 3/83; n
9
as for n
8
with
ZK-3; n
10
VF-356, 135, 639, 612, 695, 40, 43, 45, 385, 229, VFMa-1, 2a, 2b, 3, 4, 6; n
11
as for n
10
without
VFMa-1, 2a, 2b, 6; n
12
ZK-28, 118, 121, 83, 57, 58; n
13
as for n
12
without ZK-58 with ZK-76, 66, 9; n
14
ZK-26, 27, 69, 122; n
15
ZK-72, 67, 56, 19, KV-1, 2, 3, 4; n
16
as for n
15
without KV-2 and with D-1, 2, 3.
Massif
Granite type
Age (Ma)
±2ó
MSWD
±2ó ÖMSWD
Isr
Age (Ma)
±2ó
MSWD
±2ó ÖMSWD
Isr
Tatric massifs
isochron variant
isochron variant
Suchý Mts.
n
1
= 5
392 ± 17
13.5
392 ± 62
0.70596 ±
0.00027
n
2
= 5
353 ± 34
19.4
353±150
0.70616 ±
0.00037
Tribeè Mts.
Monazite series
n
3
= 5
337 ± 33
4.94
337 ± 73
0.70594 ±
0.00079
n
4
= 4
349 ± 12
0.55
0.70586 ±
0.00023
Tribeè Mts.
Allanite series
n
5
= 6
432 ± 69
2.06
432 ± 99
0.70522 ±
0.00046
n
6
= 5
305 ± 125
1.39
305±147
0.70579 ±
0.00059
Nízke Tatry Mts.
Kralièka type
n
8
= 6
361 ± 40
0.3050.71601 ±
0.00144
n
9
= 7
361 ± 40
0.307
0.71596 ±
0.00143
Ve¾ká Fatra Mts.
n
10
= 16
359 ± 47
53.6
359 ± 344
0.70631 ±
0.00069
n
11
= 12
422 ± 77
34.9
422±455
0.70570 ±
0.00087
Nízke Tatry Mts.
Ïumbier & Praivá
n
7
= 8
369 ± 122
0.1150.70782 ±
0.00135
Veporic massifs
isochron variant
isochron variant
Sihla type
n
12
= 6
373 ± 163
0.129
0.70537 ±
0.00101
n
13
= 8
298 ± 79
0.056
0.70563 ±
0.00078
Rimavica type
n
15
= 8
393 ± 24
0.48
0.70771 ±
0.00071
n
16
= 10
385 ± 47
0.55
0.70766 ±
0.00087
Hronèok type
n
14
= 4
247 ± 8
0.952
0.71140 ±
0.00099
148 PETRÍK
2
σ
) contrasting with the U/Pb age of 306 ± 10 Ma (Broska et
al. 1990). After subdividing the sample set according to cri-
teria based on the allanite and monazite dichotomy (Broska
& Gregor 1992; Petrík & Broska 1994) broadly correspond-
ing to I- and S-type subgroups, respectively, two slopes are
obtained in the Nicolaysen diagram. The monazite-bearing
group yields 337 Ma ± 33 Ma with one outlying sample T-27
(a leucocratic vein) below the isochron (Fig. 3A). This sam-
ple has a significantly decreased Sr content (60 ppm, com-
pared to the observed range of 60070 ppm) allowing us to
presume that the original Rb/Sr was lower (Table 1). Using
equations (A1, A2) for the age of system opening the values
of 265302 Ma are obtained for estimated Sr 100 and 200
ppm (Table 2). Excluding this sample from the monazite
group improves the isochron statistics to 349 ± 12 Ma and
MSWD = 0.55 (Table 1).
The allanite-bearing group with very low Rb/Sr ratios
yields 432 ± 69 Ma with one sample T-37 (leucocratic vein)
steepening the slope. Unfortunately, in the absence of chemi-
cal data for this sample there is no possibility to evaluate its
chemistry. Again, the main granitoid body supplies only to-
nalites with low, tightly grouped Rb/Sr ratios which produce
isochrons with very high errors. For example, excluding T-37
would give 305 ± 125 Ma (Table 1).
Fig. 2. Rb/Sr system in the Suchý granitoid core: (A) Isochron with outlying samples SR-1, 6, 7.
87
Sr/
86
Sr
(350)
ratios of the samples are also
shown; (B, C, D) Correlations between Rb, Sr, K
2
O and CaO. Reconstructed SR-1 position (90 ppm Rb) is shown in B, D.
Table 2: Calculations of the age of system opening using the examples of the Suchý, Ve¾ká Fatra and Tribeè granitoids using equations
(A1, A2). See Appendix for details.
Rb
Sr
Rb
Sr
87
Sr/
86
Sr
87
Rb/
86
Sr
Massif
Sample
Intrusive
age
I
Sr
ppm
ppm
Measured
Recon.
Measured
Recon.
Age
(Ma)
(Ma)
Measured
Reconstructed
S
m
S
r
R
m
R
r
t
c
Suchý
353
0.70616
40.22
312.2
90
312.2
0.7087
0.70803
0.3728
0.8341
251
SR-1
140
1.2976
302
Ve¾ká Fatra
340
0.70649
99.77
148
99.77
200
0.71512
0.71594
1.9518
1.4443
227
VFMa-2
350
0.71622
198
Tribeè
350
0.70586
153.71
60.45
153.71
100
0.7391
0.74263
7.3795
4.4610
265
T-27
200
2.2304
302
0.705
0.710
0.715
0.720
0.725
0
0.5
1
1.5
2
2.5
3
87
Rb/
86
Sr
87
Sr/
86
Sr
SR1
SR7
SR6
100
1000
10
100
1000
Rb (ppm)
Sr (ppm)
SR1
SR7
SR6
0
20
40
60
80
100
120
140
0
1
2
3
4
5
6
K
2
O (%)
Rb (ppm)
granitoids
aplite veins
mus-sill granites
pegm. granites
SR1 reconstr.
SR1
SR7
SR6
0
100
200
300
400
500
600
700
800
0
1
2
3
4
5
6
CaO (%)
Sr (ppm)
SR1
SR7
SR6
353±34 Ma
MSWD=19.4
A
B
C
D
D
SR2
SR2
SR2
SR2
MULTIPLE SOURCES OF THE WEST-CARPATHIAN VARISCAN GRANITOIDS 149
The Nízke Tatry pluton
The Nízke Tatry granitoid pluton belongs to a petrological-
ly key area with various granitoid types dated by the Rb/Sr
method (Bagdasaryan et al. 1985). No high precision zircon
data are available at present from the area. While the south-
ern slopes of the Nízke Tatry consist of orthogneisses (main-
ly ductilely deformed S-type granitoids, Petrík et al. 1998)
the ridge and northern slopes are formed by the postkinemat-
ic, undeformed Ïumbier tonalite/granodiorite and the Pra-
ivá Granite. The specific, leucocratic Kralièka Granite crops
out within the orthogneiss belt. It is believed to have been
formed by partial melting of the orthogneisses (Zoubek
1951). The Ïumbier/Praivá granitoids form a tight array
corresponding to 369 ± 122 Ma, I
Sr
= 0.70782 and MSWD =
0.115, whereas the Kralièka type yields 361 ± 40 Ma with
the high I
Sr
= 0.71601, MSWD = 0.305 (Fig. 3B, Table 1).
There is one obvious outlier in the Ïumbier/Praivá sample
set (ZK-3), a sample discussed already by Krá¾ (in Cambel et
al. 1990a) who hypothesized its possible high age (with the
Ïumbier/Praivá initial Sr ratio of 0.716 it gives 595 Ma). It
is argued here that ZK-3 belongs to a different granite type,
possibly akin to the Kralièka Granite rather than to the Ïum-
bier/Praivá type (as all the rocks on the main ridge between
Chopok and Ïeree peaks) thus having the same age. The
Kralièka granite isochron including ZK-3 gives an age iden-
tical to Ïumbier/Praivá age (361 ± 40 Ma). The Rb and Sr
chemistry of the Kralièka granites is compared with other
Nízke Tatry granitoid types in Fig. 4. Also shown is a newly
analysed set of samples (labeled Chopok) from the area be-
tween Chopok and Ïeree. The Kralièka type granitoids dif-
fer by their much lower Sr contents overlapping with the
Chopok type and orthogneisses.
The Ïumbier/Praivá granitoid samples come from locali-
ties which are more than 40 km apart implying Sr isotopic in-
homogeneity. They include both monazite and allanite-bear-
0.700
0.705
0.710
0.715
0.720
0.725
0.730
0.735
0.740
0.745
0.750
0
1
2
3
4
5
6
7
8
87
Rb/
86
Sr
87
Sr/
86
Sr
T27
0.705
0.710
0.715
0.720
0.725
0.730
0.735
0.740
0.745
0
1
2
3
4
5
87
Rb/
86
Sr
87
Sr/
86
Sr
B
Tribeè Mts.
monazite s.
349±16 Ma
Nízke Tatry Mts.
Kralièka type
361±40 Ma
Ïumbier/Praivá type
369±122 Ma
ZK3
0.700
0.710
0.720
0.730
0.740
0.750
0
1
2
3
4
5
6
7
87
Rb/
86
Sr
87
Sr/
86
Sr
KV2
Bac5p
Veporic u.
Rimavica g.
385±47 Ma
0.705
0.706
0.707
0.708
0.709
0.710
0.711
0.712
0.713
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
87
Rb/
86
Sr
87
Sr/
86
Sr
Veporic u.
Sihla allanite type
298±79 Ma
Vepor type
298±79 Ma
A
C
D
0.700
0.750
0.800
0.850
0.900
0.950
0
5 10 15 20 25 30 35 40 45 50 55 60
87
Rb/
86
Sr
87
Sr/
86
Sr
F
Veporic u.
Hronèok type
247±8 Ma
0.700
0.705
0.710
0.715
0.720
0.725
0
0.5
1
1.5
2
2.5
3
87
Rb/
86
Sr
87
Sr/
86
Sr
Ve¾ká Fatra Mts.
422±77 Ma
E
¼ubochòa
leucogranite
Fig. 3. Rb/Sr isochrons for granitic rocks of the Tribeè Mts (A), Nízke Tatry Mts. (B), Rimavica Granite (C), Sihla type tonalite (D),
Ve¾ká Fatra Mts. (E) and Hronèok type granite (F). Crosses: samples age-corrected to 350 Ma.
150 PETRÍK
Vepor pluton (the Sihla and Rimavica granitoids)
In their original work Bagdasaryan et al. (1986) interpreted
the Rb/Sr data obtained on Sihla I-type tonalites as an isoch-
ron giving (as recalculated in Table 1) 373 ± 163 Ma and
data on Vepor/Ipe¾ granodiorites as isochron 254 ± 150 Ma.
By redefining the granitoids after the allanite/monazite di-
chotomy criterion, as in the case of the Tribeè tonalites, a
new array (8 allanite-bearing samples) is obtained corre-
sponding to 298 ± 79 Ma (MSWD = 0.056) concordant with
the U/Pb age 304 ± 3 Ma (Bibikova et al. 1990), Fig. 3D.
The monazite-bearing samples are apparently disturbed and
their increased
87
Sr/
86
Sr ratios indicate different source(s).
The samples age-corrected to 300 Ma do not form any mix-
ing line, rather than two plateaus of the Sihla and Vepor/
Ipe¾ groups (not shown in Fig. 3).
Rimming the southeastern boundary of the Vepor pluton, the
Rimavica S-type granitoids represent a rather inhomogenous
group with strong Alpine overprint. Their Rb/Sr age claimed
by the authors (Cambel et al. 1988) is 393 ± 24 (as recalculat-
ed in Table 1) based on eight samples taken as much as 22 km
apart. A constant Sr isotope ratio can hardly be expected over
such an area. Actually, twelve samples were measured from
five localities, two of them, Krokava and Chyné (KV and D
in Notes to Table 1) covered by five and four samples, respec-
tively. The Chyné Group yields 316 ± 111 Ma, the Krokava
group yields 394±195 Ma. The Krokava samples also supplied
zircons for the U/Pb dating (350 ± 5 Ma, Bibikova et al. 1990).
Other samples (leucocratic veins of muscovite granitoids Bac-
5p and KV-2, Fig. 3C) have apparently increased Sr initial ra-
tios of 0.71138 and 0.71238 respectively (age-corrected to 350
Ma, further on denoted by subscript
350
). Thus, the S-type
granitoids of the SE Veporic Superunit seem to comprise sev-
eral granite types (intrusions?) with Rb/Sr ages overlapping
the zircon age.
Sm/Nd systematics
In contrast to Rb and Sr, typically dispersed elements, Sm
and Nd reside mainly in accessory minerals. In the West-Car-
pathian granitoids where hornblende is rare, the relevant ac-
cessories are monazite in the S-type, and allanite and titan-
ite in the I-type rocks. As the Sm/Nd ratio changes only
slightly during partial melting, the Nd evolution line of a
granite may be extrapolated into the past where, at the inter-
section with the depleted mantle (DM) evolution line, it pro-
vides the crustal residence age (T
DM
). Due to much slower
diffusivity of rare earth elements (REE), the Nd isotopes do
not homogenize and may preserve source characteristics (e.g.
Pin & Duthou 1990). An attempt to identify these source(s)
is made below using both Sm/Nd and Rb/Sr data.
The bulk of the Sm/Nd data comes from Kohút et al. (1999)
who provided twenty-one samples covering all main granite
occurrences (one sample per massif except the Ve¾ká Fatra
Mts. with five samples). The authors found that the granitoids
lack homogenization of
143
Nd/
144
Nd isotopes, which is also
expressed by their model ages (two stage T
DM
,
147
Sm/
144
Nd,
and
143
Nd/
144
Nd values for depleted mantle are after Liew &
Hofmann 1988) in the range of 1.60.62 Ga. This range was
Fig. 4. Rb vs. Sr in the Nízke Tatry Mts.: Kralièka, Ïumbier/Praivá
type granitoids and orthogneisses. The Kralièka type and Chopok
type are identical in terms of Rb/Sr ratios.
ing rocks with subaluminous nature showing one of the high-
est I
Sr
within I- and S-type granitoids (except the Kralièka
type). Their close association with orthogneisses and their
presumed derivatives (Kralièka and Chopok granite?) having
extremely high I
Sr
, is considered significant for explaining
this anomaly.
Ve¾ká Fatra Mts.
The granitoids of the Ve¾ká Fatra Mts. are the only ones in
the Western Carpathians where Rb/Sr and Sm/Nd systemat-
ics are available (in addition to K/Ar and
40
Ar/
39
Ar data)
through the comprehensive work by Kohút (1992) and Kohút
et al. (1996, 1998, 1999). Mainly for geological reasons, Ko-
hút (1992) treated the groups of main pluton granitoids sepa-
rately from the leucocratic ¼ubochòa granites, showing cut-
ting contacts with the zoned pluton. While all the samples
give 359 ± 47 Ma (Table 1), the main granitoids yields 422 ±
77 Ma and the ¼ubochòa granite samples fail to form an iso-
chron at all (Fig. 3E). Although the author accepts the high
age interpreting it as that of a pre-existing pluton he also
discusses the possibility of pseudoisochron due to the inho-
mogeneity of source(s). Considering the U/Pb zircon age of
356 ± 25 Ma obtained from the main pluton (Kohút et al.
1997), the latter interpretation seems to be more probable in
explaining different initial ratios of the main petrographic
types. The ¼ubochòa leucogranites form a negative slope, the
sample with apparently lower
87
Sr/
86
Sr (VFMa-2) also hav-
ing the lowest concentration of Sr (148 ppm). The possible
increase of the Rb/Sr ratio allows us to try an open system in-
terpretation. The ages of 227 Ma for the system opening are
obtained assuming original Sr 200 ppm and the intrusive age
of 340 Ma, and 198 Ma for the intrusive age of 350 Ma (Ta-
ble 2). Similarly, anomalous Ve¾ká Fatra orthogneiss samples
(5, 44 in Bagdasaryan et al. 1992) may be explained by a Sr
loss (not shown).
10
100
1000
10
100
1000
Rb (ppm)
Sr (ppm)
Kralièka type
Ïumbier/Praivá
Chopok type
orthogneisses
MULTIPLE SOURCES OF THE WEST-CARPATHIAN VARISCAN GRANITOIDS 151
interpreted analogically with other workers on the European
Variscides as resulting from source inhomogeneities. The
sources are regarded as mixtures of at least two end members
(Liew & Hofmann 1988; Pin & Duthou 1990; Janouek et al.
1995). Kohút et al. (1999) also identified a gabbro from the
Veporic Superunit and the Kralièka Granite from the Nízke
Tatry Mts. as samples with the highest
143
Nd/
144
Nd
(350)
=
0.511834 and lowest
143
Nd/
144
Nd
(350)
= 0.512474 ratios, re-
spectively with corresponding T
DM2st
= 1.6 and 0.62 Ga
[DM2st refers to two-stage mantle melting according to Liew
& Hoffman (1988)]. The bulk of granitoids shows a lesser
Nd
(350)
isotopic range between 0.51215 (Tribeè tonalite) and
0.51197 (Povaský Inovec leucogranite) with corresponding
T
DM2st
= 1.111.4 Ga. This range most probably reflects vari-
able proportions of (at least) two contrasting sources of the
granitoid magma.
Summary of the isotope systematics
The detailed inspection of the Rb/Sr systematics of the most
important granitoid massifs showed that (1) the main body to-
nalites and granodiorites if subdivided according to the allan-
ite /monazite criterion yield dates within error concordant with
U/Pb zircon ages. However, due to the small ranges of the Rb/
Sr ratios they show too large errors (Tribeè, Ïumbier/ Praivá
type, Sihla type). (2) The incorporation of high Rb/Sr samples
occurring often only as leucocratic veins or sills results in the
increase of the presumably apparent age since the veins arising
from a different (metapelitic) protolith (e.g. Suchý, Tribeè
Mts., Veporic Superunit) have higher initial
87
Sr/
86
Sr ratios.
(3) Although an initial slope may form due to higher I
Sr
of the
leucocratic melts, the hypothesis of a source mixing line ex-
isting in the initial
87
Sr/
86
Sr ratios of the main granitoid groups
does not seem to be confirmed. (4) Correlation between the
distances of outliers above the isochron and their anomalously
low Rb/Sr ratios (and vice versa) may be interpreted in terms
of the Rb/Sr system opening at a time different from the initial
closure time. Using the equations (A1, A2) and good guesses
for the original Rb/Sr ratios, late Variscan to early Alpine ages
are obtained for this opening.
Interpretation of the isotope systematics
The need for differing precursors
The Sm/Nd data show that the most radiogenic samples
have the lowest Sm/Nd ratios. Such rocks (gabbro, tonalites)
have steep light rare earth element patterns, but flat Nd evolu-
tion lines which intersect the DM evolution line at the young-
est ages (Fig. 5A). In contrast, the samples with the highest
Sm/Nd ratios (flat light rare earth element patterns characteris-
tic mainly of leucogranites) are least radiogenic, which means
that they must have started their crustal history at a very low
Nd isotopic ratio, that is they have high DM model ages.
Lithological and model age contrasts exist between the end-
members as is confirmed by a negative correlation between
143
Nd/
144
Nd
(350)
and SiO
2
shown in Fig. 5B. Thus, a young
mafic, infracrustal end member (IC
m
) is required to mix with
an old, felsic supracrustal end member (SC
f
) to give the ob-
served span in
143
Nd/
144
Nd
(350)
ratios. The requirement of a
low Sm/Nd ratio for the IC
m
end member precludes a mid
ocean ridge type basalt with Sm/Nd 0.33 (e.g. Jenner et al.
1987), and points rather to light rare earth element enriched
gabbros and diorites. The SC
f
end member best correlates with
peraluminous leucocratic melts formed by metapelite/me-
tagreywacke dehydration melting in upper crustal conditions.
The end-members
IC
m
end-member. The only known basic rocks with low
Sm/Nd ratios found in a close relation to granitoids are dior-
itic rocks. They are known from many West-Carpathian
basement massifs, where they form small-sized bodies within
granitoids commonly too small to be shown on geological
maps. Diorites, as known from the Malé Karpaty Mts. (Cam-
Fig. 5. (A) Nd evolution diagram, dotted: gabbro and diorite mafic enclave, dashed: felsic rocks (Kralièka type), thin lines: Tatric and Ve-
poric granitoids; Depleted mantle (DM) evolution after Liew & Hofmann (1988). (B)
143
Nd/
144
Nd
(350)
vs.
SiO
2
; gabbro: KV-3 from the con-
tact zone of the Veporic and Gemeric superunits (Kohút et al. 1999); enclave: from the Rochovce Granite (Hrako et al. 1999); closed
symbols: Ve¾ká Fatra granitoids.
0.5115
0.5117
0.5119
0.5121
0.5123
0.5125
0.5127
45
50
55
60
65
70
75
80
SiO
2
143
Nd/
144
Nd
(350)
gabbro
Kralièka
granite
Rochovce
MME
0.5090
0.5095
0.5100
0.5105
0.5110
0.5115
0.5120
0.5125
0.5130
0.5135
0
500
1000
1500
2000
2500
Age (Ma)
143
Nd/
144
Nd
Rochovce
MME
DM
gabbro
Gemeric granite
Kralièka
granite
A
B
152 PETRÍK
bel & Pitoòák 1980; Cambel & Vilinoviè 1987), are fine- to
medium-grained plagioclase- and hornblende-dominated rocks
with SiO
2
ranging from 54 to 63 % and steep rare earth ele-
ment patterns (Sm/Nd = 0.120.18). The main carrier of light
rare earth elements, besides hornblende, is allanite. Cambel &
Vilinoviè (1987) showed that major and minor elements of
these diorites are found along trends defined by granitoids in
Harker diagrams (Fig. 6). Since much of the granite variation
may be interpreted by a magma differentiation process, such
as crystal fractionation (Vilinoviè & Petrík 1984), the ob-
served trends may coincide just because the compositions of
cumulates and diorites are similar. This would preclude simple
mixing relations, as indicated in the diagram Zr vs. SiO
2
(Fig.
6D), but it does not rule out the diorite magma playing a role
in granite genesis. Even more indicative, that mafic magmas
are involved, is the presence of mafic microgranular enclaves
(MME) in I-type tonalites (Petrík & Broska 1989). The Tribeè
MME with dioritic to tonalitic compositions lie on linear
trends with host tonalites in both major and trace element vari-
ations, Figs. 7A,B. The compositional range of the enclaves is
best explained by their mixing with granitoid magma before
being individualized into enclaves. The fact that the MME oc-
cur only in the most mafic varieties of host tonalites implies an
interaction (mixing) of both magmas which has shifted the
host granitoid magma toward a more mafic composition.
Thus, the diorites, occurring either as individual bodies or as
MME, appear a suitable IC
m
candidate in the granite magma
genesis. They themselves appear to be products of the hybrid-
ization of a mantle-derived gabbroic (basaltic) precursor by a
felsic magma.
SC
f
end member. Felsic rocks with high Sm/Nd ratios are
typically represented by leucogranites occurring within para-
and orthogneiss complexes. They commonly show flat rare
earth elements patterns often with increased heavy rare earth
elements. Peraluminous leucogranites are considered to be
typical products of partial dehydratration melting of
metapelite precursors (Montel & Vielzeuf 1997; Stevens et
al. 1997; Patino-Douce & Harris 1998). Their light REE de-
pleted nature is known from the geochemical studies of gran-
ites of collisional orogenic belts (Dietrich & Gansser 1981;
Nabelek & Glascock 1995) which showed that they had Sm/
Nd ratios typically between 0.20.4. The strongly peralumi-
nous Kralièka Granite with the lowest
143
Nd/
144
Nd
(350)
and
highest
87
Sr/
86
Sr
(350)
ratios is considered to be a melting
product of the Nízke Tatry orthogneisses which also have flat
REE patterns (Sm/Nd = 0.20.3). The orthogneisses were in-
terpreted as ductilely deformed S-type granitoids (Petrík et
al. 1998). Thus both para- and orthogneisses may produce
characteristic leucogranites when being melted. They have
the properties of the SC
f
end-member which escaped Sr iso-
topic homogenization common in main granite bodies, and
reflect the
87
Sr/
86
Sr ratio of their source. The high
87
Sr/
86
Sr
value indicates a recycled crustal material. This is, in the
case of orthogneisses, confirmed by the high Nd T
DM2st
age
Fig. 6. Harker diagrams for K
2
O (A), MgO (B), V (C) and Zr (D) in the Malé Karpaty granitoids and diorites. (AC) data from both Brat-
islava and Modra massifs, (D) the Bratislava Massif only (source data Cambel & Vilinoviè 1987).
0
1
2
3
4
5
6
7
8
50
55
60
65
70
75
80
SiO
2
K
2
O
Bratislava massif
Modra massif
BM diorites
MM diorites
0
100
200
300
400
500
600
50
55
60
65
70
75
80
SiO
2
Zr (ppm)
BM diorites
BM main body granites
BM leucogranites
0
1
2
3
4
5
6
7
8
50
55
60
65
70
75
80
SiO
2
MgO
0
50
100
150
200
250
45
55
65
75
SiO
2
V
(ppm)
A
B
C
D
MULTIPLE SOURCES OF THE WEST-CARPATHIAN VARISCAN GRANITOIDS 153
(1.6 Ga) and the upper intercept zircon age (for the Western
Tatra orthogneiss >1.6 Ga, Poller et al. 1999a). The me-
tagreywackes (gneisses) have not yet been dated by high pre-
cision methods, however earlier zircon datings for the Tatra
paragneiss range between 620700 Ma (Cambel et al. 1990).
Mixing of the end-members
The relationship between the end-members characterized
above and the whole group of granitoids is shown in diagram
Sm/Nd vs.
143
Nd/
144
Nd (Fig. 8A). Diorites, spatially and ge-
netically related to granitoids, are preferred to the gabbro
which is tectonically sandwiched between metapelites and the
Alpine Rochovce Granite (Krist et al. 1988) with no apparent
relationship to them. The end members are bounded using the
following data.The Sm/Nd data for diorites (IC
m
end member)
come from the Tatry Mts. Poller et al. (1999b) found
ε
Nd(330)
values of 02 which correspond to
143
Nd/
144
Nd
(330)
=
0.5122130.512315 [initial
ε
Nd(330)
calculated using magmatic
zircon age]. The value of 0.51228 within the range given
above was used for the mixing model. The range of Sm/Nd ra-
tios (0.120.19) is taken mainly from the Malé Karpaty dior-
ites. The SC
f
end member is bounded by the Sm/Nd ratios of
leucogranites (Suchý and Povaský Inovec garnet aplites,
Kralièka Granite) ranging from 0.16 to 0.29, and the
143
Nd/
144
Nd ratios of the Western Tatra micaschists (Poller et al.
1999b) ranging from 0.51162 to 0.5118. The outlined fields
with the joining mixing line (calculated according to Faure
1989) cover the observed scatter of granitoids. The two outli-
ers are the Veporic two-pyroxene gabbro, apparently a pure
mantle-derived rock with
ε
ND(350)
= 5.6 and the Gemeric Gran-
ite with extremely high Sm/Nd and
87
Sr/
86
Sr
(350)
ratios (0.29
0.31, 0.7200.734 respectively) suggesting a different su-
pracrustal source.
Sr vs. Nd isotopes
The mixing relations of IC
m
and SC
f
end-members are also
illustrated in a (
87
Sr/
86
Sr)
350
vs. (
143
Nd/
144
Nd)
350
diagram (Fig.
8B). Two mixing lines are shown between the same IC
m
end-
Fig. 7. Harker diagrams of MgO (A) and Zr (B) in granitoids and mafic microgranular enclaves in the Tribeè Mts. (source data Petrík &
Broska 1989). Formed presumably from the same magma as diorites, the enclaves show mixing relations with I-type tonalites.
0
1
2
3
4
5
6
7
40
50
60
70
80
SiO
2
MgO
S-type
I-type
Enclaves
0
100
200
300
400
500
600
40
50
60
70
80
SiO
2
Zr (ppm)
A
B
Fig. 8. (A) Mixing in
143
Nd/
144
Nd vs. Sm/Nd plot (Nd IC ppm: 60, SC: 15). (B)
87
Sr/
86
Sr vs.
143
Nd/
144
Nd plot with mixing line [Sr used in mix-
ing (ppm): IC
m
600, SC
f
122/150, Nd SC
f
15/18]. Tick marks at 10 %. MKm Malé Karpaty gneisses. Source data: Kohút et al. (1999)
individual points (closed symbols Ve¾ká Fatra granitoids), Poller et al. (1999b) the fields of micaschists and diorites.
0.12
0.14
0.16
0.18
0.20
0.22
0.24
0.26
0.28
0.30
0.32
0.5116
0.5118
0.5120
0.5122
0.5124
0.5126
(
143
Nd/
144
Nd)
350
Sm/
N
d
High Tatra
diorites
gabbro
Gemeric granite
0.5116
0.5117
0.5118
0.5119
0.5120
0.5121
0.5122
0.5123
0.5124
0.5125
0.5126
0.700
0.705
0.710
0.715
0.720
0.725
(
87
Sr/
86
Sr)
350
(
143
Nd/
144
Nd)
350
Ïumbier/Praivá
gabbro
W
est
ern
Tat
ra
m
icaschi
sts
Kralièka
Western Tatra
micaschists
Gemeric granite
SC
f
High Tatra
diorites
MKm
A
B
IC
m
IC
m
SC
f
154 PETRÍK
Fig. 9. Malé Karpaty granitoids and metamorphic rocks in the AB
plot (Debon & Le Fort 1983) compared with experimental melts
(Montel & Vielzeuf 1997). Evolution trend of granitoids is shown
by the arrow. Source data Cambel & Vilinoviè (1987) and Cambel
et al. (1990).
member as in Fig. 8A and two SC
f
end-members with differ-
ent
87
Sr/
86
Sr ratios, 0.710 and 0.716. They represent the I
Sr
values of the Malé Karpaty gneisses (Bagdasaryan et al.
1983) and the Kralièka Granite (Kohút et al. 1999), respec-
tively. The
143
Nd/
144
Nd ratio of the first SC end-member is
assumed to be the same as for orthogneisses, at the upper lim-
it of the Tatra micaschist range (Poller et al. 1999b). The mix-
ing range covers the observed field of granitoids which are
spread mainly between diorite and gneiss end-members.
However, some of them with relatively high
143
Nd/
144
Nd ra-
tios are shifted to higher
87
Sr/
86
Sr values (Ïumbier tonalite)
thus lying on the other line, diorite Kralièka Granite. An
end-member with such a high
87
Sr/
86
Sr ratio seems to be nec-
cessary to explain the relatively increased I
Sr
(0.7060.708) of
some more mafic types (Ïumbier/Praivá): a smaller SC
f
end-member proportion (60 % in this model) is sufficient to
increase the I
Sr
while keeping the high Nd isotopic ratio and
the more mafic composition of the tonalites. The S-type gran-
itoids with
87
Sr/
86
Sr
(350)
around 0.7060.707 would require
6080 % of the gneissic end-member which is in agreement
with their more felsic nature.
The mechanism of mixing
The mechanism of mixing can hardly be traced unambigu-
ously. In principle three processes are conceivable: (1) melt-
ing of a mixed source rock, (2) mixing of contrasting magmas
and (3) assimilation of a felsic rock by a mafic magma. All of
them have been invoked in literature. On the basis of Sm/Nd
data from lower crustal xenoliths, Pin & Duthou (1990) pre-
ferred a composite source mixed on a small-scale. However,
the potential source rocks in the Western Carpathians (parag-
neisses, orthogneisses) do not show a mixed character and ac-
tually they were treated as end-members. Therefore, melting
and assimilation of a metagreywacke precursor by the hybrid
gabbro-diorite magma and subsequent mixing and mingling
are considered more likely.
An important result of melting experiments with various
metasedimentary rocks is that they can produce only peralu-
minous and mostly leucocratic melts (Vielzeuf & Montel
1994; Montel & Vielzeuf 1997). Slightly more mafic peralu-
minous melts originate by melting of a metagreywacke pro-
tolith as demonstrated by Montel & Vielzeuf (1997). Such
melts resemble the compositions of typical two-mica S-type
granitoids which form bulk massifs in the Western Car-
pathians. Montel and Vielzeufs results are shown in an AB
plot (after Debon & Le Fort 1983) and compared with Malé
Karpaty granitoids and metamorphic rocks (Fig. 9). The
greywacke starting compositions are matched by less peralu-
minous and less mafic varieties of Malé Karpaty gneisses.
The more mafic greywacke-derived experimental melts (cir-
cles), straddle the boundary of leucogranites and overlap the
peraluminous part of the Malé Karpaty monzogranites. How-
ever, they do not cover minor subaluminous and metalumi-
nous granodiorites. Therefore, the input of a mafic end-mem-
ber is necessary to get the more mafic, metaluminous
granodiorites and tonalites (Patino-Douce 1995; Castro et al.
1999). This is also supported by the lower I
Sr
of the Malé Kar-
paty granitoids (0.707; Cambel et al. 1982) compared to that
of gneisses (0.710; Bagdasaryan et al. 1986).
Generally, the input appears to have been more pronounced
in I-type granitoids with I
Sr
between 0.706 and 0.705. The
contrasting mineralogical composition and petrological prop-
erties of the S- and I-type granitoids, as inferred by Petrík &
Broska (1994), may thus reflect varying proportions of the ma-
fic gabbroic infracrustal end-member, rich in water and rare
earth elements. Such magmas originate above a subducting
slab (Peacock 1993). The melting of deeply buried metapelites
in the course of Variscan thrusting is documented by extensive
migmatization. Janák et al. (1999) estimated the melting con-
ditions of the Tatra migmatites at 700750 °C, 11001200
MPa (kyanite zone) and 680825 °C, 530800 MPa (silliman-
ite zone). The peak temperatures seem to require a mantle-de-
rived heat source. The hybrid diorite zone present in the area
(Kohút & Janák 1994) supports the role of infracrustal mag-
mas both as suppliers of heat and material.
Other granitoid types
Besides the common S- and I-type granitoids discussed
above, the A-type granites of the Veporic Superunit, and spe-
cialized granites of the Gemeric Superunit are treated sepa-
rately.
The Rb/Sr age of the Hronèok A-type granite is 247 ± 8 Ma
as recalculated according to the data of Cambel et al. (1989)
and redefinition by Petrík et al. (1995), Fig. 3F, Table 1. It is
-50
0
50
100
150
200
0
50
100
150
200
B=Fe+Mg+Ti
A=Al-(Na+K+2
Ca)
Starting material
average greywacke
P=300MPa
P=500MPa
gneisses
BM granitoids
metaluminous domain
peraluminous domain
leuco
granitoids
MULTIPLE SOURCES OF THE WEST-CARPATHIAN VARISCAN GRANITOIDS 155
concordant with the zircon dating which yielded the lower and
upper intercept ages of 238.6 ± 1.4 Ma and 1096 Ma ± 44, re-
spectively (Puti et al. 2000). The I
Sr
(= 0.7114), the second
highest after the Kralièka Granite, and mildly alkalic chemis-
try with high Rb/Sr ratios (218) point to a mature source, pos-
sibly older biotite granites. The intersection of the Hronèok
protolith Sr evolution (I
Sr
= 0.7114 at 240 Ma) with the mantle
value at 1 Ga gives the Rb/Sr ratio about 0.32, a value typical
of granites. This, and the high I
Sr
, precludes the Sihla tonalite
as a potential precursor as suggested by Petrík & Kohút
(1997).
The Gemeric granites with I
Sr
0.7200.734 (after Cambel et
al. 1990) also show the most extreme Rb/Sr and Sm/Nd ratios
(>10 and 0.29 respectively). They also have the highest single
stage Nd age = 2.4 Ga, Fig. 5A (two stage Nd age is 1.3 Ga at
t = 280 Ma). In the absence of high precision zircon data no
protolith age constraints can be made. The Permian age ap-
pears most probable for an event when a muscovite and quartz
rich source (recycled metapelite) underwent melting to pro-
duce the observed highly specialized Rb, Li, F, B, Sn, Mo en-
riched melts.
Conclusions
Existing Rb/Sr data from several Western Carpathians
granite massifs were re-interpreted after a detailed inspection
of outlying samples. It appears that a mixing line in source
87
Sr/
86
Sr ratios is not neccessary to explain higher Rb/Sr
ages from these massifs. The high Rb/Sr samples (vein
leucogranites) are often unrelated to other granitoids and,
with their increased I
Sr
, generally reflect heterogeneous
sources of S-type granitoids. Some individual samples lying
above and below the isochron may be interpreted in terms of
the Rb/Sr system opening at a time different from the initial
closure. The samples from the Tatra belt granitoids indicate
Permian to Triassic ages for this event, coeval with exten-
sional magmatism in the Vepor Belt.
While being homogenous in terms of I
Sr
, the main body
granitoids still preserve a range of initial
143
Nd/
144
Nd ratios re-
flecting various proportions of at least two contrasting source
components. The components were identified with old su-
pracrustal metasediments producing peraluminous leucograni-
toids and young basaltic (gabbroic) producing diorites. The as-
similation of the supracrustal component by the diorite magma
may have produced observed isotopic, trace and major ele-
ment variations of both S- and I-type granitoids.
The following source rocks, arranged with decreasing pro-
portions of the supracrustal component, are recognized
among the West-Carpathian granitoids: (1) Gemeric granites
derived from a several times recycled crustal material with
extreme Sr initials (I
Sr
> 0.720), possibly muscovite
metapelite. (2) The Kralièka type granite (I
Sr
= 0.715) and its
equivalents derived from a recycled crustal complex domi-
nated by older S-type granitoids (orthogneisses). (3) The
Hronèok A-type granite (I
Sr
= 0.7114) derived from a mature
high Rb/Sr, probably granitic source. (4) Peraluminous leu-
cocratic aplitic veins, migmatite related in metamorphic
complexes, the products of gneiss dehydration melting
(Stráovské vrchy, Povaský Inovec, Malé Karpaty Mts.).
(5) Undeformed, peraluminous, mainly S-type granitoids with
I
Sr
= 0.7080.706 showing transitional characteristics, derived
from a metagreywacke (gneissic) protolith with minor in-
fracrustal contribution (Bratislava type granitoids). (6) Sub- to
metaluminous I-type granodiorites and tonalites (I
Sr
= 0.705)
with moderate infracrustal contribution. (7) Dioritic rocks and
MME probably themselves products of crustal contamination
of mantle-derived gabbroic melts.
The variable proportions of H
2
O and REE-rich IC
m
end-
member (7) and H
2
O and LREE-poor SC
f
end-member (4)
may explain the contrasting mineralogical and petrological
properties observed and inferred for the major (5, 6) groups of
S- and I-type granitoids (Petrík & Broska 1994) which follow
mainly from contrasting water contents.
Acknowledgement: The thorough and detailed reviews of
V. Janouek and the anonymous reviewer helped to consider-
ably improve an earlier version of the manuscript. J. Krá¾
pointed to the biotite isochron age of the Suchý granite. Mi-
lan Kohút is thanked for making available his unpublished
data. This work was done within the project GA 4078 (Slo-
vak Grant Agency).
References
Bagdasaryan G.P., Gukasyan R.Kh., Cambel B. & Veselský J. 1983:
The results of Rb/Sr dating of the Malé Karpaty metamorphic
rocks. Geol. Zbor. Geol. Carpath. 34, 387397 (in Russian).
Bagdasaryan, G.P., Gukasyan, R. Kh., Cambel, B. & Veselský, J.
1985: Rb/Sr dating of the Ïumbier zone granitoids of the Níz-
ke Tatry Mts. Geol. Zborn. Geol. Carpath. 36, 637645 (in
Russian).
Bagdasaryan G.P., Gukasyan R.Kh. & Cambel B. 1986: Rb/Sr iso-
chron age of the Vepor pluton granitoids. Geol. Zbor. Geol.
Carpath. 37, 365374 (in Russian).
Bagdasaryan G.P., Gukasyan R.Kh., Cambel B. & Broska I. 1990:
Rb-Sr isochron dating of granitoids from the Tribeè Mts. Geol.
Zbor. Geol. Carpath. 41, 437442.
Bibikova E.V., Cambel B., Korikovsky S.P., Broska I., Gracheva
T.V., Makarov V.A. & Arakeliants M.M. 1988: U-Pb and K-Ar
isotopic dating of Sinec, Rimavica granites (Kohút zone of Ve-
porides). Geol. Zbor. Geol. Carpath. 39, 147157.
Bibikova E.V., Korikovsky S.P., Puti M., Broska I., Goltzman Z.V.
& Arakeliants M.M. 1990: U-Pb, Rb-Sr, K-Ar dating of Sihla
tonalites of Vepor pluton (Western Carpathian Mts.). Geol.
Zbor. Geol. Carpath. 41, 427436.
Broska I. & Gregor,T. 1992: Allanitemagnetite and monazite-il-
menite granitoid series in the Tribeè Mts. Spec. Vol. IGCP 276,
GÚD, Bratislava 2536.
Broska I., Bibikova E.V., Gracheva T.V., Makarov V.A. & Caòo F.
1990: Zircon from granitoid rocks of the Tribeè-Zobor crystal-
line complex: its typology, chemical and isotopic composition.
Geol. Zbor. Geol. Carpath. 41, 393406.
Burnham C.W. 1979: The importance of volatile constituents. In:
Yoder H.S. (Ed.): The evolution of igneous rocks (Fiftieth An-
niversary Perspectives). Princeton University Press, Princeton
(Russian translation), Nauka, Moscow, 439482.
Cambel B. 1980: To the problem of granitoid rocks of the Western
Carpathians. Acta Geol. Geogr. Univ. Comen. 35, 101110 (in
Russian).
Cambel B. & Petrík I. 1982: The West Carpathian granitoids: I/S
classification and genetic implications. Geol. Zbor. Geol. Car-
path. 33, 255267.
156 PETRÍK
Cambel B. & Pitoòák P. 1980: Geochemistry of amphiboles from
metabasites of the Western Carpathians. Acta Geol. Geogr.
Univ. Comen. 35, 4590 (in Slovak).
Cambel B. & Vilinoviè V. 1987: Geochemistry and petrology of the
granitoid rocks of the Malé Karpaty Mts. Veda, Bratislava, 1
247 (in Slovak with English summary).
Cambel B., Bagdasaryan G.P., Gukasyan R.C. & Dupej J. 1988: Age
of granitoids from the Kohút Veporic zone according to Rb-Sr
isochron analysis. Geol. Zbor. Geol. Carpath. 39, 131146.
Cambel B., Bagdasaryan G.P., Gukasyan,R.C. & Veselský J. 1989:
Rb-Sr geochronology of leucocratic granitoid rocks from the
Spisko-gemerské rudohorie Mts. and Veporicum. Geol. Zbor.
Geol. Carpath. 40, 323332.
Cambel B., Krá¾ J. & Burchart J. 1990a: Isotope geochronology of
the Western Carpathian basement. Veda, Bratislava, 1183 (in
Slovak with English summary).
Cambel B., Mikló J., Khun M. & Veselský J. 1990b: Geochemistry
and petrology of quartz-clayey metamorphic rocks of the Malé
Karpaty basement. GÚ SAV, Bratislava, 1267 (in Slovak).
Castro A., Patino-Douce A.E., Corretgé L.G., de la Rosa J., El-Biad
M. & El-Hmidi H. 1999: Origin of peraluminous granites and
granodiorites, Iberian massif, Spain: an experimental test of
granite petrogenesis. Contr. Mineral. Petrology 135, 255276.
Dallmeyer R.D., Neubauer F., Handler R., Fritz H., Muller W., Pana
D. & Puti D. 1996: Tectonothermal evolution of the internal
Alps and Carpathians: Evidence from
40
Ar/
39
Ar mineral and
whole rock data. Eclogae Geol. Helvet. 89, 203227.
Debon F & Le Fort P. 1983: A chemical-mineralogical classification
of common plutonic rocks and associations. Trans. Royal Soc.
Edinburgh: Earth Sci. 73, 135149.
Dietrich V. & Gansser A. 1981: The leucogranites of the Bhutan Hi-
malaya (crustal anatexis versus mantle melting). Schweiz. Min-
eral. Petrogr. Mitt. 61, 177202.
Faure G. 1989: Principles of isotope geology. John Wiley and sons,
New York. 1590.
Hovorka D. 1980: The West Carpathians crust origin and plutonite
formations. Geol. Zbor. Geol. Carpath. 31, 523535.
Hradetzky H. & Lippolt H.J. 1993: Generation and distortion of Rb/
Sr whole-rock isochrons effects of metamorphism and alter-
ation. Eur. J. Mineral. 5, 11751193.
Hrako ¼., Kotov A.B., Salnikova E.B. & Kovach V. 1998: Enclaves
in the Rochovce granite intrusion as indicators of the tempera-
ture and origin of the magma. Geol. Carpathica 49, 125138.
Janák M., Hurai V., Ludhová L. & Thomas R. 1999: Partial melting
and retrogression during exhumation of high-grade
metapelites, the Tatra Mountains, Western Carpathians. Phys.
Chem. Earth (A), 24, 3, 289294.
Janouek V., Rogers G. & Bowes D.R. 1995: Sr-Nd isotopic con-
straints on the petrogenesis of the Central Bohemian Pluton,
Czech Republic. Geol. Rdsch. 84, 520534.
Jenner G.A., Cawood P.A., Rautenschlein M. & White W.M. 1987:
Composition of back-arc basin volcanics, Valu Fa ridge, Lau
basin: Evidence for a slab-derived component in their mantle
source. J. Volcanol. Geotherm Res. 32, 209222.
Kohút M. 1992: The Ve¾ká Fatra granitoid pluton an example of
a Variscan zoned body in the Western Carpathians. In: Vozár J.
(Ed.): The Paleozoic geodynamic domains of the Western Car-
pathians, Eastern Alps and Dinarides. Spec. Vol. IGCP Project
276, Bratislava, 7992.
Kohút M. & Janák M. 1994: Granitoids of the Tatra Mts., Western
Carpathians: Field relations and petrogenetic implications.
Geol. Carpathica 45, 301311.
Kohút M., Carl C. & Michalko J. 1996: Granitoid rocks of the Ve¾ká
Fatra Mts. Rb/Sr isotope geochronology (Western Car-
pathians, Slovakia). Geol. Carpathica 47, 2, 8189.
Kohút M., Krá¾ J., Michalko J. & Wiegerová V. 1998: The Hercyn-
ian cooling of the Ve¾ká Fatra Mts. Massif evidence from
40
K/
40
Ar and
40
Ar/
39
Ar thermochronometry and the current sta-
tus of thermochronometry. Miner. Slovaca 30, 253264 (in Slo-
vak with English summary).
Kohút M., Todt W., Janák M. & Poller U. 1997: Thermochronome-
try of the Variscan basement exhumation in the Ve¾ká Fatra
Mts. (Western Carpathians, Slovakia). Terra Abstracts 9, 1,
EUG 9, Strasbourg, 494.
Kohút M., Kotov A.B., Salnikova E.B. & Kovach V.P. 1999: Sr and
Nd isotope geochemistry of Hercynian granitic rocks from the
Western Carpathians implications for granite genesis and
crustal evolution. Geol. Carpathica 50, 477487.
Korikovsky S.P., Kahan , Puti M. & Petrík I. 1987: Metamorphic
zoning in the crystalline complex of the Suchý Mts. and high
temperature autometasomatism in peraluminous granites of the
Stráovské vrchy Mts. Geol. Zbor. Geol. Carpath. 38, 181203
(in Russian).
Kováè M., Krá¾ J., Márton E., Plaienka D. & Uher P. 1994: Alpine
uplift history of the Central Western Carpathians: geochrono-
logical, paleomagnetic, sedimantary and structural data. Geol.
Carpatica, 45, 2, 8396.
Kováèik M., Krá¾ J. & Maluski H. 1996: Metamorphic rocks in the
southern Veporicum basement: their Alpine metamorphism and
thermochronologic evolution. Miner. Slovaca 28, 185202 (in
Slovak with English summary).
Krá¾ J. 1994: Strontium isotopes in granitic rocks of the Western
Carpathians. Mitt. Österr. Geol. Gesell. 86, 7581.
Krá¾ J., Goltzman Y.V. & Petrík I. 1987: Rb-Sr whole rock isochron
data of granitic rocks from the Stráovské vrchy Mts.: the pre-
liminary report. Geol. Zbor. Geol. Carpath. 38, 171180.
Krá¾ J., Hess J.C. & Lippolt H.J. 1997:
207
Pb/
206
Pb and
40
Ar/
39
Ar age
data from plutonic rocks of the Stráovské vrchy Mts. base-
ment, Western Carpathians. In: P. Grecula, D. Hovorka and
M.Puti (Eds.): Geological evolution of the Western Car-
pathians. Miner. SlovacaMonograph, 253260.
Krist E., Korikovsky S.P., Janák M. & Boronikhin V.A. 1988: Com-
parative mineralogical-petrographical characteristics of met-
agabbro from borehole KV-3 near Rochovce and amphibolites
of Hladomorná valley formation (Slovenské rudohorie Mts.).
Geol. Zbor. Geol. Carpath. 39, 171194.
Liew T.C. & Hofmann A.W. 1988: Precambrian crustal components,
plutonic associations, plate environment of the Hercynian fold
belt of Central Europe: Indications from a Nd and Sr isotopic
study. Contr. Mineral. Petrology 98, 129138.
Ludwig K. R. 1994: Isoplot, a plotting and regression program for
radiogenic isotope data, ver. 2.75. U.S. Geol. Surv. Open-file
Report 91445, 135.
Marquer D. & Peucat J.J. 1994: Rb-Sr systematics of recrystallized
shear zones at the greenschist-amphibolite transition: examples
from granites in the Swiss Central Alps. Schweiz. Mineral.
Petrogr. Mitt. 74, 343358.
Montel J.-M. & Vielzeuf D. 1997: Partial melting of metagreywack-
es, Part II. Compositions of minerals and melts. Contr. Miner-
al. Petrology 129, 176196.
Nabelek P.I. & Glascock M.D. 1995: REE-depleted leucogranites,
Black Hills, South Dakota: a consequence of disequilibrium
melting of monazite-bearing schists. J. Petrology 36, 10551071.
Patino-Douce A. E. 1995: Experimental generation of hybrid silicic
melts by reaction of high-Al basalts with metamorphic rocks.
J. Geophys. Res. 100, 1562315639.
Patino-Douce A.E. & Harris N. 1998: Experimental constraints on
Himalayan anatexis. J. Petrology 39, 689710.
Peacock S.M. 1993: Large-scale hydration of the lithosphere above
subduction slabs. Chem. Geol. 108, 4959.
Petrík I. & Broska I. 1989: Mafic enclaves in granitoid rocks of the
Tribeè Mts., Western Carpathians. Geol. Zbor. Geol. Carpath.
40, 667696.
Petrík I. & Broska I. 1994: Petrology of two granite types from the
MULTIPLE SOURCES OF THE WEST-CARPATHIAN VARISCAN GRANITOIDS 157
Tribeè Mountains, Western Carpathians; an example of allanite
(+magnetite) versus monazite dichotomy. Geol. J. 29, 5978.
Petrík I., Broska I., Bezák V. & Uher P. 1995: The Hronèok type
granite, a Hercynian A-type granite in shear zone. Miner. Slo-
vaca 27, 351363 (in Slovak with English summary).
Petrík I., Broska I. & Uher P. 1994: Evolution of the Western Car-
pathian granite magmatism: Age, source rock, geotectonic set-
ting and relation to the Variscan structure. Geol. Carpathica
45, 283291.
Petrík I. & Kohút M. 1997: The evolution of granitoid magmatism
during the Hercynian orogen in the Western Carpathians. In: P.
Grecula, D. Hovorka & M.Puti (Eds.): Geological evolution
of the Western Carpathians. Miner. SlovacaMonograph,
235252.
Petrík I., Siman P. & Bezák V. 1998: The granitoid protolith of the
Ïumbier Nízke Tatry orthogneisses: Ba distribution in K-feld-
spar megacrysts. Miner. Slovaca 30, 265274 (in Slovak with
English summary).
Pin Ch. & Duthou J.L. 1990: Sources of Hercynian granitoids from
the French Massif central: inferences from Nd isotopes and
consequences for crustal evolution. Chem. Geol. 83, 281296.
Plaienka D., Grecula P., Puti M., Kováè M. & Hovorka D. 1997:
Evolution and structure of the Western Carpathians: an over-
view. In: P. Grecula, D. Hovorka & M.Puti (Eds.): Geological
evolution of the Western Carpathians. Miner. SlovacaMono-
graph, 124.
Poller U., Todt W., Janák M. & Kohút M. 1999a: The geodynamic
evolution of the Tatra Mountains constrained by new U-Pb sin-
gle zircon data on orthogneisses, migmatites and granitoids.
Geol. Carpathica 50, Spec. Iss., 129131.
Poller U., Todt W., Janák M. & Kohút M. 1999b: The relationships
between the Variscides and the Western Carpathians basement:
new Sr, Nd and Pb-Pb isotope data from the Tatra Mountains.
Geol. Carpathica 50, Spec. Iss., 131133.
Puti M., Kotov A.B., Uher P., Salnikova E.B. & Korikovsky S.P.
2000: Triassic age of the Hronèok pre-orogenic A-type granite
related to continental rifting: a new result of U/Pb isotope dat-
ing (Western Carpathians). Geol. Carpathica 51, 5966.
Stevens G., Clemens J.D. & Droop G.T.R. 1997: Melt production
during granulite-facies anatexis: experimental data from
primitive metasedimentary protoliths. Contr. Mineral. Pe-
trology 128, 352370.
Uher P. & Broska I. 1996: Post-orogenic Permian granitic rocks in
the Western Carpathian-Pannonian area: geochemistry, miner-
alogy and evolution. Geol. Carpathica 47, 311321.
Vielzeuf D. & Montel J.-M. 1994: Partial melting of metagreywack-
es I. Fluid-absent experiments and phase relationships. Contr.
Mineral. Petrology 117, 375393.
Vilinoviè V. & Petrík I. 1984: Petrogenetic modelling of the differ-
entiation of granitoid magmas: a cumulate-rich character of
Modra granodiorite. Acta Montana 68, 205224 (in Slovak).
Zoubek V. 1951: The report on geological investigations on the south-
ern slope of the Nízke Tatry Mts. between the Bystrá and Jasen-
ská valleys. Vìstník Ústø. Úst. Geol. 26, 162166 (in Czech).
System opening
The time elapsed since the system opening (t
1
)
is given by:
t
1
= 1/
λ
ln[(S
m
S
r
)/(R
r
R
m
)
+ 1]
(A1)
where S
m
, R
m
and S
r
, R
r
are measured and reconstructed
87
Sr/
86
Sr
and
87
Rb/
86
Sr ratios, respectively and
λ
is the
87
Rb decay constant.
The age of the Rb/Sr change (t
c
) is then:
t
c
= t
2
t
1
(A2)
where t
2
is intrusive age of the sequence. The reconstructions of
SR-1 and T-27 samples are shown in Fig. A1. A series of samples
Appendix
Fig. A1.
87
Sr/
86
Sr ratio evolution with episodical change of the Rb/Sr ratio as illustrated by the Suchý SR-1 granodiorite (A) and Tribeè T-27 granite
(B). The Rb/Sr ratio either decreases (A) or increases (B) at time t
1
(R
r
→
R
m
) that corresponds to the slope (S
m
S
r
)/(R
r
R
m
) (eq. A1). The age of the
change is t
2
t
1
(eq. A2). d = S
m
S
r
corresponds to the excess (A) or deficit (B) of radiogenic Sr of the sample, inherited from the time prior to the
Rb/Sr change. S
m
and S
r
are measured and reconstructed
87
Sr/
86
Sr ratios; R
m
and R
r
are measured and reconstructed
87
Rb/
86
Sr ratios, respectively.
with the same t
c
and various degrees of Rb/Sr change would form
an isochron corresponding to the t
c
. It is noted that the equation
(A1) neglects the decrease of
87
Rb/
86
Sr ratios with time, but the er-
ror so introduced is much smaller than the uncertainty due to the
Rb/Sr ratio reconstruction. There is also an implicit assumption
that the Rb escape (sample SR-1) was not accompanied by a
change in the
87
Sr/
86
Sr ratio. This seems unrealistic when we real-
ize that the
87
Sr resides precisely at the sites of its formation, i.e.
in the Rb
+
positions of K-rich minerals. However, the change of
87
Sr/
86
Sr ratio requires decoupling of radiogenic and common Sr.
This may occur when the rock is thermally overprinted and the bi-
otite-produced
87
Sr escapes to plagioclase until a new whole rock
87
Sr/
86
Sr ratio is established. In the case of biotite to sillimanite
breakdown, interlayer cations including Rb, and Sr (common and
0.705
0.706
0.707
0.708
0.709
0.710
0.711
0.712
0
0.2
0.4
0.6
0.8
1
87
Rb/
86
Sr
87
Sr/
86
Sr
0.700
0.710
0.720
0.730
0.740
0.750
0
1
2
3
4
5
6
7
8
87
Rb/
86
Sr
87
Sr/
86
Sr
S
m
S
r
R
m
R
r
d
d
t
1
t
2
SR1
T27
d
d
S
m
S
r
R
m
R
r
t
1
t
2
A
B
158 PETRÍK
radiogenic) are likely to escape together without the change of
87
Sr/
86
Sr ratio. The
87
Sr excess in the SR-1 sample seems to be
preserved from an earlier history confirming that the
87
Sr/
86
Sr ra-
tio does not change in the course of the reaction. However, as
pointed by Hradetzky & Lippolt (1993) if Sr is emitted mainly
from plagioclase, the
87
Sr/
86
Sr increases, because it is common Sr
that escapes. If so, the data obtained for low Sr outliers (VMFa-2,
T-27 in Table 2) represent upper limits for the age of system open-
ing possibly indicating rather an Alpine than a late Variscan event.
Mineral isochron
While Sr mobility is typical of weathering products, Rb escaped
during high temperature acid leaching (above 600 °C, Korikovsky
et al. 1987) implying a thermal overprint, redistribution and ho-
mogenization of
87
Sr between minerals (Fig. A2a, path 123).
The new whole rock
87
Sr/
86
Sr ratio (I
Sr
)
m
is not influenced by the
subsequent Rb or Sr escape because biotite undergoing the break-
down releases both radiogenic and common Sr. Therefore, the
high-temperature system opening has no effect on the mineral iso-
chron age provided that the Rb escape occurred simultaneously
with mineral
87
Sr homogenization (path 12356). Actually,
Krá¾ (2000, personal comm.) obtained a mineral isochron for SR-1
biotite corresponding to approximately 300 Ma. Such an age (t
c
)
for the system opening would require a reconstructed Rb value of
140 ppm (Table 2). This seems too high a value compared to the
observed range (40.2115.6 ppm). A delay between the metamor-
phism and Rb/Sr change would, however, raise the biotite
87
Sr/
86
Sr
ratio above mineral isochron (Fig. A2b, path 123567 or 8
9) and generate an apparent biotite mineral age. The neccessary
delay (angle
δ
) is strongly dependent on the biotite Rb/Sr change
(path 568), for example at t
c
= 251 Ma the apparent biotite age
of 300 Ma is produced at 75 % Rb/Sr ratio drop and the delay of
12 Ma, or at 50 % drop and the delay of 24 Ma. The geological rel-
evance of the delay between metamorphism and system opening is
not discussed here mainly because of the lack of the neccessary
high-precision mineral trace element data.
Fig. A2.
87
Sr/
86
Sr mineral evolution: (A) A metamorphic event occur-
ring at the time corresponding to the angle
α
(path 13), is immediately
followed by various decreases of Rb/Sr ratio (paths 34, 356). (B)
The metamorphic event is followed by various degrees of the Rb escape
after a time delay (angle
δ
, paths 357 and 359). In this case the
87
Sr/
86
Sr evolution produces mineral pseudoisochrons with higher
age than that of the metamorphic event. (I
Sr
)
i
and (I
Sr
)
m
are intrusive
and metamorphic Sr initial ratios, respectively.
87
86
Rb/ Sr
87
86
Sr
/
S
r
(I )
Sr i
(I )
Sr m
2
3
4
5
1
biot
ite
A
87
86
Rb/ Sr
87
86
Sr
/
S
r
(I )
Sr i
(I )
Sr m
2
3
4
5
6
7
1
biot
ite
8
9
B
6