GEOLOGICA CARPATHICA, 51, 5, BRATISLAVA, OCTOBER 2000
EXTREMELY ISOTOPICALLY HEAVY SULPHUR IN BARITE
CONCRETIONS FROM SLOVAKIA
, MILAN MIÍK
, KAROL ELIÁ
, ELÍGIA FERENÈÍKOVÁ
, EMÍLIA HARÈOVÁ
and IVAN RÚÈKA
Department of Isotope Geology, Geological Survey of Slovak Republic, Mlynská dolina 1, 817 04 Bratislava, Slovak Republic
Department of Geology and Paleontology, Faculty of Sciences, Comenius University, Mlynská dolina G, 842 15 Bratislava, Slovak Republic
(Manuscript received May 14, 1999; accepted in revised form June 20, 2000)
Abstract: Extreme values of
S: +105.3 , +105.2 , +87.9 , +87.2 and +79.7 were determined in barite
concretions from the Aptian-Lower Albian marly limestone of the Krína Nappe of the Western Carpathians, Slovakia.
The phases relation in inclusions from these concretions, and the results of thermo-vacuometric impulse decrepitation
analyses indicate temperatures of 5060 °C, which correspond mostly to secondary inclusions. For the purpose of
comparison, barite concretions from Rohoník, Slovakia, from Gaiseltal, Germany, and from Havana, Cuba, were
analyzed. Barite concretions with extremely high
S values were formed during late diagenesis of organic matter-
rich sediment in the depth range of very low pore water sulphate concentrations, below the sulphate reduction zone.
Key words: Western Carpathians, fluid inclusions, diagenesis, barite concretions,
With the exception of Hoefs (1997, p. 58) who reported on
the isotopically heaviest sulphur found in sulphates exceed-
ing the value of
S +120 relative to CDT (Canyon Di-
abolo Troilite), all other authors published data with consid-
erably lower values for barite concretions: +44.0 to +57.9
(Rafter & Mizutani 1967), +54.2 to +78.5 (Goldberg et al.
1969), up to +77.3 (Chukhrov & Ermilova 1973), +82.6
(Ustinov et al. 1982), +80.6 (Bogoch et al. 1987),
+40.7 to +53.4 (Siegel et al. 1987), +50 to +70 (Brum-
sack 1989), +28.0 to 53.0 (Clark & Mosier 1989), +32 to
+36 (Leniak et al. 1999). Our finding of a barite concre-
tion with +105.2 and +105.3
S was an impulse to focus
our attention on the problem.
Localities with heaviest sulphur in barite from the Aptian-
Lower Albian Formation of the Krína Nappe
The barite concretions with extremely high values of
were found in the Aptian-Lower Albian strata of the Krína
Nappe, near the boundary of two core mountains of the Central
Western Carpathians Mts.: Stráovské vrchy hills loc.
Zbyòov, and Malá Fatra Mts. loc. Faèkov Saddle (Fig. 1).
The pelagic marly limestones of AptianLower Albian age
are approximately 200 m thick. Barite concretions occur in the
layer of dark gray slaty marls (Kysela et al. 1983) with rare in-
tercalations, partly cherty dark gray biomicritic limestones 5
20 m thick. In the marly matrix with glauconite and belemnite
rostra are disseminated large subangular to sub-rounded clasts
(with diameters of 1 to 20 cm, exceptionally 80 cm) of dark
and light gray, orbitoline-bearing limestones. Köhler (1980)
determined the species Orbitolina (Mesorbitolina) aff. minuta
Douglas, which points to derivation of the clasts from Upper
Aptian limestones. The body of the breccia could be interpret-
ed as incoherent submarine sliding (or slumping) of partly lith-
Sample from Zbyòov, NW from Vlèia hill (Pl. Ia) repre-
sents an irregular tuberous block (olistolit about 20 cm large)
of gray limestone.
Sample from the Faèkov Saddle is a spherical concretion
4 cm in diameter. It was found loose in debris. According to
its almost perfect spherical shape, we could assume, that it
weathered out from marls.
Fig. 1. Sketch map of Slovakia with occurrences of barite concre-
Corresponding author: Fax: 00421-7-54771-940; firstname.lastname@example.org
302 REPÈOK et al.
Sample Zbyòov, appr. 300 m W from Plieky Hill consists of
barite with witherite filling about 1 cm cavity in the limestone.
Sample Zbyòov from elevation point 469.5 m, represents
an egg-shaped concretion, with a diameter of 8 cm, imper-
fectly individualized from the limestone.
Barite concretions from other areas
For comparison, barite concretions from Rohoník, Slova-
kia, from Gaiseltal, Germany, and from Havana, Cuba, were
The barite concretion from the loam pit of cement works,
in the Sarmatian marly clays Vienna Basin, Rohoník, Slova-
kia, are identical with those reported by Krua (1946) from
Moravian localities. The barite concretions are formed by as-
semblage of microspherulites (Pl. Ie).
The barite concretions from Eocene coal mine in Gaiseltal,
Neumarkt, Germany, were reported by Krumbiegel (1959).
They are accompanied by xylite-coalified stems. Our speci-
men is formed by a cluster of barite microspherulites (Pl. If).
Krumbiegel (1959) supposes Ba inflow of waters from subja-
cent evaporite rocks (gypsum and salt bearing marls) of Up-
per Buntsandstein (Lower Triassic).
The barite concretions from Cuba are of melikaria or ro-
sette type. They occur in the marls (chalk limestone) of the
Upper Eocene-Lower Oligocene Consuelo Formation (Pl.
Ib,c,d), in a pit of Tejar Matos brickworks, avenida Antonio
Soto, Havana, Cuba. The barite concretions in them were
found for the first time by H. Hess (Brönnimann & Rigassi
Plate I: a barite concretion with aborescent crystal growth, from
the Aptian-Lower Albian marly limestone of the Krína Nappe from
Zbyòov (2781), Western Carpathians, Slovakia. Thin section, cross-
polarized light; b the barite concretions from marls chalk lime-
stone from the Upper Eocene-Lower Oligocene Consuelo Forma-
tion, pit brickwork Tejar Matos, avenida Antonio Soto, Havana,
Cuba; c peripheral part of the barite concretion Havana, Cuba.
Thin section, cross-polarized light; d rib of rosette concretion
from Pl. Ib; barite crystal with arborescent clay inclusions. Thin sec-
tion; e the barite concretion from the loam pit, in the Sarmatian
marls Vienna Basin, Rohoník, Slovakia. The barite concretion con-
sists of microspherulites. Thin section; f the barite concretion
with microspherulite structure from Eocene coal pit in Gaiseltal,
Neumarkt, Germany. Thin section.
Fig. 2. Sulphur isotopic composition of the described barite concretions compared with data of other authors.
EXTREMELY ISOTOPICALLY HEAVY SULPHUR 303
304 REPÈOK et al.
The barite was converted to hydrogen sulphide in the re-
duction acid mixture (HCl, H
and HI). This product was
swept by nitrogen carrier gas into the solution of zinc acetate
in water, resulting in precipitation of ZnS. The ZnS was
dried, mixed with CuO and combusted at 800 °C, in vacuum
line. The evolved SO
gas was isolated and measured on a
MAT 250 mass spectrometer. The experimental uncertainity
for the analysis process was estimated at lower than ± 0.1 .
Comparison of isotopic measurements of
S in BaSO
NBS 127: +20.32 (Hut 1987); +20.58 (Dept. of Isotope
Geology, GÚD resp. GSSR).
The fluid inclusions in the studied barites are abundant
enough, but very small. Their observation for interpretation
of decrepitation thermo-vacuometric impulse (TVI, multi-
tude 30 grains, size 0.40.7 mm) analysis (Kantor & Eliá
1974) was possible only with maximal magnification (with
The description of localities and surrounding rocks was
done in the section on Geological setting. Some additional
data concerning the samples will be mentioned here.
Sample from Zbyòov, NW of Vlèia Hill. The central part
of the concretion was powder-like, towards the rim the rhyth-
mic growth of barite crystals with arrangement of clayey in-
clusions in dentritic patterns is visible (Pl. Ia). The transition
to the surrounding marly limestone is diffuse. The measured
S was +105.3 . The replicate analysis yielded
the value of +105.2 (Table 1).
Concretion from the Faèkov. We prepared three samples
for analyses. Two from the rim of the concretion gave results
S +87.2, and +87.9 , and one from the
Sample Zbyòov, appr. 300 m W of Plieky Hill. The value
S +47.5 was measured in the barite from the cavity
filling (Table 1).
Sample Zbyòov from elevation point 469.5 m. A plate cut
from the concretion was crushed, homogenized and analyzed
with the result
S +33.0 . This is the lowest value, mea-
sured on barite concretions from Barremian-Aptian marly
limestones of the Krína Nappe (Table 1).
S of the studied barite concretions increases with
the amount of clayey component in the marly limestones.
This finding is in accordance with the supposed distribution
of sulphate sulphur in the later stages of diagenesis (see fur-
ther), in view of stricter enclosure of the system below the
Several other barite concretions were analyzed for the pur-
pose of comparison from the following localities:
Rohoník, loam pit of a cement works, in the Sarmatian
marls of the Vienna Basin, Slovakia. The barite concretion
consists of microspherulites (Pl. Ie). The value of
+16.2 which is the lowest one, that could have been mea-
sured in our set of barite concretions (Table 1).
Plate II: a the fluid inclusions in the barite concretion from the
Aptian-Lower Albian marly limestone at the Krína Nappe from
Zbyòov (2781), Western Carpathians, Slovakia; b primary, two-
phase liquid-gas inclusions, not belonging to any of the fissure sys-
tems in the barite concretion from the Aptian-Lower Albian marly
limestone at the Krína Nappe from Faèkov Saddle (2839b), West-
ern Carpathians, Slovakia; c rarely, three-phase inclusions may
also be observed, in which, besides liquid and gas, very small, col-
orless, so-called daughter minerals can be visible. Barite concretion
from Faèkov Saddle (2839b) Western Carpathians, Slovakia; d
secondary, predominantly one-phase inclusions in the fissures cut-
ting the crystallographic directions, so-called strangled inclusions
(necking down) in the barite from Faèkov Saddle (2839b), Western
in marle limestones
200 m NW from Vlèia Hill
Zbyòov, Stráov Mts., Slovakia
repeat.prep. and anal.
barite concretion, rim
1 km E from Faèkov Saddle,
barite concretion, core
barite concretion rim
250 m SW from elev. pt. 469.5 m
Zbyòov, Stráov Mts., Slovakia
barite filling of cavity
appr. 300 m W from Plieky Hill
Zbyòov, Stráov Mts., Slovakia
loam pit Rohoník, Slovakia
barite concretion, rim
brickwork Tejar Matos
suburb of Havana,Cuba
barite concretion, core
barite concretion, rim
coal strip pit, Gaiseltal,
barite concretion, core
Havana. The barite concretion of rosette shape and dentritic
patterns of inclusions within the barite crystals (Pl. Ib,c,d)
comes from marls (chalk limestone) from the Upper
Eocene-Lower Oligocene Consuelo Formation, pit brickwork
Tejar Matos, avenida Antonio Soto, Havana, Cuba. Two sam-
ples were prepared, one from the rim yielded the value of
+47.3 and another one from the core +66.3 (Table l).
Gaiseltal. Barite concretion from Eocene coal mine in
Gaiseltal, Neumarkt, Germany (Pl. If). Two samples were
prepared, on which the values of
S were measured:
+65.6 at the rim, and +65.3 at the core (Table 1).
The fluid inclusions in the studied barites from Zbyòov,
NW of Vlèia Hill (Pl. Ia) are abundant enough, but very
small (Pl. IIa).
Three types of primary and secondary fluid inclusions were
distinguished (sample 2839b) according to phase composition:
monophase aqueous; two-phase liquid-vapor, and very rare
three-phase, liquid-vapor-solid inclusions. The monophase in-
Table 1: Isotopic compostion of the barite concretions from some
occurrences: Slovakia, Cuba, Germany.
EXTREMELY ISOTOPICALLY HEAVY SULPHUR 305
306 REPÈOK et al.
clusions are dominant. The volumetric vapor-to-liquid ratios
in the two-phase inclusions vary from several % to 7080 %.
From the genetic point of view, the following inclusions
have been distinguished:
1) Primary inclusions randomly distributed in the host
crystal (Pl. IIb,c).
2) Pseudosecundary inclusions comprising all types of the
3) Secondary, predominantly one-phase inclusions cross-
cutting growth planes of the host barite (Pl. IId).
Decrepitation thermo-vacuometric impulse (TVI) analyses
(Kantor & Eliá 1974) according to very low temperatures
(from 50 to 60 °C), point to secondary or primary-secondary
inclusions, respectively. According to the phases relation in
inclusions and the results of the TVI decrepitation analyses,
the temperatures at the origin of barites lay from 50 to 60 °C
(secondary). Similar temperatures were obtained for the in-
clusions in barite concretions from the Appalachian Moun-
tains (Nuelle & Shelton 1986). Saunders & Swann (1994)
presented in the barites from the cap-rock at the Hazlehurst
salt dome, Mississippi, value of
S +39.5 , with homog-
enization temperatures from 44 to 73 °C.
Before our attempt to explain the process leading to the ex-
tremely heavy sulphur accumulation in the barite concretions
described here, a confrontation with the observations of other
authors would be useful.
Changes of sulphur isotope ratios in the concretions
from different stages of the lithogenesis
Sulphur isotope fractionation in the sediments and the
changes of their isotope composition during concretion
growth, are described in several studies (Gavellin et al. 1960;
Vinogradov et al. 1962; Müller et al. 1966; Vinogradov &
Zaritskii 1968; Hartmann & Nielsen 1969; Chukhrov 1970;
Chukhrov & Ermilova 1971, 1973).
Isotopic fractionation of sulphur in recent marine sediments
was determined by Belyi (1988, p. 32; original English text):
...1) usually postulated cycle of reaction of the bacterial re-
duction-diffusion of sulphate ion (SO
... and 2) reactions of oxidation of biogene H
ation of metastable products of the oxidation (O
) ... which are the most
intensive near the water-sediment surface and determine sig-
nificantly the mass transfer of sulphur. The multi-step dispro-
portionation of metastable compounds of sulphur is character-
ized on the whole by isotopic fractionation several times
higher than in the sulphate-reduction process. Both effects to-
gether provide «instant» steady-state isotope fractionation of
sulphur which is close to value of the constant of equilibrium
for isotopic exchange in the system SO
S at temperature
of the porous solutions.
Jørgensen (1979) constructed a mathematical model that
allows the calculation of the vertical
S distribution in sul-
phate, free and metal sulphide. This model may be used for
both, open and closed systems of diagenesis. Rates of diffu-
sion, sedimentation, and sulphate-reduction, as well as the
bacterial isotope fractionation factor may be independently
Chukhrov & Ermilova (1973), and others, explained the
changes in isotopic composition of sulphur during the growth
processes of concretions in the three known lithogenetic stag-
es: a) early diagenesis, b) late diagenesis and c) epigenesis.
Concretions of the early diagenetic stage
In the early diagenesis stage, when the sediment is not to-
tally isolated from the marine water, sulphide and sulphate
sulphur of concretions in the growth process must be step by
step enriched in isotope
S. Therefore, in the sulphate and
sulphide concretions, the value of
S decreases during the
concretion growth process. This means that in cores of barite
or pyrite concretions from the early diagenesis stage, the sul-
phur must be heavier, than in their marginal parts, which has
been suggested by the work of several authors (Gavelin et al.
1960; Vinogradov & Zaritskii 1968; Chukhrov & Ermilova
1971, 1973; Brumsack 1989).
Concretions of the late diagenetic stage
The formation of such concretions occurs in the sediment
isolated from the basin water. Since the regeneration of de-
pleted sulphide sulphur in conditions of late diagenesis does
not take place and system is practically closed, the process of
sulphide and sulphate concretions growth gradually causes
enrichment of the sulphur, i.e. the
S value increases. The
quantity of sulphate sulphur in the sphere of bacterial sul-
phate-reduction is small. Therefore, the total quantity of late
diagenetic sulphate concretions in the rock is very small.
Concretions, that had been growing already in the stage of
early diagenesis (with decreased value of
S), could also
have grown in the stage of late diagenesis (with increased
S). In such concretions, the sulphur of the late formed
concretion parts becomes substantially heavier (Vinogradov
& Zaritskii 1968; Chukhrov 1970; Chukhrov & Ermilova
1971, 1973; Presley & Kaplan 1968; Anderson et al. 1989,
etc.). Coleman & Raiswell (1981, p. 337) wrote: ... The
S show a fairly clear trend to heavier values
towards the concretion margins.
Nuelle & Shelton (1986), explained the heavy isotope en-
richment in the barite nodules as the results of decreased bio-
genic influence with the distance from the barite source. The
heavy isotope enrichment may be the result of enhanced ac-
tivity of sulphur-reducing bacteria near a submarine-spring
barium source, and at redox interface. Cecile et al. (1983) ex-
plained the heavy sulphur as a reflection of repeated cycles
of sulphate dissolution and precipitation, concentrations of
heavier sulphates in pore waters of anoxic zones, or a combi-
nation of these and other factors.
Concretions of the epigenetic stage
These concretions start to form after infiltration of conti-
nental water, the sulphate of which is remarkably less en-
EXTREMELY ISOTOPICALLY HEAVY SULPHUR 307
S, than that of sea water. Dissolution of the sul-
phate from remnant seawater in the sediments can result in
gradual decrease of its
S isotope. A characteristic pattern of
epigenetic concretions is decreasing of
S in the process of
their growth. In many cases in the epigenetic stage further
growth of concretions, which had previously been formed in
the diagenetic stage, takes place. During this additional
growth of late diagenetic concretions, the values of
growing parts gradually decrease, and turn to negative ones
(e.g. Rye et al. 1978; Graber & Chafetz 1990). The speciality
of many epigenetic concretions is an increased content of the
mechanical admixtures. Some of these concretions are filled
by allogene inclusions (Chukhrov & Ermilova 1973).
In the barite concretions from marly limestones from Aptian
Lower Albian of the Krína Nappe of the Western Carpathians
(Zbyòov and Faèkov Saddle) extremely high values of
+105.3 , +105.2 , +87.9 , +87.2 and +79.7 were
On the basis of the change of sulphur isotope composition
from the centre to rim of the barite concretions, their origin in
the later stage of diagenesis can be assumed. The
S of stud-
ied barite concretions from marly limestones from Aptian
Lower Albian of the Krína Nappe of the Western Carpathians
(Zbyòov and Faèkov Saddle) increases with the amount of the
clay component in surrounding marly limestones and of their
content of organic matter. This finding is in accordance with
the above mentioned distribution of sulphate sulphur in the lat-
er stages of diagenesis, in view of stricter enclosure of the sys-
tem below the sediment-water border.
On the basis of study of fluid inclusions in barites from the
regions of Zbyòov and Faèkov Saddle we have concluded,
that the process of their origin was rather complex. The phas-
es relation in inclusions, and the results of TVI decrepitation
analysis indicate temperatures between 5060 °C, which cor-
respond mostly to the secondary inclusions.
The barite concretions with extremely high
were most probably formed during late diagenesis of clayey
calcareous sediment rich in organic matter, in the depth range
of very low pore water sulphate concentration, below the sul-
phate reduction zone.
Acknowledgements: The authors wish to express their thanks
to Ing. A. Kováøová for help with the isotopic analysis, Ing.
M. Sládková for chemical preparation, D. Zaoviè and A. Ma-
derová for separation of samples (all from the Geol. Survey of
the Slovak Republic) and the reviewers Prof. RNDr. I. Rojk-
oviè, DrSc. (Faculty of Natural Sciences, Bratislava), RNDr.
K. ák, CSc. (Czech Geological Survey, Prague), Prof. S.
Halas (University Lublin, Poland), for valuable comments.
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