GEOLOGICA CARPATHICA, 51, 4, BRATISLAVA, AUGUST 2000
PERMIAN LACUSTRINE PHOSPHATIC SANDSTONE IN THE
SOUTHERN GEMERIC UNIT,
WESTERN CARPATHIANS, SLOVAKIA
ANNA VOZÁROVÁ and IGOR ROJKOVIÈ
Faculty of Science, Comenius University, Mlynská dolina, 842 15 Bratislava, Slovak Republic
(Manuscript received November 20, 1999; accepted in revised form March 15, 2000)
Abstract: Lenses of phosphatic sandstone occurring in the Permian sediments of the títnik Formation contain intraclasts
of microsphorite as well as minute apatite crystals in the matrix. The microsphorite is composed of pelmicritic and
microsparitic aggregates of fluorapatite. The sandstone contains up to 18 weight percent P
. The phosphatic sand-
stone originated in an eutrophic lacustrine environment as a result of phosphorus concentration in lake sediment due
to the iron redox cycling and the associated microbiological effects. Two contrasted depositional realms are sug-
gested: 1. a shallow, lacustrine low-energy depositional regime in which adsorption and desorption of iron-bound
phosphorus between oxygen-deficient bottom water and anoxic sediment led to the formation of microsphorite de-
posit; 2. a relatively high-energy depositional regime during which river deltas invaded the lacustrine environment
and affected phosphorite reworking. Apatite crystals in the matrix are accompanied by Fe-dolomite, uraninite, U-Ti
oxides, Ti oxides, framboidal pyrite, chlorites, muscovite and albite. Their formation reflects diagenetic to very low-
grade metamorphic redistribution. A hydrothermal association of minerals represents sulphide mineralization occur-
ring in quartz-carbonate veinlets.
Key words: Western Carpathians, Permian, lacustrine phosphorite, mineral composition, REE, diagenesis, metamorphism.
The Permian sequences in the Western Carpathians are domi-
nated by continental, mainly coarse-grained red-beds sedi-
mentary formations. Their origin was related to a transpres-
sional and extensional tectonic regime. Therefore, the
occurrence of phosphatic sandstone in the Permian sequence
of the Southern Gemeric Unit is unique, compared to other
Permian sediments in the Western Carpathians. Phosphatic
sandstone forms thin lenses (0.2 to 0.4 m thick; 2 to 6 m
long, max. 2 m wide) within the relatively monotonous
sandy-shaly complex of the títnik Formation. The Southern
Gemeric Permian deposits show a peculiar geodynamic posi-
tion. They represent the post-collisional sequence with re-
spect to the Hercynian orogeny that prograded to the initial
stage of the Alpine orogeny.
The sedimentary complex of the títnik Formation was
first described as a marine Permian facies (Bystrický &
Fusán 1955). The first finding of phosphatic sandstone was
mentioned as marine (Tréger 1973). However, detailed litho-
facies analysis suggests a continental origin for this sedimen-
tary complex (Vozárová & Vozár 1988), though the origin of
the phosphatic sandstone has not been explained satisfactori-
ly. This paper attempts to elucidate the origin of the Permian
phosphate-bearing facies on the basis of detailed geological,
petrological, and geochemical analysis.
The Permian rocks in the Southern Gemeric Unit are classi-
fied into the Goèaltovo Group which represents a Late Her-
cynian post-orogenic sequence (Fig. 1). The sequence consists
mostly of continental volcano-sedimentary and terrigenous
rocks that grade upwards into near-shore sabkha-lagoonal fa-
cies. The basal conglomerates of Goèaltovo Group uncon-
formably overlie the Early Paleozoic basement of the Southern
Gemeric Unit, the latter is represented by flysch sediments of
the Gelnica Group and tós Formation (Vozárová & Vozár
1988). Mahe¾ (1986) places the Goèaltovo Group into the Me-
liata Unit of the Inner Western Carpathians. However, this in-
terpretation is not supported by geological data, as the rocks of
the Meliata Unit thrust over the Early Paleozoic as well as
over the Late Paleozoic rocks of the Southern Gemeric Unit.
Moreover, the Meliata Unit is rootless in the present Alpine
structure. On the other hand, a paleogeographical relationship
to Early Paleozoic basement can not be excluded due to the
character of clastic detritus.
The Goèaltovo Group (Vozárová & Reichwalder in Baja-
ník et al. 1981) is divided into the lower Roòava Formation
and the upper títnik Formation (Fig. 2A).
The Roòava Formation is represented by oligomictic
metaconglomerate in the lower part and by alternating meta-
conglomerates, quartzose metasandstones and sandy shales
in the upper part. The whole sequence shows mineral maturi-
ty, though it is structurally immature. It represents continen-
tal alluvial sediments with channel facies prevailing over
sheet-flood facies. The Roòava Formation contains two dis-
tinct horizons of metaconglomerates associated with volcan-
ogenic horizons. The lower horizon is composed of quartz
detritus and fragments of quartzose metagreywacke, with
subordinate fragments of quartz-muscovite phyllite and por-
phyroide. This horizon is overlain by rhyolite pyroclastics (5
to 20 m thick) and, in places, by rhyodacite flows. The upper
266 VOZÁROVÁ and ROJKOVIÈ
horizon of metaconglomerate consists of quartz pebbles and
volcaniclastic material. This material bears calc-alkaline
rhyolite-dacite characteristics with dominant subaeric pyro-
clastics. The Lower Permian age of the Roòava Formation
sediments has been documented by the presence of microf-
lora (Planderová 1980), especially by genera Potonie-
isporites, Striatodisaccites and Vittatina.
The highly deformed rocks of the Bôrka Nappe (Mello et
al. 1997, 1998) are lithologically similar to the Roòava
Formation. The oligomictic metaconglomerate, metasand-
stone and phyllite showing a subordinate contribution of
rhyodacite volcanic rocks correspond to the Jasov Forma-
tion (the Jasov development according to Reichwalder
1973). The rhyodacite volcaniclastic sequence with subor-
dinate clastic sediments is classified into the Buèina Forma-
tion (former Buèina Beds, Fusán 1959).
The títnik Formation consists of alternating sandstone,
siltstone and shale arranged in cyclic sedimentary sequenc-
es. It also comprises horizons of redeposited acidic volcani-
clastic material. The lower part of the títnik Formation
shows an abundance of this material, and contains irregular
lenses and laminae of albite. The concentration of albite in
these lenses is so high that the rock attains the albitolite
character. The sequence is interpreted as having been de-
posited in alkaline lakes, where zeolitization of rhyolite de-
tritus occurred, and was followed by the transformation of
zeolites to albite (Vozárová & Vozár 1988). Calcitized dolo-
stone (dedolomite) represents the upper part of the títnik
Formation. Calcite pseudomorphs after dolomite crystals
and minute relics of dolomite enclosed in calcite indicate a
dedolomitization process (Miík, pers. commun.). These
sediments overlie lenses of phosphatic sandstone (Tréger
1973). The sequence with phosphatic sandstones represents
interfingering of fine-grained lacustrine sediments and fluvial
sandstones. In the uppermost part of the sequence homoge-
neous fine-grained sediments alternate with massive sand-
stones and with sandstones showing graded bedding (Fig.
2B). Finely laminated shales and siltstones, commonly inter-
layered with thin turbiditic sandstones represent the lacustrine
part of the sequence. Facies changes are abrupt between fluvi-
al distributary sandstones and channel fill facies.
Three types of bedding structures were recognized in the
1. graded bedding which begins with coarse grains at the
base, gradually becoming finer upwards;
2. horizontal bedding marked by alternating layers of differ-
ent grain size (parting-linneation);
3. sandy turbidites rich in microsphorite intraclasts.
These facies correspond to the distal river delta association
interfingering with the lacustrine association. The lacustrine
association is characterized by alternation of very fine-
grained, laminated sandstones, siltstones and shales. It indi-
cates still water conditions, locally interrupted by influx of
Shale sequences in the títnik Formation contain siderite
concretions and to a lesser extent quartz-barite, magnetite-he-
matite and pyrite concretions showing compositional similari-
ties to hydrothermal vein deposits noted in the area (Mikovic
& Varèek 1983; Turan & Vanèová 1983).
The carbonate and phosphate-bearing sediments as well as
the hosting sandstone and shale sequences contain no fossils.
Only the uppermost part of the títnik Formation was paleon-
Fig. 1. Geological map of the Goèaltovo area (after Mello et al. 1996 adopted). Explanations: 1 Mesozoic rock complexes of Turnaic
and Meliatic units. 24 Permian of the Southern Gemeric Unit: 2 sediments of the títnik Formation, 3 horizons of phosphatic
sediments 4 sediments of the Roòava Formation. 5 Early Paleozoic rocks of the Southern Gemeric Unit (Gelnica Group).
PERMIAN LACUSTRINE PHOSPHATIC SANDSTONE, WESTERN CARPATHIANS 267
tologically dated (hill Háj, 1.5 km E from Goèaltovo village
uf 1963). Nìmejc (in uf 1963) reported the Upper Per-
mian Pseudovoltzia liebeana (Gein) Florin and Sphe-
nozamites from that part of the formation. uf (1963) has
also found the Upper Permian Carbonicola McCoy 1855.
Uranium bearing sandstone with sulphide mineralization
occurs in the títnik Formation and crops out on the slopes of
Kopané and Stará hora hills 2 km W from Goèaltovo
(Fig. 1). This mineralization is associated with phosphatic
sandstone and occurs in banded lenses 0.2 to 0.4 m thick and
2 to 5 m long (Tréger 1973). The lenses tend to concentrate
in a horizon which is up to 60 m thick (timmel 1967).
Melnikova (1974) found that the content of P
is up to 33
weight percent (average content at about 11 %). Our samples
up to 18 % (Rojkoviè et al. 1989a).
Petrology of phosphatic sandstone
The sequence consists of alternating sandstone with pres-
sure oriented psammitic and aleuropsammitic texture and il-
lite-muscovite shale. The sandstone is fine- to medium-
grained, with grain size ranging from 0.06 to 0.2 mm (Figs. 3,
4). Microsphorite intraclasts and carbonate concretions occur
in sandstone in the Kopané hill (Figs. 511). Clastic grains are
angular or slightly rounded and moderately sorted. Sorting
Fig. 2. A. Lithostratigraphic scheme of the Goèaltovo Group. Expla-
nations: 1 conglomerate, 2 sandstone, 3 shale, 4 dolo-
mitic limestone, 5 albitolite, 6 phosphatic sandstone, 7 rhy-
olitedacite pyroclastics, 8 tuffaceous/sedimentary mixed rocks,
9 rhyolitedacite. B. Lithofacial scheme of the middle part of the
títnik Formation with horizon of the phosphatic sandstones. 1
fine- to medium-grained sandstone, 2 lenses of phosphatic sand-
stone, 3 fine- to very fine-grained sandstone, 4 homogenous
siltstone, mudstone and shale with intercalation of fine-grained
sandstone and locally of sandy turbidites, 5 shale with minor in-
tercalation of siltstone and very fine-grained sandstone.
268 VOZÁROVÁ and ROJKOVIÈ
Fig. 6. Oval intraclast of phosphorite (light grey) with carbonate
veinlets (white) in the sandstone. Go 21, transmitted light, parallel
Fig. 7. Elongated intraclast of phosphorite (light grey) with orient-
ed inclusions of quartz grains (dark grey) smaller than clastic
grains of quartz in the sandstone. Go 21, transmitted light, parallel
Fig. 8. Oval intraclast of phosphorite (light grey) with chlorite vein-
let (dark grey transversal in centre) in the sandstone. Go 3/1, trans-
mitted light, parallel polar.
Fig. 5. Sandstone with oval and lobed intraclasts of the phospho-
rites (grey) and larger oval concretion of carbonate (light grey).
Fig. 4. Sandstone with the thin layer of heavy minerals from Fig. 3.
Clastic grains of quartz, feldspars and especially sericite in the ma-
trix (white scales) are oriented transversally to the thin layer of
heavy minerals. Go 7, transmitted light, crossed polars.
Fig. 3. Sandstone with a thin layer of heavy minerals represented by
zircon (grey) and ore minerals, mainly U-Ti oxides (black). Go 7,
transmitted light, parallel polar.
varies from 1.0 to 0.5
according to visual scale of Folk
(1974). The sandstone is finely laminated. The lamination
consists of the alternation of laminae (parting lamination)
composed of grains of two different size classes (0.1 to 0.2
mm and 0.05 to 0.1 mm). Quartz is a dominant clastic mineral.
It is mostly of monocrystalline type and part of it is of volcanic
PERMIAN LACUSTRINE PHOSPHATIC SANDSTONE, WESTERN CARPATHIANS 269
contains shale intraclasts (up to 4 mm in diameter). Zircon oc-
curs as rounded grains as well as prismatic crystals (up to 40
m long) that are disseminated in the matrix. However, heavy
minerals, like zircon and ore minerals (grains up to 50
rarely up to 0.1 mm), are also concentrated along the horizon-
tal lamination of the sandstone (Figs. 34).
The fabric of the sediment is slightly pressure-deformed,
and the minerals show common recrystallization features.
Elongated quartz grains are preferentially oriented parallel to
the strips of white micas (Figs. 34). They are often slightly
recrystallized, mainly at the margins and along internal frac-
ture systems. The matrix of the sandstone consists of aggre-
gates of white mica associated with chlorite, apatite and car-
bonate, with subordinate amounts of albite and fine-grained
quartz. Strips of phyllosilicates are deformed by crenulation
cleavage. In general, muscovite prevails over chlorite, and it
is also more abundant in fine-grained sandstone. Chlorite
(from 0.1 to 0.2 mm) occurs in the form of disseminated
scales or sheets which alternate with muscovite. Tourmaline
is not oriented (grains from 0.01 to 0.1 mm). Ore minerals
are mostly disseminated in the sandstone (grains from 10 to
m, rarely up to 0.1 mm in size). They also form veinlets.
Fine-grained sandstone is accompanied by shale. The shale
shows lepidoblastic structure, and is dominated by musco-
vite, with subordinate contribution of chlorite, quartz, car-
bonates and ore minerals.
Mineralogy of phosphatic sandstone
There are two forms of apatite in the phosphatic sandstone:
a) Oval (Figs. 511), irregular elongated and lobed intrac-
lasts (mostly from 1 to 5 mm in size), which are mostly sub-
anisotropic in polarising light. Weak anisotropy of the inter-
locking apatite ground-mass can be observed under high
b) Small crystals (from 5 to 20
m in size) in the sandstone
matrix (Figs. 1213).
Microsphorite intraclasts are deformed and oriented paral-
lel to phyllosilicate layers in the matrix. They contain car-
bonate veinlets as well as fragments of quartz and feldspar of
smaller size than the corresponding fragments in the sand-
stone matrix (Fig. 7). The intraclasts show relics of the origi-
nal lamination of the microsphorite sediment. The lamination
embraces thin laminae enriched in extremely fine quartz de-
tritus. The morphology and character of internal deformation
of the intraclasts suggest that they were only partly indurated
during transport (Figs. 911). This implies that the intraclasts
originated from reworking and redeposition of an original
strata-bound microsphorite deposit by highly turbulent water
flow. Alpha-autoradiography of ore minerals (leucoxene, U-
Ti oxides) shows that they are concentrated around the intra-
clasts, and are also disseminated in the sandstone matrix
(Figs. 1415). Clusters of euhedral apatite in the sandstone
matrix represent a younger generation of phosphate, related
probably to the diagenetic cement formation (Figs. 1213).
The two generations of apatite are cut by quartz-carbonate
veinlets and by sulphides (Fig. 6). The chemical composition
of phosphate in intraclasts as well as in the sandy matrix cor-
Fig. 9. Oval and elongated intraclasts of phosphorite (light grey)
in the sandstone with clastic quartz grains (white). Go 4/1, trans-
mitted light, parallel polar.
Fig. 10. Folded plastically deformed intraclast of phosphorite
(light grey) in the sandstone with clastic quartz grains (white). Go
1/1, transmitted light, parallel polar.
Fig. 11. Oval aggregate of albite (in left) and elongated deformed
intraclast of phosphorite (light grey) in the sandstone. Go 3/2,
transmitted light, parallel polar.
origin. Clastic muscovite and chloritized biotite are less com-
mon. Scarce plagioclase grains of albite-oligoclase composi-
tion and up to 0.3 mm in size are noted. The sandstone also
270 VOZÁROVÁ and ROJKOVIÈ
responds to fluorapatite (Table 1). A well-defined empirical
relation between the carbonate content and the a-cell dimen-
sion of carbonate fluorapatite (francolite), the marine variety
of apatite, provides a method for calculating the CO
in the crystal lattice (Gulbradsen 1970 and Schuffert et al.
= 1.64 and
= 7.21 in our
samples (Go 24 and Go 3/2) does not indicate carbonate-ion
substitution in the fluorapatite which might be the result of
metamorphic purification of the crystal structure (Table 2).
The matrix apatite is accompanied by a diagenetic to very
low-grade metamorphic association of minerals represented
by Fe-dolomite, uraninite, U-Ti oxides, Ti oxides, framboidal
pyrite, chlorites, muscovite, and albite.
Fe-dolomite forms oval concretions up to several cm, and
it also fills fissures in association with quartz and sulphides
(Figs. 56). The Fe-dolomite is fine-grained in concretions
(grains up to 50
m), but it is coarser grained (0.2 to 0.5 mm)
in veinlets (up to 1 mm thick). The chemical composition of
the dolomite is shown in Table 3.
The following ore minerals occur in Goèaltovo phosphatic
sandstone: uraninite, U-Ti oxides, pyrite, pyrrhotite, magne-
tite, marcasite, chalcopyrite, tetrahedrite, bornite, covellite,
chalcocite and secondary iron hydroxides and torbernite
(Melnikova 1974; Rojkoviè et al. 1989b).
Uraninite forms small grains (2 to 10
m across) concen-
trated at the margins of Ti-oxides. Alpha-autoradiography
suggests that uraninite also rims apatite intraclasts.
Fig. 12. Columnar and hexagonal sections of recrystallized apatite
(darker with higher relief) in the sandstone matrix. Go 21, trans-
mitted light, parallel polar.
Fig. 14. Grains of U-Ti oxides (black) in the sandstone. Go 21,
transmitted light, parallel polar.
Fig. 13. Columnar and hexagonal sections of recrystallized apatite
(light grey) in the sandstone matrix. Go 21, SEM-BEI.
-autoradiography confirms accumulation of uranium in
the grains of U-Ti oxides from Fig. 13.
Table 1: Chemical composition of apatite.
Atomic proportion (to 8)
PERMIAN LACUSTRINE PHOSPHATIC SANDSTONE, WESTERN CARPATHIANS 271
U-Ti oxides occur in the form of small grains up to 0.1
mm disseminated in rock. Alpha-autoradiography confirms
radiation of alpha particles from isolated grains of leucox-
enized ore minerals (Figs. 1415). Their inhomogeneity ob-
served under scanning electron microscopy as well as their
chemical composition suggest that they represent inter-
growths of uraninite and Ti oxides (uranium-bearing leu-
coxene, Table 4).
Rutile frequently occurs as elongated and irregular grains
up to 0.2 mm across showing brown and beige internal re-
flection and twinning lamellae in reflected light. The elon-
gated grains often show orientation concordant to cleavage.
The trellis-like texture of Ti-oxides (up to 0.1 mm) represent-
ing replacement of ilmenite by Ti-oxides in former allogenic
Fe-Ti oxides is rarely observed (Fig. 16). Rare rounded
grains of magnetite up to 40
m are noted.
Pyrite grains (up to 10
m) and framboidal aggregates (up
m) are disseminated in rock (Fig. 17). In Permian
rocks of the Western Carpathians more abundant framboidal
pyrite has been found only in the continental arkosic sand-
stone with abundant coalified plant remnants in the Hronic
Unit of the Kozie Chrbty Mts. (Rojkoviè 1997).
Chlorites are represented either by fine-grained aggre-
gates showing preferential orientation in the matrix or by dis-
ordered aggregates in cavity fills and fine veinlets. Both
Fig. 17. Partly recrystallized framboidal aggregate of pyrite
(white) in the sandstone. Go 1, SEM-SEI.
Fig. 16. Trellis of rutile (light grey) represents relict of clastic Fe-
Ti oxide replacement. Go 21, reflected light, parallel polar.
(Berry et al. 1974)
Table 2: X-ray diffraction analyses of fluorapatite.
Table 3: Chemical composition of carbonate in the sample Go 23.
types of chlorites show the same optical features and have
similar chemical composition.
The analysis of chlorite and muscovite was done in the
Laboratory of electron microanalysis of the Geological Sur-
vey of Slovak Republic in Bratislava using a JEOL-733 SU-
PERPROBE electron microprobe. The accelerating voltage
was 15 kV, the beam current 1112 nA and the counting time
20 sec. Natural and synthetic standards were used for calibra-
tion, and a ZAF correction procedure was employed.
Table 4: Chemical composition of U-Ti oxides in the sample Go 20.
272 VOZÁROVÁ and ROJKOVIÈ
The studied chlorites belong to the Mg-Fe chlorite group
(Table 5). They contain more Fe than Mg, and consequently
show a negative optical character. The dark colour of the
chlorites as well as their distinct pleochroism points to the
prevailing content of Fe over Mg. According to the common-
ly used classification of Hey (1954), the composition of the
chlorites corresponds to trioctahedral chlorite of thuringite
group (calculated on the basis of 28 oxygens). The chlorites
contain 5.35 to 5.56 Si atoms and have a Fe/(Fe+Mg) ratio of
0.39 to 0.42 with Fe
of 3.57 to 3.77. This is within the
range of ripidolite. Subordinate chlorite with higher content
of Fe belongs to the chamosite group. The content of 5.66 to
5.80 Si atoms and ratio Fe/(Fe+Mg) of 0.38 to 0.41 is within
the range of picnochlorite.
Muscovite forms aggregates of fine oriented scales, which
are bent by crenulation cleavage in some places. The clastic
micas can be distinguished from the neoformed muscovite by
their shape and distinctly larger size. They are irregularly
disseminated within the rock fabric and show secondary al-
teration features at their margins. Chemical analysis (Table
6) indicates the dioctahedral character, with a content of 6.1
to 6.4 Si atoms and approximately 4 (4.064.2) ions in Y po-
sition (calculated on the basis of 22 oxygen atoms). The
composition of the analysed muscovite is characterized by
(Mg, Fe) of 0.33 to 0.47 and Al
of 5.4 to 5.6. The Si/Al
ratio in tetrahedral component is greater than 6:2. This is
equilibrated by substitution of Al by bivalent ions in octahe-
dral component. The dominant interlayer cation in X position
is K, with a subordinate contribution of Na and Ca (with
more than 1.7 atoms).
Albite is represented by xenomorphic grains often without
twinning. Its chemical composition is close to pure albite (99
mol. % of albite component and 1 % of anortite plus ortho-
A younger generation of pyrite, pyrrhotite, chalcopyrite and
marcasite in carbonate and quartz-carbonate veinlets repre-
sents a hydrothermal association of minerals. Carbonate
grains up to 0.5 mm form aggregates and veinlets showing
pressure twinning in the reflected light. Xenomorphic grains
of pyrrhotite (0.05 to 0.2 mm in size) forming aggregates up
to 2 mm occur in close association with chalcopyrite (0.1 to
0.5 mm) which encloses euhedral pyrite (Fig. 18). Euhedral
grains of marcasite (up to 5
m) rim and replace pyrrhotite.
Goethite and torbernite are products of supergenic alter-
ation. Goethite forms colloform and zoned aggregates up to
several mm in size. Pseudomorphs of goethite replacing py-
rite crystals and framboidal pyrite are common. Torbernite
scales (from 10 to 20
m across) are disseminated in sand-
stone as well as in the apatite intraclasts (Fig. 19). They rim
phosphorite intraclasts and form veinlets (up to 20
filling fissures of the rock. Green internal reflection in re-
flected light is characteristic.
Atomic proportion to 28 oxygen
*MF = Fe/Fe + Mg
Atomic proportion to 22 oxygen
Table 5: Chemical composition of chlorites (in weight %).
Table 6: Chemical composition of muscovite (in weight %).
PERMIAN LACUSTRINE PHOSPHATIC SANDSTONE, WESTERN CARPATHIANS 273
Fig. 19. Torbernite scales (white) in the margin of phosphorite in-
traclast (grey) and in the quartz (black). Go 21, SEM-BEI.
Fig. 18. Crystals of pyrite (py) in pyrrhotite (po) and chalcopyrite
(ccp). Go 5, reflected light, parallel polar.
Grade of metamorphism
The assemblage of metamorphic minerals represented by
muscovitechloritealbite is very constant through a broad
temperature range, from the latest stage of diagenesis to a very
low- and low-grade of metamorphism. It is indicated by the
presence of high-aluminium Fe-chlorite, which is characteris-
tic of Al-Fe rich protolith. These trioctahedral chlorites con-
tain 12 cations in octahedral component on the basis
and an approximately equal content of Al in both
(tetrahedral and octahedral) components.
The chlorites represent a group of minerals of variable
composition reflecting the chemical conditions of their ori-
gin. Cathelineau (1988) demonstrated the application of a
chlorite geothermometer based on the Al
content of chlo-
rite in hydrothermally altered andesite. An increase in Fe
and decrease in the octahedral vacancy accompanies this
Si and Fe
Mg substitutions in chlorite reflect
changes not only in temperature (Kranidiotis & MacLean
1987) but also in the oxygen and/or sulphur fugacity of the
coexisting fluids (Walshe 1986; Bryndzia & Scott 1987).
Several calculations of the chlorite geothermometry were
based on these series of linear relations (Cathelineau &
Nieva 1985; Cathelineau 1988; Jowett 1991; Zang & Fyfe
1995). The temperatures of the studied chlorites, calculated
on the basis of several methods, vary in the range from 250
to 366 °C (Table 7).
Methods taking into account X
gave higher temperature
than those using only Al
. The differences in temperature
are about 60 °C calculated in the single chlorite pairs by the
different methods. The empirical models of Cathelineau &
Nieva (1985) and Zang & Fyfe (1995) indicate maximum
temperatures lower than 300 °C (around 250 to 290 °C),
which correspond to very low-grade metamorphism. The
wide range of the calculated temperatures may reflect insuf-
ficient equilibrium of coexistent chlorite pairs. No geother-
mometer includes the whole range of natural conditions with
different temperatures, coexisting mineral phases, Fe/
(Fe+Mg), oxygen fugacity etc.
The associated muscovite belongs to low Na-bearing white
mica with Na/(Na+K) values from 0 to 0.12 mol. %. Negligi-
K substitution has no effect on a and b cell dimen-
sions. The chemical composition of muscovite has been used
for numerical calculation of b
values and the following
geobarometric estimations according to the method proposed
by Guidotti et al. (1989). The average b
value calculated on
the basis of
Al and Si content atoms reaches
0.9009 nm (n = 13 and standard deviation = 0.0006 nm).
Guidotti & Sassi (1986) compared this value to the boundary
between the low- and medium-grade of regional metamor-
phism based on the division of the metamorphic series in the
sense of Miyashiro (1961). It corresponds to data from the
Barrowian metamorphic terrain, which is well described
from Scotland (Fettes et al. 1976).
The climax of regional metamorphism of the títnik For-
mation sediments cannot be estimated precisely due to the
very broad stability field of the chlorite-muscovite-albite as-
semblage. The illite crystallinity indicates temperatures from
200 to 250 °C (ucha & Eberl 1992), which correspond to
the minimum temperatures calculated according to the chlo-
& Nieva (1985)
Zang & Fyfe
Table 7: Temperatures calculated according to different chlorite
274 VOZÁROVÁ and ROJKOVIÈ
shale sandstone sandstone sandstone sandstone
Sample Go 5 Go 5a Go 7 Go 9 Go 13 Go 15 Go 21 Go
Go 24 Go
182 173 140
900 1800 1000
12.40 13.10 21
1590 1990 3300 5250 5900 3600 2510 3320 2630
620 573 340
4.8 13.9 37
rock* sandst. sandst. shale shale sandst. sandst. sandst. sandst. sandst. sandst.
*sandst. = sandstone
Table 8: Chemical composition of rocks.
Table 9: Trace elements in rocks (in ppm).
Table 10: Rare earth elements in sandstones (in ppm).
Fig. 20. Distribution of the rare earth elements in the sandstone
Geochemistry of phosphatic sandstone
The major and minor elemental analysis of the phosphatic
sandstone reveals very distinct enrichment in CaO (15 to 28
weight percent) and P
(12 to 18 weight percent), which
reflects the abundance of apatite and Fe-dolomite. Higher
loss of ignition (LOI), from 3 to 7 weight percent is mainly
due to loss of CO
during ignition of Fe-dolomite (Table 8).
The trace element analysis of the sandstone shows in-
creased uranium content and moderately increased lead con-
tent. Concentration of these elements confirms the presence
of uranium mineralization in the study sequence (Table 9).
Increased concentration of copper could be correlated to
chalcopyrite and, to a lesser extent, to torbernite. Phosphatic
sandstone near Goèaltovo contains up to 500 ppm of REE
and up to 250 ppm Y (Table 10). The nature of distribution of
REE and Y in the rock paragenesis remains unknown,
though we presume that they are bound to apatite and urani-
um minerals. Earlier results suggested the presence of slight
negative Ce anomaly in the phosphatic sandstone (Rojkoviè
1997). However, the detailed AAS-ICP analysis done for the
purpose of this study revealed no negative Ce anomaly in the
phosphatic sequence (Fig. 20).
Phosphatic sediments of the títnik Formation represent a
part of transgressive sequence reflecting transition from the
continental to the sabkha-lagoonal sedimentary regimes (Fig.
21). The following lithofacial features were observed:
1. gradual development of the títnik Formation from the
coarse-grained continental Roòava Formation;
2. distinct upward decrease of grain-size in siliciclastic
sediments and transition to lagoonal terrigenous-carbonate
facies in the upper part;
3. rapid vertical changes of lithology, which are well docu-
mented in the phosphorite-bearing sequence.
PERMIAN LACUSTRINE PHOSPHATIC SANDSTONE, WESTERN CARPATHIANS 275
The redeposition of phosphorite clasts indicates abrupt
changes of the paleoenvironment, from a low-energy phos-
phogenic regime to a high-energy regime strongly influenced
by traction flows of fluvial distributary channels.
The main argument supporting the idea of continental ori-
gin of these phosphatic sediments is the absence of marine
fauna. Moreover uf (1963) has found fresh-water bivalve
tests of the species Carbonicola. On the basis of this fact and
on the observed sedimentological features, we interpret the
títnik Formation phosphatic sediments as lacustrine depos-
its. Cyclic alternation of sandstone and shale with well-de-
veloped bedding is a typical feature. The shale contains
sandy laminae and considerable amounts of silt detritus. The
sandstone shows massive structure with moderate sorting,
and represents traction flow sediment. Sorting ranges from
0.5 to 1.0
according to the visual scale of Folk (1974). The
moderate sorting of lenticular sandstone bodies is the result
of deposition in river distributary channels which advanced
into the lacustrine basin. These sediments contain phospho-
rite intraclasts and shale clasts. Rapid influx of clastic detri-
tus and sudden progradation of detrital material into the
lacustrine domain was associated with down-slope redeposi-
tion by a system of flows, similar to turbidite currents. This
sedimentary process is documented by graded bedding of the
sandstone. The fine-grained, horizontally laminated sedi-
ments indicate a low energy sedimentary realm.
Lacustrine phosphorite represents a unique type of phos-
phate accumulation. Concentration of phosphate minerals
was described in recent eutrophic lakes (Kleeberg & Dudel
1997; Penn & Auer 1997) as well as in oligotrophic lakes
(Lake Baikal, Callender & Granina 1997). Phosphate miner-
als were also reported from the Upper Carboniferous coaly
tonsteins associated with limnic coal-bearing facies
(Rókowska 1990; Stadler & Werner 1962; Burger et al.
Fig. 21. Facies section of the títnik Formation sedimentary basin. Explanations: 1 sandstone with subordinate conglomerate interca-
lations, 2 sandstone lithofacies, 3 siltstone, mudstone, shale with intercalations of sandstone, locally sandy turbidite, 4 shale
with subordinate intercalations of siltstone and fine-grained sandstone, 5 dolomite, dedolomite, shale, 6 phosphatic sandstone, 7
sediments of the Roòava Formation, 8 rock complexes of the Early Paleozoic basement.
1997). A characteristic feature of recent eutrophic lakes is a
low content of oxygen and high content of nutrients. They
are shallow (up to 18 m), transparent only over a few meters
of water column, and their drainage area has flat relief. The
interpretation of a continental origin for the phosphatic sedi-
ments in the títnik Formation is based on the absence of any
faunal assemblages. Abundant fauna is typical of shallow
water marine phosphates as well as in the associated sedi-
ments. Sedimentary features of the títnik Formation indi-
cate a high-energy depositional regime. Redeposited intrac-
lasts of phosphorite showing in places plastic deformation
are here commonly observed. The clasts of phosphorite are
mostly structureless and cryptocrystalline. The remnants of
the original lamination can be seen in some clasts. Inclusions
of fine-grained siliciclasts are common. However, the origin
of the investigated primary phosphates can hardly be docu-
mented with certainty because of considerable post-deposi-
tional alteration of the sequence.
Rivers supplied particulate phosphorus from weathered
rocks. Continental weathering is the most important source
of phosphorus. Föllmi (1995) described the high dependence
of the total phosphorus flux rate on total and chemical conti-
nental weathering. Coupling processes between climate and
continental weathering (changing from a high rate of total
weathering to prevalent chemical weathering) controlled this
mechanism. Several authors (e.g. Fox et al. 1986, the modern
Amazon estuary) described phosphorus enrichment in mod-
ern rivers and estuaries. The original phosphate deposit was
formed in a freshwater anoxic basin with high microbial ac-
The depositional model of the títnik Formation assumes
sedimentation in a relatively flat drainage area with occur-
rences of limnic ponds (Vozárová & Vozár 1988). The phos-
phorus was bound to iron hydroxides during transport and it
276 VOZÁROVÁ and ROJKOVIÈ
was released by reduction in suboxic/anoxic bottom water or
in the sediment pore waters. This mechanism was described
from shallow marine and deltaic sedimentary systems (Bern-
er 1973; Krom & Berner 1981 and de Lange 1986).
Apatite precipitated most probably within the topmost part
of an organic-rich sediments column, as a result of complex
phosphorus transformations in the interface environment.
The common association of framboidal pyrite and apatite
suggest that the precipitation took place in the upper part of
anoxic sulphidic diagenetic zone and was accompanied by
intense degradation of organic matter. The sediments in most
eutrophic lakes are enriched in organic sulphur (Urban et al.
1999). Sedimentary formation of pyrite is consistent with an-
oxic conditions at the sediment-water interface, the deposi-
tion of organic-rich sediments, and severe eutrophication
(Manning et al. 1999). Pyrite framboid formation is consid-
ered to be a consequence of greigite formation in weakly re-
ducing conditions spatially linked to redox interfaces (Wilkin
& Barnes 1997).
The presence of Fe-chlorite suggests the existence of a thin
suboxic diagenetic zone in surface sediment. Precipitation of
the phosphates could also be affected by the composition of
detritus, which was locally extremely rich in felsic rhyolite
material. Volcaniclastic detritus was poor in Na, K, Ca, Mg
ions, and, on the contrary, enriched in P. However, aggres-
sive acid waters of eutrophic lakes decomposed volcaniclas-
tic detritus resulting in the increased water alkalinity. A suf-
ficient Ca content enabled the formation of microsphorite,
most probably under microbial control. Bacterial concentra-
tion of dissolved phosphate could also lead to precipitation
of apatite due to concentration/release cycles associated with
oscilation of the suboxic/anoxic interface (Gächter & Meyer
1993). Free Na ions could be adsorbed by clay minerals,
which were most probably represented by smectite. This sug-
gests complex and multi-stage origin of the títnik Forma-
tion phosphatic sediments.
The observed sedimentary structures and the evidence of
phosphorite redeposition allow us to suggest recurrent changes
in the phosphogenic environment, in which traction flows af-
fected distribution of phosphatic particles and their mixing
with siliciclastic sediments. This process might reflect water-
level fall, during which river systems invaded the lacustrine
environment, and, in extreme cases, caused down-slope
transport of detrital phosphorite. A flat drainage area could
be suggested by the absence of coarser-grained clastic sedi-
ments (conglomerate and coarse-grained sandstone). Rede-
position of phosphorite clasts could also occur due to high-
energy events, like storms. This process could lead to
disturbance of the water column stratification and to the mix-
ing of anoxic bottom water with oxygenated water resulting
in further adsorption of phosphorus by ferric iron.
The secondary stage of phosphate precipitation occurred
during later stages of diagenesis. Apatite precipitated from
anoxic pore waters to form cement between siliciclastic
grains as well as thin rims around the microsphorite intrac-
lasts. The precipitation of apatite was accompanied by for-
mation of Fe-chlorite. During diagenesis, smectite was re-
placed by illite, the excess sodium was bound in albite, and
uranium was adsorbed by phosphorite intraclasts. The subse-
quent very low-grade metamorphism affected the recrystalli-
zation of microsphorite and the formation of a chlorite-albi-
te-muscovite assemblage from diagenetic chlorite and smec-
tite. Alpine hydrothermal processes have contributed to the
formation of quartz-carbonate veinlets with sulphides that
cut phosphorite intraclasts as well as apatite aggregates in
cement. The products of supergene processes are iron hy-
droxides and torbernite.
The sandstone facies of the títnik Formation contains in-
traclasts of microsphorite and small crystals of apatite in the
matrix. Apatite is accompanied by uranium mineralization,
which is represented by uraninite and U-Ti oxides. Pyrite,
pyrrhotite, marcasite, and chalcopyrite occur in quartz-car-
bonate veinlets. The phosphatic sandstone shows distinct en-
richment in phosphorus (up to 18 weight percent P
flecting abundance of apatite. The total REE content is
moderately high, with maximum up to 500 ppm and Y up to
The phosphatic sandstones in the títnik Formation reflect
phosphogenesis in a lacustrine environment that was invaded
and destroyed by fluvial systems. Finely laminated shales
and siltstones, commonly interlayered with thin turbidite
sandstones represent the lacustrine part of the sequence. The
fine-grained sediments show abrupt facies changes towards a
belt of fluvial distributary channel sandstones and channel
fills. Sedimentary structures indicate recurrent changes of the
environment dynamics, from low to high-energy conditions.
Intraclasts of microsphorite in the sandstone are interpreted
to be the result of reworking and winnowing of original stra-
ta-bound phosphate deposits formed in an organic carbon-
rich eutrophic lake. Phosphorus was concentrated in this en-
vironment as a result of riverine supply of particulate P
phases as well as phosphate sorbed on ferric iron com-
pounds. Under anoxic conditions, phosphorus was liberated
into the pore waters of lacustrine sediment and aided the pre-
cipitation of apatite. This iron redox pump mechanism was
microbially controlled and concentrated phosphorus in a thin
suboxic and in the upper part of an anoxic sulphidic diage-
netic zone in organic-rich lacustrine sediments.
Subsequent diagenetic to very low-grade metamorphic
processes caused recrystallization of the primary apatite and
formation of the associated minerals, including Fe-dolomite,
chlorite, muscovite, albite. During this process phosphates
adsorbed U, Y, REE, Cu and Pb. The Alpine hydrothermal
processes mobilized disseminated elements and concentrated
them into the sulphides of quartz-carbonate veinlets.
Acknowledgements: The study was partly supported by
Grant 1/4090/97 of VEGA. We thank ¼. Pukelová from
Geological Institute of Slovak Academy of Sciences, J.
Kubová from Faculty of Science of Comenius University and
P. Koneèný from Geological Survey of the Slovak Republic
for the analyses of some of the rocks and minerals. This
manuscript benefited greatly from the reviews of K.P. Kra-
jewski, Z. Kukal and M. Miík.
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