GEOLOGICA CARPATHICA, 49, 4, BRATISLAVA, AUGUST 1998
MAIN FEATURES OF THE PRE-GOSAU PALEOKARST
IN THE BREZOVSKÉ KARPATY MTS.
(WESTERN CARPATHIANS, SLOVAKIA)
Geological Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 842 26 Bratislava, Slovak Republic
(Manuscript received March 17, 1998; accepted in revised form June 16, 1998)
Abstract: The considerable areal extent and great thickness of Middle/Upper Triassic carbonate sequences favourably
influenced the development of paleokarst during the Paleoalpine karst period in the Brezovské Karpaty Mts. Carbon-
ate formations provide data concerning the first-pre-Gosau-phase of the Paleoalpine karst period. Freshwater lime-
stones, bauxites, reddish ferrugineous silty clays, Valchov Conglomerate, shallow doline-like depressions and deeper
canyon-like forms represent the most important pre-Gosau karst sediments and forms.
Key words: Cretaceous, pre-Gosau paleokarst, doline- and canyon-like depressions, red clays, bauxites.
The fundamental features of the nappe structure in the Cen-
tral Western Carpathians originated during the Cretaceous
(Plaienka 1997). The Paleoalpine (Uppermost Albian/Cen-
omanian-Senonian; Roth 1970) and Mesoalpine (Trümpy
1960) or Epipaleoalpine development (Èinèura 1990)
caused subaerial development of extensive parts of the
Western Carpathians (Èinèura 1990; Michalík & Èinèura
1992; Èinèura & Köhler 1995). Contributions which also
deal with older karst periods of the Alpine epoch started to
appear only during the last decade. Systematic research on
karst phenomena older than Neoalpine features (Miocene,
Pliocene) was initiated. The Paleoalpine karst period (karst
period and karst phase are used here in the sense of Bosák et
al. 1989) was defined as the longest and most important pa-
leokarst period in the Western Carpathians (Èinèura 1990;
Èinèura & Köhler 1995).
Relics of forms and sediments belonging to Paleoalpine
karst can be found in practically all Slovak mountains in
which Middle/Upper Triassic limestones and dolomites occur.
The karst of the Brezovské Karpaty Mts. (Fig. 1) has been
studied for more than five decades. The Pannonian (Upper-
most Miocene) and younger karstification was thought to be
the oldest karst phenomena until a short time ago. A summary
of previous contributions describing Pannonian and younger
karst forms was collected by Stankoviansky (1982).
A brief outline of geology with regard to paleokarst
The region of the Brezovské Karpaty Mts. is mostly com-
posed of Mesozoic units belonging to two individual cycles:
1. pre-Gosau (Triassic to Lower Cretaceous), and 2. Gosau
(Upper Cretaceous). The marginal parts and embayments
into the mountain consist of Neogene sediments.
Pre-Gosau paleokarst developed on Middle/Upper Trias-
sic carbonate complexes of the Nedzov Nappe. Wetterstein
Dolomite (Ladinian to Kordevolian, 300 to 500 m thick) and
Hauptdolomite (Carnian to Norian, 400 to 600 m thick)
dominate in the structure of the mountain. Owing to the
thickness and large extent of both dolomitic units in subsur-
face and nearsurface of the mountains, a large number of
karst forms developed in them.
The Valchov conglomerates (Coniacian) as a basal unit of
the Brezová Group (Senonian; Samuel et al. 1980; Salaj et
al. 1987) represent the most important factor to distinguish
the pre-Gosau karst from other karst forms. The conglomer-
ates transgressively overlay karstified Upper Triassic lime-
stones and dolomites.
Sediments belonging to the Gosau cycle unconformably over-
lay the Hauptdolomite, Wetterstein Dolomite and other Middle
Triassic limestones. Therefore, it can be expected, that Jurassic
and Lower Cretaceous carbonate sequences destroyed by the
pre-Gosau karst solution before the Senonian in numerous plac-
es were only several metres to several tens of metres thick (Fig.
2). This idea is supported, for example, by the occurrence of spi-
cules of sponges and radiolarians in red clayey or silty matrix of
Fig. 1. Orientation map.
the Valchov conglomerates. Such occurrences can be interpreted
as insoluble residua of Jurassic radiolarian limestones and spong-
olites (Borza 1962; Èinèura 1997a). The first phases of the Pale-
oalpine karst period are recorded by this way in carbonate forma-
tions of the Brezovské Karpaty Mts.
The following karst sediments and morphological forms
belonging to pre-Gosau paleokarst can be distinguished: 1.
Freshwater limestones, 2. Boehmite-kaolinite bauxite, 3. Red
ferrugineous silty clays, 4. Valchov Conglomerate, 5. Shal-
low doline-like depression, and 6. Deeper canyon-like de-
1. Occurrences of freshwater limestones have been known
in the Brezovské Karpaty Mts. (Pustá Ves Formation,
Michalík et al. 1993). Relatively extensive outcrops N of
Koèín village represent the most important site (Perel 1964),
consisting of brown to chocolate brown thickly bedded to
massive limestones with abundant organic remnants (especial-
ly of algae). They overlay the Wetterstein Dolomite and can be
Fig. 2. Lithostratigraphic section of the Nedzov Nappe and the Senonian Gosau facies, A modified after Salaj et al. (1987), and B
present interpretation: 1sandy shale, sandstones (Scythian), 2Gutenstein Limestone (Anisian), 3Steinalm Limestone (Anisian), 4
Reifling Limestone (Ladinian), 5Ramin Limestone (Ladinian), 6Wetterstein Limestone (Anisian to Ladinian), 7Wetterstein Dolo-
mite (Carnian), 8Lunz Formation (Carnian), 9Hauptolomite (Norian), 10Dachtein Limestone (Rhaetian), 11crinoidal limestones
(Liassic), 12Oberalm and Barmstein Limestones (Malmian), 13marls and clayey limestones (Lower Cretaceous), 14gap (Barremi-
an to Turonian, about 20 Ma), 15freshwater limestones (?Turonian), 16Valchov Conglomerate (Coniacian), 17marls and sand-
stones (Santonian), 18marls and sandstones (Campanian), 19limestones and conglomerates (Maastrichtian), 20boehmite-kaolinite
bauxite (Lower to ?middle Cretaceous).
MAIN FEATURES OF THE PRE-GOSAU PALEOKARST 299
dated, most probably, to middle, or basal Upper Cretaceous
(?Turonian to Lower Coniacian; Salaj et al. 1987).
We regard them (together with bauxites) as the oldest
known karst sediments of the pre-Gosau paleokarst deposited
in lacustrine basins developed especially on the surface of
karstified carbonate complexes (uvala-like depressions?),
mostly on the Wetterstein Dolomite. Pebbles of such fresh-
water limestones were found in the Valchov conglomerates
in the nearby Myjavská pahorkatina Upland.
2. Red (probably lens-shaped?) boehmite-kaolinite bauxite
is relatively rare. It represents a new find of bauxite in Slova-
kia. Minerals (boehmite, kaolinite, chlorite) were detected by
X-ray analysis (Èinèura 1997b; ucha, pers. comm). Bauxite
occurs in the bottoms of deeper canyon-like depressions un-
derlying the Valchov conglomerates, and represents the old-
est Paleoalpine karst sediments.
3. Red ferrugineous silty clays often fill different karst
cavities; sometimes they also compose the matrix of the Val-
chov conglomerates. The clay fraction consists of chlorite,
kaolinite, illite and illite/smectite (ucha, pers. comm.), and
it does not differ substantially from the materials known
from adjacent areas (Èinèura 1997a).
4. The coarse- and medium-grained Valchov conglomer-
ates sometimes pass into breccias. The clasts are unsorted to
poorly-sorted, angular to semi-ovate, composed of different
limestones and dolomites of Triassic (60 to 75 %) and Juras-
sic age (25 to 30 %), and of some eruptive rocks (Salaj et al.
1987). The variable matrix is formed by red ferrugineous
clay and/or silty clay, or fine clasts of limestone, dolomite
5. Shallow, only several metres deep and 2 to 3 m wide do-
line-like depressions are relatively common feature in the
Brezovské Karpaty Mts. Such depressions and different
kinds of fissures developed in dolomites and limestones are
sometimes filled with red ferrugineous clays. The Valchov
conglomerates represent a more frequent fill (Fig. 3). Their
matrix consists of red clay or other materials. It can be stated
without any doubt that such shallow doline-like depressions
are older than the basal conglomerates and they originated
during the pre-Gosau paleokarst phase before the Senonian,
i.e. within the first phase of the Paleoalpine karst period.
6. Deeper depressions, most probably of canyon-like
shape, occur mostly in the NW part of the Brezovský Karst.
They are more or less, linear, but not strictly straight-lined.
They occur mostly on Hauptodolomites, less frequently on
Dachstein limestones. Their width on the surface does not
exceed a few tens of metres. The fill (bauxite, red ferrugine-
ous silty clays and Valchov conglomerates) indicates their
Marine deposition in the region of the present Nedzov
Nappe ended with a 20 to 30 m thick sequence of Lower Cre-
taceous marls and clayey limestones, about 120 Ma (Salaj et
Extensive areas of the Slovak Western Carpathians, as
well as of the Austrian Northern Calcareous Alps and Hun-
Fig. 3. Small doline-like depression W of Brezová pod Bradlom
village: 1Hauptdolomite, 2Valchov Conglomerate, 3debris.
garian Transdanubian Mid-Mountains were exposed to sub-
aerial destruction during the Turonian to Coniacian before
the transgression of the Gosau sea (Bárdossy & Kordos
1989; Leiss 1989; Èinèura 1990).
Deeper, probably canyon-like depressions developed be-
fore the Gosau transgression during the middle Cretaceous
indicating intensive entrenchment of karst streams. Pre-
bauxitic materialferrugineous silty claysuccessively
accumulated on the bottom of depressions. The material was
derived from weathering crusts on crystalline basements and
transported by wind during the dry climatic season or by
floods during the wet period. Deep karst depressions repre-
sented traps with the physico-chemical conditions necessary
for the bauxitization of ferrugineous silty clays and the origin
of boehmite-kaolinite bauxites (cf. Èinèura 1997b).
Karst solution in the pre-Gosau phase destroyed thickness-
es of several metres to several tens of metres of limestones,
especially of Jurassic age, in some places. Different shallow
doline- or uvala-like depressions were later formed on Wet-
terstein dolomites. Their bottoms were flooded during heavy
precipitation. Intermittent lakes originated with the growth
of freshwater algae which contributed to the deposition of
The character of the pre-Gosau karstification reflected the
position of theWest-Carpathian realm encircled by tropical or
subequatorial waters of the Tethys Ocean during the middle
Cretaceous (Èinèura 1987). The pre-Gosau karstification in
the Brezovské Karpaty Mts. probably, represents the first
manifestation of the Paleoalpine karst period; in other seg-
ments of the Western Carpathians it started later. The phase
was interrupted by the transgression of the Gosau sea after
about 20 Ma. The basal transgressive units (Valchov Con-
glomerate) unconformably covered and buried paleokarst mor-
phology and sediments.
Post-Gosau karst evolution
Sediments of the gradually deepening and differentiating
Gosau sea buried and conserved morphological forms and
sediments of the pre-Gosau karst of the Brezovské Karpaty
Mts. Paleokarst features were buried under a thick sequence
of marine sediments at the end of Paleogene.
The fact that Upper Cretaceous sandstones also occur in
Eggenburgian basal conglomerates indicates, that substantial
parts of the pre-Gosau paleokarst were covered by Gosau
sediments at the beginning of the Miocene. A significant
karstification phase probably developed only during the Ott-
nangian before the deposition of the Jablonica conglomerates
(Karpatian). Some parts of the pre-Gosau karst were ex-
humed at this time and exposed to a new karstification. Nev-
ertheless, clasts of Cretaceous sandstones are still present in
the Jablonica Conglomerate (Kováè 1985). The Brezovské
Karpaty Mts. have been a part of the West-Carpathian main-
land since the Karpatian. The exhumation of pre-Gosau karst
was probably completed and new forms and sediments be-
longing to the Neoalpine karst period developed.
1. Freshwater limestones (?Turonian to Coniacian), togeth-
er with bauxites, are thought to be the oldest known karst sed-
iments of the pre-Gosau paleokarst. They were deposited in
lacustrine basins developed especially on the surface of car-
bonate complexes. Limestone fragments occur in the Conia-
cian Valchov conglomerates.
2. Shallow paleokarst depressions filled with the Valchov
conglomerates, are older than their fill and originated during
the Paleoalpine karst period.
3. Deep karst depressions with occurrences of boehmite-
kaolinite bauxite represent the oldest morphological forms of
the pre-Gosau age.
4. The Brezovské Karpaty Mts. have been a part of the
West-Carpathian mainland since the Karpatian. The exhuma-
tion of pre-Gosau paleokarst practically finished at that time,
and new karst forms and sediments of the Neoalpine karst pe-
riods started to develop.
Acknowledgements: The contribution was supported by the
Common Scientific Grant Agency of the Ministry of Educa-
tion of the Slovak Republic and the Slovak Academy of Sci-
ences (Project No. 4079). The composition of the clay miner-
als (boehmite, kaolinite, chlorite) was analysed by Dr. V.
ucha from Comenius University (Mineralogy) and by Dr. L.
Pukelová from the Geological Institute of the Slovak Acad.
Sci., Bratislava (X-ray diffraction). The author would like to
give special thanks to Dr. Bosák for critical reading and valu-
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