GEOLOGICA CARPATHICA, 49, 5, BRATISLAVA, OCTOBER 1998
329339
LITHOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT
OF LOWERMIDDLE JURASSIC CRINOIDAL LIMESTONE
FORMATIONS OF THE VYSOKÁ NAPPE UNIT
(MALÉ KARPATY MTS., WESTERN CARPATHIANS)
EDUARD KOA
Slovak Geological Survey, Mlynská dolina l, 817 04 Bratislava, Slovak Republic
(Manuscript received February 4, 1998; accepted in revised form September 1, 1998)
Abstract: The LowerMiddle Jurassic sequence of the Vysoká Unit in the Malé Karpaty Mts. (Western Carpathians,
Slovakia) comprises a complex of crinoidal limestones. The paper suggests newly dividing this unit into four formations:
Trlenská Fm., Vývrat Fm., Prístodolok Fm. and Vils Fm., all of which are described in detail. Two of them, the Vývrat
and the Prístodolok Fms., are defined as new formal lithostratigraphic units.
A connection is supposed between rhythmical facies changes in these sediments and relative sea level fluctuation.
Two significant regressions are recognisable in a generally shallowing upward sequence with an uncertain number of
cycles of lower order between them. The influence of eustatic and regional tectonic activity control on relative sea
level changes has been not distinguished. The curve of sea level changes suggested by sequence stratigraphic analysis
is comparable to the curve published by Haq et al. (1988). Lateral facies changes have been studied across the Vysoká
Nappe Unit. The LowerMiddle Jurassic crinoidal complex is a part of a slope apron rimming the toe-of-slope of a
carbonate plateau which probably originated due to tectonic collapse of the large Triassic carbonate platform during
the Early Jurassic. Its proximal development (near to apex) was recognized at the SW and the distal development at
the NE edge of the Vysoká Unit. Sedimentation of the crinoidal limestones was terminated by an abrupt rise of the
relative sea level and followed by deposition of nodular limestone formations.
Key words: Lower Jurassic, Western Carpathians, carbonate sedimentology, lithostratigraphy, sequence stratigraphy,
sea level change, slope apron, crinoidal limestone.
Introduction
During the early 60s, several papers discussing the lithology
and stratigraphy of the LowerMiddle Jurassic crinoidal lime-
stones of the Vysoká Nape in the Malé Karpaty Mts. were pre-
pared, as a result of substantial research by the team of Mahe¾
and co-workers. The lithofacies characteristics of these sedi-
ments have been described in more detail by Kullmanová
(1965), Szalontay (in Mahe¾ 1966) & Pevný (1964). However,
no lateral and/or vertical facies relationships of the sedimentary
bodies of different development, their geometry and position in
the lithostratigraphic framework have been suggested by these
authors. Nevertheless, the research provided a great amount of
biostratigraphic data.
There are three main areas where the LowerMiddle Juras-
sic crinoidal limestones occur: Vývrat-Prístodolok, Buková
hora and Smolenice (sea below, Fig. 1). Fortunately, the out-
crops are distributed across the whole body of the Vysoká
Nappe Unit (the study area). For exact localization of the out-
crops, profiles and type localities see Koa (1997).
On the basis of the work mentioned above and after very de-
tailed field research the author proposes in the present paper to
divide the crinoidal complex into four formations: Trlenská
Fm., Vývrat Fm., Prístodolok Fm. and Vils Fm.; two of them
are suggested as new formal lithostratigraphic units. Within
these formations, some lateral lithological changes are evident
across the Vysoká Unit, supporting the idea of the paleodistrib-
utary system with its proximal deposits preserved at the SW
and the distal ones at the NE margin of the Vysoká Unit (see
Fig. 1. Geological sketch of the Vysoká Nappe Unit showing
distribution of the LowerMiddle Jurassic crinoidal limestones
(black areas) and location of the most important localities
(modified after Borza & Michalík 1987; Michalík 1997).
330 KOA
below). For this reason there are two descriptions given in
some of the definitions of the formations: one for the devel-
opment of the sediments studied at the type locality, and an-
other one for their lateral equivalents.
Trlenská Formation
The Trlenská Fm. was defined by Bujnovský et al. (1979) in
the Trlenská Valley in the Ve¾ká Fatra Mts. (S of Ruomberok)
in the Liassic sequence of the iprúò Group. In spite of the fact
that it was originally defined as a unit belonging to the Tatric
Superunit, this term has been also applied to the basal part of
the crinoidal complex of the Vysoká Unit in the Malé Karpaty
Mts. (Michalík in Plaienka et al. 1991).
In the study area this formation crops out at the E foot of
the crest part of the Prístodolok Hill, in the massif of Me-
saèná and in a wider area NW from Smolenice. Its thickness
is about 20 m at Prístodolok and 4060 m in the vicinity of
Smolenice (profile Smolenice, Fig. 2).
At the Prístodolok Hill the Trlenská Fm. is represented by
bedded (1020 cm in thickness) sandy crinoidal limestones,
fresh fracture surfaces are dark grey to blue-black, with ir-
regular nodules and longitudinal lenses of brown and grey si-
licites. Weathered surfaces are brown to brown-grey in co-
lour, with abundant quartz grains and silicified bioclasts
(unbroken, completely preserved shells of brachiopods, also
bivalves and belemnites are common) are clearly visible (Pl.
I: Fig. a). Microscopically, they are packstones composed
mainly of crinoidal detritus, coarse biodetritus, with clastic
sand-size quartz grains (510 %) and some foraminifers. In
this development, lithoclasts of grey biomicritic limestones
(see below) are common.
In the NE part of the study area the lateral equivalents of
these limestones crop out at several localities near
Smolenice (Hlboè Valley, Prielohy, Driny, see Koa 1997).
These are sandy crinoidal packstones to grainstones without
biomicritic lithoclasts, indistinctly bedded to massive and
grey on the weathered surface.
The base of the formation is not exposed in outcrops. In
the saddle between the Prístodolok and the Vysoká Hills,
however, the geomorphology as well as the outcrops of the
underlying Kopienec Fm. and the Trlenská Fm. in close
proximity allow us to localize their boundary. However, this
boundary documents a significant (and probably quite
sharp) change in sedimentation style from the marl and clay
dominated sediments of the Kopienec Fm. to crinoidal lime-
stones which is interpreted as a major regression H/S (Fig.
10) in this area.
The chronostratigraphical range is Sinemurian?Lotaring-
ian (Mahe¾ et al. 1966; Pevný 1964; Michalík 1997, personal
communication).
Vývrat Formation (newly suggested name)
The name of the Vývrat Fm. is after the locality of Vývrat
(road crossing, hunting cottage, Fig. 1) situated at the SW
edge of the study area.
The type profile of 55 m of stratigraphic thickness is found
in an little old quarry situated beside the former forest rail-
way at the S slope of the Prístodolok Hill (profile Vývrat 2).
The lower part of the natural exposure of the little klippe at
the left bank of the Vývrat creek ca. 150 m S (profile Vývrat
1) can serve as a reference profile for this formation. It is rea-
sonable to study both, the relatively fresh, weakly weathered
former, and the natural latter outcrop, for recognition of the
diagnostic lithological features of the Vývrat Fm. Further
larger outcrops of this formation are located on the S, SE and
W slopes of the Buková hora Hill (profile Buková hora), on
the S slopes of the Parná Valley and typically for the devel-
opment of the NE part of the study area in the Vrtichov Quar-
ry in the Hlboè Valley (NW of Smolenice) (profile Smolen-
ice, Fig. 1, also see Koa 1997). The thickness of the
formation is about 100 m.
The limestones are thick bedded to platy (10100 cm, most-
ly 1525 cm). Their typical textures are fine- to medium-
grained crinoidal packstones. The rocks are strongly silicified,
dark grey, grey to brown-grey on fresh fracture surfaces (occa-
sionally also red!, see Koa 1997), grey or brownish grey on
weathered surfaces. Typically a great amount (4090 %) of
large irregular lenses and stratiform layers of grey and brown
cherts occurs. The bedding planes (which are not necessarily
conformable with the primary bedding planes!, Fig. 5) are
characteristically wavy, probably due to compaction of a se-
lectively silicified sediment (Pl. I: Fig. b).
Thinning-upward cycles with occurrence of 0.53 cm
thick marly and about 5 cm thick nodular limestone interca-
lations are visible in this formation. In the upper part of it,
also layers of biodetrital, occasionally reddish to purple co-
loured limestones occur, showing features of the overlying
formation (Fig. 2).
On the weathered surface, lithoclasts (in some cases also
thin lenses and/or layers) of grey fine-grained biomicrites
are visible in a coarser grained crinoidal biomicritic matrix.
They are typical for the development exposed at the
localities Vývrat-Prístodolok and Buková hora. They are not
present in the development of the NE part of the study area.
The lateral equivalent of this formation in the NE part of
the study area is an alodapic complex of bedded (5 to 30
cm) crinoidal packstones intercalated by 1 to 10 cm thick
layers of marls, limy shales to bituminous shales which
enclose thin (0.1 to 3 cm) lenses and intercalations of the
crinoidal limestones identical with the neighbouring ones
(Pl. I: Fig. e). The limestones are grey to greyish brown on
fresh fracture surfaces, rusty brown on weathered surfaces.
The silicification is more considerable in the upper part of
the formation. Nevertheless, there are some small chert
nodules and lenses occurring throughout the formation.
These sediments represent a more distal, relatively deeper fa-
cies of the Vývrat Fm.
The base of the Vývrat Fm. is very obvious in the NE part
of the study area, where the grey thick bedded to massive
Fig. 2. Simplified lithological collumns of selected profiles and
lithostratigraphic scheme of the LowerMiddle Jurassic crinoidal
complex.
I
LITHOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT OF CRINOIDAL LIMESTONE FMS. 331
332 KOA
sandy crinoidal grainstones of the Trlenská Fm. are overlain
by the complex of rhythmically alternating crinoidal lime-
stones and marlstones of the Vývrat Fm. The upper boundary
is not evident. Conventionally it is based on the rate of silic-
ification; in the uppermost parts of the Vývrat Fm. the litho-
logical features are practically identical with those of the
overlying formation, however they are interlayered with
thick layers of stratiform cherts.
Chronostratigrafically this formation belongs to the Pliens-
bachian (Mahe¾ et al. 1966; Pevný 1964; Michalík 1997, per-
sonal communication). In the NE part of the study area
where, the overlying layers belong predominantely to the
Vývrat Fm., it is assumed that the stratigraphic range is
broader (PliensbachianBajocian?Bathonian), however, it
has not been proved on a profile.
Prístodolok Formation (newly suggested name)
The name is after the Prístodolok Hill at the SW edge of
the study area (Fig. 1).
The type profile is at a little klippe rising on the left bank
of the Vývrat Creek, about 300 m SE from the former hunting
cottage Vývrat, where a continuous outcrop of this formation
is known and parts of the under- and overlaying formations
are also exposed (profile Vývrat 1). Very good profiles ex-
posing up to 25 m stratigraphic thickness are found on the
rocky crest of the Prístodolok Hill (profile Prístodolok 1, 2)
as well as on the series of SW-NE oriented rocky ridges SE
from the Buková hora Hill (profile Buková hora). In the NE
part of the study area this formation is replaced by the
Vývrat Fm. Its thickness is about 35 m at the locality of
Vývrat-Prístodolok. At Buková hora the thickness of this
formation together with the overlying one (see below) is
about 100 m.
It is made up of grey, greyish pink, pink to purple red, in-
distinctly bedded to massive crinoidal nodular-like
limestones. The seemingly nodular character of these
limestones is partially due to the high content (095 %) of li-
thoclasts (nodules, intraclasts) of pink and grey fine-
grained biomicritic limestones. The lithoclasts are enclosed
in a coarser sandy crinoidal matrix. Their amount varies
rapidly vertically and laterally.
Vertically the decrease of micritic lithoclast content ap-
pears as an interlayer of a coarse grained, at Vývrat and
Prístodolok typically dark red sandy crinoidal biosparite
which may contain deformed white nodules. A
considerable concentration of coarse biodetritus including
fragments as well as complete belemnite rostra is very
characteristic. The presence of small (0.515 mm) beige ex-
traclasts i.e. exotic lithoclasts (?Triassic dedolomites
Miík 1997, personal communication, Pl. I: Fig. c) is typical.
The preferential tectonic deformation can cause a shaly char-
acter of these layers.
The lenses and layers of purely detrital limestones in a se-
quences of limestones rich in biomicritic lithoclasts are al-
ways found in the outcrops of this formation. Their thickness
and number vary rapidly both laterally and vertically.
The basal part of this formation is rich in small irregular
nodules and lenses to stratiform layers of orange and/or grey
silicites. Their abundance and size decrease upwards. In the
upper parts of the formation the silicites are rather rare and
their occurrence bears upon the zones of inhomogenities
such as, for example paleodistributary channels fills (Fig. 7,
see Koa 1997).
The succession from the Prístodolok Fm. to the overlying
Vils Fm. with sharp contact between them outcrops at the lo-
cality Vývrat-Prístodolok. At Buková hora the transition is
fairly continuous, indicating the lateral substitution of the
two lithofacies up to the base of the formation overlying the
Vils Fm. (Fig. 2).
Stratigrafically we assign the Prístodolok Fm. to the Toar-
cian. However, locally its stratigrafical range can be broader
(PliensbachianAalenian(?Bathonian at Buková hora),
Mahe¾ et al. 1966; Pevný 1964; Michalík 1997, personal
communication).
Vils Formation
Defined by Hauer (1853) as a complex of crinoidal lime-
stones with a huge amount of brachiopods. The name is after
the village of Vils in Tyrol (Austria). In the Carpathians it was
described by Hauer & Richthofen (1859) at the localities Stará
Kremnica and Dolhoja. túr (1860) applied this term to the Ju-
rassic crinoidal limestones of the Klippen Belt at the locality
of Dolná Súèa (now called the Krupianka and Smolegowce
Limestones).
In a complete profile with a stratigraphic thickness of 44 m
with transitions to the under- and overlying formations the
Vils Fm. crops out along the former forest railway on the S
slope of Prístodolok Hill (profile Vývrat 2). Laterally this
outcrop can be followed almost continually toward the little
klippe at the left bank of the Vývrat Creek to the W (profile
Vývrat 1) and toward the W brink of the crest of Prístodolok
Hill to the E (profile Prístodolok 1). Lensoid bodies of typi-
cally developed limestones of the Vils Fm. also crop out on
the small ridge SSE of Buková hora Hill (profile Buková
hora, Figs. 1, 2, see above, also see Koa 1997).
Fig. 3. Typical microfacies of crinoidal grainstones of the Vils Fm.
Vývrat. 2135 m, X, scale bar = 1 mm.
LITHOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT OF CRINOIDAL LIMESTONE FMS. 333
These are pink, greyish rose to grey, massive to indistinctly
bedded crinoidal grainstones (Fig. 3), predominantly coarse
grained, containing ca. 10 % of coarse sandy, or even coarser
clastic quartz grains. On weathered surfaces they are grey and
rough due to the quartz grains. Large (210 mm in diameter)
completely preserved crinoidal columns prepared by weather-
ing are also visible. The crinoidal ossicles are also conspicu-
ous on fresh fracture surfaces.
The upper boundary of the Vils Fm. is sharp, erosive at the
locality Vývrat-Prístodolok (Figs. 2, 9), with a layer of brecci-
ated biomicritic limestone at the base of the overlying forma-
tion of the true nodular limestones with rare occurrence or
lack of crinoidal detritus (lower nodular limestones after Borza
& Michalík 1987). In the range of Buková hora it has a contin-
uous transition to the same facies.
Stratigraphically the Vils Fm. is placed to the interval of
AalenianBathonian (Mahe¾ et al. 1966; Pevný 1964;
Michalík 1997, personal communication).
For lists of identified fossils as well as for discussion of fur-
ther problems related to determination of the lithostratigraphic
relevance of the sediments described above (such as the possi-
ble influence of their subaerial exposure, intensity and type of
weathering, variability in colour, relation between the primary
and secondarytectonically conditioned bedding, prob-
lems of irregular distribution of silicites and biomicritic litho-
clasts etc.) see Koa 1997.
Problem of nodularity and nodular character
of limestone of the Prístodolok Fm.
Miík (1964, p. 66) in the chapter discussing the problem
of the nodularity of the Lower Liassic untypical Adneth
limestones wrote: The nodularity of the untypical Adneth
limestones (with transitions to weakly crinoidal limestones)
is always due to their clastic structure. The nodules are in
reality clasts of micritic limestones often containing calcified
sponge spicules, with no crinoidal detritus. This description
corresponds very well to that of the character of the nodu-
larity of the limestones of the Prístodolok Fm. (even if their
composition: biomicritic lithoclasts in crinoidal matrix is
typical for both of the underlying formations of the crinoidal
complex as well).
In the lithoclasts of the biomicritic limestones, a relatively
high percentage (1020 %) of calcified sponge spicules is
very typical. They also contain (often unbroken, complete)
ostracodes, foraminifers and thin shelled bivalves (Fig. 4).
Crinoidal fragments and silt-size quartzs are relatively rare.
Microscopically they represent a characteristic spiculite mi-
crofacies in all of the Trlenská, Vývrat and Vils formations in
their typical development in the SW part of the study area.
The material of the lithoclasts may have been deposited in a
relatively deeper environment and, after erosion, been trans-
ported in semiplastic condition and redeposited together with
their obviously coarser sandy crinoidal matrix formed under
relatively shallower conditions (Fig. 4, Pl. I: Fig. d). The ma-
trix is composed of coarse crinoidal detritus, sand- and silt-
size clastic quartz, brachiopodal, bivalval and bryozoan biode-
tritus, with rare foraminifers but no sponge spicules and
Fig. 4. Thin section showing contact of coarser grained crinoidal
matrix and fine-grained biomicritic lithoclasts containing calcified
sponge spicules, ostracodes and small gastropodes. Prístodolok
Fm. Vývrat.147 m, X, scale bar = 1 mm.
Fig. 5. Bedding planes of limestones of the Prístodolok Fm. are
not parallel to stratification. The limestone is primarily enriched in
biomicritic lithoclasts (light). Nodules and lenses of silicites are
distributed symmetrically in these layers. Prístodolok Hill.
334 KOA
ostracodes. For the most part it is red stained by Fe-colloids.
Especially within the detrital interlayers the colloids clearly
mark out the internal structure of the strongly corroded crinoi-
dal ossicles (Pl. I: Fig. f). The percentage of micrite varies in
the range of 050 %.
The obvious heterogeneity of the nodules and the crinoi-
dal matrix (i.e. the differences in granulometry of the quartz
and biodetrital grains, differences in association and propor-
tion of the allochems, as well as the plastic deformation of the
lithoclasts and their reworking by erosion and transport) indi-
cate that the nodules are actually clasts (plasticlasts) form-
ing by redeposition of partially lithified and completely unlith-
ified sediments (Figs. 6, 7).
Macroscopically, the matrix is characterized by coarser
rough structure and relatively darker colours: pink to red on
the weathered surfaces, whereas the biomicritic lithoclasts
are generally pale grey to white and smooth (Fig. 5).
The amount of the biomicritic lithoclasts in the sandy crinoi-
dal matrix varies in a range of 595 % (Fig. 2). Depending on
the ratio between the two components the sediment shows fea-
tures of the true nodular limestones of various types. It is
probable that the pressure solution at the contacts of the pre-
lithified and relatively solution resistent biomicritic lithoclasts
played some role during the deep burial diagenesis of the sedi-
ments. However, evaluating the significance of these features
and the primary heterogeneous character of the sediments, in-
traformational breccia formation seems to be plausible.
Fig. 7. Detail of margin of distributary channel filled by mixture of
biomicritic lithoclasts (light, plastically deformed) and sandy and
crinoidal detritus. There are no or only rare lithoclasts found
outside the channel infill. Prístodolok Hill. Prístodolok Fm.
Prístodolok 220 m.
Fig. 6. Sedimentary model of origin of the facies found in the
proximal development of the crinoidal complex (see profiles
Vývrat. 1, 2, Prístodolok. 1, 2) showing how relative sea level
changes influenced sedimentation. (No scale. For more
explanation see text).
Discussion of indicators of sedimentary processes
and their importance for paleoenvironmental
reconstruction
An analysis of the controling factors of both the lateral and
vertical facies changes in the sedimentary processes is the sub-
ject of this chapter, on a small scale and also on a regional
scale.
Considering our knowledge of the investigated sedimentary
complex we cannot apply the approach of sequence stratigra-
phy all-embracingly. Use of the terms and categories of se-
quence stratigraphy in this paper is limited by various limiting
factors, such as:
insufficient precise (micro)biostratigraphical data;
imperfect, rather uncontinuous exposure;
different numbers of depositional cycles in the studied
profiles due to relatively rapid alternation of sedimentation
and erosion under conditions of changing energy;
problems of correct distinction of allocyclic and autocy-
clic processes;
LITHOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT OF CRINOIDAL LIMESTONE FMS. 335
Fig. 8. Blockdiagram showing facies zonation and development of
the crinoidal complex. (No scale. For more explanation see text).
Fig. 9. Obviously erosional contact between crinoidal grainstone
of the Vils Fm. and the overlying micritic limestone. Vývrat 2145
m, X, scale bar = 1 mm.
insufficient (or better lack) of correlative data on the rela-
tive sea-level changes in the related areas.
Discussion of the possible relation of the facies
changes to relative sea-level changes
There are several indicators of the relative sea-level chang-
es, such as (Fig. 10):
1) thinning upward of sequences (beds thicknesses) with in-
tercalations of marly and nodular limestones occurring in the
uppermost part of the Vývrat Fm. (see above);
2) periodical changes in the proportion of biomicritic lime-
stones and the crinoidal matrix;
3) periodically occurring layers of red coarse detrital crinoi-
dal limestones enriched in belemnite rostra;
4) periodical occurrence of exotic lithoclasts (up to 2 cm
large) of beige coloured microcrystalline limestones contain-
ing less than 1 % of silt-size clastic quartz (?Triassic dedolo-
mites, Miík, personal communication) exclusively fixed upon
those layers;
5) an oolitic ironstone layer with ferruginous crusts and
banded ?microbialites, considerably enriched in amonites just
below the base of the Vils Fm.;
6) sharp errosional contact between the Vils Fm. and the
overlying nodular limestone formation with a basal breccia
layer at the locality Vývrat-Prístodolok.
A model for the sedimentary processes and their relation
with the relative sea level changes, as will be explained here-
after, is illustrated in Fig. 6.
Soták & Plaienka (1996) described the same facies from
the northern part of the Veporic Superunit as a toe-of-slope ac-
cumulation. As we do not have enough data on the paleotec-
tonic setting of the study area, the author´s suggestion is to re-
gard the sedimentary paleoenvironment as a slope and toe-of-
slope s.l., with an area producing platform carbonate material
behind its upper margin, that is landwards.
Parts A) and B) of Fig. 6 show the facies zonation of the
sedimentary environment. A flat coast served as the source
area of lithologically well sorted (more than 99 % of quartz
grains) material. Kullmanová (1965) considering the elonga-
tion coefficient of the quartz grains (1.41.8) supposed its ori-
gin in acid magmatites and metamorphites. Practically no feld-
spars and very few small muscovites are present, as well as
rutile, zircon and epidote as accesoric constituents. The ab-
sence of kaolinite also indicates secondary origin of the silici-
clasts, which may have been redeposited from previously sort-
ed source rocks (e.g. Triassic terrigenous clastics). As for the
clay minerals, the X-ray difractography analysis only showed
the presence of illite.
The crinoidal meadows may have produced a large amount
of crinoidal detritus covering large areas of a relatively shal-
low submarine plateau (carbonate ramp), and trapped the
greater part of the terrigenous siliciclastics (mostly quartz).
The sediments consisting of 6080 % of lime mud (micrite)
were deposited on its more distal parts. During the regression
and lowstand systems tract (Fig. 6a) a considerable part of
the unlithified to weakly lithified sediment was eroded and
transported outside the ramp, partially down the slope and
336 KOA
partially through a system of incised submarine valleys (can-
yons). From the canyons mouths the material derived both
from the crinoidal biotops and the more distal parts of the
ramp was further transported by a system of distributary
channels (Fig. 7). Consequently, it was deposited (partially
in form of intraformational breccias) forming huge canyon
fed slope aprons at the toe-of-slope. Sediments consist of a
mixture of redeposited lithoclasts of biomicritic platform car-
bonates and coarser grained biodetrital (mainly crinoidal)
material representing the main feeding channel fill. Less dif-
ferentiated sediments consisting mainly of crinoidal detritus
and lime mud were deposited in the interchannel area.
After the relative sea level rise, the erosion stopped and
sedimentation was resumed on the ramp causing starvation of
the area behind its margin. A small amount of well washed
clastic material was supplied to this area through a system of
distribuary channels keeping its function henceforth. The ma-
terial was deposited in the channels and on the slopes of
the aprons creating thin condensed layers of detrital, strongly
porous, typically red coloured limestones (Pl. I: Fig. g). The
bioclasts have been strongly corroded and impregnated by Fe-
colloids during the slow transport. A great number of belem-
nite rostra is typical for these layers. As the sea level rose, the
shoreline may have reached outcrops of the source of the beige
microcrystalline carbonate extraclasts, which are very charac-
teristic of these layers (see above).
Subsequent fall of the relative sea level caused recurrance of
the normal sedimentation behind the plateau margin.
A very significant indicator of the influence of the relative
sea-level change on sedimentation is the occurrence of a thin
strongly ferruginous ooidal ironstone layer (lens) and related
banded ferrugenous ?microbialites (Burkhalter 1995; now li-
monitic crusts, irregular coats and large Fe-pisolites)
considerably enriched in amonites fauna just below the base
of the Vils Fm. (Pl. I: Fig. h) representing a sedimentary record
of the main regression T/A (Fig. 10, forced regression systems
tract, e.g. Hunt et al. 1992; Plint & Nummendal, in press; also
see Burkhalter 1995). At the end of the regression period, the
sedimentary area of the well washed crinoidal biosparites
closely connected to the crinoid meadows was moved to or be-
low the plateau margin (Fig. 8c). The crinoidal grainstones of
the Vils Fm. overlie downdip the top part of the apron sedi-
ments as it is visible in sections Vývrat 1, 2 and Prístodolok 1, 2.
Sedimentation of crinoidal grainstones of the Vils Fm. come
to on end due to a significant fall in sea-level resulting in
erosion.
Reconstruction of the paleoenvironment and
development of the crinoidal complex
The LowerMiddle Jurassic complex of the crinoidal lime-
stones of the Vysoká Unit is part of a large submarine slope
Plate I: Fig. a. Clast of the Trlenská lmst. in its proximal develop-
ment. Silicified bioclasts (mainly brachiopods), quartz grains and
biomicritic lithoclasts can be seen on its weathered surface. Scale
bar = 1 cm. Fig. b. Thick bedded, strongly silicified limestones of
the Vývrat Fm. Wavy, irregularly deformed bedding planes are
typical. Vývrat. 2, ca. 20 m. The shoe is 30 cm long. Fig. c. Bazal
part of a detrital layer within the Prístodolok Fm. Note its consid-
erably brecciated shape and the beige microcrystalline exotic li-
thoclasts (at the lower and upper margin of image). Polished sec-
tion, Vývrat.145 m, scale bar = 0.5 mm. Fig. d. Marks of erosion
on the periphery of biomicritic lithoclasts. Its right margin is
marked by an almost completely dissolved bivalve shell, the lower
margin shows obvious marks of erosion disclosing its clastic ori-
gin. Prístodolok Fm. Vývrat. 1, II, 10
×
. (Figure is turned left of
90°). Fig. e. Intercalating alodapic crinoidal limestones and marls,
marly shales to bitumenous shales represent the distal facies of
the apron-related sediments. Vývrat Fm. Vrtichov quarry, Smolen-
ice. Fig. f. Typical view of sandy crinoidal matrix in thin section.
Intense corrosion of bioclasts is characteristic. Prístodolok Fm.
Vývrat.155 m, X, 25
×
. Fig. g. Weathered surface of limestones of
the Prístodolok Fm. in detrital development. Large clastic quartz
grains and concentration of coarsest biodetritus characterize the
condensed sediments filling the main feeding channels in the
proximal part of apron. Prístodolok 1.32 m. Fig. h. Condensed
oolitic ironstone layer representing record of forced regression.
Strongly corroded echinodermal fragments (echinoid spines main-
ly) serve as cores of ferrugenous ooides and pisolites.
Fig. 10. Lithostratigrafic scheme of the crinoidal complex also
displaying supposed trends of the relative sea level changes (full
curve) and information useful for sequence stratigraphy. The
broken curve after Haq et al. (1988). SB = sequence boundary,
LST = lowstand systems tract, TST = transgresive systems tract,
FRST = forced regression systems tract.
I
LITHOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT OF CRINOIDAL LIMESTONE FMS. 337
338 KOA
apron. It was created on the toe-of-slope of a submarine pla-
teau (foot of the shelf slope, compare with Soták & Plaienka
1996) by redeposition of nonlithified or partially lithified ma-
terial derived from the plateau (see above). Relatively shallow
water conditions are supposed for this sedimentary system,
i.e. tens to a few hundreds of metres. The top part of the sedi-
mentary body is represented by the series cropping out at the
locality of Vývrat-Prístodolok. Its distal development is repre-
sented by the succession at the locality of Smolenice.
Indicators suggesting the architecture of this sedimentary
body are:
1) the most frequent character of the sedimentsan in-
traformational breccia, a heterogeneous mixture of the litho-
clasts of biomicritic limestones (formed in a relatively deeper
environment) and sandy crinoidal matrix (formed in a relative-
ly shallower environment);
2) transport of the sediment by a system of distributary
channels (Fig. 7);
3) considerable lateral gradation of the grain size of the ma-
terial transported (depending on the position in relation to
the main feeding channels, Pl. I: Fig. g);
4) a trend of change of the character of sedimentsfrom
the relatively shallower towards the relatively deeper environ-
mentin the direction Vývrat-Smolenice (Fig. 1), lateral
changes towards the relatively deeper facies within the indi-
vidual formations in this direction;
5) a trend of change in the formation thicknesses in the same
direction;
6) development of a huge body of the crinoidal grainstones
of the Vils Fm. at the locality of Vývrat-Prístodolok, while
they are rare or absent in the more distant localities.
The beginning of sedimentation of the crinoidal complex at
the Hettangian-Sinemurian boundary was connected with a
considerable shallowing (main regression H/S, Fig. 10) of the
sedimentary area and represented an essential change of the
character of sedimentation: marlstones, siltstones and clay-
stones of the underlying Kopienec Fm. were followed by dep-
osition of sediments of the Trlenská Fm. It stands to reason
that the shallowing was due to tectonic uplift in the area of the
simultaneously initiated opening of the Zliechov Basin. The
crinoidal complex described could thus represent the syn-rift
sediments deposited in an elevated and dissected domain at its
northern margin.
The formation of the system of canyons and channels trans-
porting material from an elevated nearshore plateau may have
been predisposed by the tectono-sedimentary conditions pre-
ceding the beginning of the Early Jurassic sedimentation cy-
cle. The lateral facies zonation of the Trlenská Fm. reflects the
depth gradient of the sedimentary area (Fig. 8a). The shallow-
est facies which was formed in the close vicinity of the canyon
mouth is composed, in adition to the crinoidal and particularly
abundant brachiopod detritus, also of lithoclasts of biomicritic
limestones (see above). Some part of the sediment was trans-
ported further by currents. Subsequently, it was deposited in
more distal areas, forming bodies of well washed biodetrital
limestones (large-scale crinoidal dunes, Jenkyns 1971). The
facies change is accompanied by change of the faunal associa-
tion: prevalence of the rhynchonellid brachiopods indicating a
high energy living environment and vicinity of the main dis-
tributary channels is changed by association of thin walled
forms with flat commissures in the more distal development.
Their colonies are preserved in situ (Michalík 1997, personal
communication).
Sedimentation of the Vývrat Fm. was accompanied by deep-
ening of the NE part of the Vysoká Unit. The formation of
thick bedded, strongly silicified grey crinoidal limestones
passes laterally into a sequence of alodapic irregularly interca-
lating grey crinoidal limestone layers (510 cm thick) and up
to 10 cm thick intercalations of marlstones, marly shales to bi-
tuminous shales. This sequence also supplements the overly-
ing Prístodolok Fm. in the distal development.
The slope apron also received unlithified carbonate mud of
platform margin origin (Fig. 8b).
A considerable sea-level fall led to a basinward shift of the
shoreline as far as the plateau margin or even beyond it (main
regression T/A, Fig. 10) ending the sedimentation of the
proximal development of the Prístodolok Fm. Subsequently, it
was overlain by an up to 55 m thick body of the well washed
and sorted crinoidal grainstones of the Vils Fm. (Fig. 8c).
The eroded top surface of the Vils Fm. at the locality of
Vývrat is overlapped by a few metres thick layer of pink to
yellowish-brown micritic limestones containing rare crinoi-
dal detritus and a breccia layer at its base. Upwards it pass-
es into the red true nodular limestones containing few or
no crinoidal columns (lower crinoidal limestones sensu
Borza & Michalík 1987).
In the slope area, the sea-level fall displaced by sedimenta-
tion of lensoid bodies of the Vils grainstones, irregularly, fin-
ger-like intercalating with the limestones of the Prístodolok
Fm. After the subsequent sea level rise sedimentation of the
true nodular limestones began on the surface of the slope
and the more distal sediments, with gradual transition or, par-
tially, with a breccia layer at the base.
The system of the distributary channels also kept its func-
tion during sedimentation of the Vils Fm. and the
(re)deposition of brecciated micritic limestones of the fol-
lowing transgressive systems tract (Fig. 10) which underlies
the laterally uniform formations of the nodular limestones of
Upper Jurassic age.
Soták & Plaienka (1996) described a very similar se-
quence of Upper TriassicLower Jurassic sediments of the
Luèatín Unit (transition element between the Veporic Unit
and the Krína Nappe Unit, analogous to the Ve¾ký Bok Suc-
cession) in the Northern Veporic Superunit giving a more de-
tailed paleogeografical reconstruction of the sedimentary
system. They related its position to the shelf slope at the tran-
sition from the Veporic margin into the Zliechov Basin.
Conclusions
The results of the facies analysis of the Lower-Middle Ju-
rassic complex of the crinoidal limestones of the Vysoká
Unit in the Malé Karpaty Mts. (Western Carpathians, Slova-
kia) are:
a) its subdivision into four formations: Trlenská Fm., Vývrat
Fm., Prístodolok Fm., Vils Fm.; two of them are newly de-
fined as formal lithostratigraphic units;
LITHOSTRATIGRAPHY AND DEPOSITIONAL ENVIRONMENT OF CRINOIDAL LIMESTONE FMS. 339
b) interpretation of the sedimentary environment as part of a
slope apron with a proximal development on the SW and a dis-
tal development on the NE margin of the Vysoká Unit;
c) the sedimentary model created on the basis of this analy-
sis also explains the question of the origin of the facies in
which lithoclasts of biomicritic limestones originating from a
relatively deeper environment are mixed with the crinoidal
calcarenites formed in a relatively shallower environment.
This facies is not only typical of the Vysoká Unit (see Miík
1964; Soták & Plaienka 1996);
d) on the basis of various indicators, the possible influence
of the relative sea level fluctuation on sedimentation has been
evaluated and a curve of the relative sea level changes is
suggested, even if there are not enough data available for a
detailed and comprehensive application of the sequence
stratigraphy approach to the sedimentary unit studied.
Acknowledgements: This paper has been worked out on
the basis of author´s MSc thesis at the Charles University in
Prague, Czech Republic, kindly supervised by Doc. RNDr.
V. Skoèek, CSc. (Charles University, Prague) and RNDr. J.
Michalík, DrSc. (Slovak Academy of Sciences, Bratislava).
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