Geology Reference
In-Depth Information
L
´ ˇ
ky
The L ´ˇky site is located in the village of L ´ˇky in
Slovakia. The village lies at the outlet of a valley
incised into the Choˇ Mountains to the Liptov
Basin, 14 km west of Liptovsk
´
Mikul
´ˇ
(Fig. 1,
Table 1). The mountain creek flows along the
valley and drains an area with maximum elevation
of 1611 m. In the centre of the village the stream
drops in a picturesque 15 m high waterfall, where
calcium carbonate is being vigorously precipitated
(Nemejc 1928; Kovanda 1971). The studied site is
at the waterfall (Figs 2c & 3d).
The Cho
ˇ
Mountains are built mainly of folded
and thrusted Triassic carbonates of the Cho
ˇ
Nappe. They adjoin the neighbouring Liptov Basin
along a master fault zone which has approximately
longitudinal orientation (Gross 1980). The basin is
developed in less resistant clastis, mainly of flysch
type, called the Central Carpathian Palaeogene
that occupy a tectonic depression. Their thickness
reaches 1500 m. The Central Carpathian Palaeo-
gene is underlain by various Mesozoic deposits,
mainly carbonates, of the Cho
ˇ
and Kr
´ˇ
na nappes.
They crop out to the south of the basin and build
the extensive Low Tatra Mountains range there. The
Central Carpathian Palaeogene has very low per-
meability, and hence it acts as a confining bed.
The artesian water migrates up along the faults
that cut the flysch rocks, mainly along the master
fault zone which separates the Liptov Basin from
the Cho
ˇ
Mountains (Franko & Hanzel 1980). It
has been suggest that the recharge zone of the arte-
sian basin is located in the Low Tatra Mountains
(Hynie 1963). However, the basin may be also fed
by water from the Cho
ˇ
Mountains, which is
suggested by the open hydrological balance of this
carbonate massif (see Franko & Hanzel 1980).
The water in the stream in the studied waterfall is
a mixture of two components. One represents moun-
tain stream water draining the Cho
ˇ
Mountains. The
stream is additionally fed by deeply-circulating
water ascending along the faults bordering the
Liptov Basin, which constitutes the second com-
ponent. Both components mix near a spa, approxi-
mately 300 - 500 m upstream from the waterfall.
Nowadays only a part of deep-circulating water
reaches a stream, because it is used in a spa which
collects water from natural springs and shallow
boreholes. The reconnaissance measurements done
in October 2008 show that the discharge of the
stream feeding the waterfall is around 60 l/s.
The waterfall occurs at the upstream (northern)
end of a southward widening ravine sharply
incised into older tufa. N
ˇ
mejc (1928) attributed
Holocene, mainly Atlantic age to the tufa, basing
on floral remains. This has been confirmed by
exploratory
study (M. Gradzi
´
ski, unpublished data, 2003).
The waterfall has a complex morphology. Its main
wall is 12 m high with a central projecting pillar bor-
dered by two depressions where water cascades
down. The wall is covered with cyanobacteria and
algae, moss curtains and some liverworts and
grasses overhanging from the waterfall head. Two
small primary caves are present at the base of the
pillar. They formed by progradation of the waterfall
wall. The occurrence of presently prograding tufa
waterfall over a cliff built of eroded Holocene
tufas proves that tufa growth was interrupted
during the Holocene, and the stream eroded the
ravine then.
H
´
j
The H
´
j site lies in southern Slovakia in the eastern
part of the Slovak Karst area, about 30 km west of
Ko
ˇ
ice (Fig. 1, Table 1). The upper section of a
fast-flowing stream was examined (Fig. 2d).
The section is 900 m long with vertical drop of
c. 80 m. The surrounding plateaus rise to altitudes
650 - 800 m
and
the
narrow
valley
is
incised
c. 150 - 200 m deep.
The plateaus are built of Triassic limestone of
Wetterstein type, belonging to the Silica Nappe
(Mello 1996). The limestone crops out in numerous
cliffs and crags on the valley slopes. The valley is
partly filled with inactive tufa over 25 m thick.
Lo
ˇ
ek (1957) determined its age as Holocene on
the base of malacofauna. An exploratory
14
C
dating done in the course of the present study has
confirmed the above view (M. Gradzi
´
ski, unpub-
lished data, 2003). The stream flowing along the
valley is incised into older tufa and forms a
narrow gorge up to 10 m deep, which is shaded
owing to its topography and a dense canopy of
tree and bush leaves during the vegetation period.
The stream is densely colonized by cyanobcteria
and algae and in some places also by liverworts
and mosses. The stream forms four waterfalls
whose distribution clearly mirrors the location of
older Holocene tufa dams. This is why Lo
ˇ
ek
(1957) wrote that the stream now only erodes Holo-
cene tufa. However, a reconnaissance study clearly
showed that calcium carbonate actively precipitates
along the stream course.
The stream is fed by springs draining a karst
aquifer. The reconnaissance measurements done in
October 2008 show that the stream carries
between 6 and 15 litres of water per second, depend-
ing on the studied place. The springs are active
throughout almost all the year, however their dis-
charges vary in time. Two springs are situated
above the studied section while the third one
within it (Fig. 2d). Three points were selected for
the study (Figs 2d & 3e - g).
14
C dating in the course of the present
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