Geology Reference
In-Depth Information
and 1 km south of the small village of Karw
´
win
the Opat
´
wka river valley (Fig. 1; Table 1). A
small stream emerges there in a spring, called by
local people the Blessed Kadłubek spring. The
area
around
is
agriculturally
used,
with
small
groves in close surrounding.
The area is covered by loess, up to a few metres
thick. Older tufa, probably of Holocene age, is
locally present as debris spread over the fields.
The spring issues at the contact between folded
Cambrian siliciclastics and horizontally lying
Miocene detrital limestone which builds a local
hill (Dowgiałło 1974). The origin of tufa in this
area was ascribed to shallow water circulation and
dissolution of Miocene limestones (Samsonowicz
1929) or Middle Devonian carbonates that occur
in close vicinity (Dowgiałło 1974). Szulc (1984)
in his unpublished paper suggests that the water
may also ascend from greater depth along the
´
wi˛tokrzyski Fault that separates Devonian car-
bonates from Cambrian siliciclastics. The opinion
on deep circulation origin of the water is confirmed
by low tritium concentration, which suggests great
residence time of the discussed water (M. Duli
´
ski,
pers. comm., 2003). The spring expels between 0.8
and 1.0 l/s (Ga˛gol & Urban 2000; M. Gradzi ´ski,
unpublished data, 2003).
Tufa deposits were studied along the uppermost
120 m section of the stream which first meanders
over a gentle slope, then abruptly turns to the right
and flows swiftly down toward a small gorge
(Fig. 2a). Here the first growing tufa appears in
form of small dams across the stream (Fig. 3a).
The stream then flows down to the junction with a
side ravine cut in loess, dry throughout almost all
the year, except thaw periods and heavy rainfalls.
At the junction of the stream and the ravine a
small fan-shaped tufa cascade forms, c. 2 m high
(Fig. 3b). The cascade and the dams are deeply
shaded in summer by a leaf canopy.
Z´zriv ´
The Z´zriv´ site is situated in northern Slovakia,
c. 12 km NWW of the city of Doln´ Kub´n in the
Mal´ Fatra Mountains, an alpine mountain chain
(Fig. 1, Table 1). The Mal´ Fatra is built of crystal-
line core, its autochthonous cover and a sequence of
nappes (Haˇko & Pol´k 1978). The autochthonous
cover and the nappes are built of Mesozoic rocks
which include many carbonate units. The neigh-
bouring peaks reach altitudes between 930 -
1600 m. Mountain meadows occupy the upper
parts of their slopes, while the lower parts are
forested with mixed coniferous and deciduous trees.
The object of the present study was a perched
tufa fan attached to the western slope of deeply
incised Z´zrivka stream valley (Figs 2b & 3c).
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