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changes. However, there is no one common
sequence of textures in the studied samples but
instead, the sequences of tufa textures deposited
on the tablets exposed throughout the whole exper-
imental period in each of the sites differ and are
characteristic for each site. This proves that depo-
sition of tufa at each site is governed by a different
local factor. Nonetheless, some regularity is present
in the seasonal sequence of textures.
Laminae built of sparry calcite crystals were
commonly formed in cold season. The H
´
j and
L´
ˇ
ky sites provide good examples. Similar regu-
larity was noted in tufas in Great Britain (Pedley
1992). Vigorous water flow in winter, along with
algal vegetation impeded by low irradiance and
low temperature, may lead to formation of tufa
composed of sparry calcite crystals. However, the
formation of sparry calcite crystals is strongly con-
trolled by local environment as they form in
fast-flowing settings almost irrespectively of
season, especially if biological activity is impeded.
Conversely, moulds of filamentous algae mark
periods when algae thrived. Thus, tufa abounding
in such components originates mainly in spring
and summer. Despite of this, the overshadowing of
the streams in summer may lead to deposition of a
tufa built of sparry calicte or to a change from depo-
sition of Vaucheria-dominated to cyanobacteria-
dominated tufa, as recorded at the Karw ´w
cascade point and at the L ´
ˇ
ky top and E points.
Tufa with micritic texture rich in diatoms is com-
monly deposited in cold seasons as at the H´j dam
point at the turn of winter and spring of 2003. Depo-
sition of such tufa is favoured by the predominance
of diatoms. A similar phenomenon was reported
earlier from different regions of Europe. For
instance, Szulc & Smyk (1994) noted predominance
of bacteria and diatoms in winter laminae of tufa
stromatolites in southern Poland. Analogously,
Arp et al. (2001) found diatom-rich biofilm in
winter in the tufa-depositing Deinschwanger Bach
in the Franconian Alb. A similar conclusion was
reached by Plenkovi´-Moraj et al. (2002) who
studied the Plitvice lake system. Sabater et al.
(2000), investigating La Solana stream in Spain,
detected the predominance of diatom community
in a spring season.
The most characteristic structures originating
during late spring - summer are larval housings.
Irion & M¨ller (1968) and Janssen et al. (1999)
pointed at seasonal significance of larval housings
in tufas in Germany and Belgium, respectively,
and regarded them as a marker of a spring season.
However, voids of similar dimensions, sharing
most probably the same origin, are detected in the
tufa sample that grew between late June - October
2003 at the L ´ˇky top site. They are distributed in
the whole, up to 14 mm thick, section of this
sample, which implies that the housings formed
throughout the entire period of sample growth.
Alike voids, similar in size but less regular in
shape, were formed within the tufa deposited at
H´j between November 2002 - March 2003. Their
irregular shapes may have been caused by postdepo-
sitional modification (see Golubi´ 1969). Therefore,
though the housings are most common at the turn of
spring and summer, they cannot be considered an
unequivocal index of this season (see also D ¨rren-
feldt 1978).
Laminae built of detritic non-carbonate com-
ponents, visible within sparry crystals, are an accu-
rate index of hydrological conditions (cf. Kano
et al. 2004). They record increased surface runoff
to tufa-depositing streams, which caused prono-
unced supply of fine-grained clastics and organic
matter from soils. The concentration of such
laminae in the tufa formed in L´
ˇ
ky clearly marks
late autumn rainy season and spring thaw periods
(Fig. 22a, b).
Differences between rate of tufa growth in
the studied sites - influence of climatic
conditions and water origin
The annual tufa growth rate for each studied site
was assessed by calculating the mean growth rate
for the sites where observation was conducted in
more than one point (Karw ´w, L ´ˇky and H´j).
This minimalized local effects caused by microen-
vironmental conditions, such as the 'waterfall
effect'. Figure 27 shows the relation between the
mean annual growth rates, chemical parameters of
feeding water and mean annual temperatures for
all sites.
The mean growth rates differ markedly between
the sites. Exceptional is the mean growth rate at
L ´ˇky: 4.994 mg/cm
2
/day. It is not only higher
than values for the other sites studied herein, but
also higher than any values for tufa growth,
known in literature. For example, the highest
value for tufa obtained by Bono et al. (2001) was
1.8635 mg/cm
2
/day, substantially lower than the
values from the L ´ˇky site. The rate of tufa
growth obtained by Zhang et al. (2001, their
table 3) in their experiment with the Ya He river
water is also lower.
On the contrary, the growth rate in L ´ˇky is
lower than those measured for the majority of tra-
vertines. Pentecost & Colletta (2007) gave a value
ranging from 13.4 - 30.9 mg/cm
2
/day for the tra-
vertine growing in La Zitelle spring in Tuscany.
Other data from travertine sites are provided in
centimetres per year. For instance, Kitano (1963)
estimated the growth rate of Futamata travertine in
Japan between 200 - 1000 mm. Values given by
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