Factors controlling growth of modern tufa: results of a field experiment - Tufas and Speleothems: Unravelling the Microbial and Physical Controls - page 142

twenty years. Differences in textures deposited
during cold and warm seasons were recognized
(e.g. Szulc & Smyk 1994; Arp et al. 2001; Kano
et al. 2003). However, there was no attempt to elu-
cidate the difference of tufa growth rate or tufa mass
increment along with changes of its texture.
Since tufas are fed by water saturated with CO 2
of soil origin, their growth depends strongly on
the development of a vegetation cover, which in
turn is related to climatic condition. Therefore,
Hennig et al. (1983) concluded that abundance of
tufa in the geological column is an indicator of
periods of relatively warm and humid climate. Pen-
tecost (1995) claimed that the majority of tufas in
Europe occur in the areas characterized by mean
annual temperatures between 5 - 15 8C and mean
annual rainfall exceeding 500 mm. No comparison
of the tufa growth rates in the same observational
period in places located in various climatic con-
dition has been undertaken.
The purpose of this study was to measure the
growth rate of modern tufa in some selected sites
in Central Europe. The sites are spread across the
Central Carpathians and one site lies in the northern
foreland of the Carpathians. They differ in climatic
conditions, type and origin of feeding water, modern
hydrology as well as in type of vegetation around
them. Main chemical parameters of parent water

were studied to examine the conditions of tufa
growth. Petrography of the actively growing tufa
was also examined. The data were used to assess
seasonality of tufa growth and to compare growth
rates, textures, and environmental factors governing
their formation.

Study sites

Four sites of active tufa deposition have been chosen
for this study. They are scattered across the Car-
pathian range, which is the main topographic
barrier in Central Europe (Fig. 1), acting as the con-
tinental divide between the Baltic and Mediterra-
nean seas and as an important climatic barrier. The
northernmost site - Karw´w - is located in the
Middle Polish Uplands, approximately 250 km
north of the main ridge of the Central Carpathians.
Two sites are situated in the main part of the
Central Carpathians: Z´zr´v´ in a narrow mountain
valley and L´ˇky at the border of a wide intramon-
tane basin. The fourth site - H´j - lies on the south-
facing slopes of the Central Carpathian chain.

Karw ´w

The Karw ´w site is located on the Sandomierz
Upland c. 25 km NWW of the city of Sandomierz

Fig. 1. Location of the studied sites.