The Dripstone of
Rožňava Cavers belongs to the highest sinter formations – dripstones –
in the
world. It is still registered in the Guinness
Book of Records as the highest sinter column in the world. However, it
would be
a great paradox if there would have been the highest dripstone in our
temperate
climate zone. Large caves and big dripstones as well are more often
created in
tropical karst where conditions for their formation are the best.
Therefore,
the highest dripstones are found in tropical areas. The highest known
dripstone 70 m
high was found on China
in the cave Zhi Jing.
34 m high and
approximately 2000 tons heavy dripstone in the Krásnohorská Cave is
a real miracle of nature. Even we know the conditions which helped to
its growth
it is hard to understand its formation has lasted for less then 10.000
years.
Its upper age limit was dated by using C14 method on a sample from its
predecessor fallen down in the past and lying below it. More then 200 kg of new sinter
is
added every year. In comparison, average growth rate of stalactites in
the
Slovak Karst is 1
gram
per decades to hundreds of years. What are the conditions of its growth
at all?
For the growth rate of a dripstone the amount of the solution
pouring on it has
significant role. There is a large sinkhole 250 m wide there on
the
plateau 250 m
just above the dripstone. It collects sufficient amount of solution
which
nourishes the dripstone. However, substantial is, that a karst conduit
of this
sinkhole bringing aggressive snow water to the cave, does not lead
directly to
the Hall of Giants. Due to high CO2
concentration in the soil on the plateau’s surface covered by a forest,
the
solution is much saturated. In the Hall of Giants, carbon dioxide
concentration
is 6 times lower, what makes sufficient partial pressure for intensive
sinter
precipitation. When the dripstone was smaller an effect of drop super
saturation falling from big height was active as well. Later, when the
dripstone
grew up, the growth process changed. The solution started to flow
freely on the
surface of its growing body and the dripstone was spreading out
similarly as
surface crusts are formed on the inclined cave walls. It was
also chance event.