Geoscience Reference
In-Depth Information
Fig. 3.57
Longitudinal profile of Snezhanka Cave (after Beron et al.
2006
)
landmarks of Snezhanka are the highly decorated
stalactite ceiling (more than 800,000 stalactites of
various shapes) and the availability of thin cylindrical
stalagmites suitable for research.
The cave was discovered on January 2, 1961 by
cavers G. Kotzev, G. Zlatarev, and B. Evtimov from
the town of Peshtera. After archeological excavations
and bore-holing in the same year by the team of N.
Dzhambazov, artifacts from the early Iron Age and
Roman-Thracian era including pottery, the remains of
a fireplace and bronze needles were found in the Great
Hall of the cave.
Snezhanka Cave has been a show cave for tourists
since 1968 and is managed by the Kupena Tourist
Society in the town of Peshtera. It was declared as a
protected natural monument by Decree 504/
11.07.1979. Since 1983 the cave has been included in
the buffer zone of the Kupena Natural Reserve.
Two thin poplar-like stalagmites -1(Fig.
3.58
)and2
(Fig.
3.59
)—were investigated (Paskaleva et al.
2008
;
Gribovszki et al.
2009
). Both are 140 cm high but 1 has a
complicated shape with a flaring middle part and a very
low natural frequency. In both stalagmites the height (H)
versus diameter (D) ratios are below (H/D \) 20. The
diameter of stalagmite 1 ranges between 8.0 and 12.4 cm
where the widest is its middle part. The H versus D ratio
is between 11.2 \ H/D \ 17.5. The results of dimen-
sions measuring are presented in Table
3.3
.
The natural frequency measured in Snezhanka
stalagmite l was exceptionally low, which can be
explained by its unusual shape.
According to mechanical test performed on four
stalagmite pieces from Snezhanka Cave, the average
density was 2.32 g/cm
3
, and the standard deviation of
Fig. 3.58
Measurement of Stalagmite 1 in Snezhanka Cave
(photo G. Suranyi)
eight values measured was 0.15 g/cm
3
. Young's
modulus was determined using data from a uniaxial
compressive strength test. The value was 6,240 MPa;
the standard deviation could not be assessed since only
one sample was tested. The mean tensile failure stress
of the four samples was 2.61 MPa with standard
deviation of 0.28 MPa. The Brazilian test was used.
