
In some parts of the
cave visitors can see broken speleothems. Thoughtless visitors broke some
of the formations before the caves were protected. However, most of the broken
formations were likely brought down in earthquakes. It is estimated that the
area's most recent major earthquake occurred on the Middle Cave fault line
between 400 and 700 years ago. The broken formations remind visitors that
faults have played an important role in the development of the caves. Before
any formations could develop, an air filled cavity had to be created. Faulting
in the area pulverized rocks along fractures, thus facilitating the movement
of acid-rich water along these pathways. The water slowly dissolved the surrounding
rock and began to widen the passage. The area was completely submerged while
most of the cave was dissolved out by a mild carbonic acid. If faults had
not concentrated this dissolving process in one place it is less likely that
caves would have formed in the area.
This picture looks up at the cross-section of a broken stalactite. You may
notice the bands of different colors. These bands indicate wet and dry phases
of the stalactites growth. However because the cycles which form these bands
are not necessarily annual and are affected by factors other than season,
they are not useful for dating the age of the formation or tracing climate
history as with tree rings.