Geology Reference
In-Depth Information
Humans and caves
widely used for cheese-making and rope manufacture,
as in the entrance to Peak Cavern, Derbyshire, England.
Kentucky bourbon from the Jack Daniels distillery relies
partly on cave spring water.
Cave tourism
started in the late eighteenth and early
nineteenth centuries in Europe, when candle lanterns
were used (e.g. Nicod 1998). Today, cave tourism is
a growth industry: fibre-optic lights illuminate some
caves, and electric trains transport tourists through the
caverns. Tourism has an injurious impact on caves
(Box 8.1). To combat the problems of cave tourism,
cave management
has evolved and is prosecuted by a
body of government and private professionals. Several
international groups are active in cave and karst man-
agement: the International Union of Speleology, the
International Speleology Heritage Association, the Inter-
national Geographical Union and the Commission for
National Parks and Protected Areas, and the Interna-
tional Union for the Conservation of Nature and Natural
Resources (IUCN).
Humans have long used caves for shelter, defence, sanc-
tuaries, troglodytic settlements, a source of resources
(water, food, guano, ore in mine-caves), and as spir-
itual sites. In the last few hundred years, caves have
been used for the mining of cave formations and guano
(especially during the American Civil War), for hydro-
electric power generation from cave streams and springs
(in China), for storage, and as sanatoria and tourist attrac-
tions. Evidence for the human occupancy of caves in
China dates from over 700,000 years ago. Many caves
are known to have housed humans at the start of the last
glacial stage, and several have walls adorned with splendid
paintings. Many caves in the Guilin tower karst, China,
have walls at their entrances, suggesting that they were
defended. Medieval fortified caves are found in Switzer-
land in the Grisons and Vallais. In Europe and the USA,
some caves were used as sanatoria for tuberculosis patients
on the erroneous premise that the moist air and constant
temperature would aid recovery. Caves have also been
Box 8.1
CAVE TOURISM
Some 20 million people visit caves every year.
Mammoth Cave in Kentucky, USA, alone has 2 million
visitors annually. Great Britain has some 20 show-
caves, with the most-visited receiving over 500,000
visitors every year. About 650 caves around the world
have lighting systems, and many others are used for
'wild' cave tours where visitors carry their own lamps.
Tourists damage caves and karst directly and indirectly
through the infrastructure built for the tourists' conve-
nience - car parking areas, entrance structures, paths,
kiosks, toilets, and hotels. The infrastructure can lead
to hydrological changes within the cave systems. Land
surfaced with concrete or bitumen is far less permeable
than natural karst, and the danger is that the feedwaters
for stalactites may be dramatically reduced or stopped.
Similarly, drains may alter water flow patterns and lead
to changes in speleothem deposition. Drainage prob-
lems may be in part alleviated by using gravel-surfaced
car parks and paths, or by including strips where infil-
tration may occur. Within caves, paths and stairs may
alter the flow of water. Impermeable surfaces made of
concrete or steel may divert natural water movement
away from flowstones or stream channels, so leading to
the drying out of cave formations or to increased sed-
iment transport. These problems are in part overcome
by the use of permeable steel, wooden, or aluminium
walkways, frequent drains leading to sediment traps,
and small barriers to water movement that approximate
the natural flow of water in caves.
Cave tourists alter the cave atmosphere by exhal-
ing carbon dioxide in respiration, by their body
heat, and by the heat produced by cave lighting. A
party of tourists may raise carbon dioxide levels in
caves by 200 per cent or more. One person releases
between 82 and 116 watts of heat, roughly equivalent
to a single incandescent light bulb, which may raise
