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| Our Adventures |
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Australia - South West Australia
Leeuwin-Naturaliste National Park:
Caves of the Cape
The Leeuwin-Naturaliste Ridge is a unique geological feature stretching
from Cape Naturaliste to Cape Leeuwin. It is composed mostly of
Precambrian hard crystalline rocks (commonly called granite) capped
by limestone and occasional sand dunes.
The ancient Precambrian granulite and granitic gneiss can be
seen at many headlands along the coast and has been dated at 2,000
million
to 650 million years old. Capping these rocks is an extremely
young Tamala Limestone, formed during the Pleistocene epoch (over
the
last 2 million yeears) from fragmented shells, calcareous algae
and other material such as silica sand, originally laid down
as sand dunes.
This type of limestone is much softer than the older, crystalline
limestones more commonly encountered through the rest of the
world, making it ideal for the fomation of caves. Caves are
formed as
water seeps or flows through it. Many follow path of an underground
stream or take on a maze-like form if formed at the water table.
The calcium carbonate that is dissolved in the seeping water
is redeposited to form a vast array of stalactites, shawls,
flowstones and other decorations. The young limestone, being particularly
soluble, creates exceptionally well-decorated cave chambers.
It
is, of course, vital not to handle the formations, as they
are
brittle and highly susceptible to damage. Their growth is impeded
by the minuscule deposits of skin oils, acids and dirt on our
hands. In the past, careless cavers have substantially damaged
the caves,
leaving rubbish, footprints, eroded areas and broken crystal
in their wake. We now know much more about the delicate and
irreplaceable nature of caves, and have devised ways to protect
them while
still
allowing access. Calgardup and Giants caves are not electrically
lit. They are self-guided, providing a natural experience of
the cave environment. Visitors are equipped with helmets, lamps
and
information for their very own discovery of of these subterranean
wonderlands.The Department of Conservation and Land Management
manages two caves in this region, Calgardup Cave and Giants
Cave.
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