Page 286 - (DK) The Ultimate Visual Dictionary 2nd Ed.

Caves Doline
SURFACE TOPOGRAPHY OF A CAVE SYSTEM

(depression Sink-hole
caused by
CAVES COMMONLY FORM in areas of collapse of
limestone, although on coastlines they cave roof)
also occur in other rocks. Limestone is Ring Gorge where
made of calcite (calcium carbonate), mark cave roof has
which dissolves in the carbonic acid fallen in
Porous
naturally present in rainwater, and in limestone
humic acids from the decay of
STALACTITE WITH Resurgence
vegetation. The acidic water
RING MARKS
trickles down through cracks and
joints in the limestone and between rock layers,
breaking up the surface terrain into clints (blocks of
rock), separated by grikes (deep cracks), and punctuated
by sink-holes (also called swallow-holes or potholes) into
Limestone terrain Impermeable
MERGED which surface streams may disappear. Underground, with clints and grikes rock
STALACTITES the acidic water dissolves the rock around crevices,
opening up a network of passages and caves, which can become large
caverns if the roofs collapse. Various features are formed when the dissolved Scar of
calcite is redeposited; for example, it may be redeposited along an underground bare rock
stream to form a gour (series of calcite ridges), or in caves and passages to form
stalactites and stalagmites. Stalactites develop where calcite is left behind as
water drips from the roof; where the drops land, stalagmites build up.

STALAGMITE FORMATIONS
Thin encrustations
Calcite (calcium of calcite (calcium
carbonate) carbonate)
crystallized
under water
Former
water table

CALCAREOUS Permeable
TUFA limestone
CRYSTALLINE
STALAGMITIC FLOOR
Encrustations
on dead stems
of small plants

Resurgence
Calcite
(calcium
carbonate)
Encrustations
with fungoid
structure
Calcite
(calcium
carbonate)
Layer of
STALAGMITIC STALAGMITIC impermeable Present
FLOOR BOSS rock water table

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