|
How caves are formed?
Some caves are just large enough to contain a small
animal. Others reach down more than 1 mile (1.6 km) under the earth's
surface. Most caves, big and small, are formed by the same thing: water.
Most
caves form as
acidic
water eats out holes in limestone. But caves can form in other ways too.
Ice caves also form when melted water runs under a glacier.
 Some caves are created by lava from volcanoes.
Long tunnels with
lava
walls can form where a molten river of rock flows beneath a solid surface.
As lava flows, the part exposed to the air cools and hardens into a rocky
shell. Inside this shell, the hot lava continues to flow. When all of the
hot lava has moved through, the shell remains as a cave.
A stream plunges down a deep hole, called a sink
hole, to feed an underground river. Animals and explorers use old sink
holes as entrances to caves.
Several large caves may form when a river moves
deep underground. Rivers that run through caves may emerge from the side
of a mountain.
 Rainwater seeping into the ground slowly
dissolves parts of rocks, forming small cracks. These cracks eventually
widen, creating deep holes. Over time, the holes become huge caves.
Caves form in sea cliffs as waves attack weak spots.
The constant pounding of waves washes away the
softer rock in a sea cliff, leaving a cave behind.
What is a Cave |
How caves are formed? |
Cave
Landscapes |
Stalagmites & Stalactites |
Cave animals |
People and caves |
