Page 75 - How It Works - Book of Amazing Answers To Curious Questions, 12

---- Environment Q�
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Volcanic mountains What are the differe type of mountain?
These mountains form when
molten rock explodes up through
the Earth's crust and can still be Volcanic Plateau Fold Fault-block Dome
volcanically active. These mountains are Plateau mountains This most common type Fault-block mountains These types of mountain
created by the buildup of are revealed through of mountain is formed form when cracked layers also form from magma.
lava, rock, ash and other erosion of uplifted when two tectonic plates of crust slide against each Unlike with volcanoes,
volcanic matter during a plateaus. This is smash into each other. The other along faults in the however, there is no
magma eruption. known as dissection. edges buckle and crumble, Earth's crust. They can be eruption; the magma simply
Examples: Mount Fuji, Examples: Catskill giving rise to long lifted, with two steep pushes up sedimentary
Mount Kilimanjaro Mountains, Blue mountain chains. sides; or lifted, with one layers of the Earth's crust
Mountains Examples: Mount gently sloping side and one and forms a round
Everest, Aconcagua steep side. dome-shaped mountain.
Examples: Sierra Examples: Navajo
Nevada, Urals Mountain, Ozark Dome

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Why do often run through tunnels Collapsing cave
Rivers
If these caves reach the
Rivers in limestone areas
surface and the roof falls
in it can create a sinkhole.
that widen into caves.
sinl<holes
appear?

Discover how limestone
landscapes are riddled
with hollows and holes

inkholes, do lines, swallow or shake holes are bowl-shaped
hollows created when limestone is eaten away by acidic
S groundwater. Limestone chemically reacts with acidic water
because it's mostly calcium carbonate -the alkali used in some
indigestion tablets to neutralise stomach acid.
Sinkholes form in two main ways. First, as acidic water seeps through
and widens cracks in limestone. If the cracks are close together, a small
hollow forms and grows bigger as rainwater flows into it.
Sinkholes also form when caves collapse. Rivers in limestone areas
often run through underground tunnels that they widen into caves. If the
cave reaches the surface and the roof falls in, it can create a sinkhole.
Holes in the ground in other rock types are sometimes called sinkholes.
An enormous sinkhole that swallowed a Guatemala City clothing factory
in May, for example, is in an area of volcanic rock and ash.

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