The New Childrens Encyclopedia

ICE EROSION

About 10 percent of Earth’s land

surface is covered by slow-moving

masses of ice called glaciers. As

glaciers move, rocks trapped in

the ice scour the land, wearing it

smooth. Water can also split rocks

as it freezes, since water in cracks

expands as it turns to ice.

WATER EROSION

As rainwater flows downhill, it

picks up small fragments of rock.

These fragments wear channels

into the earth, gradually carving

out the beds of rivers. In the same

way, ocean waves and tides grind

down the rocks of the shoreline,

creating bays, headlands, cliffs,

and rock pillars called stacks.

TAKE A LOOK: THE POWER OF WATER

u STEP 1 As a river flows

around a meander, it erodes

the outside of each bend.

u STEP 2 The bends

gradually change shape,

until a shortcut is created.

u STEP 3 Sediment

deposited by the river cuts

off the meander.

Rivers constantly erode away the rock of their own beds, which gradually

changes their courses. This can create features such as oxbow lakes.

u DEPOSITION The sediments

transported by rivers and by ocean

tides can be deposited in large

quantities, creating new land

features such as this spit.

. TWELVE
APOSTLES These rock
formations off the coast of
Victoria, Australia, were
created by the sea eroding
limestone headlands.

Waves are steered into
the headlands by the
shape of the coastline.

The headlands are worn

into stacks by constant

wave erosion.

EARTH

EROSION

Oxbow

lake

Sediment

Erosion

As the coastline is
eroded, the harder
rock is left as
headlands.