Page 18 - Super Earth Encyclopedia

DYNAMIC EARTH

Earth’s crust is constantly moving, driven by heat currents that
originate deep within the planet. The movement is very slow, but Most of the North
immensely powerful. It has divided the crust into huge rocky plates American continent
that are pulling apart in some places and grinding together in lies on the North
American Plate.
others. The moving plates are slowly changing the global map. The Pacific Plate is
one of the biggest
Crust oceanic plates.
Heat current rises Hot mantle rock The East Pacific Rise is
from near Earth’s core flows sideways a spreading rift where
to just below the crust. beneath the crust. new oceanic crust
is being created.

Mantle Hotspots are
areas of isolated
volcanic activity.
As the mantle
rock cools, it sinks
back into the
mantle where it
heats up again.
Core

Sinking, cool mantle
drags some of the
crust down with it.
DEEP HEAT

Radioactive rock deep inside the planet releases energy, which KEY
generates heat in the same way as a nuclear reactor. The heat Volcanic zone
rises through the mantle to the surface in convection currents Hotspot
that circulate through the heat-softened mantle rock. The Earthquake zone
currents make the rock flow very slowly, so it rises to beneath
the crust, spreads sideways, and sinks again as it cools. Plate boundary

FRACTURED SHELL
MAGNETIC FIELD Magnetic Geographic The cool, brittle crust is broken into
North Pole North Pole
Earth’s outer core is made sections known as tectonic plates.
of molten iron-rich metal. Lines of Horizontal convection currents in
This is kept in motion by rising magnetic the Earth’s crust keep these plates
and sinking heat currents, and force constantly on the move. They are
by the way the planet spins in either pulling apart or pushing
space. The moving liquid metal together, causing earthquakes and
generates electrical currents that volcanoes. New crust is created
create a magnetic field around where the plates are being pulled
Earth. This has a north and south Geographic apart, and old crust is crumpled
pole, which are not quite aligned South Pole up or destroyed where the
with Earth’s geographic poles. Magnetic plates are colliding.
South Pole

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