• Ever wondered what our earth is made
• Think of it as an apple.
• An apple consists of the skin, the pulp
and the core in the middle.
• Similarly, the earth is made up of the thin
outermost layer called the crust, the
innermost part called the core, and the
part in between them called the mantle.
The Earth interior
• Between the core and the crust, the
intermediate zones form the
mantle, which is mainly solid rocks but
there is also a layer of molten rock called
magma nearer the core.
• Temperatures are high, at about 2000oC.
• German scientist Alfred Wegener
formed this idea of Continental
• He argued that todays continents
once formed a single landmass,
which he named Pangaea (Greek
for "all land").
• It broke into pieces due to the
weaknesses in the earth's crust as
they were made up of less dense
materials, which drifted centimetre
by centimetre over millions of
years until they arrived at where
they are now.
• It is believed that the crust, beneath the
oceans as well as the continents, together
with the upper part of the mantle is divided
into huge slabs called plates.
• The movement of the plates is explained
by the earlier theory of Continental Drift.
• There are eight identified major plates
plus an assortment of smaller ones.