EMMANUEL COLLEGE OF B.Ed TRAINING, VAZHICHAL
EMMANUEL COLLEGE OF B.Ed
TRAINING, VAZHICHAL
UNIT - 3
IN SEARCH OF
EARTH’S
SECRETS
CONTENTS1. Crust
Continental Crust & Oceanic Crust
2. MantleUpper Mantle & Lower Mantle
3. CoreOuter Core & Inner Core
CRUST
- The comparatively thin outer
shell
of the Earth.
- Approximately 40 km thick.
- Two parts- continental crust &
oceanic crust.
Continental crust andoceanic crust
• As silica and alumina are the chief contents,
the continental crust is also known
as SIAL.
• As silica and magnesium are the chief contents, the oceanic crust is also known as SIMA.
MANTLE
• Located beneath the crust.
• Extends upto 2900 km from
the
crust.• Two parts- upper mantle, lower
mantle.
Upper mantle and Lower mantle
Upper mantle
• The upper mantle, made up of silicon compounds, is in a solid state.
Lower mantle
• The lower mantle, located beneath the
upper mantle, is in a semi-liquid state.
CORE
• Central part of the Earth.
• From 2900 km to 6371 km
• Two parts- outer core, inner core.
Outer core and inner core
• The materials in the outer core are in a
molten state.
• Due to the high pressure prevailing at
the centre, the inner core is in a solid
state.
As it is mainly made up of the minerals
nickel (Ni) and iron (Fe), it is also
known as NIFE.
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