Presented bySARUKRISHNA V M

B.Ed GEOGRAPHY

EARTH’S INTERIORKnowledge is limitedTemperature and pressure

increase with depth.Depth of mine – 9 km onlyDepth of magma chamber – 64

km onlyAnalysis on the basis of seismic

waves

Earthquake waves

1. Primary waves – moves fast through solid and slow through liquid

2. Secondary waves – moves only through solid

Magma chamber

Magma chamber

LAYERS OF EARTH

1. Crust

2. Mantle

3. Core

CRUST Outer most layer. Divided into 2 sub- layers

Sial - ocean crust Sima - continental crust.

Age – 4500million years ago.Sima– 3600 million years.Sial – 200 million years.

Depth up to 40 km. Average density 2.9 g/cm3

SIAL- The Oceanic CrustSi – silicon and Al – aluminum.High density.Iron and calcium are also

present.Younger part of crust – 200

million years old.

SIMA – The Continental Crust

Si – silicon and Ma – Magnesium. Low density.Aluminum, potassium, and

sodium.Older part of the crust – 3600

million years.

2 layers Of Crust

•Oceanic crust or Sial(very dense, made of basalt)

•Continental crust or Sima(less dense, made of granite)

CRUST- Points to remember

Outer most layer Sub divisions – sial and simaSial – oceanic crust- very dense –

younger in ageSima- continental crust- less

dense – older in age

Mantle forms the second layer

MANTLEsecond layer of the interior of the earth.Two sub - layers –1. Upper mantle. 2. Lower mantle.Thickness varies between 35km – 2900

km.Average density is 4.5 g/cm3

Upper portion of mantle and crust together known as Lithosphere.

lower mantle – Aesthenosphere.

UPPER MANTLESolid in state.Thickness – 40 – 400km.Lithosphere About 100kmBroken into platesSeven major plates and 12 minor

plates.AesthenosphereHigh temperature.Melting of rocksConvectional currents

LOWER MANTLE

Molten in stage. Thickness- 400km 2900 km. Also known as mesosphere.Lies below the Aesthenosphere

MANTLE

Upper mantle

Lower mantle

Mantle – points to rememberSecond layer of the earthDivide into two - upper mantle and lower mantleUpper mantel and crust forms

lithosphere.Convectional currents are found in

Aesthenosphere

Core forms the third layer

COREThird layer of the earth.

Formed by nickel and iron.

Also called as NifeNife – Ni - nickel and Fe – ferrous or ironTwo parts 1. Outer core. 2. Inner core.Temperature is 11000˚ C.

Inner core is in solid state.

CORE – divided in two layers

1. Inner coreMolten in stageDepth varies

from 2900km – 5150 km.

Density – 10.7 g/cm3.

2. Outer coreSolid in state High

temperatureHigh pressureDepth varies

from – 5150 km – 6371 km.

Density – 15 g/cm3

CoreTwo layers 1.Outer core 2. Inner core

Core – points to rememberThird layer of earth.Dived into two – inner and outer

core.Outer core – molten in stageInner core solid un sate.High temperature and pressure

EARTH AND EGG !!!!!!

shell

Yolk

Egg white

SHELL – CRUST

EGG WHITE – MANTLE

EGG YOLK - CORE

Summary tableName of the layer

Subdivision

thickness density Temperature

CRUSTSial

Sima

8 – 40 km

16 km

2.8 g/cc

2.9 g/ccIncrease at a rate of 1˚C/ 32 m

MANTLEUpper mantle

Lower mantle

About 100 km

About 2800 km

3- 11 g/cc

2200˚C (approximately)

COREOuter Core

Inner Core

About 2150 km

About 1255km

11 – 10 g/cc

5000˚ C ( approximately)

ASSIGNMENTS

Prepare a summary table for three layers of the earth.

Draw a neat diagram showing layers of the earth.