Transcript Earth's interior layers.

Earth’s interior layers.
• The major layers of
the Earth consist of the
crust, mantle, outer
core and inner core.
INNER CORE
• The core is composed mainly of iron and
nickel. In the inner core, iron and nickel are
solid.Although the inner core is very hot,
pressure from the weight of the rest of the
Earth doesn’t allowed the material to melt.
Iron’s normal temperature of melting is
15350C, but in the earth inner core it could
stand 40000C with no melting.
OUTER CORE.
• Because less weight is exerted on the outer
core, the pressure is less there, so iron and
nickel present here in liquid state.
• The molten outer core flows at the very
slow rate which means electrons from the
metals produce an electrical current.
• This electrical current powers the earth’s
magnetic field.
THE MANTLE
• The mantle is composed of hot iron-rich
silicate rocks.
• Flow in the mantle occurs as convection
currents; hot material in the mantle rises,
cools and then sinks.
• Mantle is elastic which means it behave in
plastic manner.
THE CRUSTAL SURFACE.
• CONTINENTAL CRUST –
is between 20 and 60 km thick. It is
composed of granitic rocks, which
are less dense than basaltic rocks of
the oceanic crust. So, most of
continental crust is above sea level.
• OCEANIC CRUST is only about 10 km thick. It is
composed of basaltic rocks, which
are more dense than granitic rocks
of the continental crust. So, oceanic
crust is below sea level.
Composition of the Earth.
40%
iron
oxygen
30%
20%
10%
0%
silicon magnesium
the other
THE THEORY OF PLATE TECTONICS
• The framework explains how
and why the surface of the earth
constantly changes is called
theory of plate tectonic.
• The theory states that the
earth’s outer shell, the
lithosphere is divided into eight
large plates.
• Because each plate moves as a
single unit, the interiors of the
plates are generally stable. All
major activity such as
earthquake or volcano occur
along the plate boundaries.
DIFFERENT TYPE OF BONDARIES
• DIVERGENT PLATE
BOUNDARIES- plates are
moving away from each other.
Very active volcanically due to
the rising of magma.
(Mid-Atlantic Ridge)
• CONVERGENT PLATE
BONDARIES- plates are
coming together. The regions of
plate collision are regions of
great mounting buildings.
(Andes, Himalayas, Sierra
Nevada)
• Oceanic – Oceanic Convergence
Collision between two oceanic plates can
result in the prosses when one plate bends
and descends beneath the other to produce
deep oceanic trench. (Marianas Trench)
• Oceanic – Continental Convergence
When an oceanic plate and a continental
plate converge, the denser oceanic plate is
subducted beneath the less dense
continental plate.A deep ocean trench is
formed and magma is generated. (Andes)
• Continental – Continental Convergence.
The collision between continental plates
has produced some of the most famous
mountain ranges. (Himalayas, European
Alps, Appalachian)
ROCKS AND MINERALS
• MINERALS are the building blocks of rocks, and
elements, in turn, are the building blocks of minerals.
• A mineral is defined as a naturally formed, inorganic,
crystalline solid, composed of an ordered arrangement of
atoms with specific chemical composition.
• Of the known 112 elements, 92 occur naturally in the
earth’s crust and combine to make 4000 different minerals.
ROCK TYPES
• IGNEOUS ROCKS are formed by the cooling and crystallization of hot,
molten rock – magma. The word igneous means “formed by fire”. Igneous
rocks make up about 95% of the Earth crust. Basalt and granite are
common igneous rocks.
• SEDIMENTARY ROCKS are formed from pieces of other rocks
(sediments) carried by water, wind, or ice. Sedimentary rocks are easy to
find on the ground beneath our feet – the uppermost portion of Earth crust.
Sedimentary rocks cover more than two-thirds of the Earth’s surface.
Sandstone, shale, and limestone are common sedimentary rocks.
• METAMORPHIC ROCKS are formed from older, preexisting rocks
(igneous, sedimentary, or metamorphic) that are transformed by high
temperature, high pressure, or both – without melting. The word
metamorphic means “changed in form”. Marble and slate are common
metamorphic rocks.
ROCK CYCLE
MINERALS
Silicates
Nonsilicates
Clay Minerals
Ferromagnesian
Carbonates
Sulfates
Oxides
Sulfides
Phosphates
Halides
Nonferromagnesians
Native Elements