Lithosphere

The crust

the outermost thin layer of the earth and it represents 1% of the earths volume

the crust composetion

igneous, sedimentary and metamorphic rocks

Continental crust

the rocks that represent landmasses on the Earth’s surface which lies beneath the atmosphere

Thickness of continental crust

it is thicker than the oceanic crust as it ranges from 30 : 100 km

formation of continental crust

Rocks rich in silica and aluminum and it is known as sial rocks

Density of continental crust

It has lower density than the oceanic crust due to the nature of its rocks and chemical composition as it is rich in aluminum

oceanic crust

The rocks found beneath the water of oceans and open seas

Thickness of oceanic crust

it is much thinner than the continental crust as it ranges from 5 : 10 km

formation of oceanic crust

rocks rich in silica and magnesium in addition to iron known as sima rocks

Density of oceanic crust

it has higher density than the continental crust because it is rich in magnesium and iron

Location of the mantle

it relies beneath the Earth’s crust

composition of the mantle

rocks rich in iron and magnesium silicates

mass of the mantle

the largest layer in terms of mass representing 67% of the earth’s mass

upper part of upper mantle

-it lies beneath the earth’s crust

-it is composed of solid rocks

-it shares with the earth’s crust to form the lithosphere

lower part of upper mantle

-it lies beneath the lithosphere

-it is composed of ductile rocks called magma that behave like highly viscous fluids

-convection currents spread within it which are the driving force that results in the movement of the tectonic plates above it

location of lower mantle

it lies beneath the asthenosphere and extends to the great depths near the outer core

physical state of lower mantle

the rocks composing it are characterized by extreme rigidity due being subjected to intense pressure that increases with depth

location of the core

it represents the deepest part of earth

composition of the core

iron and nickel

mass of the core

it represents about 33% of the earth’s mass

physical state of outer core

molten liquid

temperature of outer core

it reaches up to 5000 c

physical state of inner core

solid due to the intense pressure exerted on it from the surrounding layers

temperature of inner core

it is extremely high

density of inner core

extremely dense

importance of magnetic field

it protects the planet earth from cosmic rays and harmful solar particles

rocks

-the primary building blocks of the lithosphere, forming the solid earth’s crust

-they are classified into igneous, sedimentary and metamorphic rocks

minerals

-they are the raw materials of rocks which are used in industry and construction

-natural, solid, inorganic, substances with a fixed or semi fixed chemical composition and specific crystalline structure

soil

a fundamental composed of the lithosphere which is crucial for agriculture and the natural ecosystem that nourishes plants and retains nutrients

the importance of lithosphere

1-it represents the solid part that supports the crust and everything above it

2-it provides physical processes and chemical and biological reactions that control the stability and balance of the planet

the effect of lithosphere on the atmosphere

it affects it through chemical reactions known as chemical weathering processes that occur to rocks

water hardness

A change in the concentration of salts and dissolved elements in water such as iron , calcium and magnesium salts

minerals with ionic bonds

they break down and dissolve easily in water

example of minerals with ionic bonds

calcium carbonate found in calcite mineral forming limestone that break down in water especially acidic water

minerals with covalent bonds

they break down and dissolve very slowly in water

example of minerals with covalent bonds

silica found in quartz forming sandstone therefore silicate rocks are more resistant to weathering

tectonic plates

they are a large group of massive rock fragments that resemble floating plates forming the lithosphere

importance of tectonic plates movement

1-continuosly reshape the earth’s surface as their effects are clear and significant despite the slow movement

2-maintain the geological balance

convergent movement

it occurs when two plates move toward each other leading to their collision which results in compression and rise of rocks forming towering mountain ranges such as: the Himalayas

divergent movement

it occurs when two plates move away from each other resulting in cracks and fissures that allow magma to erupt from earth’s interior are formed which leads to the formation of volcanic mountains, a new ocean floor, rifts and widening of coastal valleys

transformation movement

it arises when two plates slide alongside each other which results in the movement of one plate gets sick therefore energy accumulates which is then suddenly released in the form of ground tremors resulting in frequent and destructive earthquakes forming faults such as san andreas fault