Zusammenfassung der Ressource
P1 - The Earth - Revision Mindmap
- The Earth
- when first formed the earth
was completely molten
- 4500 million years old as it is
older than oldest rocks
- studying rocks tells us more
about earth
- erosion - the earth's
surface is made of rock
layers, the layers are
compacted sediment
produced by weathering
and erosion
- craters - the moon's surface is
covered with impact craters from
meteors, earth also has been been
eroded
- mountain formation - if
new mountains weren't
being formed, earth's
surface would have
eroded down to sea level
- folding - some rocks look as if they've
been folded in half, requires huge force
over time
- Structure Of Earth
- thin rocky crust
- - thickness varies between
10km and 100 km
- - oceanic crust lies
beneath the oceans
- - continental crust forms continents
- the mantle
- - extends almost halfway to the centre of the earth
- has a rougher density than rock in crust
- very hot but under pressure
- the core
- - accounts for over half of the earth's radius
- -made of nickel and iron
- - decay of radioactive
elements inside the earth,
keeping hot
- Sea Floor Spreading
- 1. convection currents in the mantle cause magma to
rise
- 2. the current moves the solid part of mantle and the tectonic
plates
- 3. when the plates are moving apart, magma reaches the suface and hardens,
forming new areas of oceanic crust
- plate tectonics
- earth has a magnetic field,
changes polarity every m years
- combined with sea floor
spreading produces rock stripes
of alternating polarity
- 4. this pushes the existing floor outwards, and the the new crust is
continuously forming at the crest of an oceanic rifge - leads to sea
floors seperating a few cm each year
- can be used to see how quickly crust formed by
width of stripes
- when oceanic and continental plates
collide the denser oceanic plate if
forced under (subduction)
- the oceanic plate melts and molten rock can rise
to form volcanoes
- mountain ranges form
along plate boundaries
as sed rock is forced
up by pressure in
collision
- earthquakes
- waves from earthquakes
- primary waves
- travels faster than s-waves
- can travels through both liquids and solids
- can travel through liquid region of outer core of
earth
- longitudinal
- vibrates backwards and forwards
- moves backwards and forwards in the
same plane as the direction of wave
movement
- sound waves travel as longitudinal
- secondary waves
- can only travel through solid
- cannot travel through liquid region of outer core
- tranverse
- each particle vibrates up and down in normal position
- moves up and down at right
angles to the direction of wave
movement
- light and water ripples and
electromagnetic waves travel in
transverse
- example: /\/\/\/\/\/\/\/\/\/\
- wave features
- amplitude - the maximum disturbance
caused by a wave, measured by the distance
from a crest of the wave to the undistrubed
- wave length - the distance between corresponding
points on two adjacent disturbances
- frequency - number of
waves produced per
second (hertz, hz)
- 1. Plates slide past eachother
- 2. pressure builds up as
plates push on each
other
- 3. eventually stored energy is
released and waves from energy
spread from epicenter
- crucial in rock cycle
- - old rock is destroyed through subduction
- - plate collision can produce high
temps causing rock to fold
- - igneous rock is formed when magma
reaches surface
- - sed rock becomes metamorphic