EARTHS INTERIOR AND PLATE TECHTONICS Flashcards
Crust
upper most layer of earth–conatians the oceqanic and continetal crust and lithosphere
Mantle
layer benath the crust where magma flows–contains the asthenosphere
core
most inner layer of earth– contains the inner and outter core
what are the 3 main layers of earth
the crust mantle and core
oceanic crust
made of igneous rock, baasalt and gabbro–apart of the earths crust
continental crust
made of granite rock called granodirate– apart of earths crust
lithosphere
earths outer most layer that consists of the crust and uper most mantle it forms a relatively cool and rigid slab of rock known as a plate
asthenosphere
the soft and weak layer beneath the lithosphere where magma flows
why does magma flow in the asthenosphere
it is close to it’s melting point so the magma becomes easily deformed
inner core
made of mostly iron-nickel
why is the inner core solid?
because it is compressed by immense pressure
outer core
made of mostly metallic iron
conevection
movement in general of either magma or just currents in general
plates/ plate tectonics
huge slabs of rigid rock that are made of crust and upper most mantel which together are called the lithosphere– the magma in the asthenosphere causes the plates to move//tectonics–moving
pangaea
the super continent that is thought to have existed before the continents drifted apart
convergent boundaries
—->
divergent boundaires
plates moving apart (land fills the gaps and will create new land, mountians or volcanoes)
Transform boundaries
—–>
subduction zones(happens btwn contiental and oceanic crusts collide)
when 2 oceanic plates are moving apart and beneath the north american plate generates water rich magma that fuels explosive eruptions
hotspot
place in the upper mantle of the earth at which hot magma from the lower mantle upwells to melt through the crust
Paleomagnetism
the difference of the way the north points in rocks–it switches every 300,00 years(magnetic convectios) shows us how earths magnetism is actually changing and how our earths plates have constantly been moving
Describe the theory of Continental Drift and the person who developed this theory.
alfred wegnerit is believed that the continents have drifted (plates) throughout millions of years
What is the evidence to support the theory of Continental Drift?
contients looked like jigsaw puzzles rock and animal fossils in diff continents across the ocean
What happens when two plates of continental crust collide?
forms a mountain range–ex himalayas – when the plates start to collide pressure builds up and they push up against and create mountians
What happens when two plates of oceanic crust collide?
it is a subduction again… a trench forms and you get a volcanic island chain
What happens when one plate of oceanic crust collides with a plate of continental crust?
forms a subduction zone–ex south american andes–some volcanoes form
What forms at a divergent boundary on oceanic crust?
mantle rocks beneath plates are hot and as they expand and igneous rocks bulge upward they fill the sea floor expanding it and it cools and solidifies
What forms at a divergent boundary on continental crust?
it forms a riff valley and eventually water will start to fill it and a linear sea will form (ex. red sea)
Although these can occur at any plate boundary, what phenomenon is most commonly connected to transform boundaries?
earthquakes as the plates pass there is tension and the earthquake is the tension being released
What is the composition of the core? How do we know this?**
its solid and we know because we use seismic waves to determine it( also emense pressure is being distributed to the center)
seismic waves
Seismic waves are waves of energy that can be caused by earthquakes.
Which layers are fluid? Which are solid?
solid: crust, upper mantle, inner corefluid: outer core, lower mantle, asthenosphere
Why is ocean crust thinner and denser than continental crust?
Because of the pressure of the water in the ocean crust that compacts it
plates
large slabs of rock
what is convection
he movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
where does heat originate
the core
why do plates move
because they are onto of the asthenosphere which is very hot and easily deformed which enables to the plates to move onto of the magma
who proved the theory of the sea floor spreading
Henry hess
Which boundary runs across California?
san Andreas fault
Where is nyc on the plate map? Is it on a boundary?
no its in the middle of one– na plate
At which type of boundary is crust being destroyed
convergent
At which type of boundary is crust being created
divergent
Trench
a long narrow ditch formed by a convergent boundary between a continental and a oceanic
