Layers of the earth Flashcards
(29 cards)
Outermost layer of the earth
Crust
Dense, thin, younger tightly packed and found in
water
Oceanic Crust
Thicker and found in lava
Continental Crust
Holds the continents, the solid and rigid outer
layer
*Composed of the crust and upper asthenosphere
Lithosphere
The mostly solid bulk of the earth’s interior
Mantle
- Semi solid and ductile, tectonic
plates move on top of this layer. Holds convection currents.
Upper Mantle / Asthenosphere
- Pressure is so great that rocks move
slower.
Lower Mantle / Mesosphere
- Innermost layer of the planet
Core
As hot as the sun, is solid due to high pressure.
Contains hardened iron
Inner core
- Less pressure allows it to stay liquid form. Has
melted iron and nickel and makes up most of the core.
Outer core
This theory believes in the fact that all continents were once
part of a bigger continent called Pangea
- This is supported by:
a.Similar landscape across different islands
b.Continents looking like puzzle pieces separated
c. Fossils of terrestrial animals spread across islands
- Discovered by Alfred Wegener
- The proof would come far later in the future through…
The Continental Drift Theory / Pangea Theory
- A theory that dives deeper into the “Why” aspect of the
pangea theory - This theory states that the convection currents are the reason
for the drifting of the continents - Using a seismograph, scientists discovered the plate margins
that run across the globe, splitting the world into the
continents. - Seismograph measures seismic waves releasing from plate
margins. - It is through these plate margins that the convection currents
are released, causing the formation of different landscapes
The Tectonic Plate Theory
A theory that explains how the tectonic plate theory affects
the landscape.
- When the oceanic and continental crust converge, the oceanic
crust goes underneath the continental crust due to its density.
- That process is called subduction and a subduction zone is the
zone where the oceanic crust sinks due to its density.
- The oceanic crust gets closer to the mantle where it burns
due to the convection currents
- After burning, the lava flows in the mantle until it finds a plate
margin underwater to pour out of
- In the plate margins, lava flows out turning into magma
which pushes the oceanic crust into the continental crust,
thus creating more lava in the process
- Convergent plates of oceanic and continental are what cause
the movement of continents because as the seafloor widens,
so does the gap between plate margins
Seafloor Spreading Theory
Results in the oceanic crust sinking and melting before
reemerging in the plate boundaries.
- Responsible for the drifting of continents
Convergent Boundaries (Oceanic to Continental)
Are responsible for the formation of mountains
- Also creates a subduction zone
Convergent Boundaries (Continental to Continental)
The denser crust sinks and forms another subduction zone
- As the denser crust sinks, some fluids are released and
partially melt the ingenious rock, possibly rising and erupting
as underwater volcanoes
Convergent Boundaries (Oceanic to Oceanic)
Occurs when two tectonic plates separate and pull away,
forming valleys, mountain wrangler, and rift valleys
- In oceanic crust divergent boundaries, the magma leaks out
of the plate boundary, cooling into magma
Divergent Boundaries
Happens when the tectonic plates slides in opposite
directions, like a two trains in a subway
- Fault lines and rift valleys are also a result of this
Transform Boundaries
are caused through convergent boundaries in
subduction zones where the motion of the plates build
pressure
- Overtime, the pressure will be too much for the rocks to
handle and the energy will release at once, causing
earthquakes
Earthquakes
formed in underwater earthquakes where the
pressure makes a huge wave
Tsunamis
The cycle of heat found in the asthenosphere
Convection Currents
- The tool used to measure seismic waves
Seismograph
Edge of a tectonic plate, usually where plates drift away or
against each other
Plate Margins
- The quantity of vibrations coming from the build up of
pressure in the mantle
Seismic Waves
