Science - Tectonic Plates Flashcards
What makes up the Lithosphere?
Rigid Rock:
- Crust
- Upper mantle
What makes up the Asthenosphere?
Semi-Liquid:
- Lower mantle
What makes up the Outer Core?
Liquid:
- Nickel
- Iron
What makes up the Inner Core?
Solid:
- Iron
Crust
- Outermost layer of the Earth
- Ranges from 5km-30km in thickness
- Broken into tectonic plates
- Plates move around on top of the asthenosphere
5 Largest Tectonic Plates
- Pacific Plate
- North American Plate
- Eurasian Plate
- African Plate
- Antarctic Plate
Continental-Continental Convergence
Mountains
Continental-Oceanic Convergence
- Oceanic Trench
- Continental Arc
Oceanic-Oceanic Convergence
- Oceanic Trench
- Island Arc
Divergent Boundaries
- Mid-ocean Ridge
- Rift Valley
Transform Boundaries
- Fault Lines
Why plates move:
Convection Currents:
- The circular motion of the current causes the magma to hit the plates and push them up
Ridge Push:
- Magma rises out of ridge, cools, pushes plates apart, new crust forms
Slab Pull:
- Subducted plate is pulled into mantle due to gravity
Who was Alfred Wegener?
A German scientist who was a:
- Meteorologist and a Geophysicist
He came up with the idea that all continents used to be one super continent called Pangea that moved apart after some time
Wegener’s Evidence
- Continents fit like puzzle pieces
- Fossils of the same species found on different continents
Why wasn’t Wegener’s idea accepted?
They didn’t understand how or why it happened
Who was Harry Hess?
He was a naval scientist.
He proposed the theory of seafloor spreading
Hess’s Evidence
Age of seafloor:
- Rock found near ridges were young, rock found near trenches were old
Sediment thickness:
- Sediment layer near ridges was thinner than near trenches
Magnetic Striping:
- Magnetic field constantly changes so magnetic mineral would align with current field which showed the flipping of the field
Volcanoes Release
- Dangerous gases
- Lava
- Rock
- Ash
Hot Spot Volcanoes
The plates moves over unusually hot parts of the mantle and the magma rises, pierces a hole in the plate, and forms a volcano. Plate continues to move and can form more volcanoes.
Earthquakes
- Plates held together with friction
- When other forces overcome friction forces, plates slip
- Releases energy into rock around it causing them to shake
- Measured using seismometer
Seismic Waves
P-waves:
- Longitudinal <>
- Fastest
S-waves:
- Transverse ^
- Slower than P-waves
Surface Waves:
- Rolling Motion @
- Slowest
- Most destructive
Define Focus
Where quake starts (underground)
Define Epicenter
Location directly above focus
Define Richter Scale
- Logarithmic Scale
- Measure of severity
