Plate Techtonics Flashcards
1
Q
Order of Earths Interior
A
Crust - Mantle - Outer Core - Inner Core
2
Q
Deepest Point
A
- Kola Superdeep Borehole
- 12 km deep
Mariana Trench (10.9 km) - 0.002% of way to middle of the Earth
3
Q
Seismic Wave
A
- conduced through the Earth
- how earthquake waves are measured
4
Q
P Waves
A
- pressure waves
- expansions and compressions on flat ground
5
Q
S Waves
A
- sheer wave (snake)
- cannot travel through liquids (outer core)
6
Q
Changes in Desities
A
- deflect waves
- change velocity of waves
- travel paths change direction at boundaries between layer
7
Q
Crust
A
- mostly silicon, oxygen, aluminum
- stiff and solid
- continental (20-80km, low density, lighter) and oceanic (5-10km, mostly Fe and Mg, higher density)
8
Q
Mantle
A
- uppermost mantle - stiff
- aesthenosphere - soft, can flow
- mesosphere - stiffer than atmosphere, but can still flow
9
Q
Composition of Whole Earth
A
- mostly silicon, oxygen, iron, and magnesium
- know through seismic data, volcanic matter, and samples of meteorites
- greater mass = greater gravitational pull
10
Q
Formation of the Earth
A
- heating from bombardment
- gravitational compression
- radioactive decay produced melt
11
Q
Compositional Layers
A
- differentiate by chemical composition, not behaviour
- continental crust (10-70km), oceanic crust, (5-7km), mantle, core
- Si, O exist in less dense composition (core)
- Fe, Mg, Ni exist in more dense composition (still exist in crust, more in core)
- Pressure, Temperature and Density increase proportionally with depth (leads to differences in mechanical behaviour and phase)
12
Q
Mechanical Layers
A
- how rocks behave in response to stress
- lithosphere (10-200km), mesosphere, outer core, inner core
13
Q
Lithosphere
A
- solid and stiff
- uppermost crust and mantle
- moves during plate tectonics
- 10-200 km
14
Q
Plate Boundaries
A
- named based on the relative motion of the plates on either side of the boundary
- volcanoes and earthquake location linked to plate boundaries
15
Q
Divergent Boundary
A
- plates move away from each other
- mostly in sea floor (seafloor spreading)
- older rocks are further from ridge
- volcanoes
16
Q
Seafloor Spreading
A
- creating new rock (magma comes up)
- produces continuous row of volcanoes called mid ocean ridge that wraps around world
- earthquakes and volcanoes occur (gases, heat, hot springs, acidic water)
17
Q
Convergent Boundary
A
- plates move towards each other
- ocean-continent convergent boundary creates mountains or subduction zone (oceanic trench, accretionary prism). Oceanic crust gets subducted getting deeper into mantle because more dense
18
Q
Ocean-Continent Convergent Boundary
A
- ocean-continent convergent boundary creates mountains or subduction zone (oceanic trench, accretionary prism).
- Oceanic crust gets subducted getting deeper into mantle because more dense
19
Q
Ocean-Ocean Convergent Boundary
A
- older, colder, denser plate subducts
- rock cooling, more dense
- Japan, Bali, Southeast Asia, Allusion Islands
- creates island arc of volcanoes
20
Q
Continent-Continent Convergent Boundary
A
- modern india, Tibet
- mountain range under the ground (mirrored)
- produces very large mountains (Everest, Himilayans)
21
Q
Transform Boundary
A
- side to side movement
- no crust created or destroyed
- commonly associated with spreading centres (divergent boundaries)
- plates going the same direction = inactive zone
- connect spreading ridges
- San Andreas fault
Can connect spreading ridges to subduction zone (Q. Charlotte fault) or connect two plates going the same direction at different rates (Nootka fault)
22
Q
Convection
A
- causes plate movement
- cool water sinks (becomes more dense) while warm water rises (becomes less dense)
23
Q
Heat
A
- the source of power for plate movement
- heat transferred through the mantle via convection
24
Q
Plate Movement
A
- heat
- convection
- weak aethenosphere so the lithosphere can slip over it
- oceanic plates are more dense and go under continental plates
