CHAPTER 13: PLATE TECTONICS Flashcards
Folding and faulting of earths crust is called?
Diastrophism\
Plate tectonics is…
how plates move over surface
Supercontinent name was…
Pangaea
Ocean that surrounded Pangaea?
Panthalassic Ocean
Who had the theory of Continental Drift?
Alfred Wegener
5 pieces of Wegeners evidence
- Shapes of continents
- Petrologic evidence
- Mountain Belts
- Palaeontology
- glaciated continents
Why was continental drift theory rejected? (2)
- too rigid to permit such large movements
2. didn’t offer a suitable mechanism that could displace such large masses
When was Continental Drift theory rejected?
1920
Evidence for Plate tectonic theory (3)
- Detailed map of sea floor
- Plate Boundaries
- Seafloor spreading
Evidence for seafloor spreading (2)
- paleomagnetism
2. age of ocean floors
What is paleomagnetism?
magnetic polarity several, as lava hardens, iron particles record location of magnetic north
Margins of plates are clalled…
Plate boundaries
How do we know where plate boundaries are? (2)
- Earthquake activity
2. earthquakes are not randomly distributed but occur in geographic patterns that outline lithospheric plates
Plates move by…. which currents?
Convection currents
3 ways plates move
- Ridge push
- Mantle drag
- Slab pull
What makes up for 90% of plate movement?
Slab pull
Which are the fastest moving plates?
Pacific and Nazca Plate
Mid-atlantic ridge moves how many cm per year
1 cm/yr
Pacific Antarctic ridge moves how many cm/yr
10cm/yr
Land masses were created how many years ago?
4 billion
Do continents grow continuously?
YESSSS
What are accreted terranes?
Instead of being subjected and recycled, terrane is too buoyant and uses instead… ex. warngellia terrane
What are passive contenental margins?
No recent activity, oceanic and continental crust same lithospheric plate
What are active continental margins?
Deep oceanic trenches, alpine belt
3 ways plate boundaries move
- divergence
- convergence
- transform
Divergence is most common with..
sea floor spreading
Convergence is common with…
Oceanic/Continentall, ocean/ocean, continental/continental COMPRESSION
The great Rift Valley is an example of…
divergence plate movement
Great African Rift Valley is an example of…
divergence plate movement
Midocean ridges are an example of…
divergence plate movement
Oceanic plates are thinner and denser tthan
continental plates
pacific ring of fire is an example of…
convergence oceanic/contenintal
Oceanic/oceanic convergence causes
oceanic trenches
Himalaya mountains are an example of…minor subduction occurs
convergence continental/continental
in transform plate boundaries, the plate…
slide against eachother
Transform plate boundaries commonly produce what earthquakes
shallow focus
The san Andreas fault is an example of…
transform plate boundry
What is mantle plume?
mostly stationary column of hot rock that extends from deep in mantle up to base of lithosphere
Hawaii is an example of a
hot spot
Guyots are
crustal motion over a hotspot produces a long trail of islands
Hot spot tracks are…
lines of inactive volcanoes in ocean basins
Yellowstone is an example of…
Hot spot
folding occurs most often when plates are
converging in regions of subduction and collision
Folding produces highs and lows called…
Anticline (top)
syncline (bottom)
inverted topography happens when…
folded rock is eroded, can result in sycline ride anticline valley… happened in Hancock
Zones of weakness in the crust are called
Faultzones
Convergence movement results in what fault
Reverse fault
Divergence movement results in what fault
Normal fault
transform movement results in
strike-slip fault
Fauting is
rocks breaking accompanied by displacement
Garben and Horst
regions that lie between normal faults and are either higher
The East African Rift Valley is a graben or scarp
GRABENNN
Orogensis is
mountain building
orogenic belt is
linear mountain range
Longest mountain range in world
Andes
Longest mountain range in North America
Rockies
