Plate Tectonic Review Flashcards
Evidence supporting contiental drift
- Shapes of continents fit together; 2. Identical fossils seperated by oceans; 3. Some rock layers match across continents; 4. Glacial evidence in today’s tropical climates
Why was this theory not widely accepted?
- Wegner didn’t know what moved the plates; 2. Could not describe how continents plow through oceans because no ocean data
Were does “slab pull” occur?
Plates pull themselves down at subduction zones due to gravity; Pulling denser ocean plate down; Trenches
Continent-Continent Convergence Volcanism
No
Convergence
Moving together and compressional stress
Rock type of Continent-Continent
Metamorphic
Physical features of C-C convergence
Folded mtns
Examples of C-C Convergence
Himalayas and Mt. Everest
O-C + O-O Subduction
Moving together and compressional stress
O-C + O-O Rock type
Igneous (Andesite, Rhyolite, and pumice)
O-C + O-O Valcanism
Yes, composite
Physical features of O-C + O-O
Island arcs, trenches, + volcanos
Examples of O-C O-O Subduction
Mt. St. Helens, Andes Mtns, Japan, and Caribbean Islands
Divergence
Moving Apart; Basalt (igneous)
Stress type of divergence
sensional stress
Volcanism of divergence
Yes, fissure eruptions
Physical features of divergence
Ridge
Examples of divergence
Mid-Ocean ridge; East African Rift, Red Sea, Yellowstone
Transfomr
Strike Slip; N/A
Stress type of transform
Shearing Stress
Volcanism of Transform
No
Physical features of Transform
Shallow earthquakes, fault fracture zone
Examples of Transform
San ANdreas Fault
Deascribe how plates move
Convection Currents + Slab Pull
Convection Currents
Hot magma rises + cold magama sinks creating a current
Slab Pull
Plates pull themseves down at subduction zones due to gravity; Ocean subducts under continent b/c denser –pulls rest of plate with it
Describe the fate of California
Coast will move North, one day it will have a penisula jutting off of it
How do fracture zones form
Along divergent boundaries; Plates moving at different speeds and plate rips; Exception– San Andreas
How are continental shelves reltated to plate tectonics?
They are not related at all; Continental shelves are due to erosion
Speed of plate movement
Speed = Distance/ Year
New Post- Wegner discoveries that helped support Wegner’s idea of plate tectonics
- Ocean Floor Evidence; 2. Pattern of Earthquakes Ouline edges of plates
ocean Floor Evidence
Ocean floor is not flat; Zebra stripes on ocean floor formed together; Ocean crust is younger than continental
Pattern of Earthquakes
Outline edges of plates; Shows that a plate can be ocean/continent combo
Lithosphere
outer layer of curst; Ridgid; Made up of ridgid upper mantle and crust
Asthenosphere
Flows/fluid; Lower mantle; Contains convections currents
Tectonic plate
Made up of ridgid upper mantle and crust; Lithosphere and upper asthenophere
Volcanos don’t form at…
Transform boundaries
Himalayas
Convergent of Australia Plate w/ Eurasia
San Andreas Fault
Transfomr Fault; N. American + Pacific Plate
Andes Mountains
Convergent Plate of Nazca + South American Plate
Mt. St. Helens
Convergent of Juan De Fuca + North American Plate
Mid Atlantic Ridge
Divergent of North American + Eurasia
Mariana Trench
Ocean- Ocean Convergence of Pacific Plate + Phillipne Plate
Red Sea
Divergent of Arabia Plate + African Plate
Iceland
Ocean Divergent of N. American andn Eurasian Plate
Crust
Ridgid/ Rocky; Si, O2
Outer Core
Liquid Iron
Mantle
Magma; Flowing solid of Ca, Fe
Inner Core
Solid Iron
How does outer core produce magnetic field
Due to currents created from outer core
