Lecture Review Quiz Flashcards
What does the study of plate tectonics include?
- The formation of plates
- How plates are formed
- How plates are destroyed
- How plates interact
Boundaries and physical properties of Earth’s interior bear directly on forces that do what?
- Deform Earth’s crust
- Trigger earthquakes
- Cause volcanos to erupt
- Drive the crustal plates around the globe
What are the two types of crust?
- Oceanic crust
- Continental crust
What is tectonics?
Tectonics is the large-scale processes affecting the structure of the Earth’s crust
What are the 10 plates or plate groupings?
- North American Plate
- Pacific Plate
- African Plate
- South American Plate
- Eurasian Plate
- Cocos/ Nazca/ Caribbean Plate
- Australian Plate
- Antarctic Plate
- Indian Plate
- Arabian Plate
What are the three types of plate boundaries?
- Divergent
- Convergent
- Transform
Divergent Boundary (Oceanic - Oceanic)
Process:
Features:
Example:
Process: Spreading center. The seafloor spreads apart; creating new seafloor; magma flows up
Features: Mid Ocean Ridge, Volcanos, Young lava flow
** Convection current
Example: Mid-Atlantic Ridge
Divergent Boundary (Continental - Continental)
Process:
Features:
Example
Process: Continental rifting process; continent splits apart creating new sea floor
Features: Rift Valley, Volcanos, Young lava flow
Example: East African Rift Valley, Iceland
Convergent Boundary (Oceanic - Continental)
Process:
Features:
Example:
Process: Plates moving together; subduction; old sea floor is destroyed
Features: Trench, Volcanic arc on land
Example: Andes Mountains, Peru - Chile Trench
Convergent Boundary (Oceanic - Oceanic)
Process:
Features:
Example:
Process: Plates moving together; subduction; old sea floor is destroyed
Features: Trench, Volcanic arc islands
Example: Mariana Trench
Convergent Boundary (Continental - Continental)
Process:
Features:
Example:
Process: Plates moving together
Features: Collision, Mountain Formation
Examples: Himalaya Mountains
Transform Boundaries (Oceanic or Continental)
Process:
Features:
Example:
Process: Plates sliding horizontally past one another
Features: Transform faulting, fault lines
Example: San Andreas Fault Line
What does a seismograph help determine?
- Location and thickness
- Some properties of the Earth’s internal zones
Primary Waves (P)
- The fastest
- Movement parallel to propagation
- Speed differs with material density and elastic properties
- Can pass through liquids
- Are slowed and refracted
- Shadow zones
Secondary Waves (S)
- Travel 1-2 km/sec slower than P Waves
- At right angles to the direction of propagation of energy
- Cannot travel through the dense rock of the lower mantle therefore reflect off it
- Can not pass through the liquid outer core
Surface Waves
- Large-motion waves
- Travel through the outer crust
- Like ripples from pebbles tossed in a pond
What is the Lithosphere?
The rigid upper mantle + crust
“floats” on partially molten Asthenosphere
What is the Moho discontinuity?
The boundary between the Earth’s crust and mantle
First identified in 1909 by Andrija Moho
Defined by the distinct change in velocity of seismic waves as they pass through changing densities of rock
Who was Alfred Wegener and what did he propose?
A German meteorologist and geophysicist
Proposed the idea of mobile continents and fitted the continents together
What was Wegener’s evidence?
- Matching sequence of rocks on different continents
- Fossil evidence/coal deposits
- Glacieel deposits in regions to warm for ice now
What did Harry Hess discuss in his writing? “History of Ocean Basins” 1962
Seafloor spreading in relation to the convection of magma in the mantle
New crust formed at ridges and old crust subducted at trenches
What did the geologists Frederick Vine and Drummond Matthews do?
Combined seafloor spreading with magnetic “striping” pattern (magnetic polarity reversals”
