Earth’s Layers
Compisitional Layers
V.S
Functional Layers
Crust, Mantle and Core
V.S
Lithsophere and Asthenosphere
Divergent boundary
Plates move away from each other
What are Plate Techtonics
Edge of tectonic plate where plate interactions occur
Seafloor spreading
Magma pushing up to push the plates away from each other (Ocean divergent)
Active margin
Where plates are actively moving
Lithsophere v.s. Asthenosphere
Crust and upper mantle vs lower mantle
Convergent boundary
2 plates come together and collide
Continental rift
Continental divergent plate boundary
Hot spot
Rising plumes of mantle material in the middle of a plate
Passive margin
Plates are not moving/no activity
What are the functional (mechanical) layers of the earth? How are they different from the
compositional layers?
Lithosphere and asthenosphere; different from compositional because they are organized by how they behave
Transform boundary
2 plates slide past each other
Where is new crust created? Destroyed? And why for each?
Created due to magma upwelling on divergent plates, and destroyed at oceanic convergent due to subduction
Plate-mantle convection
Convection currents in the asthenosphere move lithosphere at the surface
What is the difference between active and passive margins? What are some examples of each?
Active margins move (western coast of N and S America) while passive don’t (eastern coast of N and S America)
Subduction
Oceanic lithosphere sinks into the asthenosphere
Be able to determine the type of plate boundary from a map/image
To determine the type of plate boundary from a map or image, look for patterns of earthquakes, volcanoes, mountain ranges, and ocean trenches, which are characteristic of convergent, divergent, and transform boundaries.
What are the two major models for the mechanism of plate tectonics?
Seafloor spreading and hotspots
Why do mid-ocean ridges form?
Seafloor spreading; oceanic divergent plates
Seafloor spreading
Magma pushing up to push the plates away from each other (Ocean divergent)
Why does subduction occur?
Oceanic plates are extremely dense so they sink under other plates
Describe the characteristics of each type of boundary, including the 3 types of convergent
boundaries and both divergent. What features are associated with each? What is the
mechanism or cause for the major features?
Divergent Boundaries: Plates move away from each other, forming ridges, rift valleys, and new crust via seafloor spreading.
Convergent Boundaries: Plates move toward each other, leading to subduction (oceanic-continental and oceanic-oceanic), mountain formation (continental-continental), and features like trenches, volcanic arcs, and island chains.
Transform Boundaries: Plates slide past each other, creating faults and earthquake activity.
What is the surface evidence for plate tectonics (in addition to those of continental drift)?
Earthquakes, volcanos, mountain ranges, oceanic ridges, ocean trenches
Slab-pull & slab-push model
Descending oceanic crust pulls the plate while elevated ridge system pushes the plate
Explain the continental drift hypothesis. What evidence was there? Why was it abandoned?
ontinents “drifted” to current positions. Abandoned due to lack of mechanism to explain