Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
- 3rd side (hint)
Where is new lithospheric material created?
|
The Oceanic Ridge & Rise System
|
|
|
The Oceanic Ridge & Rise System is what kind of plate boundary?
|
Divergent
|
|
|
Magma erupting from the OCR&RS consists of what kind of earth?
|
Basaltic
|
Dealing with oceanic crust after all...
|
|
Divergent Plate Boundary:
- Earthquakes? abundance/depth - Volcanic Activity? - Heat flow high, medium, or low? |
- Common amt of earthquakes
- Abundant volcanic activity - High heat flow |
|
|
Why does the OCR&RS have shallow earthquakes?
|
Rising asthenosphere & magma bring heat close to the surface, such that close-to-melting earth flows instead of breaking
|
Imagine a freshly baked (and warm!) cookie vs. a hardened (and cold!) cookie...
|
|
How old is the lithospheric material usually when destroyed by subduction?
|
It is denser than the material that is atop it, and thus older & colder as well.
|
|
|
Zones of subduction are also known as:
|
Deep ocean trenches
|
|
|
A bi-product of subduction is:
|
Magmatic arcs (of volcanoes)
|
Chain of __ parallel to trenches & above subducted slabs of lithosphere
|
|
How is a magmatic arc formed in subduction?
|
Magma rises to surface through cracks in the overriding plate.
|
You can't always push one rock under another perfectly, can you?
|
|
Convergent Plate Boundary:
- Earthquakes? abundance/depth - Volcanic Activity? - Is the heat flow high, medium or low? |
- Abundant (Range from shallow to deep)
- Abundant/Common - Arc: High, Trench: Low |
There are arcs & trenches btw...
|
|
Explain how two plates move in a transform fault
|
They move parallel to each other in opposite direction
|
Sliiiiiidddeeee....
|
|
Of the two parts of a transform fault, which is the seismically quiet zone and which is where the action occurs?
|
Quiet - Fracture Zone
Not so quiet - Transform |
|
|
What fills the gap between two diverging lithospheric plates?
|
Magma
|
WHAT IS THE CHOCOLATEY SYRUP TO MY BREAKING...CHOCOLATE???!??
|
|
3 types of divergent plate boundaries?
|
1 - OR&RS
2 - Young ocean basins (intermediate stages of continental rifting & ocean-basin formation) 3 - On-land rifting (characterized by abnormally high heat flow & extensive faulting w/ volcanic activity) |
Think of faulting, rifting and volcanic activity
|
|
3 types of convergent plate boundaries?
|
1 - OceanicPlate to OceanicPlate
2 - OceanicPlate to ContinentalPlate 3 - ContinentalPlate to ContinentalPlate |
|
|
Explain OceanicPlate to OceanicPlate convergence.
|
Subduction of older, colder, more denser oceanic plate, with the less dense, younger, warmer crust formed over it. Forms deep ocean trenches and associated volcanic island arcs.
|
Hot Young-Ins
---------------------------------- Cooled down Old-timers |
|
Explain OceanicPlate to ContinentalPlate convergence.
|
Subduction of high-density oceanic plate beneath lower-density continental plate, making an oceanic trench parallel to continent with chain of volcanic mtns on the continent.
|
Helps to think about it picture-wise.
|
|
Explain ContinentalPlate to ContinentalPlate convergence.
|
Intense compression of the continental rocks occurs. Linear belts of folded mtns along the suture zone are forms.
|
Remember that no matter how less dense 1 continent plate is to other, they're both less dense than the asthenosphere beneath them.
|
|
What are 2 types of transform faults?
|
1 - Ridge transforms (oriented perpendicular to axes of mid-ocean ridges, offsetting the ridge axes)
2 - On-land transforms (2 continental blocks slide past each other) |
|
|
Intraplate?
|
Interiors of plates
|
|
|
What are large pulses/plumes of basaltic magma from deep mantle sources?
|
Hotspots
|
|
|
What has given birth to the Hawaiian island chain of volcanoes and the Emperor Seamount chain in the North Pacific?
|
Hotspots that remain permanently in one spot while the lithospheric plate continues to move over long periods of time.
|
|
|
Transform Plate Boundary:
- Earthquakes? abundance/depth - Volcanic Activity? - Is the heat flow high, medium or low? |
- Abundant (Shallow)
- No Volcanic Activity - MidOceanRidge: High - OnLand: Low |
|
|
Hotspots:
- Earthquakes? abundance/depth - Volcanic Activity? - Is the heat flow high, medium or low? |
- Common (Because of active plate motion as volcanic chain continues)
- Abundant - High |
|
|
Intraplate Region:
- Earthquakes? abundance/depth - Volcanic Activity? - Is the heat flow high, medium or low? |
- Rare
- Rare - Low |
|
|
What dictates a left-lateral vs a right lateral?
|
Which direction is the opposing parallel plate moving in?
|
|
|
Sinistral strike slip fault?
|
Left-lateral
|
|
|
Dextral strike-slip fault?
|
Right-lateral
|
|
|
What is the fracture zone?
|
A scar of a ridge transform
|
aka why does it exist?
|
|
Formula for the spreading rate of a ridge or a rise?
|
Distance Traveled
--------------------------- Time |
Keywords: Spreading Rate of this divergent plate boundary
|
|
What's the main difference(s) between a ridge and a rise?
|
A rise is more broad with small rift valleys if any.
A ridge is more pointed with a deep rift valley |
Rise ~= Plain + crack
Ridge = Tall, skinny mtn with a canyon inside |
|
MAR?
|
Mid-Atlantic Ridge
|
|
|
EPR?
|
East Pacific Rise
|
|
|
Ranges for Convergent Margin Earthquakes:
- Shallow? - Intermediate? - Deep? |
1) 0-30 km
2) 30-400 km 3) 400-700 km |
|