T1.1: Boundary Types And Intraplates Flashcards
Destructive plate boundary definition
- Convergent plate boundary
- boundary where tow plates meet and one plate is subducted forced under the other
- usually occurs between denser oceanic plate and continental plate
- Can cause fold mountains or island arcs
Constructive plate boundary defintion
- Divergent plate boundary
- boundary where two plates are moving away form eachother and are pulled apart in opposite directions
- Specifically forms mid-ocean ridges
Collision plate boundaries
- Type of convergent PB
- refers to two continental plates colliding where one is subducted under the other but still pushes the other plate up causing fold mountains to form.
Fold mountains definition
- created where two or more tectonic plates are pushed together
- As they compress rocks are warped and one is subducted under to push the other up into a fold mountains
- occurs at destructive plate boundaries and collision plate boundaries.
Island arc
- a curved chain of volcanic islands located at a tectonic plate boundary
- Forms at a destructive plate boundary as the subducted plate is melted under the other tectonic plate.
- This melts into magma which travels up and seeps through the unsubducted less dense plate to form a series of volcanoes
- They form in parallel to the oceanic trench or plate boundary forming an arc.
Constructive plate boundary features
L - Low magnitude
E - Effusive eruptions
R - Rift valley
O - Ocean ridge
Y - Young basaltic rock
S - Shallow Benioff zone
Destructive plate boundary (ocean-ocean & ocean-continent) features
I - Islands arc
M - mountains
E - explosive
T - trench
H - high magnitude
O - old rock
D - deep
Collision plate characteristics
- Shallow to intermediate depth
- Moderate magnitude earthquakes
- Fold mountains
Transform plate boundary characteristics
- Shallow focus (Benioff zone)
- Moderate magnitude
- No volcanic activity mostly
- Ridges/ scars on surface
Intraplate tectonics definiton
- refers to tectonic activity which occurs not at a plate boundary but within the interior of the plate
How do intraplate tectonic volcanoes occur?
- Magma plume (hot rock and magma) exists in the convection currents and rises to the bottom of the interior of a plate
- this burns through the tectonic plate moving magma up and through the layers of basalt rock
- forms a Volcanic hotspot
Volcanic hotspot definition
- Refers to the volcanoes that form above magma plumes which allow magma to seep above into a tectonic plate.
- Can form volcanic chains
Caldera definition
This refers to a large depression/ crevice as a volcano erupts and collapses at an intraplate boundary
Seamount definition
Seamount: an underwater volcano with very steep sides
Atoll definiton
Atoll: refers to a ring shaped coral reef or island formed from volcanic hotspots in the ocean
