U3L3 Flashcards
plate tectonics and landforms
explain how the lithosphere and asthenosphere are involved in tectonic plate movement.
the lithosphere is divided up into large pieces called tectonic plates that move on top of the convection currents in the slow flowing asthenosphere
what two types of lithosphere make up tectonic plates?
continental lithosphere - thicker, older, less dense
oceanic lithosphere - thinner, younger, denser
state the theory of plate tectonics
describes the large scale movements of the lithosphere divided up into slabs called tectonic plates on top of the convection currents in the asthenosphere
list the 6 volcanic landforms
- shield volcanoes
- cinder cones
- composite volcanoes
- lava plateaus
- craters
- calderas
list the 3 types of lava from least to most viscous
- Basaltic - least viscous (fast but less explosive, low slopes)
- Andesitic - more visocous
- Rhyolitic - most viscous (slow but more explosive, steep slopes)
what is pyroclastic material?
hot ash and bits of rock that may be ejected into the atmosphere by a volcano
list the 3 types of mountains and at what boundaries they form
folded mountains - convergent
fault block mountains - convergent + divergent
volcanic mountains - convergent + divergent
define volcano
anywhere gas, ash, or melted rock comes out of the ground
explain magma vrs. lava
magma = melted rock underground
lava = melted rock above ground
due to the change in chemical composition
list and describe the 3 main stresses
and boundaries
- compression - squeezing - convergent - folds + faults
- tension - pulls rock apart - divergent - faults
- shear stress - rock twisting/distortion - transform
how does the theory of plate tectonics relate to stress and deformation?
the movement of the tectonic plates causes stress on the rocks, which can cause deformation such as bending, tilting, or breaking it. creates folds and faults.
what landforms form at convergent boundaries due to compression?
- folded mountains
- fault block mountains
- volcanoes
- ocean trenches
what landforms form at divergent boundaries due to tension?
- fault block mountains
- rifts
- mid ocean ridges
- ocean trenches
what landforms form at transform boundaries due to shear stress?
- earthquakes
- visible boundaries with deformed rock
what type of fault occurs at a convergent boundary due to compression?
reverse fault
what type of fault forms at a divergent boundary due to tension?
normal fault
what type of fault occurs at transform boundaries due to shear stress?
strike-slip fault
how do volcanoes form at hot spots?
- magma rises from the hot spot to the surface and forms and undersea volcano
- the volcano grows to become a volcanic island
- as the plate travels a new part of the lithosphere moves over the hot spot and the cycle repeats, creating a volcanic island chain
