unit 8 (earth's interior) review Flashcards
Inner/outer core
solid (inner)/liquid (outer) iron and nickel; responsible for magnetism
Asthenosphere
Upper portion of the mantle below the crust that is weak and allows tectonic plates to slide over it
Oceanic vs continental plates
Oceanic plates: basalt, thinner but denser (subduct)
Continental: granite, thicker but less dense (go over)
Lithosphere
Layer of the Earth containing the rigid uppermost mantle and crust
Viscosity
Substance’s resistance to flow
Subduction (2 types)
Occurs only at convergent boundaries
1) Oceanic-oceanic: Older, denser plate subducts beneath newer, causing deep sea trenches and volcanic island arcs
2) Oceanic-continental: Ocean plate subducts beneath continental, causing deep sea trenches (also) and inland volcanoes
(Subduction does not occur at continental/continental boundaries)
Magma vs lava
Magma is below ground; lava is above ground
Basaltic magma
Not viscous (flows easily), very little gas/silica, rarely explosive eruptions
Andesitic magma
Somewhat viscous (flows somewhat easily), some gas/silica, sometime explosive eruptions
Rhyolitic magma
Very viscous (doesn’t flow easily), explosive, high silica concentration
Cinder cone volcanoes
- Smaller than & found on sides of other volcanoes
- Andesitic magma
- Small, violent eruptions
- Lava fragments from a volcano accumulate into a cinder cone
Shield volcanoes
- Basaltic lava
- Gentle eruptions
- Lava builds up in layers with each gentle eruption
Composite/stratovolcanoes
- Rhyolitic magma
- Most violent/dangerous explosions
- Layers of volcanic material from previous eruptions gather around (usually singular) vent
- Subduction boundaries
Caldera
Depression at the top of a volcano when magma erupts, collapsing the top
The pacific plate is moving __
Northwest
