4.1 APES lab quiz

crust

very outer layer of the lithosphere, earth’s surface

lithosphere

thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)
- oceanic plates - basalt (denser
- continental plates - granite (less dense)

asthenosphere

solid, flexible outer layer of mantle, beneath the lithosphere

mantle

liquid layer of magma surrounding core, kept liquified by intense heat from core

core

dense mass of solid nickel, iron, and radioactive elements that release massive amount of heat

convection cycle

• magma heated by earth’s core rises towards the lithosphere

• rising magma cools and expands, forcing oceanic plates apart

  • creates, mid ocean ridges, volcanos, spreading zones/seafloor spreading

• magma cools, and solidifies into new lithosphere

• spreading magma forces oceanic plate into continental (subduction zone)

  • sinking oceanic plate melts back into magma

  • also forces magma up, creating narrow, coastal mountains and volcanoes on land

divergent plate boundary

• plates move away from each other, new lithosphere made

• rising magma plume from mantle forces plates apart

  • forms: mid oceanic ridges, ocean basins, volcanos, seafloor spreading, and rift valleys (on land)

transform plate boundary

• plates slide past each other in opposite directions

  • forms: earthquakes, tsunamis

convergent plate boundary

• plates move towards each other

• leads to subduction (one plate being forced beneath another: lighter continental plates rise over ocean plates)

  • forms: mountains, island arcs, earthquakes and volcanos

oceanic-oceanic

• one plate subducts the underneath other

  • forces magma up to the lithosphere surface, forming mid ocean volcanoes

    • island arcs

  • off shore trench

oceanic-continental

• dense oceanic plate subducts beneath continental plate and melts back into magma

  • forces magma up to the lithoshpere surface

  • coastal mountains (andes.) volcanos on land, trenches, tsunamis

continental-continental

• one plate subducts underneath other, forcing surface crust upward (mountains)

  • ex: himalayas

transform fault boundary

• plates sliding past each other in opposite directions creates a fault (fracture in rock surface)

  • earthquakes and tsunamis

  • occurs when rough edges of plates get stuck on each other

  • pressure builds as plates keep sliding, but edges stay stuck

  • when stress overcomes the locked fault, plates suddenly release energy that shakes the lithosphere

  • if underwater, then creates giant waves

ring of fire

• pattern of volcanoes all around Pacific plate

  • offshore island arcs (Japan)

transform faults

• likely location of earthquakes

hotspots

• areas of especially hot magma rising up to lithosphere

  • yellowstone National park

  • mid ocean islands (iceland, hawaii)