Earth LayersThe earth isn’t a solid sphereIt is made of 4 major layers- Crust- Mantle- Outer core- Inner core
Crust “outer skin”Continental crust is
about 70km thickOceanic crust is
about 10 km thick (this is why so much
ocean drilling occurs)
MantleAbout 2900 km thickMade of mostly Iron, Silicon and MagnesiumAsthenosphere is
the upper part of
the mantleVery viscous
Inner CoreApprox 1300 km
radiusSolid ball of Iron and
NickelExtremely hotStays a solid due to
very high pressure
Quick checkT/F – all layers are made of solid rockT/F – thickest layer is the mantleT/F – Inner core is made of liquid Iron
and nickelT/F – Outer core is made of silicon and
oxygen
AnswersF – all layers are made of solid rockT – thickest layer is the mantleF – Inner core is made of liquid Iron and
nickelF – Outer core is made of silicon and
oxygen
DefinitionsTrench – steep walled valley where 2
plates meetSlab pull – plates subducting pulls the
rest of the plate with itRidge Push – new forming rock pushes
plate away from spreading centre
DefinitionsSpreading Centre – area where plates
move apart from each other
Rift Valley – a spreading centre that occurs on land
Collisions at Plate BoundariesConvergent- Plates come together- Often subduction occurs (one slides
under the other)
**More on this in a moment**
Collisions at Plate BoundariesTransform- Plates slide past each other- Produces earthquakes- Eg. San Andreas Fault
Convergent BoundariesThere are three different types of
convergent boundariesThese depend on what type of plates
come togetherOceanic-continentalOceanic-oceanicContinental-continental
Oceanic-ContinentalThe oceanic plate subducts beneath the
continental plateEg. Coastal BCThe Juan de Fuca (oceanic) plate
subducts under the North American (continental) plate
This causes coastal mountains and land volcanoes