13.3 Plate Boundaries

8 major plates but several smaller ones too

huge pieces of crust and rigid upper mantle that fit together at their edges to cover earth’s surface

few cm

place where 2 of earth’s tectonic plates are moving apart associated w volcanism, earthquakes, and high heat flow magma comes to the surface creating new crust and they move apart

on the seafloor and at rift valleys

long, narrow depression that forms when continental crust begins to separate at a divergent boundary

place where 2 of earth’s tectonic plates are moving toward each other

process by which one tectonic plate slips beneath another tectonic plate

dense

minerals high in iron and megnesium

less dense

minerals high in feldspar and silica

slip beneath the continental plate cuz its more dense

3 oceanic-oceanic oceanic-continental continental-continental

ocean trench created when an oceanic plate is subducted beneath another oceanic plate the descending plate carries water with it magma forms and rises volcanic islands form

an oceanic plate is subducted between a continental plate descending plate carries water with it to the mantle magma forms and volcanic mountains form

2 continental plates collide into one another form long after an oceanic plate has converged with a continental plate many continental plates have oceanic crust attacthed to them over time oceanic plate is completely subducted the attacthes continental crust cannot subduct therefore the continents collide and uplift occurs mountain ranges form

region where 2 tectonic plates slide horizontally past each other characterized by long faults and shallow earthquakes faults can be 100s of km in length

transform boundary