the hypothesis that states that the continents once formed a single landmass, broke up, & drifted to their present location
continental drift
a hypothetical protocontinent of the remote geologic past that rifted apart to form the continents of today
supercontinent
a long, undersea mountain chain that has a steep, narrow valley at its center
mid-ocean ridge
a crack at the center of a valley
rift
the process by which new oceanic lithosphere (sea floor) forms as magma rises to Earth's surface
sea-floor spreading
the study of magnetic minerals in rock
paleomagnetism
the theory that explains why & how continents move & is the study of the formation of features in the Earth's crust
plate tectonics
the solid, outer layer of Earth's crust
lithosphere
the two sub-layers of the Earth's crust that move, float, & sometimes fracture
tectonic plates
the solid, plastic layer of the mantle beneath the lithosphere
asthenosphere
crust beneath the ocean
oceanic crust
the crust that which the continents rest on
continental crust
an area that runs in the pacific ocean
pacific ring of fire
a tectonic plate where two plates are moving away from each other
divergent boundary
a boundary where two plates are moving towards each other
convergent boundary
all rocks with magnetic fields that point north
normal polarity
all rocks with a magnetic field that point south
negative polartity
the process by which collision of Earth's crustal plates results in one plate's being drawn down
subduction zones
two tectonic plates slide alongside each other
transformation boundary
a curved chain of volcanic islands located at a tectonic plate
island arc