Plate Tectonics Flashcards
continental drift
The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations
mid-ocean ridge
A long undersea mountain chain that has a steep narrow valley at its center, that forms from the asthenosphere and that creates new oceanic lithosphere.
sea-floor spreading
The process by which new oceanic lithosphere (seafloor) forms as new magma rises
paleomagnetism
The study of the alignment of magnetic minerals in rock, specifically as it related to the reversal of Earth’s magnetic poles
plate tectonics
The theory that explains how large pieces of the lithosphere, called plates, move
lithosphere
The solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantle
asthenosphere
The solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it
divergent boundary
The boundary between tectonic plates that are moving away from each other
convergent boundary
The boundary between tectonic plates that are colliding
transform boundary
The boundary between tectonic plates that are sliding past each other horizontally
rifting
The process by which Earth’s crust breaks apart; can occur within continental crust or oceanic crust
supercontinent cycle
The process by which supercontinents form and break apart over millions of years
Pangaea
The superconinent that formed 300 million years ago and that began to break up beginning 250 million years ago
Panthalassa
The single, large ocean that covered the Earth’s surface during the time the supercontinent Pangaea existed
subduction zone
an area where oceanic crust sinks below continental crust
ridge push
the pushing force that plates experience as they slide down the raised asthenosphere underneath Mid Ocean Ridges.
slab pull
a force that results from denser oceanic plates sinking beneath less dense continental plates along convergent boundaries and subduction zones.
