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 has a steep, narrow valley at its center, that forms as magma rises from the asthenosphere, and that creates new oceanic lithosphere as tectonic plates move apart
sea-floor spreading
the process by which new oceanic lithosphere sea floor forms as magma rises to Earth surface and solidifiers at a mid-ocean ridge
paleomagnetism
the study of the alignment of magnetic minerals in rock, Earth’s magnetic poles: also the magnetic properties that rock acquires during formation
plate tectonics
the theory that explains how large pieces of the lithosphere, called plates, move and change shape
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 slowy, 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 coliding
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
terrane
a piece of lithosphere that has a unique geologic history and that may be part of a larger piece of lithosphere, such as a continent
supercontinent cycle
the process by which supercontinents form and break apart over millions of years
Pangae
the supercontinent that formed 300 million years ago and that began to break up beginning 250 million years ago
Panthalassa
the single, large ocean that covered Earth’s surface during the time the supercontinent Pangaea existed
