Chapter 13 - Drifting Continents: Plate Tectonics Flashcards
pangaea
supercontinent; previously-single large land mass
laurasia
landmass that would eventually become North America, Greenland, and Eurasia
gondwana
landmass that would eventually become South America, Australia, Africa, India, and Antarctica
continental drift
theory by Alfred Lothar Wegener proposing that continents move slowly across Earth’s surface
plate tectonics
theory describing the origin, movement, and recycling of lithospheric plates and the resulting landforms
subduction
a process in which oceanic lithosphere of one plate bends and dives into the mantle beneath another plate
plate boundaries
the place where lithospheric plates meet
active continental margin
follows a plate boundary
passive continental margin
has a broad sloping continental shelf and does not coincide with a plate boundary
ridge push
the process by which magma rising along a mid-ocean ridge lifts oceanic lithosphere and forms a slope
mantle drag
caused by convection within the asthenosphere
slab pull
the weight of the subducting portion of a plate accelerates plate movement by pulling the plate deeper into the mantle
divergent plate boundary
occurs where two plates move apart
convergent plate boundary
occurs where two plates move toward each other
transform plate boundary
occurs where one plate slips laterally past another
decompression melting
the process of melting hot mantle through changes in pressure
rift
a region where continental crust is stretching and splitting
rift valley
a long valley with volcanoes formed by rifting of continental crust
wadati-benioff zone
a sloping pattern of increasingly deep earthquake centers in subduction zones
flux melting
the process in which the mantle mixes with seawater and melts into magma
continental arcs
long chains of volcanoes that form only on the margins of continents where subduction is occuring
accretionary prism
folded mass of sediments and rock that forms during subduction when sediments and rocks on the seafloor are scraped up against the edge of the overriding continent
island arc
chain of volcanic islands formed where oceanic lithosphere of one plate is subducting beneath oceanic lithosphere of another plate
pacific ring of fire
a zone of volcanically active mountain chains resulting from subduction on the margins of the pacific ocean
collision
occurs where the continental crust of two plates converges
accreted terrane
a mass of crust that is transported by plate movement and fused onto the margin of a continent
hot spots
volcanically active and isolated locations on Earth’s surface that is caused by a vertical column of hot rock (mantle plume) that extends down as far as Earth’s outer core
mantle plume
a mostly stationary column of hot rock that extends from deep in the mantle up to the base of the lithosphere
fold
a wrinkle in the crust that results from deformation caused by geological stress
fault
a fracture or break in the crust where movement and earthquakes occur
anticline
a fold in the crust with an archlike ridge
syncline
a fold in the crust with a U-shaped dip
orogenesis
the building of mountain ranges by any tectonic process
orogenic belts
mountain ranges grouped together linearly that forms most commonly along plate boundaries, particularly in areas of collision and subduction
