chapter 13 tectonics Flashcards
hot spot
a vocanically active region that is caused by a mantle plume
mantle plume
a vertical column of hot rock that extends down as far as the earths outer core
hot spot tracks
lines of inactive volcanoes in ocean basins
fold
a wrinkle in the crust that results from deformation caused by geologic stress
fault
a fracture or a break in the crust where movement and earthquakes occur
block landform
fracture in crust where movement and earthquakes occur, usually near plate boundaries
orogenesis
mountain building
orogenic belt
a linear mountain range
the ______ ______’s waters supply for 1.4 billion people, which could lose 70% of its glaciers by the _____ __ ___ _____.
tibetan plateau
end of the century
pros of hydropower megaporjects
water and flood security
flood protection
hydroelectricity
cons of hydropower megaprojects
unwanted environmental consequences
unwanted social consequences
international conflict
potential dam failure
pangaea
supercontinent that formed 300 million years ago
pangaea split into Laurasia and gondwana about _____
200 million years ago
laurasia
eventually became north america, greenland and eurasia
gondwana
eventually became south america, australia, africa, india and antarctica
continental drift
theory proposed continents move slowly across earths surface
plate tectonics
theory describing origin, movement, and recycling of lithospheric plates and the resulting landforms
subduction
the process which oceanic lithosphere of one plate bends and dives into the mantle beneath another plate
how many tectonic plates are there
7 primary and 7 secondary, the largest plate is the pacific plate
active vs passive continental margin
active- consists of deep sea trench and narrow continental shelf
passive- broad, sloping continental shelf and does not coincide with plate boundary
ridge push
process by which magma rising along a mid ocean ridge lifts oceanic lithosphere and forms a slope
mantle drag
movement of a plate caused by friction between moving asthenosphere and the lithosphere
slab pull
weight of a subtracting portion of a plate accelerates plate movement by pulling the plate deeper into the mantle
divergent vs convergent vs transform plate boundaries
divergent- where two plates move apart
convergent- where two plates move towards each other
transform- where one plate slips laterally past another
decompression melting
melting hot mantle through changes in pressure
rift
region where continental crust is stretching and splitting
rift valley
a long valley with volcanoes formed by rifting of continental crust
oceanic lithosphere is consumed and recycles in process of _______
subduction
continental lithosphere is not subducted because __________
it is less dense than oceanic lithosphere and too buoyant
flux melting
the process in which the mantle mixes with seawater and melts into magma
volcanic arc
a long chain of volcanoes on the margin of a continent where subduction is occurring
continental arc
a long chains of volcanoes that forms only on the margins of a continent where subduction is occuring
island arc
a chain of volcanic islands formed where oceanic lithosphere of one plate subducts beneath oceanic lithosphere of another plate
collision
the process in which contiental rust of two plates converges
accreted terrane
a mass of crust that is transported by plate movement and fused onto the margin of a continent
