Plate Tectonics 3 Flashcards

Terms Definitions
divergent boundaries include...
How are landslides triggered?
continent-continent characteristics
mountain buildingthrust faulting (sexual)NO VOLCANOES
ocean-ocean characteristics
denser oceanic crustthrust faulting-compressionhave trench, accretionary wedge, magmatic arc, and back arc basin
What is volcanism associated with?
plate tectonics
how THIN is oceanic crust?
what kind of collisions are responsible for the highest mountains on earth?
polar wandering
aparent movement of the poles
ancient poles were in different positions than the present poles.
the larger the inclination angle is the _______ it is to the north or south pole.
earth's outer core is primarily made up of what element?
Mafic composition
Lower amounts of silica (SiO2) and higher amouts of Fe, Mg and Caex: Basalt
Transform Margins
2 plates moving past eachother via side-by-side contact*Pacific and North American Plate (San Andreas Fault)*
divergent plate boundary
boundary between plates that are moving apart
which of the surface waves have the largest amplitude
tools needed to understand the earth
siesmograph/seismometer--machine for detecting earthquakes and computers
Heat source in plates is....
core and radioactive decay
how fast do gas clouds travel at?
100 mph
island arc
curved line of volcanoes that form a string of islands parallel to the oceanic trench
plate tectonics
Earth's surface is divided into a few large, thick plates that move slowly and change in size.
what types of surface waves are there?
Love and Rayleigh
rifts and ridges are the source for what kind of crust?
oceanic crust
a zone of the earth;s mantle that lies beneath the lithosphere and consists of around one-hundred km of deformable rock; softer than the lithosphere; no defined edges
magmatic arc
both island arcs at sea and for belts of igneous activity on the edges of continents
Only one kind of wave is in the atmosphere infrasound. what is it?
Why is propagation important?
We can observe seismic waves that are able to travel to great depths when we cannot.
example of convection
the hot water in the pot you are cooking
Velocity is a characteristic of what?
velocity is a characteristic of geological materials.
Why is the Theory of Plate Tectonics important?
Elegantly explains many geologic phenomena. For example, the locations and causes of earthquakes, volcanism, mountain-building, rift zones, and mid-ocean ridges, etc.
What happens when an earthquake happens near or beneath an ocean?
it can generate large scale water waves.
example of conduction
the handle to the pot of hot water you are cooking.
When and how was the Theory of Plate Tectonics developed?
Developed in the 1960sAdvancing mapping and surveying technologySea floor mapping discovered the Mid-Atlantic Ridge.
what happens when new magma cools and soidifies?
the magnetic particles are permanently aligned with the current field
what does the motion of liquid iron establish?
it establishes an electric current that generates the magnetic field
How is ground motion amplified and reduced?
it is amplified by soft rock and reduced by hard rock
preserved remains
folds up
large body of land
Observation of plate tectonics, glacier evidence at equator, ferns and swamps in "wrong places"
organism whose fossil provided evidence for continental drift, fossilized leaves of an extinct plant found in South Africa Australia, India and Antarctica
used originally to find submarines actually found pole reversals in ocean floors
Natural, ancient magnetization in a rock thats used to determine the polarity of earths magnetic field.
california divergent baundary is in
southernmost california
polar wander
paleomagnetism, iron minerals point to the magnetic north from their formation (where it was when they were formed), this being true if the continents formed apart evidence point to two poles
transform boundary
the boundary between tectonic plates that are sliding past each other horizontally
Alfred Wegener
credited with the theory of Continental Drift
the process by which oceanic crust sinks beneath a deep ocean trench and back into ther mantle at a convergent plate boundary.
which type of volcano isthe smallest?
cinder cones
Equilibrium in the earth's crust such that the forces tending to elevate landmasses balance the forces tending to depress landmasses.
continental drift
the hypothesis that the continents slowly move across Earth's surface
earth's magnetic field
paleomagnetism, similar to bar magnet, positive and negative ends, compass points to magnetic north
mid-ocean ridge
An underwater moutain chain where new ocean floor is formed.
the layer of rock between the Earth's crust and core
folded mountains
form when rock layers are squeezed together and pushed upward
Subduction zone
The region where oceanic plates sink down into the asthenosphere.
a large section of Earth's oceanic on continental crust and rigid upper mantle that moves around on the astherosphere
continental rifting become valleys that may be filled with _____or ______
sweet water, sea water
the amount of force placed on an object
3 types are
compression tension and shearing
continental puzzle
shorelines of continents match up like a puzzle
deep ocean trenches
forms where the oceanic crust bends downward
Divergent boundary
A plate boundary where two plates move away from each other
the process by which the shape of a rock changes because of stress
transfer of heat by the movement of a heated fluid
the pulling of a tectonic plate as its edge subducts deep into the mantle
convergent boundary
a palte boundary where 2 plates move toward each other.
reverse faults
type of fault where the hanging walls move upward along a fault
caused by compression
rock sequences and mountain ranges
Observation of plate tectonics, rock types, structures, processes matched across continents such as mountain ranges in north America linking with ranges in northern Europe
What was the name of this supercontinent?
Pangaea (means: all land)
fault block
the block of crust on each side of the fault
what is the mid atlantic ridge?
under water chain of mountains and volcanoes
if the sea floor is spreading and Earth is not getting any bigger, where is crust being destroyed?
deep sea trenchens or subdouction zones
Divergent Boundaries
Harry Hess
discovered seafloor spreading
\"Paddle footed fish eaters\"\r\nSub-aqueous flight!
2nd type of force
slab pull
liquid magma that reaches the surface
Instrument used to measure horizontal or vertical motion during an earthquake.
destructive forces
slowly wear away the surface
Ridge Push
Tectonic process associated with convection currents in Earth's mantle that occurs when the weight of an elevated ridge pushes an oceanic plate toward a subduction zone.
ex. of reverse fault
Cascade mt. range
convection currents
force that moves the plates
continential crust
crust under the land, thicker
A type of convergent boundary (ex. Himalayas)
What is the most earthquake proned state in the United states?
seismic waves
viberations that travel through earth carrying the energy released during an earthquake
inner core
solid, dense center of the Earth
fountain of water and steam that builds up pressure underground and erupts at regular intervals.
plates crumple up to form what ranges
form at subdution zones, under the ocean, where the denser plate subducts under the less dense plate.
A contour that connects points of equal age on the world's ocean floors as determined by magnetic reversal data and fossils from deap-sea drilling.
sea-floor spreading
process that continually adds new material to the ocean floor
2 tectonic plates collide 3 types ><
in seafloor spreading magma erupts along
mid oceans ridges
The layer of rock that forms the Earth's outer surface.
Types of divergent boundaries
Oceanic (seafloor spreading) and continental (land moves farther away)
scientific theory
a well-tested concept that explains a wide range of observations
Evidence from magnetic stripes
scientists discovered that the magnetic stripes on the ocean floor are made of iron and switch when the poles switch
Mid-ocean Ridges
Where new crust is formed, around divergent, oceanic-oceanic boundaries
Continental Volcanic Arc
Mountains formed by igneous activity associated with the subduction of oceanic lithosphere beneath a continent
inner core's iron
what causes the Earth's magnetic field?
The name of the single landmass that broke apart 200 million years ago, that means "all the earth" in Greek.
A dark, dense, igneous rock with a fine texture, found in oceanic crust
the sinking of regions of the Earth's crust to lower elevations
What igneous rock is the oceanic crust made up of?
outer core
Earth's solid core spins inside the hot, molten metal layer
Continental crust
The material that makes up landmasses. It is the thickest crust.
Known for his theory of continental drift?
Alfred Wegener
S wave
a secondary wave or shear wave; a seismic wave that causes particles of rock to move in a side-to-side direction perpendicular to the direction in which the wave is traveling; S waves are the second fastest seismic waves and can only travel through solids
hot spot
a concentration of heat in the mantle capable of producing magma, which rises to Earth's surface; the Pacific plate moves over a hot spot, producing the Hawaiian Islands
An earthquake that was rated a 3 on the Richter scaled would be ______.
a bowl shaped area that may form at the top of a volcano around the central volcanoes vent.
fluid layer of the mantle on which the crust floats
Seafloor Spreading
The process that creates new sea floor as plates move away from each other at the mid-ocean ridges
Mid Ocean Ridge
an undersea mountain chain where new ocean floor is produced; a divergent plate boundary
crude oil
petroleum as it comes out of the ground and before it has been refined or processed into useful products. It is made from plankton as it dies and leaves brown specks in the mudrock. These ooze with thick heavy oil.
convection current
a current caused by the rising of heated fluid and sinking of cooled fluid
normal fault
a type of fault where the hanging wall slides downward; caused by tension in the crust
transform plate boundary
two plates slide past each other while moving in opposite directions and can cause earthquakes
Tectonic Plate
A segment of the Earth's crust that is a rigid slab of rock ∼100 km thick each of which moves on a plastic layer just below it (Earth's asthenosphere, the upper part of the mantle).
African, S. American, N. American, Eurasian, Indo-Australian, Antarctic, Pacific
Name the 7 major plates.
Magma below the crusts is forced up at thte mid-oc
Seafloor spreading.
the theory of plate tectonics
the formation and movement of earth's plates.
Mid Ocean atlantic ridge
a deep sea mountain range running from Iceland to Anarctica; a distance of about 10,000 miles.
Compare the temperatures of the lithosphere and the athenosphere.
the asthenosphere is warmer because it is liquid and the lithosphere is solid
What is the theory of Continental Drift?
All the continents were once 1 big super continent and over time they all spread away.
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