plate tectonics review Flashcards

Terms Definitions
continental crust
a radioactive isotope
forms ridges and valleys
not ocean floors, mantle.H
Mid-ocean ridge
Sea-floor spreading occurs at________
a liquid's resistance to flow
another name for the crust
a crack in the earth's crust
the commonest type of solidified lava
convergent boundary
boundary between two colliding tectonic plates
S-P intervals
The intervals between the waves
the outer layer of the Earth
plates slide past called what boundries
oceanic crust
crust under the ocean, thinner
Mercalli Scale
a scale of earthquake intensity
inner core
(inner)solid, dense center of the Earth
Oceanic-Continental plate convergence
creates trenches and volcanic belt
transform boundary
the boundary between tectonic plates that are sliding past each other horizontally
a section of the lithosphere that slowly moves over the atmosphere carrying pices of continental and oceanic crust
Convection Current
current in earth's mantle that transfers heat in earth's interior and is the driving force for plate tectonics
the shaking that results from the movement of rock beneath Earth's surface
Who created the Continental Drift theory?
Alfred Wegener
Puzzle Pieces
light and shadow fit together like
divergent boundary
the boundary between two tectonic plates that are moving away from each other
an ancient continent made up of present-day Africa, South America, Antarctica, Australia, and India
Mantle Plumes
Hotspots: Localized sources magma -> rise to surface -> erupt as large isolated volcanoes / chain volcanoes
- Plume deep inside mantle -> lithospheric plate moves on top -> linear chain volcanic islands/seamounts
continental drift
the hypothesis that the continents slowly move across Earth's surface sea-floor spreading the process by which molten material adds new oceanic crust to the ocean floor
How many landmasses did all contients once form?
tectonic plates
a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle
the layer of rock between the Earth's crust and core
Hot Spot
Location on Earth's surface where a stationary column of magma from deep within the mantle slowly rises to form a volcano
Rift Valley
A long, narrow depression that forms when continental crust begins to separate at a divergent boundary
island chain
chains of islands created as a lithosphere plate moves over a hotspot and is melted to become a volcano. as the plate moves off to the hotspot, the extinct volcanoes can become islands.
plate tectonics
theory of formation and movement of the plates that cover the earth's surface
Convergent plate boundary
boundary between two colliding plates, often associated with mountain building ocean trenches and volcanic islands
outer core
liquid, size of mars, iron and nickel
Evidence of Continental Drift
Fossil evidence, rock evidence, evidence from ancient glaciers
Rayleigh waves
Surface waves that travel in a backward-rotating, elliptical motion, causing both vertical and horizontal ground movement. Can travel through solid, liquid, and gas. Fourth to arrive. Dangerous.
the rising of regions of the Earth's crust to higher elevations
What state of matter is the inner core?
sea-floor spreading
the process by which molten material adds new oceanic crust to the ocean floor
The boundary formed by the collision of two lithos
Convergent Boundary
P wave
a primary wave or compressin wave; a seismic wave that causes particles of rock to move in a back and forth directionin which the wave is traveling; P waves are the fastest seismic waves and can travel through solids, liquids, and gases
mantle convection
a recurring current in the mantle that occurs when hotter, less dense material rises, cools, and then sinks again. This current is believed to be one of the driving forces behind tectonic plate movement.
transform fault boundaries
join two segments of a mid-ocean ridge
Slab Pull
Is a force at a subduction boundary that the sinking edge of the subducting plate exerts on the rest of the plate.
transform plate boundary
Boundary between two plates that are sliding past each other.
Subduction Zone
Where a denser oceanic plate is forced under a continental plate making an ocean trench
Strike-slip Fault
break in rock caused by shear forces, where rocks move past each other without much vertical movement. It is along a transform boundary.
Describe the continental crust.
relatively thick, old, and less dense
hot spots and mantle plumes
example the hawaiian island chain, caused by rising plumes of mantle material`
Normal polarity
a magnetic field that is the same as that which exists at present
Transform fault boundary
a boundary in which two plates slide past each other without creating or destroying lithosphere
Why do the tectonic plates move?
convection currents in the asthenosphere caused by the great heat in earth's core
Who was one of the first people to suggest that al
Alfred Wegener
Convergent (ocean to ocean) Boundary
slower plate is subducted deep trench is formed
Exclusive Economic Zone (EEZ)
a coastal zone that is 200 nautical miles wide over which the nation has jurisdiction over
landforms, climate change, fossils
what are the 3 types of evidence that supports Wegener's theory?
What was the reaction to sea floor spreading?
They believed him because they found the Min-Atlantic Ridge. He was American, so they liked him. And he was a Geologist.
unpaired electrons
have magnatism
divergent continental boundary
rift valley
force that squeezes rocks together
magma that reaches Earth's surface
What causes plates to move?
denser fluid
sinks to the bottom
Plate boundary that causes linear scarps or valleys.
giant waves caused by earthquakes, volcanoes and landslides
Dark-colored igneous rocks that are rich in iron and magnesium.
the large northern landmass that separated after the break up of Pangaea including North America, Europe, and Asia
Super continent that existed 250 million years ago.
convection currents
Circular currents in the mantle (lithosphere) caused by the magma being heated by the core of the Earth.
large ancient land mass that was composed of all the continents joined together.
volcanic arc
where two continental plates pull apart
Convergent (Continent-Continent)
Non Volcanic mountain ranges are formed. An example would be the Himalayas.
the central, spherical part of the Earth below the mantle
A scientist who studies fossils to learn about prehistoric life
What is Alfred Wegener's hypothesis called where h
Continental Drift.
Strike-Slip Faults
Form when opposing forces cause rock to break horizontally
created when plate movement bends and uplifts layers
magnetic field
the lines of force surrounding a permanent magnet or a moving charged particle
ancient climates
coal deposits have been found in antractica, glacial deposits have been found on africa, Indian, australia, and south america
continental drift evidence #5
ancient climate dramatic changes (northern hemisphere - large tropical swamps, southern hemisphere - glacial debris and ice sheets)
traces of an organism that lived in the past
one of a family of granular intrusive rocks
transform/slip boundary
A boundary where two plates rub together vertically or horizontally in opposite directions forming a fault. Earthquakes occur here.
rock which has been changed from one form to another
Pole Reversal
when the magnetic poles of earth switch
The movement or formation of plate tectonics
Continental Drift
Divergent Ocean/Ocean Boundary
Sea Floor Spreading occurs as oceanic plates move apart at the mid-ocean ridge.
Motion, process, seismicity, topography and volcanism
name the five characteristics that apply to all plate boundaries... (ABC order)
subduction, subduction zones
places where plates are pushed down into the upper mantle
The soft layer of the mantle on which the lithosphere floats.
extinct volcano
volcano that is not expected to erupt ever again
Passive Margin
looks like plate margin but NOT. Place where continental and ocean crust come together. No active geology taking place- trailing behind plate.
How do earthquakes occur?
Stress build up in rocks, potential energy is stored, energy is suddenly released when rocks break/slip
sea floor spreading
The process that creates new sea floor as plates move away from each other at the mid-ocean ridges
Destructive Force
a force that means the break down or destroying of land (usually happens when plates are destroyed and melted back into magma)
Convergent Boundry (Ocean to Ocean)
When two ocean plates push together causing underwater volcanoes
Gandwana was a form of which two countries?
South America, and Africa
What is Stress?
it is the amount of force placed on a given materi
How did drilling samples show that sea-floor spreading really has taken place?
The samples of rock, the rock was younger at the ridges and older as you move toward shore (away from ridges)
bends up
long, narrow, steep-sided depression in the seafloor formed where one crustal plate sinks beneath another
scientist think that convection currents flow in the Earths
Harry Hess
Theory of plate tectonics
Not on a plate boundary
study of the earth's magnetic field
youngest oceanic crust
at the ridge crest
A light-brown to gray, fine-grained extrusive igneous rock with a felsic composition. The extrusive equivalent of granite.
Divergent Continental/ Continental Boundary
forms a fault
Lower mantle where convection currents happen.
The point beneath Earth's surface where rock breaks under stress and causes an earthquake
.:Occurs when stress sqeezes an object:.
may cause damage due to weakened buildings
The study of the movements and deformation of the earth's outer layers
Thrust Fault
Convergant boundarys. moves up, rivers stop, creates hills. collide and push up.
The transfer of energy through empty space.
Describes magma or igneous rock that is rich in feldspars and silica and that is generally light in color.
Diverging Boundaries
Forms when two Lithospheric boundaries move apart from each other.
Belts where molten rock (magma) from the upper mantle or lower crust come to the surface (emerging liquid rock called lava).
Where does sea floor spreading take place?
mid-ocean ridges
Earthquake magnitude
measure of ground shaking during and earthquake, which depends of distance from epicenter and the geological material.
A compass needle points to the magnetic ______pole which is 11 degrees ___-
north north
Primary Wave
(P-waves) cause rock particles to move back and forth, compress and stretch, and can move through solids and liquids.
these rocks are located at the mid ocean ridges
A break in Earth's crust where slabs of rock slip past each other.
Geological Time
The measurement of time from the formation of Earth to the present
What is it called when two tectonic plates collide
Mid-ocean Ridges
Mountain ranges found in the middle of the Atlantic & Pacific Oceans
Deep Trenches
______ ______ mark the edge of the subducting oceanic plate.
scientific theory
a well tested concept that explains a wide range of observations
mid ocean ridge
An underwater moutain chain where new ocean floor is formed
surface waves
are the slowest and largest of the seismic waves and cause most of the destruction during an earthquake
plate boundaries
The areas where plates come in contact with each other
oceanic plates
Thin plates that form the ocean floor; more dense than continental plates.
the force applied to a unit area of surface
.:Mid - Ocean Ridge:.
.:Underwater mountain ranges that are in the cente
What 2 types are lithosphere?
Continental (150 km thick)
Oceanic (7 to 100 km thick)
this happens to the temperature of the ocean flow when you leave the mid-ocean ridge
the temperature decreases
igneous rock
a type of rock that forms from the cooling of molten rock at or below the surface
Wave lengh
the force on a tsunami and how far it streaches.
What is happening in the himalaya Mountains and what kind of plate boundary is there? Why are there no volcanoes? What kinds of rocks form here?
Converging boundary -continent meets continent
The two thick continental plates collide and both of them have a density that is much lower than the mantle, which prevents subduction (there may be a small amout of subduction or the heavier lithosphere below the continental crust might break free from the crust and subduct).
There is no ocean to provide cold to hot reaction to erupt a volcano it is a continent plate instead of an ocean plate
there are metamorphic rocks in the himalaya Mountains
Boundaries3 types of boundaries and definition:1.2
Places where tectonic plates touch1. Convergent- 2
What are the features of Divergent plate boundaries?
Plates moving apart, new oceanic lithosphere created, mid ocean ridges for example.
Explain the main difference between a shield volcano and a cinder cone volcano in appearance and origin.
Shield volcano - A low, flat, gently sloping volcano built from many flows of fluid, low-viscosity basaltic lava
Cinder Cone Volcano - a small, steeply sloped volcano that forms from moderately explosive eruptions of pyroclastic material
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