Plate tectonics test Flashcards

Terms Definitions
Thinnest layer.
the original continent
half liquid half solid
What causes convection currents?
The study of planet Earth
2 types of crust
continental, oceanic
abrupt rupture when stressed; earthquakes break rocks due to brittle nature of crust
a usually light-colored igneous rock that is found in continental crust
Sometimes the blocks of the lithosphere on either side of a fault line "lock up" and motion is stopped. Pressure and tension builds until the faults break apart and suddenly move past one another. This movement begins deep within the earth at a point called this.
The ___________ plate always sinks when it comes in contact with its opposite, a continental plate
A mafic, coarse-grained igneous rock composed predominantly of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar.
plastic "silly putty" lower mantle convection currents
A light-brown to gray, fine-grained extrusive igneous rock with a felsic composition. The extrusive equivalent of granite.
the region below the lithosphere, variously estimated as being from fifty to several hundred miles (eighty-five to several hundred kilometers) thick, in which the rock is less rigid than that above and below but rigid enough to transmit transverse seismic waves.
absolute age
the exact age of something
composite volcano
a volcano composed of alternating layers of ash and lava
plate tectonics
the theory that the Earth's lithosphere is divided into tectonic plates that move around on top of the asthenosphere
plate boundaries- characteristics
catagorized by HOW THEY MOVE
Breaks into Earth's crust where rocks have slipped past each other
oceanic plate
denser plate made mostly of basalt
the central, spherical part of the Earth below the mantle
the study of changes in Earth's magnetic field, as shown by patterns of magnetism in rocks that have formed over time
continental crust is made up of ____________.
(high in quartz and feldspar)
What type of plate boundary forms Mount Saint Helens?
boundary where plates slide past each other
What was the single, huge continent that formed before the continents started to spread apart called?
The procces by which the ocean floor
age of sedimentary rocks
determined by relative dating
2 plates seperated. (Occurs at the Mid-Ocean Ridge
plate tectonics evidence
rocks, fossils, climate, puzzle fit, glaciers, sea floor spreading
Herry Hess
Man credited with Theory of Palate Tectonics
A dark, dense, igneous rock with a fine texture, found in oceanic crust
transform boundary
when to plates slide past each other.
a rigid layer formed by the uppermost part of the mantle and the crust together
1st type of convergent plate boundaries
oceanic to continental
contour line
line that connects points of equal elevation on a topgraphic map
Scratches left on rocks and bedrock by glacier movement
the remains of a prehistoric plant or animal that has hardened into rock
divergent boundary
plates move away from each other along
Von Humboldt
(1801) found similarities in the rocks of S. America and Africa.
What type of plate boundary forms the Himalayans?
CMB/D layer
the boundary between the mantle and the outer core. its about 200km thick, it has large lateral variations in both composition and thickness. we see an intense drop in P velocities in the bottom 20 most km, indicating partial melting. We think that this might be the graveyard for old pieces of lithosphere.
subduction zone
the region where an oceanic plate sinks down into the asthenosphere at a convergent boundary, usually between continental and oceanic plates
radioactive decay
is a spontaneous breakdown of an atomic nucleus resulting in the release of energy and matter from the nucleus
the force exerted on a surface divided by the area over which the force is exerted
convenction current
the flow that transfers heat within fluid
amount of force placed on a given material
Sea floor spreading
the process by which molten material adds new oceanic crust to the ocean floor
Convection Currents
the upward movement of warm air and the downward movement of cool air
Plate Boundaries
The cracks between the plates of the lithosphere.
the type of stress that occurs when an object is squeezed
Movement of heat thryough a fluid by a series of currents (burner to water)
Divergent Plate Boundary
where two plates are moving apart, magma comes up to create new crust
convergent plate boundary
a boundary where two plates are colliding. turn the existing lithosphere back into the interior. compressional forces cause reverse or thrust faults.
convection Current
a current caused by the rising of heated fluid and sinking of cooled fluid
Material make up of oceanic and continental volcanoes
Oceanic: basalt
Continental: granite
sea-floor spreading
the process by which the ocean floor sinks beneath a material to the ocean floor
seafloor spreading
The process that creates new sea floor as plates move away from each other at the mid-ocean ridges
Thickness of the outermost layer of the earth
50 to 100 KM
theory of continental drift
proposed by Alfred Wegner, that the continents were once joined together and have since drifted apart
When Pangea began to split it became two continent
Laurasia and Gondwana.
What is the importance of paleomagnetism and symmetry?
The importance of paleomagnetism and symmetry is the paleomagnetism allowed scientists to contrast a magnetic polarity time scale and symmetry allowed them to notice patterns in the ocean. This lead to new discoveries such as the similarities between ages/width and stripes (magnetic)
Theory of Plate Tectonics
theory that the crust is made of plates that move due to convection currents
give four examples of a convergent boundary
the himalayas the peru/chile trench the ring of fire and the andes mountains
200 million years ago all the land masses were together as part of a single giant supercontinent called pangaea and they drifted apart because of the gravitation pull of the moon
What is the hypothesis of continental drift?
hunter sanchez
himalayan mnts......
divergent coundary
Earth's Thickest Layer Is...
Tectonic plates touch at.................
Stress that pulls rock apart
Where is new crust made?
beneath asthenosphere, strong lower part of mantle, extends from the bottom of asthenosphere to Earth's core
plastic-like part of the manlte beneath the lithosphere
rift valley
a valley with steep sides
Antonio Snider
(1858) published maps depicting continental drift.
San Andreas fault
is a transform boundary
Richter Scale
scale is 1:0 measures magnitude
Alfred Wegener
Suggested that the continents don't stay in one place, but instead that they had drift around the world over time
Mid-Ocean Ridges
Large under-water mountain chain where new crust is formed
the land mass that included all continents at one time
Glomar Challenger
gathered information about rocks on the seafloor
a large selection of Earth's oceanic or continental crust and rigid upper mantle that moves around on the asthenosphere
Seven great land masses surrounded by oceans
the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist
when plates slide past eachother, also creating faults
a concave shape with an open top
areas where sea-floor-spreading takes place
mid ocean ridges
sedimentary rock
rocks fromed from sediment derived not only from rock fragments but also from plant and animal remains
normal fault
caused by tension forces that cause rock to move downward in relation to the fault surface
Continental Plate
Tectonic plate that lies under a continent
is the ancient core of a continent, which is tectonically stable.
deep-ocean trench
Deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
a type of ingneous rock that generally contains large crystals and forms when magma cools slowly beneath Earth's surface.
Plate Boundary
this what scientists call the edges where two (or more) tectonic plates meet
active volcano
a volcano that is currently erupting, showing signs that it is likely to erupt in the near future, or has erupted in recorded history
denser oceanic will always sink and be destroyed Ex: Cascades
boundary formed by collision of two plates.
Convergrnt Boundary
a measure of the amount of damage done to an area by an earthquake
<100 km
What is the seismicity of a divergent plate boundary?
mountain range
a series of mountains that are closely related in orientation, age, and mode of formation
hot spot
A constant stream of magma, one of which formed Hawaii
Strike-Slip Fault
This is shearing. This happens at a transform boundary.
a force that acts on rock to change its shape or volume
the closer you are to a ridge the ------ the rocks are
Love waves
Surface waves that shear the ground in a horizontal direction. Can only travel through solids. Third to arrive.
inner core
A dense sphere of solid iron and nickel at the center of earth.
Oceanic Crust
is crust that is dense and made of rock that is rich in iron
and magnesium.
Pacific Ring of Fire
a zone of active volcanoes that encircles the Pacific Ocean
body waves
these are the s and p waves because they travel through the body of the Earth.
Plate tectonic motion is measured by a............
Global Positioning System (GPS)
Convergent Plate Boundaries
Plates come together at a rate of a few cm/year; crust buckles up to form folded mountain chains (the process of orogeny); sea floor crust is taken back into the Earth (the process of subduction); volcanoes form from melting during subduction; great earthquakes occur due to break-up of subducting crust; ocean trenches form as a result of subduction.
What were the two continents thatPangea split into
About 180 million years ago, Gradually, Pangea bro
explain the differences in height between continental and ocean crust?
oceanic- mass of rock w/ basaltic composition (5km thick) continental- composed of igneous and granite, (35-60km thick)
What are the 2 major flaws of continental drift?
1: the drift did not satisfactorily explain what large force pushes the continents to such a great distance
2: scientist questioned how the continents were moving, since Earth's crust was solid
give evidence
The Earth's mantle
Oldest Ocean Rocks
(2 myo)
Lighter materials went toward the.......
Hannah Belloli
Beautiful girl! She's amazing!<3
Africa, Antarctica, Australia, India, & South
primary waves
aka P waves underground (bodywaves)
arrive first at epicenter--- travel through anything (solid liquid gas) push, pull waves
seismic wave
waves that travel through Earth
continental crust
The thickest type of crust.
divergant boundary
constructive boundary, a boundary where plates move apart
The outer part of the earth(crust)
Harry Hess
Discovered mountains on the ocean floor now known as a mid ocean ridge.
evidence for plate tectonics
paleomagnetism, earthquake patterns, ocean drilling, and hot spots
the leading edge of a continental plate and oceanic plate converge and the denser oceanic plate sinks into the asthenosphere
when magma erupts onto earths surface, the magma is called?
The northern section of Pangea after it broke apart
continental drift
Wegner's theory that the continents where once a single landmass and broke into large pieces, which drifted apart
are deep focus earthquakes more common in trenches or along mid ocean ridges?
Richtor Scale
the scale used to measure the intensity of earthquakes
fracture zone
linear zone of irregular topography on the deep-ocean floor that follows transform faults and their inactive extensions
Transform Boundaries
boundary between two plates that are sliding past each other. Example-California
Fractional Crystallization
The process by which the crystals formed in a cooling magma are segregated from the remaining liquid at progressively lower temperatures.
wearing away of rock due to wave action
the uppermost part of the mantle and the crust together
tectonic plate
a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle
divergent boundaries
where new ocean floor is continually being produced
Transform plate boundary
Places where crustal plates shear laterally past one another. Crust is neither produced nor destroyed at this type of junction.
what happens to plates when they sink and hit the mantle
dormant volcano
volcano that has not erupted for thousands of years, but could erupt again
Mid-ocean ridge
An underwater moutain chain where new ocean floor is formed
Convergent Boundaries
- Boundaries between two plates that are colliding
- the are 3 types...
Magnectic Revearsal
Magnectic rocks at the Mid-Ocean Ridge that change
Plates are what make up the surface of the earth crust. they constantly move due to the mantle layer underneath moving.
heat transfer
The movement of energy from a warmer object to a cooler object.
Normal polarity
A magnetic field the same as that which presently exists.
scientific reaction: NO
meckenism for contients, they would be wrong, his profession, nationality
Ring of Fire
Circle of volcanoes around the pacific ocean
what is ridge push
Newly formed crust rises slightky above older crust.But when new crust cools it sinks into the mantle
earths inner core is a dense ball of solid.....
more under top
the _____ dense oceanic plate goes _____ while the other goes on the____
How has the reversal of the magnetic poles help explain seafloor spreading?
(draw a diagram)
transform fault boundary
a boundary in which two plates slide past each other without creating or destroying the lithosphere
Outer Core
a layer of molten iron and nickel that surrounds the inner core of Earth
relation of faults, foci, and epicenters
related to earthquakes
foci is the origin of the earthquake underground, epicenter is the location of surface above focus
faults are fractures along movement
S - P interval
The time it takes between the arrival of the P Wave and the arrival of the S Wave
list the 3 types of magma in order from least amount of silica to most amount of silica.
basaltic, andesitic, and rhyolitic
in the trench it was really cold then as the mountain gets higher it gets hotter but in the v shaped valley there is a volcano so the water is boiling
Explain the mid ocean ridge
What are three clues of evidence for continental d
Fossils, Glacier markings, and age of rocks
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