transform
plate boundary commonly found in conjunction with mid-ocean ridges as it works to offset spreading and plate divergence
boundaries
Intense geologic activity is concentrated at plate _________
GPS satellites and lasers
tools that can be used to directly measure plate motion
lithosphere
Tectonic plates are composed of ________ and move around on the asthenosphere
boundary
Convergence of two ocean plates forms an ocean-ocean convergent ___________.
intricate coastlines, beautiful valleys, dramatic mountains and undersea trenches
The surface of Earth is notable for many geologic features including _________
seamount
a mountain beneath the ocean that does not reach the surface is called a ___________. It may be a worn-down island or may never have been tall enough to break the water surface
oceanic fracture zones
cracks and steps that cross the seafloor and run at right angles to mid-ocean ridges
Pacific
Subduction of both sides of the _________ Ocean produces the Ring of Fire
continental collision
when two continental masses converge
continental shelves
some continents continue outward form the shoreline under shallow seawater, forming submerged benches called __________
tectonics
the study of the origin and arrangement of the broad structural features of Earth's surface
stages of continental rifting
ascension of magma causes uplift of the crust, stretching of the crust causes crustal blocks to drop into faults forming a rift, continuation of rifting splits the continent into two and a narrow ocean forms as seafloor spreading takes place, continuation
island arcs
curving chains of mostly volcanic islands across the seafloor
continental rift
a divergent boundary that forms within a continent
two plates move toward each other
Convergent boundaries are formed when _________
surface
the __________ of Earth is notable for many geologic features such as beautiful valleys, intricate coastline, and deep ocean trenches
subduction
The Pacific Ring of Fire is a result of ___________ on both sides of the Pacific Ocean
in conjunction with mid-ocean ridges
the majority of transform boundaries are found ________
abyssal plains
the relatively smooth surfaces of the ocean floor
centimeters
the yearly rate of tectonic plate movement is best measured in ____________
mid-ocean ridges
broad symmetrical ridges that cross ocean basins
triple junction
the place where three plate boundaries meet
the driving forces must exceed the resisting forces
in order for a tectonic plate to move, what must the relationship between driving and resisting forces be
horizontal
the type of plate movement that occurs at transform faults
a string of volcanoes
the Pacific Ring of Fire is formed by _________
ocean fracture zones
cracks and steps that cross the seafloor and run mostly at right angles to mid ocean ridges
characteristics of slab pull
subducting oceanic lithosphere is denser than asthenosphere, subducting plates move faster than nonsubducting plates, gravity is a major force in slab pull
characteristics of continental rifting
if rifting continues the continent can be split into two pieces, stretching of the crust causes crustal blocks to drop down, rifting begins with a broad uplift as magma ascends
mid-ocean ridges
earthquakes are more common along the edges of continents and ___________ ridges
convergent
boundaries that are formed when two plates move toward each other
subduction
the process of one plate sliding beneath another plate
volcanoes in the Andes Mountains of South America, Volcanoes of the Cascade Range in the U.S Pacific Northwest, Volcanoes of southern British Columbia
areas on Earth that represent convergent boundaries
different in character and origin from curved island arcs
Island chains and seamounts cross parts of the ocean floor. These oceanic islands and associated seamounts are _________
magnetic field
Convection currents in Earth's outer core produce the _____________
boundaries
the location of earthquakes is a better guide to plate _________ than the location of volcanoes
San Andres
fault in California is a transform fault that has formed linear valleys, abrupt mountain fronts, and lines of lakes
if this is true, then the oldest basalt should be the farthest form the mid-ocean ridge and the thickest sediment cover should be farthest from the mid-ocean ridge
According to plate tectonics, oceanic crust forms from upwelling magma that spreads outward from a mid-ocean ridge. Which of the following statements support this?
oceanic plates are dense and continental plates are buoyant
Oceanic plates subduct beneath continental plates because ______________
convergent boundary
when two ocean plates come together, a _________ is formed
lithosphere
the process of plate tectonics circulates materials between the asthenosphere and the ____________
ridge push
gravity causing the plate to slide away from the topographically high ridge, pushing the plate outward
tectonics
continental outlines and similar geology on neighboring continents support the theory of plate ___________
land bridges
were originally proposed to explain fossil evidence as provided by the presence of Mesosaurus and Glossopteris on continents separated by large oceans. One supercontinent that split apart by continental drift better explains this evidence
outer core
the layer of Earth that behaves as a dynamo(electrical generator), producing the magnetic field is the _________
chains
as plates move over hot spots, island _______ in oceans can be formed by volcanism
transform
the zigzag pattern of mid-ocean ridges reflects the alternation of the spreading segments with ______ faults
subduction
earthquakes are common along the western coast of South America as a ________ zone occurs due to oceanic lithosphere moving beneath the continent
volcanism and hot spot activity
island and seamount chains are formed by ___________
solid mantle in the asthenosphere rises toward the surface and begins to melt due to decompression
at mid-ocean ridges as two plates diverge, ___________
island arc
when two oceanic plates converge, some magma erupts under the ocean, forming volcanoes that may rise above the sea. These volcanoes can form a curved _________
normal
basalt forming today from cooling magma at the mid-ocean ridge would have _________ polarity
two continental plates colliding and forming mountain ranges
The Tibetan and Himalaya Plateau are the result __________
seafloor spreading
the image shows the Mid-Atlantic Ridge, a submarine volcanic mountain belt that is a key location in the process of ___________. This hypothesis was developed by Harry Hess and Robert Dietz.
earthquakes are common along the western coasts of North and South America, ocean trenches and associated island arcs have numerous earthquakes, there are few earthquakes on the abyssal plains
accurate statements about the distribution of earthquakes
glaciers
scratch marks made on rocks in the southern continents by ancient ________ show that the continents were once connected around the South Pole and then moved apart by continental drift
Wegener could not explain how or why the continents moved from place to place
the hypothesis of continental drift, as proposed by Alfred Wegener, was not accepted because ___________
many-more than 40 times
How many times did Earth's magnetic field switch in the last 10 million years?
Kauai is younger than Midway, Midway is the oldest of the listed islands, Kauai is closer to Kilauea than Midway
the three accurate pieces of information that can be obtained from the graph?
mid-ocean ridges
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