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WorksheetsPlate Tectonics Seafloor Spreading
Total questions: 47
Worksheet time: 2hrs 12mins
An underwater mountain chain caused by a divergent boundary, where new ocean floor is formed.
mid ocean ridge
volcano
rift valley
trench
Subduction zones in the ocean can create which features?
islands
volcanoes
earthquakes
all of the above
What is a Subduction zone?
When an oceanic plate moves under a continental plate
When two plates slide by each other
When two plates move away from each other.
When a continental plate moves under an oceanic plate.
What two words are BEST used to describe how the seafloor spreads?
Magma and convection
Earthquakes and convection
Volcanoes and convention
Volcanoes and earthquakes
Lithosphere
Layer where oceanic and continental crusts are found
Layer where magma is found
Layer where very hot rock rises and falls
Wegener used the following evidence to prove his theory of continental drift?
The shape of the continents
Similar fossils found on separate continents
Rocks found on separate continents
All of the above
Oceanic crust subducts under continental crusts because
Oceanic crust is less dense
Oceanic crust is more dense
Continental crust is more dense
Oceanic crust and continental crust is the same
The mantle convection pictured here happens at a ______________ plate boundary.
Convergent
Divergent
Transform
The YOUNGEST seafloor is located?
Closest to the mid-ocean ridge
Farthest from the mid-ocean ridge
What did one earthquake say to the other earthquake?
"Sup Bro"
Nothing earthquakes don't talk
"Hello"
"It's all your fault!"
What do scientists believe is the force behind the plate tectonics theory? (Scientists believe that differences in density cause hot, plastic like rock to be forced upward toward the surface.)
the Sun's gravity
the movement of the planets
gravity slab pull
convection currents
How do scientists explain the formation of underwater mountain ranges? (Hot, less dense magma is forced upward and through the seafloor to form these ridges.)
strike-slip faults
seafloor spreading
continental drift
convection currents
How did scientists use the magnetic polarity of the Earth's crust to prove the theory of seafloor spreading? (Rocks in Earth's crust show permanent evidence of Earth's polarity at a given time.)
They were able to reverse the polarity of crust samples using an electromagnet.
They showed that the patterns of polarity in Earth's crust on one side of a mid-ocean ridge mirrored the other side.
They showed that the polarity of Earth's crust was different on each side of the mid-ocean ridge.
They used a magnetometer to change the magnetic signature of rocks on either side of the mid-ocean ridge.
What evidence further supports the theory of seafloor spreading? (The crust near the mid-ocean ridge younger than the crust far from the mid-ocean ridge.)
Sediment is older and thinner farther from the mid-ocean ridge.
Thermal energy is higher under the abyssal plain.
Thermal energy is higher over the abyssal plain than close to the mid-ocean ridge.
Sediment is very thick at the mid-ocean ridge.
What does plate tectonics cause? (Scientists believe the hot interior of Earth causes movement of the plates and formation of Earth's topography.)
forms mountains
forms ocean basins
causes volcanoes
all answers are correct
What tool helps us study the seafloor?
Submarine
Echo Sounder
Radar
Richter Scale
What is directly below the Earth's crust?
Lithosphere
Mantle
Outer Core
Inner Core
Molton rock located in the Mantle is called what?
Magma
Lava
Plastic
Flow
What happens to the molten rock when it hits the Earth's surface from the mid-ocean ridge?
The lava will spill out onto the land, burning everything in its path
The lava will damage the water molecules in the ocean, making the seafloor inhabital
The lava will solidify, becoming part of the seafloor
The lava will solidify and block any new lava from reaching the Earth's surface
Where is the oldest rock going to be located on the seafloor?
Closest to the mid-ocean ridge
Along the mid-ocean ridge
Furthest away from the mid-ocean ridge
Basalt that is closest to the mantle
A state in which magnetized objects would reverse and orient themselves to point south is called what?
Southern polarity
Reversed polarity
Normal polarity
Magnetic reversal
How can scientists know what kind of polarity the Earth was in at any given time?
Scientists can guess based on how long it takes for magnetic reversal to happen
Scientists can use a compass to determine polarity presently
Scientists can use magnetic signatures in rocks and determine their age
Scientists are not able to determine this information
Convection is occurring in the earth because there is
A temperature and density difference in the earth
No temperature or density difference in the earth
