Science Quiz 3
Why are magnetic bands in the eastern Pacific Ocean so far apart compared to the magnetic bands along the mid-atlantic ridge?
Because Pacific is moving at a faster rate than Atlantic
Describe why seafloor spreading is like a moving conveyor belt?
In seafloor spreading, new oceanic crust is added at the mid-ocean ridge, and as intrusion continues, seafloor moves towards the edge of the oceanic plate, where it is ultimately pulled back down into the magma below
Rock samples taken from areas near ocean ridges were found to __________ than samples taken from areas near deep-sea trenches.
beyounger
An imaginary line on a map that shows points that have the same age is called a(n)
isochron
The thickness of ocean sediments that are close to a mid-ocean ridge is ____________ the thickness of ocean sediments that are far from mid-ocean ridges.
less than
A ____________ happens when the flow in the outer core changes, and Earth's magnetic field changes direction
magnetic reversal
The study of the history of Earth's magnetic field
paleomagnetism
Harry Hess' theory of ________________ explained how ocean crust is generated and destroyed.
seafloor spreading
The theory that explains how new oceanic crust is formed at ocean ridges, slowly move away from ocean ridges, and destroyed at deep-sea trenches is called
seafloor spreading
A device that can detect small changes in magnetic fields is called a(n)
magnetometer
Which is younger?
oceanic crust
According to the data shown in the figure above, what was Earth's magnetic polarity like 5 million years ago? (hint: compare the colors to see direction)
the reverse of today
Maps made from sonar and magnetometer data showed an ocean floor that had features, such as mountain ranges and trenches, that were bigger than anything found on land.
true
An expedition brings up a piece of rock from the Gauss normal epoch. According to the figure, what is the probability that it came from a time when the magnetic field is the same as today?
very likely