Earth Science Geology, the Environment, and the Universe

Section 2: Seafloor Spreading

Self-Check Quizzes-English

1
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.
A)more than
B)the same as
C)always 100 times
D)less than
2
The theory of _____ explains how ocean crust is formed and destroyed.
A)continental drift
B)continental movement
C)seafloor spreading
D)plate tectonics
3
What is an isochron?
A)a line on a seafloor map that connects points of equal age
B)a point on a seafloor map that has a magnetic reversal
C)a line on a seafloor map that connects points of equal elevation
D)a line on a seafloor map that marks a mid-ocean ridge
4
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?
<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0078746361/561751/70_pmagntc_gm_171c.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (71.0K)</a>
A)very likely
B)unlikely
C)likely
D)highly unlikely
5
According to the data shown in the figure, what was Earth's magnetic polarity like 5 million years ago?
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A)there was no magnetic field
B)the reverse of today
C)the same as today
D)pointing in an east-west direction
6
__________ is a device that can detect changes in the strength of the magnetic field.
A)GPS
B)sonar
C)magnetometer
D)satellite
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