15 15 pts question 13 since the original discovery of

1.5 / 1.5 pts
Question 13
Since the original discovery of magnetic reversals, scientists have shown
that these reversals have occurred over the past 10 million years at an
average rate of 4 to 5 reversals per million years. The last such reversal
occurred about how many years ago?
680,000 years
780,000 years
Correct! Correct!
880,000 years
980,000 years
1.5 / 1.5 pts
Question 14
What is the typical rate of seafloor spreading?
Correct!
Correct!
6–10 centimeters per year
11–15 centimeters per year
16–20 centimeters per year
1.5 / 1.5 pts
Question 15
If new crust is indeed being produced at the rifts, where does the
additional older crust go?
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6/19/2020 Lesson 2 Quiz: GEOL105L-73411 (ONL) Geology Lab
8/9
1.5 / 1.5 pts
Question 16
Most of Earth’s volcanoes are located in the _______________ around
the Pacific Rim just beyond the oceanic trenches, where magma, which is
less dense than the surrounding rock, rises to the surface and erupts.
Correct!
Correct!
Ring of Steam
1.5 / 1.5 pts
Question 17
Stretching forces generated in the lithosphere immediately above the
rising portion of a convection cell result in rifting of the lithosphere and
ultimate formation of what type of plate boundary?
convergent
transform
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6/19/2020 Lesson 2 Quiz: GEOL105L-73411 (ONL) Geology Lab
divergent
Correct!
Correct!
hot spot
1.5 / 1.5 pts
Question 18
Pushing forces generated in the lithosphere above the adjacent
downgoing portion of the convection cell result in the formation of a deep-
sea trench that eventually develops into what type of plate boundary?
9/9
Quiz Score:
25.5
out of 30
Not yet graded / 3 pts
Question 19
How do some rocks store information about Earth's magnetic field?
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