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1.)a.)Which features are parallel to the mid-ocean ridge: none of the above both

ID: 637419 • Letter: 1

Question

1.)a.)Which features are parallel to the mid-ocean ridge:

none of the above

both of the above

paleomagnetic stripes

transform fracture zones

b.) The crust is thicker than the lithosphere.

False

True

c.) Due to subduction, the oldest seafloor on Earth is not more than about:

200 million years old

2 million years old

2 billion years old

20 million years old

d.) Which type of plate tectonic boundary has no volcanic activity?

transform boundaries

divergent boundaries

subduction zones

e.)Which of the following are often found at the base of submarine canyons on the seafloor:

the continental shelf

ocean trenches

abyssal fans

atolls

coral reefs

f.) Which boundary is referred to as the Mohorovicic discontinuity (or Moho):

crust - upper mantle

none of the above

lithosphere - asthenosphere

outer core - inner core

upper mantle - lower mantle

Explanation / Answer

Answer a. Paleaomagnetic stripes.These strips can be used to understand the changing magnetic orientation of the earth throughout its history which in return can help to deduce geologic chronology.

Answer b. False.Lithosphere consists of the crust and the upper layer of the mantle that is in solid state. Hence the Lithosphere will be thicker than the crust which actually forms a part of the lithosphere itself.

Answer c. 200 million years old.However, the continental crust is much older that can date back 4.6 billion years. Fun fact- the cross section seen at the Grand Canyon covers a stratigraphy which dates back almost 2 billion years!

Answer d. Transform boundaries. These boundaries consist of two plates sliding past each other horizontally on the surface of the earth. They can form interlocks which create high pressure zones. When this pressure is released, seismic activities are recorded but no volcanic activity. The earthquakes generated here are shallow too since they are restricted to the crust.

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