Seafloor Spreading Quiz

Question 1

As the seafloor spreads apart, magma moves upwards & becomes solid as

Accepted Answer

it cools and forms new seafloor.

Question 2

The Glomar Challenger was a research ship equipped with a drilling rig that allowed

Accepted Answer

rocks to be sampled from the ocean floor.

Question 3

The ages of the rocks became increasingly older as samples were taken

Accepted Answer

farther from the mid-ocean ridges.

Question 4

Using sound waves, researchers discovered underwater

Accepted Answer

systems of ridges, canyons & mountains.

Question 5

The discovery of underwater ridges & mountain ranges were not explained until

Accepted Answer

the early 1960's.

Question 6

As the newly formed ocean crust flows sideways from the ridge it is carried in both directions.

Accepted Answer

TRUE

Question 7

The evidence for the seafloor spreading theory was later supported by more fossil evidence.

Accepted Answer

FALSE

Question 8

Hot magma rising up below mid-ocean ridges pushes aside the ocean crust causing it to

Accepted Answer

flow or move sideways.

Question 9

These magnetic field reversals also show that the seafloor is spreading at the ridges because

Accepted Answer

there is a perfect matching pattern in the rock record., the rocks were analyzed for polarity and dated.

Question 10

Scientists have determined that Earth's magnetic field has reversed itself many times over

Accepted Answer

thousands or millions of years.

Question 11

Earth's magnetic field direction is recorded in the rocks as magma cools and

Accepted Answer

the iron filaments line-up & "freeze" as it turns to rock.

Question 12

Underwater mountain ranges (or mid-ocean ridges) were found stretching

Accepted Answer

along the center of most of the ocean floor.

Question 13

As new seafloor moves away from the mid-ocean ridge, it contracts as it cools and

Accepted Answer

becomes denser.

Question 14

The dense, colder seafloor sinks which helps form the mid-ocean ridges.

Accepted Answer

TRUE

Question 15

Before echo sounding technology, to record the depth of the ocean you would have to

Accepted Answer

repeatedly lower a rope to the bottom & record the data.

Question 16

Scientists studied the rock samples taken from the ocean floor and discovered that the

Accepted Answer

youngest rocks were located at the mid-ocean ridges.

Question 17

Echo sounding was widely used during World War II to

Accepted Answer

find & destroy enemy submarines.

Question 18

Harry Hess' explanation became known as the ____ theory.

Accepted Answer

seafloor spreading

Question 19

Using ____ along the mid-ocean ridges, new seafloor features & lifeforms were discovered.

Accepted Answer

submersibles

Question 20

Harry Hess suggested that hot magma rises up from the Earth's mantle at

Accepted Answer

mid-ocean ridges.

Questions 20