Seafloor Spreading

Question 1

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

Accepted Answer

thousands or millions of years.

Question 2

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 3

______ suggested that hot magma rises up from the Earth's mantle at mid-ocean ridges

Accepted Answer

Harry Hess

Question 4

Harry Hess' explanation became known as the ____ theory.

Accepted Answer

seafloor spreading

Question 5

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 6

Using sound waves, researchers discovered underwater

Accepted Answer

systems of ridges, canyons & mountains.

Question 7

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

Accepted Answer

FALSE

Question 8

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

Accepted Answer

farther from the mid-ocean ridges.

Question 9

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 10

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

Accepted Answer

TRUE

Question 11

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

Accepted Answer

along the center of most of the ocean floor.

Questions 11