Ch. 1 sec 4-5 Sea Floor Spreading

Question 0

What did sonar help accomplish?

Answer 0

It helped discover that the ocean floor isn’t flat but has mountains and valleys and discovered the mid ocean ridges

Question 1

Sonar-

Answer 1

Used to map the ocean floor.

Question 2

What did Harry Hess do?

Answer 2

He studied mid oceanic ridges and came up with “sea floor spreading”

Question 3

What’s sea floor spreading?

Answer 3

A theory which states that molten material comes up through cracks at mid ocean ridge, it hardens and spreads the sea floor by pushing older rock away.

Question 4

What theory backed up continental drift?

Answer 4

Sea floor spreading

Question 5

What is an evidence from molten material?

Answer 5

The sea floor near the mid oceanic ridge is volcanic

Question 6

What’s and evidence from magnetic stripes?

Answer 6

1. Earth has changed polarity several times and it’s recorded in the ocean.
2. The magnetic stripes are the same distance from the mid ocean ridges showing that the ocean floor was made at the same time and the sea floor has spread.

Question 7

Evidence from the age of the rock drilling samples

Answer 7

1. Scientists drill rock samples and find the age of the rock is the same distance from the mi ocean ridge, showing that the rock was ,made at the same time. and was split apart by Sea Floor Spreading.

Question 8

Subduction

Answer 8

The process where ocean floor runs into ocean floor or ocean floor runs into continental crust and ocean floor sinks down forming a trench.

Question 9

What happens when two oceanic crusts collide?

Answer 9

Islands

Question 10

Ocean crust collides with Continental crust

Answer 10

Trenches

Question 11

Continental crust collides with Continental crust

Answer 11

mountains

Question 12

The subduction zone

Answer 12

the whole area where subduction

Question 13

Plates-

Answer 13

Parts of the lithosphere that is broken off

Question 14

Plate tectonics-

Answer 14

A geological that states that pieces of Earth’s lithosphere are moving in constant slow motion, driven by convection currents in the mantle.

Question 15

What makes Earth’s plates move?

Answer 15

Convections currents rise from the asthenosphere and spread out beneath the lithosphere

Question 16

What are the edges of the plates called?

Answer 16

Plate boundaries

Question 17

Transform boundaries-

Answer 17

A place where 2 boundaries are sliding past each other. Causing earth quakes.

Question 18

Divergent boundary

Answer 18

Where two plates move apart

Question 19

What happens to divergent boundaries on land?

Answer 19

Rift valleys

Question 20

Rift Valley

Answer 20

a deep valley that forms where two plates move apart

Question 21

What happens when divergent boundaries occur in the ocean?

Answer 21

it causes mid-ocean ridges

Question 22

Convergent boundary

Answer 22

Where two plate boundaries collide and it causes mountains

Question 23

Faults

Answer 23

Breaks in the earths crust where rocks slipped past each other

Question 24

J. Tuzo Wilson came up with what theroy?

Answer 24

Plate tectonics

Question 25

Pangea broke into two continents, what were their names?

Answer 25

Laurasia, Gandwanaland