Chapter 14

Question 1

Continental Drift

Answer 1

Wegener’s hypothesis which suggested that continents are in constant motion on Earth’s surface

Question 2

Pangaea

Answer 2

Name given to the super continent that began to break apart approximately 200 million years ago

Question 3

Mid-ocean ridge

Answer 3

Long, narrow mountain range on the ocean floor; formed by magma at divergent plate boundaries

Question 4

Normal Polarity

Answer 4

When magnetized objects, such as compass needles, orient themselves to point north

Question 5

Magnetic reversal

Answer 5

An event that cause a magnetic field to reverse direction

Question 6

Seafloor spreading

Answer 6

The process by which new oceanic crust forms along a mid-ocean ridge and older oceanic crust moves away.

Question 7

Reversed polarity

Answer 7

When magnetized objects reverse direction and orient themselves to point south

Question 8

Plate tectonics

Answer 8

theory that Earth’s surface is broken into large, rigid pieces that move with respect to eachother

Question 9

Lithosphere

Answer 9

The rigid outermost layer of Earth that includes the uppermost mantle and crust

Question 10

Divergent plate boundaries

Answer 10

The boundary between two plates that move away from eachother

Question 11

Transform plate boundaries

Answer 11

The boundary between two plates that slide past eachother

Question 12

Convergent plate boundaries

Answer 12

The boundary between two plates that move towards eachother

Question 13

Subduction

Answer 13

The process that occurs when on tectonic plate moves under another tectonic plate

Question 14

Convection

Answer 14

The circulation of particles within a material caused by differences in thermal energy and density

Question 15

Ridge push

Answer 15

The process that results when magma rises at a mid-ocean ridge and pushes oceanic plates in two different directions away from the ridge.

Question 16

Slab pull

Answer 16

The process that results when a dense oceanic plate sinks beneath a more buoyant play along a subduction zone, pulling the rest of the plate that trails behind it.

Question 17

Who came up with the theory of Pangaea and why couldn’t he prove it?

Answer 17

Alfred Wegener

He could not explain how the continents moved

Question 18

What are four pieces of evidence to prove Pangaea-

thoroughly explain

Answer 18

Climate- Glacier grooves were found South America, Africa, India, and Australia where glaciers could not exist today.
Glacier sediments were also deposited in these continents.
Rock- Appalachian mountains match the same age, type, and geological structure of the Caledonian Mountains
Fossil- Glossopterius was found in South America, Africa, India,Australia, and Antarctica. Could not have traveled across the ocean.

Question 19

who came up with the theory of seafloor spreading?

Answer 19

Harry Hess

Question 20

What causes seafloor spreading

Answer 20

Plates separate at a divergent plate boundary, magma rises to the surface, cools, and pushes older crust apart.

Question 21

Why is seafloor spreading a recycled process?

Answer 21

The older oceanic crust that the newly formed crust subducts underneath the continental crust. The older crust is heated into molten rock, magma, and can rise back up through the mid-ocean ridge.

Question 22

Explain 2 pieces of evidence that supports seafloor spreading

Answer 22

The age of the crust and the magnetic reversal shown in the crust.

Question 23

Where is the seafloor created? Destroyed?

Answer 23

It is created it the mid-ocean ridge when magma pushes up through it. It is destroyed at the subduction zone when in melts into magma.

Question 24

If new seafloor is being created, why isn’t the Earth getting bigger?

Answer 24

As more is being created, the older crust is being destroyed. Both happen almost simultaneously.

Question 25

How much do plates move?

Answer 25

A few centimeters each year, about 2.5.

Question 26

What is a subduction zone?

Answer 26

the place where one tectonic plate moves under another more buoyant and less dense tectonic plate

Question 27

What are the three plate boundaries?

Answer 27

Convergent, divergent, transform

Question 28

How do the three different plates move?

Answer 28

convergent: —>
transform: —->

Question 29

What forms at each boundary? .

Answer 29

Convergent:
oceanic/oceanic- trench, subduction zone, island arc
continental/continental- mountains
oceanic/continental- trench, subduction zone
Divergent:
oceanic/oceanic- mid-ocean ridge
continental/continental- rift valley, fault block mountains
Transform: earthquakes, ridge-like feature, looks like a scar.

Question 30

Give examples of what forms at each boundary?

Answer 30

Convergent:
oceanic/oceanic- Marianas Trench, Marianas Islands
continental/continental- Himalyas Mountains
oceanic/continental- Cascadia mountain range
Divergent:
oceanic/oceanic- mid-atlantic ridge
continental/continental- Great rift valley in Africa
Transform: San Andreas Fault

Question 31

Describe the crust

Answer 31

Thinnest layer of the earth- has two types:
oceanic- dense, made of basalt
continental- less dense, made of granite

Question 32

Describe the mantle

Answer 32

Made of magma that is convecting, largest layer

Question 33

Describe the outer core

Answer 33

Liquid iron and nickel that is hot and fast, creates the magnetic field

Question 34

Describe the inner core

Answer 34

solid iron and nickel

Question 35

What is the lithosphere and the astenosphere?

Answer 35

lithospere- upper mantle and crust

asthenosphere- lower mantle, molten rock