Earth's Structure

Question 1

How many lithospheric plates are there?

Answer 1

12 large ones and several smaller ones

Question 2

When was the continental drift theory proposed and by who?

Answer 2

Proposed in 1912 by Alfred Wegener

Question 3

Divergent plate boundaries

Answer 3

• seafloor plate separation

- continental plate separation

Question 4

Convergent plate boundaries

Answer 4

• ocean-continent
• ocean-ocean
• continent-continent

Question 5

Transform plate boundaties

Answer 5

-shift in a “shearing” motion

Question 6

Sources of energy for plate motion

Answer 6

• 80% radioactive decay

- 20% remnant heat from Earth formation

Question 7

Hot spots

Answer 7

• areas where columns of hot mantke materiak underlie the lithosphere
• stationary relative to plates, can create chains of volcanic islands

Question 8

Energy

Answer 8

the ability to do work, causes things to move or change

Question 9

Forms of energy

Answer 9

• gravitational
• thermal
• chemical
• radiant
• nuclear
• elastic (strain)

Question 10

Physical laws of energy

Answer 10

• cannot be created or destroyed

- entropy always increases

Question 11

Sources of energy

Answer 11

• external (solar energy makes up 99.9% of total energy reaching Earth’s surface)
• internal (radioactive decay, remnant heat from Earth formation)

Question 12

Remant heat causes:

Answer 12

• powers volcanoes and earthquakes

- pushes up mountains (indirectly powers landslides)

Question 13

Solar energy causes:

Answer 13

• motion in the atmosphere and oceans

- powers waves and storms

Question 14

Gravity powers:

Answer 14

• landslides

- impacts

Question 15

elastic energy:

Answer 15

• builds up as plates move and faults lock
• crust deforms and stores elastic energy
• elactic energy released as heat/seismic waves when fault

Question 16

Stress

Answer 16

• force per unit area
• can be parallel or perpendicular
• causes strain

Question 17

Strain

Answer 17

• deformation response to an applied stress
• elastic deformation (reversible)
• plastic deformation (irreversible)

Question 18

Faults

Answer 18

-Geologic structures along which displacement has occurred

Question 19

Normal fault

Answer 19

hanging wall moves down fault plane

Question 20

Reverse fault

Answer 20

hanging wall moves up fault plane

Question 21

thrust fault

Answer 21

low angle reverse fault

Question 22

strike-slip fault

Answer 22

vertical fault, lateral motion (right/left)

Question 23

Mineral

Answer 23

• naturally occurring
• inorganic solid
• definite chemical composure

Question 24

Rock

Answer 24

a solid aggregate or mass of minerals

Question 25

How many minerals have been identified on earth?

Answer 25

Nearly 4,000

Question 26

Igneous rocks

Answer 26

form from magma that originates deep in the earth and moves up toward the surface

Question 27

What percent of magma reaches earth’s surface?

Answer 27

10%

Question 28

Magma crystallizes in the interior as _____

Answer 28

intrusions

Question 29

Sedimentary rocks

Answer 29

formed by compression, dehydration, cementation of

sediments

Question 30

Metamorphic rocks

Answer 30

The transition of one rock into another by temperatures, pressures and/or chemical conditions unlike those in which it formed

Question 31

Rock cycle

Answer 31

The processes and paths by which one rock type is converted to another, both within the earth and at the surface

Question 32

Hydrologic cycle

Answer 32

Solar energy drives movement of water between atmosphere and oceans and continents

Question 33

Biogeochemical cycle

Answer 33

Transfer of chemical elements through a series of reservoirs