chapter 12 earths history and interior

Question 1

anthropocene

Answer 1

the age of human transformation of earths biological and physical systems

Question 2

___ of earths land surface taken to grow food for people

Answer 2

40%

Question 3

the universe began about ___ years ago with the big bang

Answer 3

13.8 billion

Question 4

distances between and across galaxies are measured in _____ ____

Answer 4

light years

Question 5

our solar system formed about ____ years ago

Answer 5

4.6 billion

Question 6

crust

Answer 6

earths molten surface that cooled and hardened into a rigid surface

Question 7

volcano

Answer 7

a mountain or hill formed by eruptions of lava and rock fragments

Question 8

cyanobacteria

Answer 8

photosynthetic bacteria

Question 9

stromatolites

Answer 9

colonies of cyanobacteria

Question 10

how old is earth

Answer 10

4.6 billion years old

Question 11

uniformitarianism

Answer 11

the principle that the same gradual and nearly imperceptible processes operating now have operated in the past

Question 12

relative vs absolute age

Answer 12

relative- compares the age of one object with the age of another without specifying how old either is
absolute- an age that is specified in years before the present

Question 13

superposition principle

Answer 13

in rock layers, the oldest rocks are located at the bottom and the youngest rocks are at the top

Question 14

radiometric dating

Answer 14

assigning ages to materials based on the radiometric half life of unstable elements within the material

Question 15

half life

Answer 15

the time it takes for half of the unstable elements to decay

Question 16

geothermal gradient

Answer 16

temperature of earths interior increases with depth

Question 17

seismic wave

Answer 17

energy released by earthquakes that travel through earths interior

Question 18

earthquake

Answer 18

sudden shaking of the ground caused by movements of the earths crust

Question 19

3 principle layers of earths interior

Answer 19

core
mantle
lithosphere

Question 20

inner core vs outer core

Answer 20

inner- composed of solid iron and nickel, extends from earths center to about 5150 km below earths surface

outer- composed of liquid iron and nickel, extends to about 2900 km below earths surface

Question 21

magnetic north pole vs geographic north pole

Answer 21

magnetic- found where the magnetic field enters the planet

geographic- found at earths axis of rotation

Question 22

lower mantle

Answer 22

layer of heated and slowly deforming solid rock that lies between the base pf the crust and the outer core, lies 2900-200 km below earths surface

Question 23

asthenosphere

Answer 23

found between depths of 100 and 200 km

Question 24

lithosphere

Answer 24

the crust and the lithospheric mantle beneath it, extending to a depth of about 100 km on average

Question 25

crust

Answer 25

the rigid outermost portion of the earth

Question 26

continental crust vs oceanic crust

Answer 26

continental- makes up continents, composed mainly of granite

oceanic- beneath the oceans, composed mainly of basalt

Question 27

granite vs basalt

Answer 27

granite- a silica rich rock made up of coarse grains

basalt- a dark heavy, fine grained volcanic rock

Question 28

magma vs lava

Answer 28

magma- melted rock below earths surface

lava- magma that spills onto the surface of earths crust

Question 29

moho

Answer 29

boundary that separates crust from lithospheric mantle; lies about 35 km deep

Question 30

plate tectonics

Answer 30

theory addressing the origin, movement. and recycling of lithospheric plates and the landforms that result