exam 1

Question 1

Original horizontality

Answer 1

the way sediment is laid down, they should be close to horizontal –> If they aren’t, horizontal, they shifted

Question 2

Superposition

Answer 2

when laying down sedimentary layers, older layers @ bottom, younger layers @ top

Question 3

Cross-cutting relationships

Answer 3

if something cuts across existing layers (ex: fault), it has to come after the layers it cuts through

Question 4

Radiometric dating

Answer 4

rocks could be dated based on decay of radioactive material
(Uses naturally radioactive isotopes)

Question 5

Half-life

Answer 5

time it takes an amount of a radioactive isotope to decay to half the amount

Question 6

after 1 half-life there are __ parent isotopes and __ daughter istopes; this is because of the __ rate.

Answer 6

1/2 parent, 1/2 daughter, constant

Question 7

pioneer in mapping oceans

Answer 7

Marie Tharp

Question 8

relative dating

Answer 8

the ORDER in which geological features formed

Question 9

absolute dating

Answer 9

exact time geological features formed (Ex: radiometric dating)

Question 10

what elements make up the core?

Answer 10

iron and nickel alloys

Question 11

what elements make up the mantle?

Answer 11

ultramafic rocks

Question 12

what elements make up the crust?

Answer 12

felsic to mafic rocks

Question 13

what components make up felsic rock?

Answer 13

silicon and oxygen

Question 14

uncomformities

Answer 14

surface b/w two rock layers representing a missing layer that was either never formed or eroded away (missing rock record)

Question 15

what components make up mafic rock?

Answer 15

magnesium and iron

Question 16

what layers make up the lithosphere?

Answer 16

crust and upper mantle

Question 17

how rigid is the lithosphere?

Answer 17

rigid

Question 18

what layers make up the asthenosphere?

Answer 18

remaining upper mantle (from lithosphere)

Question 19

how rigid is the asthenosphere?

Answer 19

semi-ductile but solid

Question 20

what layers make up the mesosphere?

Answer 20

lower mantle

Question 21

how rigid is the mesosphere?

Answer 21

rigid

Question 22

what phase is the outer core?

Answer 22

liquid

Question 23

what phase is the inner core?

Answer 23

solid

Question 24

angular uncomformity

Answer 24

tectonic forces causing compression and uplift

Question 25

why do seismic waves propagate?

Answer 25

elasticity of earth

Question 26

what does P-wave stand for?

Answer 26

pressure (compression) or primary wave

Question 27

what is the fastest wave?

Answer 27

p-wave

Question 28

what direction does p-wave go in?

Answer 28

parallel

Question 29

what is the s-wave?

Answer 29

sheer or secondary

Question 30

which is the slower wave?

Answer 30

s-wave

Question 31

what direction do s-waves go?

Answer 31

perpendicular

Question 32

wavefront

Answer 32

line connecting peaks and troughs

Question 33

ray

Answer 33

perpendicular path to wavefront that points in direction of wave propagation

Question 34

refraction

Answer 34

waves create bent paths due to varying speeds

Question 35

examples of geosystems

Answer 35

climate, plate tectonics, geodynamics

Question 36

Geologic record

Answer 36

info preserved in rocks formed throughout history

Question 37

Hutton’s original theory of uniformitarianism:

Answer 37

- Earth’s processes are slow + Time is recorded in rocks = great changes are accomplished over large periods of time - Earth = old - Geologic processes occur at CONSTANT rate of long periods of time

Question 38

Modern Theory of uniformitarianism:

Answer 38

Principles of geologic time remain constant, but rates and intensities VARY

Question 39

geodesy

Answer 39

study of earth’s shape and surface

Question 40

what was the shape of earth according to ancient greece vs. today?

Answer 40

- spherical - not perfect sphere

Question 41

examples of isotope dating methods

Answer 41

uranium-lead, potassium-argon, rubidium-strontium, carbon-nitrogen

Question 42

earth's topography ranges ___ , we know because of __

Answer 42

20 km; surface elevation

Question 43

nebular hypothesis

Answer 43

formation of solar system

Question 44

which planets are closest to the sun?

Answer 44

heavier planets

Question 45

Which is thicker: continental or oceanic crust?

Answer 45

Continental is thicker (we know because of changes in elevation)

Question 46

How do we know earth is layered?

Answer 46

*seismic waves, Isostasy, 2 crusts w/ 2 densities, Trenches in the ocean (sea floor spreading)

Question 47

order of layers of earth

Answer 47

solid iron inner core --> liquid iron outer core --> mantle --> crust

Question 48

the largest layer of earth's mass =

Answer 48

mantle

Question 49

isostasy

Answer 49

equilibrium b/w forces of GRAVITY pulling down and BUOYANCY pushing surface up

Question 50

Why do continents ride higher on underlying mantle than oceans?

Answer 50

- Difference in densities and buoyancy - Upper mantle is ductile

Question 51

which is denser: continental or oceanic crust?

Answer 51

ocean crust = denser than continental

Question 52

why to continents float?

Answer 52

difference in density; continental crust is made up of lighter rock than the higher density oceanic rock

Question 53

which is thicker: continental or oceanic crust?

Answer 53

continental

Question 54

What causes the lithosphere to be more rigid than the asthenosphere?

Answer 54

the lithosphere is at a lower temp than the asthenosphere

Question 55

What causes abrupt changes in density between earth’s major interior layers?

Answer 55

Chemical composition of those layers

Question 56

what drives the magnetism of earths core?

Answer 56

heat inside the core

Question 57

where can s-waves not travel?

Answer 57

the outer core; 3000-5000 km (depth)

Question 58

can the p-waves make it through the core?

Answer 58

yes, but they are refracted

Question 59

how do we know there is a liquid outer core?

Answer 59

the s-waves can't travel through it and the p-waves are refracted

Question 60

how might a geochronologist determine how old rocks are?

Answer 60

radio-metric dating, fossilization, super-position, original horizontality

Question 61

mechanical properties of crust

Answer 61

rigid and solid

Question 62

mechanical properties of mantle

Answer 62

solid and ductile

Question 63

mechanical properties of outer core

Answer 63

liquid and ductile

Question 64

mechanical properties of inner core

Answer 64

solid and rigid

Question 65

what materials can p-waves travel through?

Answer 65

solids and liquids

Question 66

what materials can s-waves travel through?

Answer 66

only solids

Question 67

how does the speed of seismic waves change in the deep interior of earth?

Answer 67

the speed increases with increasing depth/pressure

Question 68

what influences speed of seismic waves?

Answer 68

density and elasticity of the material its traveling through