chapter 8: plate tectonics Flashcards

1
Q

vicariance

A

isolation of a population

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2
Q

ectotherm

A

relies primarily on its external environment to regulate the temperature of its body
- reptile/amphibian

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3
Q

Endotherms

A

able to regulate their body temperatures by producing heat within the body
- birds

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4
Q

geologic/deep time

A

all of earth’s history

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5
Q

index fossils (guide fossils)

A

wide-ranging species; lifestyles more independent of small-scale patches
- ex: freely dispersed marine habitats

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6
Q

eons (3)

A

~1 billion years
- Archaen
- Proterozoic
- Phanerozioc (all of life)

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7
Q

era (current era?)

A

2nd largest time scale
- current era = Cenozoic!!

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8
Q

period

A

2+ eras

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9
Q

cambrien period

A

increase oxygen = explosion life

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10
Q

carboniferous period

A

increase in plant life = increased in buried dead plants = created fossil fuels today

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11
Q

life is about ___ years old

A

3.7 billion

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12
Q

half-life

A

amount of time for 1/2 radioactive material to decay to stable element
- calculate ratio of radio/stable to date samples

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13
Q

earth is about how old?

A

4.55 billion

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14
Q

are rocks today as old as earth?

A

NO, younger!

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15
Q

radio carbon dating

A

age of organic materials by tracking decay (1/2 life) of carbon-14 (isotope)

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16
Q

ways of estimating times

A

radio active decay/radio carbon dating, tree-rings, glacial ice cores/growth lines, luminescence (time since burial = amnt of light)

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17
Q

continental drift theory

A

continents/portions of continents rafted across earth’s surface on viscous upper mantle (above crust; crust = fixed to oven basins)

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18
Q

earths crust is..

A

dynamic

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19
Q

plate tectonics theory

A

Earth’s lithosphere, is separated into plates that move over the asthenosphere
- plates come together, separate, and collide
- origin/destruction of plates and their drifts

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20
Q

lithosphere

A

earth’s solid outer crust/top layer of earth
- crust + upper mantle

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21
Q

plate subduction

A

one plate goes under the other, causes mountains or volcanoes
- main driver of plate tectonics today

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22
Q

before tectonics

A

core = too hot = holds continents together (1.8+ billion years ago); only had life in oceans until it cooled

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23
Q

tillites

A

glacial deposits in africa and South America where the poles once were
- wegener’s theory

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24
Q

sea floor spreading

A

plate’s move apart
- mid-oceanic ridges form and underwater mountain ranges can form

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25
Q

stratigraphic evidence for continental drift

A

formation of mountains, oceanic ridges, island chains, glaciers, coal beds, sand dunes

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26
Q

paleoclimatic evidence for continental drift

A

all continents in Southern hemisphere have tillites (@ S.)

27
Q

paleontological evidence for continental drift

A

fossils and records

28
Q

trenches

A

formed at subduction zones
- deep cuts in ocean floor
- on sides of island arcs “V”-shaped
- lower gravitational pull
- ~ 10 km deep

29
Q

earliest continental crust

A

basaltic material melted and oceanic plates move down into hot mantle; small proto-continents form (Archean)

30
Q

central rift valley

A

zone w/ frequent, shallow earthquakes bc of submarine mountain ranges

31
Q

magnetic reversals

A

poles switch directions
- changes in orientation of earth’s magnetic field
- caused by change in magma flow through mantle

32
Q

magma

A

molten rock

33
Q

asthenosphere

A

deep, fluid layer of mantle (mostly molten rock)

34
Q

3 plate movements

A

ridge push (“sea floor spreading”), mantle drag, slab pull (subduction)

35
Q

what generates plate movement?

A

heat (convection) and earth’s forces

36
Q

sea floor spreading

A

at mid-oceanic ridges, plates split

37
Q

what occurs at mid oceanic ridges?

A

formation of new crust
- older rock spreads apart

38
Q

mantle drag

A

lateral flow/friction b/w plate and mantle
- recycling of lithosphere
- pulls old lithosphere under, (so new can form in subduction)

39
Q

subduction

A

denser plate slides down into magma, less dense plate covers the other
- when plates crash
- lithosphere recycling: when old plate goes under, gets heated by core, reused

40
Q

what force drives subduction?

A

force due to the weight of the denser plate sinking (older)
- biggest drifting force

41
Q

divergent boundaries occur at…

A

mid-oceanic ridges
- w/ sea floor spreading
- plates move apart

42
Q

convergent boundaries occur at..

A

subduction sites
- subduction and collisions

43
Q

transformation boundaries occur at…

A

major fault lines
- plates rubbing together
- linear faults

44
Q

how old are todays continents

A

100 million years

45
Q

order of 3 supercontinents:

A

oldest): rodinia –> panotia –> Pangaea

46
Q

pangaea

A

life is introduced
- and adapts/spreads

47
Q

laurasia

A

Pangaea splits –> N. supercontinent

48
Q

gondwana

A

Pangaea splits –> S. supercontinent

49
Q

rodinia

A

original supercontinent
- glaciation
- 1.1 billion years ago
- split 3 ways

50
Q

panthalassia

A

1 global ocean during pangaea

51
Q

pannotia

A

2nd supercontinent
- cambrian explosion of life
- 4 way split
- 2 large oceans form
- ~500 million years ago

52
Q

ithsmas

A

small piece of land connecting 2 larger pieces of land

53
Q

currently this is the __ period in earth’s history.

A

driest

54
Q

epeiric sea/epicontinental seas

A

formed when sea level rise and falls

55
Q

continental islands

A

island breaks off from continent
- easier access to colonize

56
Q

oceanic islands

A

volcanic islands
- soil = high in nutrients
- longer time to colonize (less access)
- adapt/evolve more

57
Q

surstsey

A

volcanic island exploded/appeard in 1960s
- 1964: 1st bacteria
- 1965: 1st vascular plant
- 2004: 400+ species

58
Q

hotspots

A

weak spot in mantle where magma is released; oceanic plate subduction = volcano

59
Q

hotspots form…

A

linear island chains
- older submerge, new appear

60
Q

triple junction

A

where 3 plate boundaries meet

61
Q

triple junction forms…

A

volcanic islands

62
Q

global circulation patterns are controlled by…

A

equatorial pole gradients and movement of land/ocean currents

63
Q

what drives weather patterns?

A

oceanic current

64
Q

Pangaea ultimate theory

A

theory we’re moving toward another supercontinent