Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

EAS > Lecture 4 > Flashcards

Lecture 4 Flashcards

1
Q

Comets

A
  • small bodies in elliptical orbits
  • ice and rock and dust particles
  • May represent samples of early solar system
  • Kuiper belt and Oort Cloud
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Asteroids and meteors

A
  • small bodies of variable composition
    - rock, metallic iron
    - sometimes strike earth (meteorites)
    - asteroid belt, Trojans, Greeks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Origin of asteroids and meteors

A
  • primordial planet remnants
  • samples of early solar system material
  • some meteorites are ejected from mars
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Origins: Nebular Hypothesis

A
  1. Gravitational collapse of rotating nebula of gas and dust
  2. With collapse, gas becomes denser and hotter at centre, nuclear fusion begins and sun starts
  3. Condensation of material in rotating disk formed building blocks that through accretion formed planets, moons and other objects
  4. Distance from sun (temperature) dictated what condensed, and thus the different compositions of the inner (terrestrial) and outer (Jovian) planets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Five key factors critical in evolution of terrestrial planets:

  1. Melting, impacts, and differentiation
A
  • as planet accretion reached maximum 4.56 billion years ago, terrestrial planets partly melted as collisions took place. Led to partial melting so that denser materials sank to center (differentiation)
  • during and after partial melting, moon and terrestrial planets struck by numerous meteorites until about 4 billion years ago. Since then, terrestrial planets and the moon have behaved as independent closed systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Five key factors critical in evolution of terrestrial planets:

  1. Volcanism
A
  • interior of planets remained hot as a result of radioactive elements that produce heat as they decay: this is the driving force behind volcanic activity
  • rate of cooling of planets depends on size. The largest planets (Earth and Venus) are still cooling whereas others have cooled down. There are indications of past volcanic activity on the moon and mars.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Five key factors critical in the evolution of terrestrial planets:

  1. Planetary mass
A
  • mass determines orbit and number of moons the planet can capture
  • also determines if planet has gravitational pull to keep atmosphere
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Five key factors critical in the evolution of terrestrial planets:

  1. Distance from sun
A

-determines if water can exist as liquid water (critical factor in volcanism and surface composition)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Five key factors critical in the evolution of terrestrial planets:

  1. Biosphere
A
  • presence or absence of a biosphere plays an essential role in the development of the biogeochemical cycles that control that composition of Earth’s atmosphere
  • photosynthetic organisms convert carbon dioxide and liquid water into oxygen gas and organic matter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Age of solar system

A

4.56 billion years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do we know the age of the solar system

A

Via radiometric dating of primitive meteorites

Radioactive decay occurs at fixed rates, providing an internal clock. We measure amounts of parent and daughter atoms

REVIEW GRAPHS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Radiometric dating gives

A

Absolute or numerical ages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Relative ages

A

Used to use before the discovery of radiometric dating and development of instruments to measure numbers (or ratios) of atoms very precisely

Shows up in rock records

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Geologic time in perspective

A

Review this slide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Precambrian/Cambrian boundary

A
  • 542 MA
  • originally denoted where fossil-bearing sedimentary deposits started
  • there are Precambrian sediments
  • we now know of numerous Precambrian fossils (e.g. stromatolites 3.5 GA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Is there a location where the entire rock record is in place

A
  • no
  • for e.g. there are Precambrian rocks covered by Pleistocene (0.13-1.80 MA) in northern Alberta
  • these gaps are caused by events such as mountain building, sea level changes, weathering
17
Q

Structure of earth is determined by 3 major compositional layers:

A

Core: metallic, iron rich, solid inner core. Liquid outer core (solid and liquid are same composition)

Mantle: dense rocky matter

Crust: thin, less dense rocky matter (because of differentiation)

18
Q

Two contrasting types of Earth’s crust:

A
  1. Continental: thickness averages 45 km but varies 30-70 km
  2. Oceanic: 8 km thick

Two types have distinctly different compositions (reflecting different origins)

19
Q

Layers of different strength: lithosphere

A

Crust and upper most mantle

Cool, rigid, brittle, breaks

Known by samples and geophysical measurement

20
Q

Asthenosphere

A

Upper mantle

Hot, weak, plastic, flows

Known by geophysical measurements and experiments (limited samples)

21
Q

Mesosphere

A

Deeper mantle

Hot, but stronger than atmosphere. Flows

22
Q

How do we know composition of core

A

Geophysical measurements, experiments, meteorites

23
Q

All three layers (lithosphere, asthenosphere and mesosphere) are

A

Solid

24
Q

Internal structure and composition of Earth

A

Draw out and review diagram in notes

EAS (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions