Brainscape's Knowledge GenomeTM

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


See full index

**Oceanography > Plate Tectonics and Formation of Oceans > Flashcards

Plate Tectonics and Formation of Oceans Flashcards

1
Q

Motivating questions

A
  • Why split up into continents?
  • Why are there mountain belts, and why are they located on some continental margins but not others?
  • Why do earthquakes and volcanoes occuur where they do?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Wegner’s Theory of Continental Drift

A

Continents at one point were all a single continent Pangea
1. Fit of the continents
2. Locations of past glaciations (glacial striations: ice moves and drags other material with it, dropstone) found where they shouldn’t be
3. Distribution of fossils (locations found on diff continents matching fossils)
4. Matching geological units (ancient mountain belts line up)
5. Paleoclimate belts (corals, palms, etc)

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

Wegner’s main pushback

A

What force could be strong enough to move continental masses?

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

Mid-20th century: the plate tectonics revolution

A
  • Bathymetry and paleomagnetic data
  • Seawater samples
  • Detection of currents
  • Measurements of seafloor hear flow
  • Samples of deep-sea sediments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Major advances in seafloor mapping

A
  • Marie Tharp and Bruce Heezen mapped ocean floor
  • Shallow, then sharply drops off, then mountain range in middle of ocean
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mechanism idea: who/what?

A
  • Harry Hess
  • Depth profile of a flat-top seamount observed on the Pacific Ocean floor. Hess names these features “guyots” in honorof flat-roofed Guyot Hall
  • Mantle is a solid
  • Convention of solid mantle drives things to move around on continents
  • Seafloor spreading and the associated circular movement of rock material in the mante is driving force
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Earth layers

A
  • Core, mantle, crust
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Evidence for plate tectonics

A
  • Global distribution of earthquakes (map out the plates)
  • Paleomagnetism (core/liquid iron generates a magnetic field, magnetic rocks field can be measured to see if it was during flipped period)
  • Ocean floor magnetic anomalies (magnetic stripes can be seen on ocean floor which shows rocks generated at center of ridge)
  • Age of the ocean floor (older when further from ridges), Pacific = fast-spreading, Atlantic = slow-spreading
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Driving force of plate tectonics

A
  • Subduction
  • This created Pacific ring of fire, valcanoes in Mexico, etc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Resulting features of plate tectonics

A
  • mid ocean risges, subduction zones
  • Earth’s lithosphere is divided into ___
  • explains earthquakes and volcanoes
    [insert image]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Types of plate tectonics

A

Divergent
Convergent
Transform

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

Divergent

A
  • Plates move away from each other
  • Mid-ocean ridges with a rift valley (magma from mantle rises up)
  • New ocena floor is created
  • Shallow focus earthquakes
  • ex: Iceland (is a hotspot)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Convergent

A
  • Plates move towards each other
  • Subduction zone (crust gets old and cold)
  • More explosion and volcanic
  • Oceanic crust is destroyed
  • Formation of ocean trench and volcanic arc
  • Deep focused earthquakes
  • Ocean-ocean collision –> islands
  • Continent-continent -> mountain range
    • No subduction, only compression, folding tall mountain uplife, mountains are eroded by weathering, youngest mountain ranges tallest
  • Ocean-continent -> trench
    • Ocean plate is subducted, continental arcs on land, explosive andesitic volcanism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Transform

A
  • Sediments of plates slide against each other
  • Oriented perpendicular to mid-ocean ridges
  • Allows neighboring mid-ocean ridges to move at different rate
  • Shallow but strong earthquakes
  • San-Andreas fault
  • Earthquakes
  • No magma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Stages of rifting

A
  1. African Rift Valley (initial stage)
  2. Red Sea (juvenile stage)
  3. Indain Ocean (mature stage)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hotspots

A
  • “Stationary sources of heat in the mantle”
  • Does not involve a plate boundary
  • Mantle becomes overheated or chemically ustable, heat rises from core-mantle boundary rises up over millions of years
  • Plume head followed by tail
  • Carries with it greenhouse gases leading to environmental change, correlated to extinction events
  • Hawaii, Iceland, Yellowstone, etc
17
Q

Formation of ocean basins through time

A

Pangea separates -> Atlantic forms -> South American and Africa separate -> India collides with Asia

18
Q

The Wilson Cycle

A

Formation -> growth -> destruction
[image]

**Oceanography (15 decks)

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