Brainscape's Knowledge GenomeTM

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


See full index

Earth System- 29992 > Lithosphere 1- plate tectonics > Flashcards

Lithosphere 1- plate tectonics Flashcards

1
Q

What is plate tectonics?

A

The concept that the Earth’s lithosphere is divided into separate, rigid plates, that move independently of one another

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

How many major tectonic plates are there?

A

12

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

What are the 3 types of plate boundary?

A

Transform
Convergent
Divergent

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

What is the movement at a transform plate boundary like?

A

plates slip by one another along deep crustal fractures

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

What happens at divergent plate boundaries?

A

Creation of oceanic lithosphere by sea floor spreading (mid ocean ridge)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens at a convergent plate boundary?

A

destruction of oceanic lithosphere by subduction along a deep ocean trench

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the lithosphere?

A

rocky outer part of earth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are conditions in the lithosphere like?

A

coolest
most rigid

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

What does the lithosphere overly?

A

weak asthenosphere
that behaves in a ductile way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What areas are encompassed by the lithosphere?

A

mountains
rocks
soil
minerals
seafloor

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

Where is the crust?

A

uppermost part of the lithosphere

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

What is the difference between the crust and the mantle?

A

Mantle is Ultramafic
Crust contains higher silica

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

What is the silica content of the mantle?

A

<45%

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

What does ultramafic mean?

A

igneous rock with very low silica content

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

What 2 types of crust are there?

A

Oceanic and continental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the thickness of continental crust?

A

25-60km (thickest in mountain belts)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can make the complex structure of continental crust vary?

A

setting/ location

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the average density of continental crust?

A

2.7g/cm*3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the rock make up of the crust especially at the surface?

A

Granitic (Si, K, Na)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the density of continental crust suggest?

A

overall intermediate composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the average thickness of oceanic crust?

A

5km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is usually covering oceanic crust?

A

4km of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the average density of oceanic crust?

A

2.9g/cm*3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the general make up of oceanic crust?

A

Basalt
Gabbro - (mafic/ low silica)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is isostacy?

A

state of gravitational equilibrium between Earth’s crust and mantle such that the crust “floats” at elevation that depends on thickness and density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can the lithosphere be called within the earth system?

A

central sphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is an example for evidence for plate tectonics?

A

continental drift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the old term for continental drift?

A

the movement of Earth’s continents relative to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is continental drift a result of?

A

plate tectonics

30
Q

Who recognised that Africa and south America fit together?

A

Ortelius (1595)

31
Q

Who was mainly responsible for the development of the continental drift theory?

A

Alfred Wegner

32
Q

What fossil evidence did Wegner have for continental drift?

A

Mesosaurus
Cynognanthus
Lystrosaurus
Glossopteris (plant)

33
Q

What 2 types of evidence did Wegner have for continental drift?

A

Rock
Fossil

34
Q

How is the mesosaurus fossils evidence for continental drift?

A

Meso is freshwater reptile which is fossils can be found in Africa and South America which are sperated by saline ocean and have vastly different present habitats

35
Q

What was the widespread karoo glaciation?

A

Evidence of ice sheet retreat in Karoo basin central Africa

36
Q

What rock and fossil evidence is there for continental drift?

A

Evidence widespread Karoo glaciation
Matching Permian fossils
Matching mountains and faults
Matching climatic evidence

37
Q

What problem did Wegner have proving his continental drift theory?

A

could not think of a mechanism to account for his observations (led to geological community generally rejecting his theory)

38
Q

What did scientists eventually discover about the age of oceanic crust?

A

ages of ocean crust varied globally but everywhere was typically <200 Million years old
Subduction zone

39
Q

What did the age distribution of Earths ocean floor reveal?

A

Divergence at mid-ocean ridges

40
Q

How will age affect the thickness of seafloor sediment?

A

Thinnest where youngest
Thickest where oldest

41
Q

What do magnetic stripes/ minerals provide a record of?

A

Earth’s reversing magnetic poles

42
Q

What will new oceanic crust polarity be?

A

magnetic signature at the time of formation

43
Q

What is another name for earthquake epicentres?

A

foci

44
Q

What can earthquake foci reveal?

A

plate boundaries

45
Q

How to divergent boundaries form?

A

through continental rifting and the opening of a new ocean basin

46
Q

What is an example of a divergent boundary?

A

Silfra fissure in Iceland forms part of the boundary between the North American and the Eurasian tectonic plates.

47
Q

How much do North American and Eurasian plates drift apart per year at the Silfra boundary?

A

2cm

48
Q

What is an “on land” example of a divergent plate boundary?

A

East African rift valley

49
Q

What is formed when oceanic subducts under oceanic lithosphere?

A

Island arcs

50
Q

What forms oceanic- continental subduction?

A

Continental arc

51
Q

What occurs at subduction zones?

A

sinking oceanic oceanic lithosphere

52
Q

What associated processes occur at subduction zones?

A

Earthquakes
Metamorphism
Fluid release
Induced convection
Melt generation

53
Q

What do subduction zones create?

A

Arc-trench systems

54
Q

What is the distribution of volcanoes closely associated with?

A

Trench positions

55
Q

What happens to oceanic lithosphere during continental collision?

A

consumed

56
Q

What is thrust tectonics?

A

shortening and thickening of the crust or lithosphere common to form mountain belts

57
Q

What are transform plate boundaries delineated by? (located)

A

transform faults

58
Q

What can the effect of transform boundaries do t mid-ocean ridges?

A

Can offset mid ocean ridges and form major crustal features on land e.g. San Andreas Fault, California

59
Q

What occurs at transform and sedimentary basins?

A

localised zones of compression and extension

60
Q

What are hotspots?

A

Isolated area of volcanism away from plate boundary associated with mantle plumes

61
Q

What do hotpot volcanoes form over time?

A

Ocean island chains like Hawaii

62
Q

Where can oceanic crust be sampled?

A

cyprus

63
Q

How thick can the lithosphere be?

A

100-200km

64
Q

What is buoyancy?

A

natural tendency of thigs to float in fluid

65
Q

What is isostatic rebound?

A

When a large ice mass has retreated from an area and the ground “bounces back”

66
Q

What are diffuse plate boundaries?

A

Ones which have contact for hundreds if km

67
Q

Why will the height of oceanic crust reduce as you move further from a mid ocean ridge?

A

as the rock here has had more time to reach buoyancy

68
Q

What does it mean to say a subduction zone is dynamic?

A

there is a flow of energy and matter

69
Q

How can the groupings of continents affect sea level

A

if there are grouped closely sea level is low if they are apart sea level is higher

70
Q
A

Earth System- 29992 (24 decks)

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