Exam 1 part 2 Flashcards

Study for the first exam

1
Q

How did the planet form?

A

The accept hypothesis is the nebula hypothesis, where a cloud called the solar nebula began to contract due to gravity about 5 billion years ago.

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2
Q

How old is the universe?

A

14 billion years ago

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3
Q

How old is our solar system?

A

Only 5 billion years old.

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4
Q

What was the nebula like?

A

It’s believed that it was a flat disk with a protosun/presun in the middle of it, the larger planets formed from rocky substances and the outer planets came from fragments of ice.

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5
Q

How did the structure of the earth form?

A

The metals sank down to the earth, the molten rock made the three sections of the earth’s interior, the atmosphere evolved from gases that were released from volcanoes.

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6
Q

The the earth a very hot or cool planet in the beginning?

A

Very hot

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7
Q

Who proposed the first hypothesis on continental drift and when?

A

Alfred Wegener, 1915

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8
Q

What was the continental drift hypothesis?

A

That the continents drifted apart to present day positions 200 million years ago

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9
Q

What 4 pieces of evidence was used to support wegner’s hypothesis?

A

1) Fit of the continents
2) Fossil evidence
3) Rock type and structural similarities
4) Paleocimatic evidence

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10
Q

What were the 3 objections to the continental drift hypothesis?

A

1) Lack of mechanism for moving continents
2) Wrong suggestion that continents break through ocean crust
3) strong opposition from all areas of the scientific community.

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11
Q

When was the seafloor spreading hypothesis proposed and by who?

A

1960s, by Harry Hess

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12
Q

How was the seafloor spreading discovered?

A

Through sonar waves, sound goes down and comes back up to the ship, the longer it takes the deeper the floor.

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13
Q

Where is seafloor generated and where is it destroyed?

A

Created at the ridges and destroyed by the trenches.

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14
Q

What does the lithosphere consist of?

A

The crust and the upper mantle

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15
Q

What are the 7 major lithosphere plates?

A

They are the 7 tectonic plates

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16
Q

In what ways are the tectonic plates always moving?

A

They are constantly moving and changing in both size and shape.

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17
Q

About how far does a tectonic plate move a year?

A

About 5 centimeters/2 inches.

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18
Q

What are the three types of plate boundaries?

A

1) Divergent (Separating, constructive, new material.)
2) Convergent (Smash together, destructive)
3) Transform (Sliding, neither creates or destroys)

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19
Q

Each plate is bounded by?

A

A combination of the three types of plate boundaries

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20
Q

Is it possible to have new plate boundaries?

A

Yes, new boundaries can be created in response to changing forces.

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21
Q

When was Pangaea?

A

200 million years ago.

22
Q

Where can you find divergent plate boundaries?

A

Most are located along the crests of ocean ridges.

23
Q

Where does seafloor spreading occur?

A

Along the oceanic ridge system.

24
Q

is there a difference in ridge topography?

A

There is a difference due to spreading rates.

25
Q

What controls spreading rates?

A

Convection

26
Q

What does ridge do?

A

Ridge has a sharp rise but a slow convection rate

27
Q

What does rise do?

A

Rise has a gradual rise but a fast convection rate

28
Q

What does a continental rift do?

A

It splits landmasses into two or more smaller segments along the rift.

29
Q

What are two examples of continental rifts?

A

East African rift valleys and the Rhine valley in Northern Europe.

30
Q

What are convergent plate boundaries?

A

They are older portions of oceanic plates that are returned to the mantle in destructive plate boundaries

31
Q

What are the plate boundaries of convergent plate boundaries called?

A

They are referred to as subduction zones/ocean trenches.

32
Q

What is the average angle of a subduction zone?

A

45 degrees

33
Q

What are the 3 different types of convergent plate boundaries?

A

1) Oceanic-Continental
2) Oceanic-oceanic
3) Continental-continental

34
Q

What do the oceanic-continental convergent plate boundaries do?

A

This is where the denser oceanic plate sinks underneath the continental plate. Along the descending plate magma is generated creating volcanic mountain chains.

35
Q

What are two examples of volcanic mountain chains?

A

Andes and Cascades

36
Q

What do the oceanic-oceanic convergent plate boundaries do?

A

When one denser/colder oceanic plate sinks underneath another oceanic plate.

37
Q

Why would once oceanic plate be denser than another oceanic plate?

A

Because the plate is colder, cold sinks under hot, it’s cold because it’s farther away from it’s ridge/divergent plate boundary

38
Q

What happens at continental-continental convergent plate boundaries?

A

Since the less dense continental plate does not subduct underneath the opposing continental plate, they converge and form mountain ranges.

39
Q

What is an example of a convergent continental-continental plate boundary mountain/mountains?

A

Mt. Everest. It’s still growing actually.

40
Q

What do transform boundary plates do?

A

They slide past each other, neither creating nor destroying, they are usually in breaks of the oceanic crust called fracture zones.

41
Q

How are hot spots created?

A

Through mantle plumes that originate deep in the mantle core

42
Q

Do tectonic plates move in the same direction?

A

No

43
Q

How do we measure tectonic plate motion?

A

Through a global positioning system, GPS. It’s in space.

44
Q

Do convection cells move at the same rate?

A

No

45
Q

Do tectonic plates move at the same rate?

A

No.

46
Q

What is the main force that moves the tectonic plates?

A

Convection cells within the mantle

47
Q

What are the names of the three forces that drive plate tectonics?

A

1) Slab pull
2) Ridge push
3) Slab suction

48
Q

What are the 4 definitions that make up a mineral?

A

1) Naturally occuring
2) Inorganic solid
3) ordered internal molecular structure
4) Definite chemical structure

49
Q

What is a rock?

A

A solid aggregate of minerals

50
Q

Is water a mineral?

A

Yes and no. When liquid or gas, it is not a mineral. When solid, yes.