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earth science period 4 > History of Earth Benchmark > Flashcards

History of Earth Benchmark Flashcards

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1
Q

How old is our earth?

A

4.54 to 4.65 billion years old

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2
Q

How does the earth change?

A

Biologically and Geographically

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3
Q

How did accretion form the earth?

A
  1. Fast Planetesimals collide
  2. Kinetic energy because heat energy
  3. Rising heat melts it all together
  4. Differentiation sorts material by density making layers
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4
Q

How did moon form?

A

Giant impact. Mars sized planet named Theia impacted earth. Some of pieces blasted off earth making the moon.

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5
Q

What degree is earth’s axis?

A

23.5

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6
Q

What does earth being tilted do?

A

Affects climate

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7
Q

How did volcanos create the atmosphere and ocean?

A
  1. mixture of metals, nonmentals and gasses
  2. They erupt and release these
  3. volcanic outgassing released 1/2 of ocean water and carbon dioxide in air.
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8
Q

How did comets and meteorites create the atmosphere and ocean?

A

Hit earth and release 1/2 of all water and most gasses we need here.

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9
Q

What was the most important thing brought to earth by comet?

A

Nitrogen.

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10
Q

What is the greatest oxygenation event?

A

The formation of oxygen by photosynthetic cyanobacteria between 2.4 and 2.0 billion years ago.

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11
Q

Oxygen bonded with iron in the ocean water causing what to form?

A

Rust.

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12
Q

What happened when the iron was rusted out of the ocean?

A

Oxygen filled the atmosphere and ocean.

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13
Q

What are colonies of cyanobacteria?

A

Stromatolites

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14
Q

What does BIF stand for?

A

Banded Iron Formations

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15
Q

What is a BIF?

A

Rocks produced from rust in ocean.

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16
Q

The iron in our steel comes from what?

A

BIF

17
Q

What are mass extinctions?

A

Changes on Earth that wipe out large amounts of living things.

18
Q

What can cause most mass extinctions?

A
  1. Volcanic Eruptions
  2. Ocean Currents
  3. Climate
  4. Ice Ages
19
Q

How else can mass extinctions be caused?

A

Comets and meteorites

20
Q

What is catastrophism?

A

earth changes suddenly and violently with storms, floods, meteorites, volcanic eruptions, earthquakes

21
Q

What is uniformitarianism?

A

Earth changes suddenly with rock cycle, plate tectonics, ice age.

22
Q

What is relative age dating?

A

Figuring out which rock is more aged than another. NOT putting a specific time on it.

23
Q

Law of original horizontality?

A

all sedimentary rocks are deposited in flat sheets covering large land areas

24
Q

law of superposition?

A

Oldest rock should be at bottom, youngest at top

25
Q

Unconformities?

A

missing gaps in the rock record
1. Rock is eroded
2. Time passes
3. New rock is deposited

26
Q

angular unconformities?

A

flat layers of rock on top of tilted ones

27
Q

disconformities?

A

Clear erosion between two layers of horizonal flat rocks

28
Q

Nonconformities?

A

sedimentary rock on top of of either igneous or metamorphic rock

29
Q

What is absolute age dating?

A
  1. Puts an actual age on something
  2. Both organic remains (carbon dating) and igneous rocks
  3. uses radioactive atoms
30
Q

What is radioactive decay?

A
  1. radioactive atoms (parent atoms) don’t stay radioactive
  2. Lose proteins from nucleus (the decay)
  3. lose a protein it’s called daughter atom
31
Q

How many types of radioactive decay are there?

A

3

32
Q

What is a decay rate?

A

Time it takes one radioactive atom to decay

33
Q

Why do decay rates start out fast and slow down?

A

More atoms at the beginning

34
Q

What is half life?

A

When half of radioactive atoms have decayed

35
Q

Do half lives change?

A

No

36
Q

Does it matter how many atoms there are with half life?

A

No

37
Q

How did we put an age on the earth?

A

We compared uranium to igneous rocks on the moon, earth, and meteorites to determine half life

38
Q

How old is the earth?

A

4.54 billion years old

earth science period 4 (2 decks)

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