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Chapter 22 Precambrian Earth Studyguide Flashcards | StudBud
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Chapter 22 Precambrian Earth Studyguide
Chapter 22 Precambrian Earth Studyguide
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earth science studyguide ECK
Flashcards
10 cards
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Practice quiz
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Questions
10
Answers
1
Which areas of North America were most affected by the formation of the Canadian Shield
the southwest
the Pacific Coast
the Midwest
Alaska
2
When would oxygen start appearing in Earth's atmosphere?
1 billion years ago
600 million years ago
yesterday
550 million years ago
3
What process is primarily responsible for the formation of Earth's oceans?
outgassing
sea-floor spreading
evolution
plate tectonics
4
Which type of cell shown in the figure existed first?
both at same time
impossible to tell
B
A
5
How were asteriods and meteorites a heat source for Precambrian earth?
they sank to the core
b. their radioactive decay of isotopes made energy
gravitational contraction by them generated cooling
their impact on Earth generated energy
6
Why don't Archean and proterozoic rocks have iron oxides?
no iron existed
no free oxygen
stromatolites were taking over the world
too much iron around
7
The oldest rocks on Earth are_______________.
3.5 million years old
1-2 billion years old
3.8 to 3.96 billion years old
1.6 million years old
8
What was the original composition of earth's atmosphere?
hydrogen and helium
nitrogen
water vapor
ammonia
9
Minerals with
low
densities crystallize from magma at _____________ denser minerals do.
always 10 degrees less than
cooler temperatures than
hotter temperatures than
the same temperature as
10
In which era or eon did life first emerge?
Archean
Mesozoic
Paleozoic
Proterozoic
