Brainscape's Knowledge GenomeTM

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


See full index

Geology 1404 > Unit 5 Poss. Test Questions > Flashcards

Unit 5 Poss. Test Questions Flashcards

1
Q

How do we use the name Precambrian?

A

Precambrian is an informal name for the earliest chapter in Earth’s history.

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

Which range of Earth’s history is represented by the Precambrian, in BY (billions of years)?

A

?

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

Which two rock types represents most of the Precambrian outcrop surfaces?

A

Igneous and Metamorphic rocks.

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

What type of fossil is most representative of the Precambrian?

A

Very few fossils are found in the Precambrian; most are single-cell organisms.

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

Where is found the largest North American Precambrian exposure?

A

The largest North American exposure is found around the Hudson Bay, Canada.

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

Where can we find exposures of Precambrian rocks in Texas?

A
  • Llano area
  • Central TX
  • Carrizo Mt. near Van Horn, TX
  • Franklin Mts. at El Paso, TX
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do we use the term “basement rocks”?

A

Usual name for Precambrian rocks.

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

Define a (Precambrian) shield.

A

Exposed portion of the basement of a continent that is composed of Precambrian rocks.

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

Define a platform.

A

“Buried” or covered surfaces of a shield.

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

Define a craton.

A

A craton is the nucleus of a continent made up of a shield and a platform.

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

What is the Canadian Shield?

A

The exposed portion of the North American craton.

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

What are the only representative “rocks” for the very beginning of the Hadean Eon?

A

4.28 BY old rocks in Nuvvuagittuq greenstone in Ungava, Quebec, Canada.

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

What is Earth’s oldest “particle” known and its age in BY?

A

Dated at 4.404 BY, one zircon crystal represents the oldest particle on planet Earth.

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

What time period (BY) is represent by the Archean Eon?

A

Represents period of 4.0 BY - 2.5 BY.

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

Which country do we find Earth’s oldest crustal rocks?

A

The Acasta gneiss is Northern Canada.

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

Describe the effect of the moon on Earth’s surface and oceans during the Early Archean Eon.

A
  • Earth’s crust rose and fell 200 feet every day.

- The oceans were subjected to 1,000 foot tides.

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

When did a large number of meteorites stop pelting the Earth?

A

Meteorites continued to pelt the Earth until 3.8 BY.

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

What type of tectonic feature can create continental crust?

A

Convergent of oceanic crusts. Creates islands arcs.

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

Describe the rocks surrounding a typical Precambrian geologic province.

A

?

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

What is graywacke sandstone and what type of environment would it represent?

A

A sandstone called graywacke that shows a decrease in grain size from the bottom to the top of the bed and composed of abundant clay and volcanic rock fragments. Graywackes always form in deep waters either beyond a continental shelf or off an oceanic island.

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

What is a “greenstone”?

A

A greenstone is former volcanic and sedimentary rocks that are rich in chlorite.

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

What do greenstone belts represent?

A

Greenstone Belts are zones of rocks rich in chlorite.

23
Q

Where do we find United States’ oldest crustal rocks and what is the formation name?

A

In the Minnesota River Valley is the Morton Gneiss which is dated at 3.5 BY, thus holds the record as the oldest US rock.

24
Q

At what period of time was Earth’s first ice age (BY)?

A

At the beginning of the Early Proterozoic, Earth experienced its first ice age of continental glaciation (2.7 - 2.5 BY).

25
Q

What is a tillite? Sometimes it is also called a _____.

A

A tillite is a sedimentary deposit that includes rocks and boulders from icebergs. Sometimes it is also called a dropstone.

26
Q

How do we subdivide the Proterozoic Eon (using modifiers)?

A

Early, Middle, and Late.

27
Q

What are banded iron formations?

A

Banded Iron Formations (BIF) are alternating layers of iron oxides and chert deposited in the sea (chert is a type of quartz).

28
Q

Why do we no longer fin BIF after 2.0 BY?

A

After 2.0 BY there would be so much free oxygen (about 1%) that very minor dissolved iron would reach the ocean and there would be no more thick deposits of BIF.

29
Q

What tectonic event occurred near Missouri during the Middle Proterozoic Eon?

A

North America began ripping apart, withe the Mid-Continental Rift.

30
Q

What mineral resources do the Keweenawan basalts contain?

A

The Keweenawan basalts are famous because they contain enormous amounts of copper metal and silver metal.

31
Q

Which supercontinent was created with the Grenville Province?

A

The Grenville was formed by continental collisions during the formation of the supercontinent Rodinia, the first supercontinent (1.3 - 1.0 BY).

32
Q

How long was a typical day during the middle Proterozoic?

A

8 hour day.

33
Q

What famous Texas feature was created with the Grenville Province?

A

The central Texas (Llano area) “Enchanted Rock” granite mass was part of the 1.2 BY Grenville province.

34
Q

What is the snowball Earth theory?

A

The snowball theory is a time when the entire Earth was covered with ice.

35
Q

Which supercontinent was created during the Late Proterozoic Eon?

A

During this time the land masses recombined to form the supercontinent Pannotia (650 MY).

36
Q

All living matter is composed of at least four elements; What are the elements?

A

{CHON} All living matter is composed of chemical compounds of the elements Carbon, Hydrogen, Oxygen, and Nitrogen. {CHON}

37
Q

What is S.E.T.I?

A

Search for Extra-Terrestrial Intelligence.

38
Q

What would be a primordial soup?

A

A primordial soup is organic compounds, formed by a variety of processes, from molecules that accumulate in the shallow oceans.

39
Q

What is a microsphere?

A

Microspheres are simple organic molecules that show great organizational complexity.

  • Some contain more than 200 linked amino acids.
  • Some have been found forming near hot springs of volcanic vents.
  • Some can grow and divide but are not considered living.
  • Some scientist feel that the original life on Earth passed through a microsphere phase.
40
Q

How often has man been able to create life from chemicals?

A

Zero.

41
Q

What was Miller able to create?

A

Miller (1953) was able to create all 20 amino acids, using only methane, ammonia, water, hydrogen gas and a spark of electricity in a glass apparatus.

42
Q

What is meant by chemical fossils?

A

A chemical fossil is fossil life detected by using non-radioactive isotopes of C12/C13 from “carbon films”.

43
Q

What is the difference between an autotroph and a heterotroph?

A

Autotrophs create their own food. Heterotrophs eat autotrophs for food.

44
Q

What is cyanobacteria?

A

Cyanobacteria are aquatic bacteria that uses photosynthesis.

45
Q

In what type of rock are most very early Precambrian fossils found?

A

Most are found in black chert.

46
Q

What is the approximate age (BY) of some of the oldest body fossils found?

A

Some of the next-oldest body fossils discovered are filaments of cyanobacteria aged at 3,465 BY, found withing the Warrawoona Group in Australia.

47
Q

What are stromatolites?

A

Stromatolites are cyanobacteria and other bactera that form colonial associations.
-Mound-like structures consisting of laminated carbonate rock produced by trapping of sediments by groups of organisms (cyanobacteria).

48
Q

What are Eukaryotes?

A

Eukaryotes are important in that they have more advanced cells than bacteria. {Eukaryotes have a nucleus}

49
Q

What are acritarchs?

A

Acritarchs are cysts of algae. In time of drought algae will create a cellular wall called a cyst to protect itself.

50
Q

Based on the fossil record, what represents the oldest known multicellular organism?

A

2.1 BY multicellular algae in Michigan with the Negaunee Iron Formation.

51
Q

What are metazoans?

A

Individual cells would clump together and form multicellular animals (metazoans). {and plants (metaphytes}

52
Q

What type of fossil evidence do we have for very old metazoans?

A

Animal Burrows, aged at 1.2 BY have been found in Australia and West Texas (during Rodinia).

53
Q

What are Ediacaran fossils?

A

Ediacaran fossils were soft-bodied creatures with no jaws and there were no predators.

54
Q

Describe the climatic environment where Ediacaran organisms lived.

A

The Ediacaran fauna existed in shallow, cold water marine environments, between 750 MY - 520 MY.

Geology 1404 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions