Question 1

The Paleoproterozoic shift at about 1.85 billion years ago from banded-iron formations to red beds signals the

Accepted Answer

A)   demise of the cyanobacteria and the rise of the eukaryotic algae.
B)   effects of the gigantic asteroid impact at Sudbury and its global ejecta.
C)   buildup of significant oxygen in the atmosphere and oceans.
D)   transition from flysch to molasse deposition in many large basins.

Question 2

__________ is a continental craton that was NOT part of Gondwanaland.

Accepted Answer

A)   Africa
B)   Laurentia
C)   South America
D)   Australia B

Question 3

The bilaterally symmetrical soft-bodied Ediacaran fossil Kimberella is thought to represent the modern __________ group.

Accepted Answer

A)   ecdysiozoan
B)   lophotrochozoan
C)   deutorozoan
D)   dinoflagellate

Question 4

Until at least halfway through Paleoproterozoic (about 1.2 billion years ago) , the main producers in Earth's marine ecosystems were

Accepted Answer

A)   dinoflagellates.
B)   multicellular algae.
C)   eukaryotic algae.
D)   bacteria, including cyanobacteria.

Question 5

The Proterozoic orogeny that built mountains along the east coast of North America is called

Accepted Answer

A)   Wopmay.
B)   Trans-Hudson.
C)   Grenville.
D)   Cordilleran.

Question 6

In the Rodinia of 800 million years ago, the area of Laurentia is bordered on the east by

Accepted Answer

A)   South China.
B)   Grenville orogenic belt.
C)   Antarctica.
D)   Australia.

Question 7

The Wopmay orogeny, involving the Slave craton and an island arc, tells us that

Accepted Answer

A)   the Proterozoic crust was still hot and plastic like the Archean crust.
B)   there were no glaciers were present on Earth at this time.
C)   Proterozoic orogenies are much like Phanerozoic orogenies.
D)   it does no good to look for Proterozoic flysch and molasse deposits.

Question 8

The Ediacaran fossil with three-fold symmetry that may be related to modern echinoderms with five-fold symmetry is

Accepted Answer

A)   Charnia.
B)   Dickinsonia.
C)   Tribrachidium.
D)   Mawsonites.

Question 9

What evidence below does NOT suggest that the Wopmay orogen had the same pattern of formation as a modern orogenic system?

Accepted Answer

A)   There is a succession of parallel igneous, metamorphic, and fold-and-thrust belts occurred.
B)   Shallow shelf deposits are covered by molasse deposits, which lie upon flysch deposits.
C)   Within fold-and-thrust belts, flysch deposits are succeeded upward by shallow-water shelf deposits.
D)   Enormous stromatolite mounds grew at the top of lagoonal dolomite sequences.

Question 10

In the Wopmay orogenic sequence of sediments, the oldest sediments are

Accepted Answer

A)   quartz sandstone that grades westward into deep-water mudstones and turbidites.
B)   flysch deposits, mainly turbidites, overlain by mudstones.
C)   river deposits with conspicuous cross-bedding.
D)   carbonate rocks that contain abundant stromatolites. A

Question 11

The main exposed part of the North American craton (Laurentia) , which was assembled from at least five microcontinents between 1.95 and 1.85 billion years ago, is called the

Accepted Answer

A)   Appalachian orogen.
B)   Cordilleran orogen.
C)   Canadian shield.
D)   Colorado plateau.

Question 12

The Ediacaran fossil Spriggina was likely an early form of

Accepted Answer

A)   fish.
B)   arthropod.
C)   mollusk.
D)   cnidarian.

Question 13

Cap carbonates resting directly on all three Neoproterozoic tillites indicate that perhaps

Accepted Answer

A)   glaciers of "snowball Earth" reached the tropics.
B)   submarine volcanism ceased and with it carbon dioxide release as well.
C)   there was a mass extinction occurred among the cyanobacteria.
D)   frozen methane hydrates suddenly thawed out.

Question 14

The Proterozoic Keweenawan basalts

Accepted Answer

A)   covered much of the Canadian Shield.
B)   formed in the closing ocean between Greenland and Canada.
C)   formed in the island arc that collided with the Slave Province.
D)   erupted in a great, elongate rift that could have pulled North America apart.

Question 15

The great Proterozoic supercontinent, which was split apart beginning about 720 million years ago, is called

Accepted Answer

A)   Nuna.
B)   Rodinia.
C)   Pannotia.
D)   Gondwanaland.

Question 16

In Neoproterozoic rocks about 570 million years old, evidence of multicellular animal life called the Ediacara fauna consists of

Accepted Answer

A)   imprints of soft-bodied organisms.
B)   resting stages (or cysts)  of dinoflagellates.
C)   trace fossils, imprints of soft-bodied fossils, and skeletal fossils.
D)   small skeletonized animals. A

Question 17

The Paleoproterozoic buildup of atmospheric oxygen resulted in

Accepted Answer

A)   resumed deposition of banded-iron formations.
B)   deposition of limestones with isotopically heavy carbon.
C)   oxidation of vast amounts of organic carbon.
D)   climatic change that brought on "snowball Earth."

Question 18

Cratons of modern proportions first began to form during

Accepted Answer

A)   Neoproterozoic.
B)   Mesoproterozoic.
C)   Paleoproterozoic.
D)   Late Archean.

Question 19

Africa was assembled in the Pan-African orogeny during

Accepted Answer

A)   Neoproterozoic.
B)   Mesoproterozoic.
C)   Paleoproterozoic.
D)   Archean.

Question 20

The 1.85-billion-year-old Sudbury impact crater contains

Accepted Answer

A)   spherical, sand-sized grains that were originally glassy.
B)   megabreccia and shatter cones.
C)   large, elongate clasts that formed as airborne globs of melted material.
D)   banded iron formations and cherts.

Exam 12: The Hadean and Archean Eons of Precambrian Time

The Paleoproterozoic shift at about 1.85 billion years ago from banded-iron formations to red beds signals the

Correct AnswerverifiedShow Answer

__________ is a continental craton that was NOT part of Gondwanaland.

Correct AnswerverifiedB

The bilaterally symmetrical soft-bodied Ediacaran fossil Kimberella is thought to represent the modern __________ group.

Correct AnswerverifiedShow Answer

Until at least halfway through Paleoproterozoic (about 1.2 billion years ago) , the main producers in Earth's marine ecosystems were

Correct AnswerverifiedShow Answer

The Proterozoic orogeny that built mountains along the east coast of North America is called

Correct AnswerverifiedShow Answer

In the Rodinia of 800 million years ago, the area of Laurentia is bordered on the east by

Correct AnswerverifiedShow Answer

The Wopmay orogeny, involving the Slave craton and an island arc, tells us that

Correct AnswerverifiedShow Answer

The Ediacaran fossil with three-fold symmetry that may be related to modern echinoderms with five-fold symmetry is

Correct AnswerverifiedShow Answer

What evidence below does NOT suggest that the Wopmay orogen had the same pattern of formation as a modern orogenic system?

Correct AnswerverifiedShow Answer

In the Wopmay orogenic sequence of sediments, the oldest sediments are

Correct AnswerverifiedA

The main exposed part of the North American craton (Laurentia) , which was assembled from at least five microcontinents between 1.95 and 1.85 billion years ago, is called the

Correct AnswerverifiedShow Answer

The Ediacaran fossil Spriggina was likely an early form of

Correct AnswerverifiedShow Answer

Cap carbonates resting directly on all three Neoproterozoic tillites indicate that perhaps

Correct AnswerverifiedShow Answer

The Proterozoic Keweenawan basalts

Correct AnswerverifiedShow Answer

The great Proterozoic supercontinent, which was split apart beginning about 720 million years ago, is called

Correct AnswerverifiedShow Answer

In Neoproterozoic rocks about 570 million years old, evidence of multicellular animal life called the Ediacara fauna consists of

Correct AnswerverifiedA

The Paleoproterozoic buildup of atmospheric oxygen resulted in

Correct AnswerverifiedShow Answer

Cratons of modern proportions first began to form during

Correct AnswerverifiedShow Answer

Africa was assembled in the Pan-African orogeny during

Correct AnswerverifiedShow Answer

The 1.85-billion-year-old Sudbury impact crater contains

Correct AnswerverifiedShow Answer

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