Proterozoic Geology

Question 0

What process marks the beginning of the Proterozoic eon?

Answer 0

The beginning of modern plate tectonics.

Question 1

How long was the Proterozoic eon?

Answer 1

2 billion years

Question 2

How was the atmosphere different in the Proterozoic from earlier eons?

Answer 2

It was oxygenated

Question 3

The continent Laurentia is made of modern day

Answer 3

Greenland and North America

Question 4

Subdivisions of Proterozoic Eon

Answer 4

–Beginnings of ‘modern’ tectonics
–Oxygenation of the atmosphere
–First major global glaciations
–Evolution of multicellular life

Question 5

When did the first multicellular life evolve?

Answer 5

1.2 billion years ago

Question 6

What is special about ediacaran fauna

Answer 6

preservation, structure

Question 7

Proterozoic life/fossils is made up mostly of

Answer 7

soft bodied organisms and trace fossils

Question 8

common Proterozoic life

Answer 8

stromatolites, algae, microbial mats…. covered most underwater substrates

Question 9

Kenorland lasted from

Answer 9

2.7 - 2.1 Ga

Question 10

Kenorland formed when?

Answer 10

End of Archean

Question 11

Huronian Glaciation

Answer 11

First major glacial episode corresponds to Kenorland supercontinent stage

Question 12

Laurentia corresponds to

Answer 12

North American craton

Question 13

Sandstone - shale - carbonate assemblages are characteristic of

Answer 13

passive margins

Question 14

Supercontinent Columbia existed during what time period

Answer 14

1.8 - 1.6 Ga

Question 15

What is significant about the Grenville orogeny?

Answer 15

It involved the formation of the supercontinent Rodinia.

Question 16

When did the Grenville orogeny occur?

Answer 16

1.3 - .9 Ga

Question 17

When did Supercontinent Rodinia exist?

Answer 17

1.1 - .75 Ga

Question 18

What was significant about Rodinia?

Answer 18

first real supercontinent - all major cratons were involved

Question 19

When did the cryogenian glaciation occur?

Answer 19

800 - 635 Ma

Question 20

What significant climatic period occurred during the cryogenian?

Answer 20

Snowball earth - glaciers extended to equator

Question 21

What caused the “snowball earth” phase?

Answer 21

runaway icehouse, continental distribution, high oxygen/low CO2

Question 22

When did Supercontinent Pannotia exist?

Answer 22

600 - 540 Ma

Question 23

Why was Pannotia significant

Answer 23

formation of Phanerozoic continents

Question 24

When did the great Oxygenation event occur

Answer 24

approximately 2.4 billion years ago

Question 25

What is evidence for the increase of oxygenation in the atmosphere?

Answer 25

banded iron formations

occurred typically in silica rich sediments - chert