QUESTIONS

Questions to be answered prior to Class 4, based on Reading "The Proterozoic Eon" (Chapter 4) in A Short History of Planet Earth: Mountains, Mammals, Fire and Ice, by J.D. Macdougal.

When did the Proterozoic Eon occur and how much of Earth’s history does it encompass?

How much of Earth’s history is encompassed in the Archean and Proterozoic Eons collectively?

What fundamental change was attributable to the abundance of stromatolites ?

What is uniformitarianism and who proposed it?

In what gases were the Archean atmosphere enriched?

What is the present day percentage of O₂ in our atmosphere?

Describe the mineral composition of Early Proterozoic, iron-rich rocks.

Why are these minerals not deposited in near surface environments today?

Describe the composition and age of most of Earth’s Banded Iron Formations (BIFs)?

Describe three lines of evidence for an oxygen poor Early Proterozoic environment.

When did the atmospheric O₂ concentration increase significantly?

When did glaciation affect the Proterozoic Earth?

What evidence suggests a Proterozoic glaciation

Describe the evolution of continents from the Archean to the Proteozoic.

Describe the life forms in the:             Archean-

                                                         Early Proterozoic-

                                                         Late Proterozoic-

On what basis did Paul Hoffman suggest a collision of the NW Territories?

Describe the event and supportive evidence for tectonism in the Lake Superior region 1.2-1.3 bya

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