Review Questions for 3^rd Test

Earth History and Global Change

GEOL 1122 – Fall 2009

Section #1 Proposed Origins and the Precambrian

(Readings - Chapter 19)

1) Define the Universe. What is the proposed age, dominant composition and size of the Universe? Describe Obler’s Paradox and what it tells us about the Universe.

2) What is the Big Bang Theory? Describe the evidence that supports this theory?

3) What is a light year? How is it measured? Why is it used to describe sizes of galaxies? How far away from the Earth is the Moon in light years.

4) Describe the shape, size, and the major components of our galaxy. What is the name of the closest galaxy?

5) What is the Nebular (Solar Nebula) Hypothesis? Describe the solar system characteristics that are explained by the theory. Describe the characteristics of earth that are explained by the theory.

6) What is estimated age, proposed origin, and current stage of development of our Sun?

7) What is pre-geologic time? Why is it called Hadean Time? What is the basis for the proposed 4.6 BY age for the Earth? What were conditions like on Earth at this time relative to climate, atmosphere and length of the day? Why is so little known about this earliest part of Earth history? Why was volcanic degassing so important during this time?

8) What are the two major subdivisions of the Precambrian? Describe the basis for these subdivisions. How much of Earth history does the Precambrian represent?

9) What are greenstone belts? What are the major components of these belts? Describe the geologic evidence that indicates how they formed.

10) The early Earth's atmosphere was apparently anaerobic. What does this mean? Describe the geologic evidence that supports this idea? What is the significance of uranite- and sulfide-rich Archean sediments?

11) When did the atmosphere become enriched in oxygen? Describe the evidence for this increase. Describe how photochemical dissociation and photosynthesis were probably responsible for increased oxygen levels. When and how did the ozone layer form?

12) How are we currently changing the atmosphere? Describe the likely consequences of these changes.

13) What are granulites? How did these and the other Archean granitic gneisses form? What do these rocks indicate about the Earth's environment, especially the crust in the early Precambrian?

14) How did the landmasses of the Archean differ from those of the Proterozoic? Describe the geologic evidence that indicates that the Archean landmasses were so different.

15) Describe the various Proterozoic rock types that indicate large stable continental landmasses existed at this time.

16) What are the 4 elemental components of all living things? What are the 5 principle compounds and their functions?

17) What are chemosynthesizers? Why are these believed to be the oldest life forms? Where are chemosynthesizers commonly found today?

18) Compare and contrast monomers and polymers. Name examples of each. What is the significance of Miller's experiments and the carbonaceous material on certain meteorites?

19) Describe the earliest fossil traces of life that are found in the Archean. How does the Archean fossil record differ from the fossil record of the Proterozoic?

20) What are stromatolites? How do they form? What is their significance in the fossil record? How could they have altered the earth's environment? What effect did the formation of vast carbonate rock formations (limestone) have on the Earth's early atmosphere?

21) What fossil evidence is there to support the idea that eukaryotes were present in the Proterozoic? Why would evolution occur at a much faster rate after the appearance of eukaryotes?

22) Describe the Edicarian Fossils. Why were these fossils important? When did they appear? 23) Define the following terms: Doppler or Redshift Effect, background radiation, Milky Way, Andromeda, meteorites, Archean, Proterozoic, banded‑iron formation, redbeds, orogenic belt, blue‑green algae, Gondwana, prokaryotes, eukaryotes, cyanobacteria and proteinoids.

Section #2 ‑ The Paleozoic Earth History

(Readings - Chapter 20)

1) How is the Cambrian‑Precambrian boundary recognized? How did the presence of broad shallow epicontinental (epeiric) seas contribute to this change?

2) What are cratonic sequences? Why are they commonly separated by a continent-wide unconformity? What is sequence stratigraphy? Are the similar rock types within a sequence always deposited at the same time at the different geographic locations?

3) What caused the substantial changes in sea level and flooding events during the Paleozoic? Why are evaporites commonly associated with the regression?

4) What was the Taconic Orogeny? Which continents were involved? What evidence is there for this collision?

5) Describe the conditions and deposits associated with the Silurian Seas. How did the Silurian Iron Ores form during this time?

6) Describe the Chattanooga Shale. What environmental changes must have occurred during the deposition of this widespread unit? What are some of the economic deposits associated with this black shale?

7) Compare and contrast the Appalachian and Acadian Orogenies. Which landmasses were involved in these collisions? How are these events recognized in the rock record?

8) What is a cyclothem? How do they form? Why are they so common in Pennsylvanian deposits? Why are they economically important?

9) What was Pangaea? How and when did it form?

10) Define the following terms: cratons, mobile belts, Iapetus, Pangaea, and Laurasia

*Learn the Eras and Periods of the Geologic Time Scale.

This will be a 10 point question on the test.