Snowball

1. What is the Great Oxidation Event (GOE) and what specific, fundamental changes occurred in Earth’s atmosphere levels of oxygen at this time and why? 2. What samples and methods were used to date the GOE in the reports? What changes in the timing of the GOE emerge from the new results? 3. The report describes the role of chemical weathering in the GOE. Explain how chemical weathering contributed to the GOE? 4. What other changes in the composition of Earth’s atmosphere occurred in concert with the oxygenation associated with the GOE? (5 points; a strong answer will explain the importance of changes in the atmospheric concentrations of CH4 and CO2 that are associated with changes in oxygen levels.) 5. The reports make comparisons with later similar “Snowball Earth” episodes in Earth’s history. When did these later events occur, and what are the parallels between these events?