GEOL766: Earth Systems Change

Discussion T1: Thursday, Sept. 25 and Tuesday, Sept. 30, 2008 (Group 1: Bobby & James): Neoproterozoic oxidation and the origin of animal life

Suggested references: Have a glance at the papers first and then decide which ones you want to talk about. You can focus on a sub-topic that you understand the best. I'll give a brief summary in the discussion questions

Topic 1: The unusual "cap carbonate" phonomenon
Major references:
1. Hoffman, P.F., and Schrag, D.P., 2002, The snowball Earth hypothesis: testing the limits of global change: Terra Nova, v. 14, p. 129-155.

Other references concerning the origin of cap carbonates:
A. Transfer of atmospheric CO2 to ocean and formation of cap carbonates
2. Hoffman, P.F., Kaufman, A.J., Halverson, G.P., and Schrag, D.P., 1998, A Neoproterozoic snowball earth: Science, v. 281, p. 1342-1346.
3. Hoffman, P.F., Halverson, G.P., Domack, E.W., Husson, J.M., Higgins, J.A., and Schrag, D.P., 2007, Are basal Ediacaran (635 Ma) post-glacial "cap dolostones" diachronous?: Earth and Planetary Science Letters, v. 258, p. 114-131.
4. Bao, H., Lyons, J.R., and Zhou, C., 2008, Triple oxygen isotope evidence for elevated CO2 levels after a Neoproterozoic glaciation: Nature, v. 453, p. 504-506.
B. Methane release and cap carbonate anomaly
5. Kennedy, M.J., Christie-Blick, N., and Sohl, L.E., 2001, Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth's coldest intervals?: Geology, v. 29, p. 443-446.
6. Jiang, G., Kennedy, M.J., and Christie-Blick, N., 2003, Stable isotopic evidence for methane seeps in Neoproterozoic postglacial cap carbonates: Nature, v. 426, p. 822-826.
7. Jiang, G., Shi, X., and Zhang, S., 2006, Methane seeps, methane hydrate destabilization, and the late Neoproterozoic postglacial cap carbonates: Chinese Science Bulletin, v. 51, p. 1152-1173.
8. Wang, J.S., Jiang, G.Q., Xiao, S.H., Li, Q., and Wei, Q., 2008, Carbon isotope evidence for widespread methane seeps in the ca. 635 Ma Doushantuo cap carbonate in south China: Geology, v. 36, p. 347-350.
9. Kennedy, M., Mrofka, D., and von der Borch, C., 2008, Snowball Earth termination by destabilization of equatorial permafrost methane clathrate: Nature, v. 453, p. 642-645.
C. Microbially mediated oxidation and/or mineralization:
10. Rothman, D.H., Hayes, J.M., and Summons, R.E., 2003, Dynamics of the Neoproterozoic carbon cycle: PNAS, v. 100, p. 8124-8129.
11. Shields, G.A., 2005, Neoproterozoic cap carbonates: a critical appraisal of existing models and the plumeworld hypothesis: Terra Nova, v. 17, p. 299-310.
12. Font, E., Nedelec, A., Trindade, R.I.F., Macouin, M., and Charriere, A., 2006, Chemostratigraphy of the Neoproterozoic Mirassol d'Oeste cap dolostones (Mato Grosso, Brazil): An alternative model for Marinoan cap dolostone formation: Earth and Planetary Science Letters, v. 250, p. 89-103.

Topic 2: The oxidation of the Ediacaran oceans
Major references:
1. Logan, G.A., Hayes, J.M., Hieshima, G.B., and Summons, R.E., 1995, Terminal Proterozoic reorganization of biogeochemical cycles: Nature, v. 376, p. 53-56.
2. Rothman, D.H., Hayes, J.M., and Summons, R.E., 2003, Dynamics of the Neoproterozoic carbon cycle: PNAS, v. 100, p. 8124-8129.
3. Fike, D.A., Grotzinger, J.P., Pratt, L.M., and Summons, R.E., 2006, Oxidation of the Ediacaran Ocean: Nature, v. 444, p. 744-747.
4. Canfield, D.E., Poulton, S.W., Knoll, A.H., Narbonne, G.M., Ross, G., Goldberg, T., and Strauss, H., 2008, Ferruginous Conditions Dominated Later Neoproterozoic Deep-Water Chemistry: Science, v. 321, p. 949-952.

Other references concerning the oxidation of the Ediacaran ocean and origin of animals:
5. Des Marais, D.J., Strauss, H., Summons, R.E., and Hayes, J.M., 1992, Carbon isotope evidence for the stepwise oxidation of the Proterozoic environment, Nature, v. 359, p. 605-609.
6. Canfield, D.E., 1998, A new model for Proterozoic ocean chemistry: Nature, v. 396, p. 450-453.
7. Knoll, A.H., Carroll, S.B., Hanson, B., Chin, G., Sugden, A., and Culotta, E., 1999, Early animal evolution; emerging views from comparative biology and geology: Science, v. 284, p. 2129-2137.
8. Derry, L.A., 2006, Fungi, Weathering, and the Emergence of Animals : Science, v. 311, p. 1386-1387.
9. Kennedy, M., Droser, M., Mayer, L.M., Pevear, D., and Mrofka, D., 2006, Late Precambrian Oxygenation; Inception of the Clay Mineral Factory: Science, v. 311, p. 1446-1449.
10. Canfield, D.E., Poulton, S.W., and Narbonne, G.M., 2007, Late-Neoproterozoic Deep-Ocean Oxygenation and the Rise of Animal Life: Science, v. 315, p. 92-95.
11. McFadden, K.A., Huang, J., Chu, X., Jiang, G., Kaufman, A.J., Zhou, C., Yuan, X., and Xiao, S., 2008, Pulsed oxidation and biological evolution in the Ediacaran Doushantuo Formation: PNAS, v. 105, p. 3197-3202.
12. Shen, Y., Zhang, T., and Hoffman, P.F., 2008, On the coevolution of Ediacaran oceans and animals: PNAS, v. 105, p. 7376-7381.
13. Scott, C., Lyons, T.W., Bekker, A., Shen, Y., Poulton, S.W., Chu, X., and Anbar, A.D., 2008, Tracing the stepwise oxygenation of the Proterozoic ocean: Nature, v. 452, p. 456-459.