1. Geological and Biogeochemical Change in the Paleoproterozoic - Roger
Buick (2.5 wks)
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Geological indicators of the rise of oxygen:
o Terrestrial: Red beds, paleosols, detrital minerals (Fe/U mobility): (Rye & Holland, 1998; Rasmussen & Buick, 1999)
o Marine: Banded iron formations (BIFs) + manganese deposits (Kirschvink et al., 2000; Roy, 2000)
o Other: Consequences of Paleoproterozoic uranium mobilization
§ Natural nuclear reactors at Oklo, Gabon (Mossman, 2001; Gauthier-Lafaye & Weber, 2003).
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Paleoproterozoic biology
o Cyanobacteria
§ Microfossils (Hofmann, 1989),
§ Stromatolites (Buick, 1992)
§ Biomarkers (Summons et al., 1999)
o Eukaryotes
§ Acritarchs (Zhang, 1986, 1997; Knoll, 1992)
§ Biomarkers (Brocks et al., 1999)
o Macrophytes
§ Grypania (Han and Runnegar, 1992)
§ Macroscopic fossils in China, 1.7 Ga (Shixing and Huineng, 1995)
o Metazoans
§ Paleoproterozoic animals? (Seilacher et al., 1998; Rasmussen et al., 2002)
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Isotopic indicators of global change
o Carbon – d13C carbon isotopes through time:
§ light d13C organics at 2.8-2.6 Ga (Schoell & Wellmer, 1981; Hayes, 1994)
§ heavy d13C carbonate excursions at 2.4-2.2 Ga (Karhu & Holland, 1996)
o Sulfur - d34S sulfur isotopes through time
§ Increasing spread between seawater and pyrite (Canfield, 1996; Canfield et al., 2000)
§ The “Canfield” sulfidic ocean: theory and evidence (d34S, Mn isotopes) (Canfield, 1998; Anbar and Knoll, 2002)
o Nitrogen – d15N measurements (Beaumont and Robert, 1999)
Papers for student review, presentation and discussion:
i. Debate on rise of oxygen (consensus view, e.g. Holland (1999)) versus no rise of oxygen (Ohmoto, 1997)
ii. Discussion on earliest morphological evidence for cyanobacteria (Schopf, 1993, 2001 vs. Brasier et al. (2001)
iii. Discussion of Anbar and Knoll (2002) –the deeply sulfidic Proterozoic ocean hypothesis.
2. Atmospheric Change & “Snowball Earth” at 2.4-2.2 Ga - David Catling (2.5 wks)
- The
Archean-Proterozoic atmosphere & influence of the biosphere
o Atmospheric chemistry and structure before and after the rise of O2: The formation of the ozone layer
o The climatic role of methane
- Mass-independent isotope fractionation in sulfur
o Isotopic fractionation: Brief review
o Recent results (Farquhar and Wing, 2003; Pavlov & Kasting, 2002)
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The Rise of Oxygen: Theories and Issues
o What
are the current theories and research on why the rise of oxygen happened?
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Paleoproterozoic Snowball Earth: A review of the
evidence and theories
o Geological evidence for glaciation (Kirschvink et al., 2000; Feng et al., 2000; Hoffman and Schrag, 2002)
o Climate theory: the ice-albedo feedback (Budyko, 1969)
Papers for student review, presentation and discussion:
i. Farquhar & Wing (2003) – review of mass independent S isotopes
ii. Was there a Paleoproterozoic “Snowball Earth” and how would it jump-start evolution? A discussion of Kirschvink et al., 2000.
3. Microbial Evolution from Anaerobes to Aerobes - Jesse Dillon, Dave
Stahl, Jim Staley, John Leigh (2 wks)
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From anerobes to aerobes
o Anerobic metabolisms
§ Methanogenesis – John Leigh
(Deppenmeier, 2002)
§ Anaerobic photosynthesis – Jim Staley
§ Sulfate respiration – Dave Stahl
(Teske et al., 2003)
§ From anaerobic to oxygenic photosynthesis – Jesse Dillon
(Xiong et al., 2000; Green and Gantt, 2000; Blankenship and Hartman, 1998; Xiong and Bauer, 2002)
Papers for student review:
i. To be added
ii. To be added
4. Bioenergetic Throughput and Entropy in an Anerobic vs. Aerobic world -
David Catling (2 wks)
- Energy and metabolism thermodynamics
- Oxygen and metabolism
- Entropy in physics vs. entropy in information theory
- Linking it all together: Entropy and life
Papers for review:
i. To be added
ii. To be added
5. Weeks 10,11:
Presentations by students on term paper topics