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Earth

Earth. Exact Age of Earth: _______. Geologic Dating Methods I: Radioactive Decay. http://www.btinternet.com/~j.doyle/SR/Emc2/decay_a-decay.gif. Geologic Dating Methods II: Known Rates of Radioactive Decay. http://people.hofstra.edu/j_b_bennington/2cnotes/halflife.JPG.

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Earth

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  1. Earth Exact Age of Earth: _______

  2. Geologic Dating Methods I: Radioactive Decay http://www.btinternet.com/~j.doyle/SR/Emc2/decay_a-decay.gif

  3. Geologic Dating Methods II: Known Rates of Radioactive Decay http://people.hofstra.edu/j_b_bennington/2cnotes/halflife.JPG

  4. Radiocarbon half-lifes Geologic Dating Methods III: Ratios of Parent : Daughter Atoms

  5. EARTH’S OLDEST ROCKS 4.03 BYA (Acosta Gneisses) 3.7 – 3.8 BYA 3.4 – 3.5 BYA 3.4 – 3.6 BYA http://pubs.usgs.gov/gip/geotime/age.html

  6. Earth’s Oldest Known Rocks (Probably do NOT date to Earth’s Formation)

  7. Geologic Forces(e.g., Plate Tectonics)

  8. Origin of Solar System

  9. IRON METEORITES(Canyon Diablo) Age: 4.53-4.58 BYA (U > Pb) http://pubs.usgs.gov/gip/geotime/age.html

  10. Canyon Diablo Crater(Near Flagstaff AZ)

  11. LUNAR ROCKS Oldest Moon Rocks: 4.4-4.5 BYA http://pubs.usgs.gov/gip/geotime/age.html

  12. Earth’s Origin (~ 4.5-4.6 BYA)

  13. 500 Million Years After Origin of Earth (Artistic Rendition) http://www.arcadiastreet.com/cgvistas/earth/images/earth_ancient_volcano_600.jpg

  14. The Earth Cools (Artistic Rendition) http://www.cartage.org.lb/en/themes/Sciences/Paleontology/Paleozoology/Precambrian/Precambrian.htm

  15. Ancient Evidence for Free Oxygen • Isua Rock (Greenland): ~ 3.7 Billion Years Old • Metamorphosed Sediments • Abundant Free Uranium – Likely Only in • Oxidizing Environment

  16. Oxygen Liberating Process?

  17. Ancient Fossil “Cyanobacteria”(3.47 BYA) Apex Chert in Western Australia (Pilbara Formation) http://marsfossil.home.netcom.com/images/pilbara_detail.jpg

  18. Fossil Stromatolites(3.5 BYA)

  19. Living Stromatolites(Shark Bay Australia)

  20. Stromatolite Formation Fig. 2.8 in Willis and McElwain 2002

  21. Living Stromatolites(Cross-Section)

  22. Fossil Stromatolites (with Fossil Microorganisms) Gunflint Chert – Ontario, Canada (2 BYA)

  23. Origin of the Cell?

  24. Origin of Organic Macromolecules?

  25. Hypothesis I: Terrestrial Accretion (Miller – Urey Experiments 1950s)

  26. Origin of Cell Membrane?

  27. Hypothesis: Drying, Rehydrating of Tide Pools Fig. 2.4 in Willis and McElwain 2002

  28. Hypothesis II: Meteoric and Cometary Infall of Organic Molecules formed Elsewhere (Present Day Meterites can contain 1% Organic Molecules)

  29. Hypothesis III: Meteoric and Cometary Infall of Cells formed Elsewhere (e.g., Mars)

  30. Reduced Rocks Predominantly Non-Oxidized Sediments

  31. Ancient Evidence for Free Oxygen • Isua Rock (Greenland): ~ 3.7 Billion Years Old • Metamorphosed Sediments • Abundant Free Uranium – Likely Only in • Oxidizing Environment

  32. Banded Iron Formations (Up to 3.7-3.8 Billion Years Ago) Evidence for Pulses of Free Oxygen

  33. Red Beds (Up to 2.3 Billion Years Ago) Evidence for Free Oxygen Accumulation

  34. Heterocysts (Up to 2.1 Billion Years Ago) Microbiology 155 (2009), 1418-1426

  35. Atmospheric Oxygen Levels http://ncbi.nlm.nih.gov

  36. Fossil Eukaryotic Cells (2.1 – 1.1 BYA) Grypania ciliaris (Alga) in Northern Michigan

  37. Fossil “Red Alga” in Arctic Canada (1200 MYA) “Bangia” Figs. 2.12 in Willis and McElwain 2002

  38. Fossil “Green Alga” in Spitsbergen (800-700 MYA) “Cladophora” Fig. 2.14 in Willis and McElwain 2002

  39. Fossil Tetrads (> 470 MYA) Bitter Springs Formation, Australia

  40. Cooksonia (420 MYA)

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