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GEOL 240 The Dinosaurs: Origin of Life and Fossil Record

GEOL 240 The Dinosaurs: Origin of Life and Fossil Record. Summary. Introduction to Plate Tectonics. Plate Tectonics. Relatively new theory - introduced about 30 years ago Unifies several branches of the Earth Sciences http://pubs.usgs.gov/publications/text/dynamic.html.

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GEOL 240 The Dinosaurs: Origin of Life and Fossil Record

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  1. GEOL 240 The Dinosaurs:Origin of Life and Fossil Record

  2. Summary • Introduction to Plate Tectonics

  3. Plate Tectonics • Relatively new theory - introduced about 30 years ago • Unifies several branches of the Earth Sciences • http://pubs.usgs.gov/publications/text/dynamic.html

  4. In 1858, geographer Antonio Snider-Pellegrini made these two maps showing his version of how the American and African continents may once have fit together, then later separated.

  5. Alfred Lothar Wegener • Developed the Theory of Continental Drift • Published “Die Entstehung der Kontinente und Ozeane” in 1915

  6. BUT - • NO MECHANISM !!!

  7. Mid-Ocean Ridges

  8. Seafloor Spreading

  9. Paleomagnetism

  10. Magnetic Striping

  11. Continental Drift +Seafloor Spreading +A few refinements = PLATE TECTONICS

  12. All Plates are surrounded bya combination of three differenttypes of boundaries • Divergent • Convergent • Transform

  13. Divergent Boundary

  14. Mid-Ocean Ridges

  15. Continental Rift Systems

  16. Convergent Boundary • Three Types • Ocean-Ocean Collision • Continent-Ocean Collision • Continent-Continent Collision

  17. Ocean-Ocean Collision

  18. Ocean-Continent Collision

  19. Continent-Continent Collision

  20. Transform Boundry

  21. Satellite measurements of plate movement

  22. Formation and Differentiation of the Earth

  23. Hadean and Archean Eons

  24. Archean (until 2.5 BYA) • Atmosphere composed of methane, ammonia, hydrogen and very little oxygen • Very primitive life – bacteria and stromatolites (3.4 –3.5 billion years ago) - prokaryotes • Cratons of significant size begin to form approximately 3 billion years ago

  25. Prokaryotes • individuals (not colonial) • single celled • no nucleus • no partitions • Originally heterotrophic (ate others)

  26. Autotrophs (organisms capable of creating their own food i.e. photosynthesis) appeared about 2 bya. • Originally referred to as blue-green algae they are actually closer to bacteria and are photosynthetic prokaryotes

  27. stromatolites

  28. Proterozoic • EON • Moderate levels of • oxygen in the atmosphere • were reached about • 2 billion years ago • Oldest multicellular life • ~1.3 bya • Stable continents form

  29. Eukaryotic Organisms • evolved ~1.7 bya • have nucleus and internal chambers called organelles w/ specific functions • unicellular, colonial or multicellular • Introduction of Sexual Reproduction ! • Multicellular “animal” life evolved ~670 Mya

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