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Ancient environments

Ancient environments. Central Kansas - 80 Ma. Setting the Stage: Major Erosional/Depositional ‘ Provinces ’. Understanding the distant past by reconstructing:. • Ancient environments • Ancient climates • Ancient life • Ancient ecosystems. “ The present is the key to the past. ”

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Ancient environments

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  1. Ancient environments Central Kansas - 80 Ma

  2. Setting the Stage: Major Erosional/Depositional ‘Provinces’

  3. Understanding the distant past by reconstructing: • Ancient environments • Ancient climates • Ancient life • Ancient ecosystems “The present is the key to the past.” “The past is the key to the present.”

  4. Ancient Environments Paleoenvironment A past environment (i.e., meandering stream, delta, ocean basin) that existed in a given area. Determined through the study of: • modern depositional systems • rocks & enclosing structures • biological remains (fossils)

  5. Paleoenvironment Present-Day environments ? Yazoo River Aerial view Cross section

  6. Paleoenvironment Present-Day environments ? Mississippi Delta Aerial view Cross section

  7. Paleoenvironment Present-Day environments ? Outer Banks Aerial view Cross section

  8. Clues Within the Sediment I Minerals? Grain size? Grain sphericity? Grain sorting? Matrix?

  9. Clues Within the Sediment II Planar Bedding Cross Bedding Ripple Bedding Imbrication Graded Bedding Cut and Fill

  10. Which way did the current flow?

  11. Ancient Stream Deposit Graded Bedding in a modern stream deposit

  12. Paleoenvironment The Geological record Paleozoic deltaic deposits in Tennessee

  13. Paleoenvironment The Geological record Paleozoic meandering stream deposits in Pennsylvania

  14. Paleoenvironment The Geological record Eocene barrier island deposits in South Carolina

  15. Paleoenvironment The Biological Record Wright whale 40 Ma whale skeleton, Egypt

  16. Ancient ClimatesPaleoclimate Temperature, humidity, rainfall, etc. in a given area during a particular ancient time interval. Determined through the study of: • modern climate • rocks & associated structures/fossils • chemistry

  17. Climate Present-Day Climates? Alpine/Polar (glaciers) Desert (dune fields)

  18. Paleoclimate The Geological Record Alpine/Polar (morraines) Desert (aeolean sandstone)

  19. Paleoclimate The Biological Record trees & other plants woolly mammoth

  20. PaleoclimateChemical records foraminifera Ice cores Scallops & other mollusks

  21. Chemical records – oxygen 18 Temperature Fluctuation Based on O-18 analyses

  22. Sea Level Fluctuation Based on O-18 analyses

  23. North America during last glacial maximum ~ 21 Ka

  24. Paleogeographic map & Paleotemperature distributions During the: Ord = Ordovician P/T = Permo-Triassic Cretac = Cretaceous PETM = Paleocene-Eocene Thermal Maximum LGM – Last Glacial Maximum LIA - Little Ice Age

  25. Ancient LifePaleontology Life that existed during a particular time interval in the distant past. Understanding gained through the: • examination of preserved remains (fossils) • comparison to living organisms

  26. PaleontologyTypes of Fossils Body Fossils Carbon Films Molds & Casts

  27. PaleontologyPresent-Day Equivalents? Tiger skull dragonfly Scallop

  28. Ancient EcologiesPaleoecology Interactions among living organisms living within a particular ancient environment. Understanding gained through the: • study of modern ecologies • examination of fossils

  29. Ecology Great Barrier Reef, Australia

  30. Reconstructing Paleoecology Study Rock Exposures Niobrara Formation (85 Ma), Kansas

  31. Reconstructing Paleoecology Determine Depositional Environment Niobrara Sea (85 Ma), North America

  32. Reconstructing Paleoecology Collect and Study Fossils Ammonite Mosasaur Plesiosaur

  33. Niobrara Sea (85 Ma), Kansas

  34. Paleobiology Study of the mode of life of organisms (i.e., how big an animal grew, how it moved, what it ate) “Fish-within-a-fish” – Niobrara Formation (85 Ma), Kansas

  35. Paleobiology Pierre Sea (72 Ma), South Dakota

  36. Paleobiology Pierre Sea (72 Ma), South Dakota

  37. Paleobiology/Paleoecology Baby mammoth – permafrost (40 Ka), Siberia, Russian Federation

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