430 likes | 783 Views
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. ”
E N D
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.” “The past is the key to the present.”
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)
Paleoenvironment Present-Day environments ? Yazoo River Aerial view Cross section
Paleoenvironment Present-Day environments ? Mississippi Delta Aerial view Cross section
Paleoenvironment Present-Day environments ? Outer Banks Aerial view Cross section
Clues Within the Sediment I Minerals? Grain size? Grain sphericity? Grain sorting? Matrix?
Clues Within the Sediment II Planar Bedding Cross Bedding Ripple Bedding Imbrication Graded Bedding Cut and Fill
Ancient Stream Deposit Graded Bedding in a modern stream deposit
Paleoenvironment The Geological record Paleozoic deltaic deposits in Tennessee
Paleoenvironment The Geological record Paleozoic meandering stream deposits in Pennsylvania
Paleoenvironment The Geological record Eocene barrier island deposits in South Carolina
Paleoenvironment The Biological Record Wright whale 40 Ma whale skeleton, Egypt
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
Climate Present-Day Climates? Alpine/Polar (glaciers) Desert (dune fields)
Paleoclimate The Geological Record Alpine/Polar (morraines) Desert (aeolean sandstone)
Paleoclimate The Biological Record trees & other plants woolly mammoth
PaleoclimateChemical records foraminifera Ice cores Scallops & other mollusks
Chemical records – oxygen 18 Temperature Fluctuation Based on O-18 analyses
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
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
PaleontologyTypes of Fossils Body Fossils Carbon Films Molds & Casts
PaleontologyPresent-Day Equivalents? Tiger skull dragonfly Scallop
Ancient EcologiesPaleoecology Interactions among living organisms living within a particular ancient environment. Understanding gained through the: • study of modern ecologies • examination of fossils
Ecology Great Barrier Reef, Australia
Reconstructing Paleoecology Study Rock Exposures Niobrara Formation (85 Ma), Kansas
Reconstructing Paleoecology Determine Depositional Environment Niobrara Sea (85 Ma), North America
Reconstructing Paleoecology Collect and Study Fossils Ammonite Mosasaur Plesiosaur
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
Paleobiology Pierre Sea (72 Ma), South Dakota
Paleobiology Pierre Sea (72 Ma), South Dakota
Paleobiology/Paleoecology Baby mammoth – permafrost (40 Ka), Siberia, Russian Federation