Download Ancient Environments

Ancient environments
Central Kansas - 80 Ma
Setting the Stage:
Major Erosional/Depositional ‘Provinces’
Understanding the distant past
by reconstructing:
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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
Which way did the
current flow?
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 Climates
Paleoclimate
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
foraminifera
Paleoclimate
Chemical records
Ice cores
Scallops & other mollusks
Chemical records – oxygen 18
Temperature Fluctuation Based on O-18 analyses
Sea Level Fluctuation Based on O-18 analyses
North America during last glacial maximum ~ 21 Ka
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 Life
Paleontology
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
Paleontology
Types of Fossils
Body Fossils
Carbon Films
Molds & Casts
Paleontology
Present-Day Equivalents?
Tiger skull
dragonfly
Scallop
Ancient Ecologies
Paleoecology
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
Niobrara Sea (85 Ma), Kansas
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