The Bighorn Basin Coring Project BBCP: Climatic, biotic, and sedimentary dynamics during the early P

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The Bighorn Basin Coring Project (BBCP)
Climatic, biotic, and sedimentary dynamics during
the early Paleogene greenhouse
Will Clyde, Dept. of Earth Sciences, Univ of New
Hampshire, Durham, NH, 03824, (will.clyde_at_unh.edu)
Scott Wing, Dept. of Paleobiology, Smithsonian
Institution, Washington, DC (wings_at_si.edu) Philip
Gingerich, Museum of Paleontology, Univ of
Michigan, Ann Arbor, MI, (gingeric_at_umich.edu)

• Outline
• Why study the early Paleogene?
• Why focus on the Bighorn Basin?
• What can we learn?

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Paleocene- Eocene Thermal Maximum
Zachos et al., 2001
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Global distribution of marine PETM sites with
documented Carbon Isotope Excursion (CIE)
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Nunes and Norris, 2006
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PETM marine carbonate dissolution (ODP Leg 208
Walvis Ridge, SE Atlantic)
Zachos et al., 2005
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PETM carbon isotope excursion and marine
dissolution (ODP Leg 208 Walvis Ridge, SE
Atlantic)
Zachos et al., 2005
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PETM marine biotic effects benthic
foraminifera (ODP Site 865)
From Thomas, 1998
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PETM marine biotic effects planktic
foraminifera (ODP Site 865)
From Kelly et al., 1998
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PETM marine biotic effects Calcareous
nannoplankton
From Gibbs et al., 2006
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Global distribution of marine PETM sites with
documented Carbon Isotope Excursion (CIE)
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Global distribution of continental PETM sites
with documented Carbon Isotope Excursion (CIE)
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Beartooth Mtns
Big Horn Mtns
Bighorn Basin
Absaroka Mtns
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Beartooth Mtns
Big Horn Mtns
Bighorn Basin
Absaroka Mtns
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Beartooth Mtns
Big Horn Mtns
Bighorn Basin
Absaroka Mtns
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Beartooth Mtns
Big Horn Mtns
Bighorn Basin
Absaroka Mtns
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Beartooth Mtns
Big Horn Mtns
Bighorn Basin
Absaroka Mtns
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Fossil Plants from Cabin Fork Section, Bighorn
Basin
Wing et al., 2005
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Clyde, 2001
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Magnetostratigraphic Framework for the Bighorn
Basin,Wyoming
Clyde et al., in press
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Paleocene-Eocene Boundary Carbon Isotope Excursion
Benthic Foraminifera Indian Atlantic Oceans
Paleosol Carbonates Bighorn Basin, WY
Modified from Zachos et al., 2001 and Koch et
al., 2005
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Summary of ecological effects of PETM on
mammalian assemblages in the Bighorn Basin, WY
After Clyde and Gingerich, 1998
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Summary of plant turnover across PET in the
Bighorn Basin, WY
Wing et al., 2005
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What could have caused this global carbon isotope
excursion??

• Volcanoes?

• Change in biosphere?

• Extraterrestrial impact?

• Catastrophic release of frozen methane hydrates?

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From Pagani et al., 2006
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From Sluijs et al., 2007
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Assuming a 5C warming at the PETM
Thus, the PETM either resulted from an enormous
input of CO2 that currently defies a mechanistic
explanation, or climate sensitivity to CO2 was
extremely high Pagani et al., 2006, Science
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Is the PETM unique or are there other
hyperthermals?
Site 1267 (Walvis Ridge), from Sluijs et al., 2007
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Abdul Aziz et al., 2006
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• What we know
• The early Paleogene represents the most recent
  interval of greenhouse climate conditions and the
  Bighorn Basin preserves the most complete
  continental record of it.
• The PETM represents a gt5C global warming event
  that was initiated over lt 10,000 years.
• The PETM is associated with a very large,
  well-documented perturbation to the carbon cycle
  that has been recorded in many localities around
  the world.
• In many ways the PETM represents a natural
  experiment analogous to the modern anthropogenic
  experiment.
• The PETM shows that temporary changes in one
  part of the Earth System (e.g. carbon cycle) can
  have profound, long-lasting, and unpredictable
  effects in other parts of the system (e.g.
  mammalian evolution)

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• What we dont know (but can potentially learn
  from coring the Bighorn Basin)
• We dont know the true magnitude of the carbon
  isotope excursion or the total amount of carbon
  released but these may be best expressed in
  continental environments like the Bighorn Basin.
• - What was the climate sensitivity to this rapid
  increase in CO2?
• - What was the source of this carbon that could
  be so rapidly mobilized under natural
  conditions?
• We dont know if there are other, smaller
  magnitude, hyperthermal events or if the PETM
  is unique. Are these hyperthermals orbitally
  paced?
• We dont know the high resolution biotic and
  sedimentary response to the PETM in a continental
  system like that preserved in the Bighorn Basin?
• And much more.
• Acknowledgements
• DOSECC
• NSF EAR-0707415 - Bighorn Basin Coring Project
  Workshop (June 24-27)

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