Continental Scientific Drilling

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Continental Scientific Drilling for
Plio-Pleistocene Paleoclimate
J. M. Russell Geological Sciences Brown
University, Providence RI Denver, CO 4 June
2009 Outline

• Temporal and spatial resolution in
  paleoclimatology
• Drilling to investigate
• Millennial-scale variability
• Glacial-interglacial climate change on the
  continents
• The Pliocene

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Iconic records of past climate document orbital,
millennial, and decadal variations
Lisiecki and Raymo, 2005 NorthGrip members,
2004 Mann et al., 2008

• Changes in the amplitude
• of climate variability
• Many (but not all) changes
• correlate to changes in
• atmospheric CO2

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Spatial variations in projected temperature and
precipitation under rising CO2
IPCC 2007
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Many iconic records lack spatial
resolution Need for new records to understand
synoptic paleoclimatology
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Sediment records define spatial patterns of
Holocene climate
Mid-Holocene lake level - present (6 kyr -
0) Wanner et al. 2008
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Spatial and Temporal Resolution of Paleoclimate
Archives
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The Value of Multiple Proxies
Mineralogy Sediments
Lake Level Water Balance
Aquatic Fossils
Winds, productivity Lake pH, salinity
Pollen
Past Landscapes Land-climate feedbacks
Organic Geochem
TEX86 Temperature D/H ratios of waxes (Convection)
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Continental drilling for paleoclimate Regional
and spatial patterns of continental climatic
and environmental change (PAGES PEP,
Timestreams I-III)
Colman, ed., 1996
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NSF Paleo-Perspectives on Climate Change Emphases

• What were the regional responses of coupled
  climate systems like ENSO, monsoons, and the
  North Atlantic Oscillation during past climate
  changes? (CCSP Questions 4.2, 4.3, 4.4)
• What does the geologic record tell us about past
  climate sensitivity, variability, and change
  under different boundary conditions, large, rapid
  changes in forcing, or past climate states?
  (CCSP 4.1, 4.2, 4.3., 4.4)
• Low- to High-latitude network to investigate
• Abrupt, millennial scale changes during MIS III
• Glacial-interglacial climate changes on the
  continents
• The Pliocene

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Abrupt, millennial-scale warming in Greenland

• Global footprint and mechanism of transmission

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Global footprint of MIS 3 millennial variations
Lynch-Stieglitz, 2004
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Transmission Mechanisms (Clement and Peterson,
2008)

• Coupled ocean-atmospheric dynamics cause
  southward shift of ITCZ and El Niño-like
  Pacific
• Southward migration of all major climate belts
  mid-latitude jet captures tropical storm tracks
  (NAO pattern)

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A global network of continental records for MIS 3?
The regional responses of climate systems such
as ENSO and the NAO during abrupt climate
changes.
WET
DRY
WET
DRY
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Continental Drilling Contributions
Petén Itzá High rainfall Strong summer monsoon
Malawi Weak winter monsoon Wet?
Hodell et al. 2008
Brown et al. 2007
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Continental climate across Pleistocene
glacialcycles
What were the regional responses of coupled
climate systems during past climate changes,
large, rapid changes in forcing or under
different boundary condition?
Continental Temperature? Precipitation? Vegetati
on?
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- This picture confirmed by numerous 20 kyr
records of African lake level that show dry LGM
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Late Pleistocene African climate The view from
Lake Malawi
Cohen et al., 2007 Scholz et al. 2007
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t
G. K. Gilbert

• Great Salt Lake
• Shoreline dating shows wet LGM climate
  (Currey and Oviatt, 1985 Oviatt,
  1999 Broecker et al., 1998)
• Storm track deflection by ice sheet

Oviatt, 1999
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Results of GSL drilling GLAD 1
Balch et al., 2005

• The last glacial termination is not archetypical.
• What are the regional (high- to low-latitude)
  responses to ice sheets, orbits, and GHGs?

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The Pliocene
Continental climate and environments under very
different climate state high temperature,
reduced ice sheets, high CO2
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The Pliocene A permanent El Niño
Wara et al. 2005 Lawrence et al., 2006 Fedorov
et al., 2007
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Poleward Expansion of the Warm Pool in the
Pliocene Brierly et al., 2009
Pliocene Tropical SSTs vary at 41K pacing
(Lawrence et al., 2006)
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The Pliocene

• How did regional climates
• vary during recent prolonged
• warm interval?
• Climate variability under permanent
  El Niño? (need for laminated seds)
• High- to low latitude effects of an
  expanded tropical warm pool?
• Temporal evolution of climate (Pliocene to
  present) in relation to the Pacific SST gradient?
  (need for long, continuous record)
• Do continental temperatures exhibit a dominant
  periodicity at 41K during the Pliocene and early
  Pleistocene?

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Conclusions

• Sediments in continental basins offer high
  spatio-temporal resolution records of
  Plio-Pleistocene climate
• The Plio-Pleistocene contains a wide array of
  climate experiments varying ice sheets,
  greenhouse gases, abrupt and gradual changes
• The outcome of these experiments on the
  continental climate is largely unknown, although
  such knowledge can provide key insight into
  mechanisms of climate change.
• The answers are accessible only through
  continental scientific drilling.