Triggers for the Late Ordovician Ice Age: Volcanic Aerosols vs. CO2

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Triggers for the Late Ordovician Ice Age
Volcanic Aerosols vs. CO2

• Konrad Cunningham UG
• Eric Santiago HSS
• Linda Sohl PI
• Mark Chandler PI

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Ordovician Period

• Started about 500 million years ago.
• Hardly any plants or animals lived on the land
  most were in the sea.
• Compared to todays Sun, the Sun of the
  Ordovician was 4 dim.
• Most land masses were in the Southern Hemisphere.

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The Ice Age of the Ordovician

• Lasted 0.5 to 1.5 million years.
• Some researchers think that there was a high
  level of atmospheric CO2
• Our hypothesis the sharp decrease in
  temperature could have been caused by a
  combination of low CO2 and high SO2 related to
  volcanic activity in the atmosphere.

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Paleogeography
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Volcano locations in the late Ordovician

• The volcanoes were part of an island arc between
  Laurentia and Baltica.
• These volcanoes were active and created 5,000
  times the volume of ash than Mt. St. Helens
  eruption in 1980.
• The eruptions were 3 of the 20 largest events in
  the last 600 million years.

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Anomaly Plots for SurfAirTemp
CO21000 ppm, Solar96
CO23000 ppm, Solar96
CO2500 ppm, Solar96
CO21000ppm Solar94
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Conclusion

• Ord_testrun3 shows that a ice age is highly
  improbable with high atmospheric CO2, no matter
  what the level of solar luminosity.
• Ord_testrun8 gives us the most probable
  conditions on Earth that would help create an ice
  age.
• Future simulations will explore the effects of
  both high SO2 and low CO2 on Ordovician climate.

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References

• Alaska Volcano Observatory
• http//www.avo.alaska.edu/activity/avoreport.php?v
  iewkaminfoid199typekaminfomonthOctoberyear
  2006
• ATMOSPHERIC TRANSMISSION OF DIRECT SOLAR
  RADIATION AT MAUNA LOA, HAWAII
• http//climate.envsci.rutgers.edu/pdf/emissions_02
  07.pdf
• Global Volcanism Program
• http//www.volcano.si.edu/
• Volcanic SO2 Archive Service
• http//www.oma.be/BIRA-IASB/Molecules/SO2archive/v
  s/orbit.php
• Mount Pinatubo Eruption
• http//geography.about.com/library/weekly/aa030901
  a.htm
• Ordovician
• http//en.wikipedie.org.wiki.Ordovian
• Impacts of Volcanic Gases
• http//pubs.usgs.gov/of/1997/of97-262/of/97-262.ht
  ml
• Ancient Oceans Separate the Continents
• http/www.scotese.com/newpage1.html
• The Geology of OhioThe Ordovician
• http//www.dnr.state.oh.us/geosurvey/oh_geol/97_Fa
  ll/ordovici.htm
• The size and frequency of the largest explosive
  eruptions on Earth