Triggers for the Late Ordovician Ice Age Volcanic

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Triggers for the Late Ordovician Ice Age: Volcanic Aerosols vs. CO 2 Konrad Cunningham

Triggers for the Late Ordovician Ice Age: Volcanic Aerosols vs. CO 2 Konrad Cunningham UG Eric Santiago HSS Linda Sohl PI Mark Chandler PI

Ordovician Period § Started about 500 million years ago. § Hardly any plants or

Ordovician Period § Started about 500 million years ago. § Hardly any plants or animals lived on the land; most were in the sea. § Compared to today’s Sun, the Sun of the Ordovician was 4% dim. § Most land masses were in the Southern Hemisphere.

The Ice Age of the Ordovician § Lasted ~0. 5 to ~1. 5 million

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 CO 2 § Our hypothesis: the sharp decrease in temperature could have been caused by a combination of low CO 2 and high SO 2 related to volcanic activity in the atmosphere.

Paleogeography

Paleogeography

Volcano locations in the late Ordovician § The volcanoes were part of an island

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.

CO 2=1000 ppm; Solar=94% CO 2=500 ppm, Solar=96% CO 2=1000 ppm, Solar=96% CO 2=3000

CO 2=1000 ppm; Solar=94% CO 2=500 ppm, Solar=96% CO 2=1000 ppm, Solar=96% CO 2=3000 ppm, Solar=96% Anomaly Plots for Surf. Air. Temp

Conclusion § Ord_testrun 3 shows that a ice age is highly improbable with high

Conclusion § Ord_testrun 3 shows that a ice age is highly improbable with high atmospheric CO 2, no matter what the level of solar luminosity. § Ord_testrun 8 gives us the most probable conditions on Earth that would help create an ice age. § Future simulations will explore the effects of both high SO 2 and low CO 2 on Ordovician climate.

References § Alaska Volcano Observatory http: //www. avo. alaska. edu/activity/avoreport. php? view=kaminfo&id=199&type=kaminfo&month=October&year=2006 § ATMOSPHERIC

References § Alaska Volcano Observatory http: //www. avo. alaska. edu/activity/avoreport. php? view=kaminfo&id=199&type=kaminfo&month=October&year=2006 § ATMOSPHERIC TRANSMISSION OF DIRECT SOLAR RADIATION AT MAUNA LOA, HAWAII § http: //climate. envsci. rutgers. edu/pdf/emissions_0207. pdf § Global Volcanism Program http: //www. volcano. si. edu/ § Volcanic SO 2 Archive Service http: //www. oma. be/BIRA-IASB/Molecules/SO 2 archive/vs/orbit. php § Mount Pinatubo Eruption http: //geography. about. com/library/weekly/aa 030901 a. htm § Ordovician http: //en. wikipedie. org. wiki. Ordovian § Impacts of Volcanic Gases http: //pubs. usgs. gov/of/1997/of 97 -262/of/97 -262. html § Ancient Oceans Separate the Continents http: /www. scotese. com/newpage 1. html § The Geology of Ohio—The Ordovician http: //www. dnr. state. oh. us/geosurvey/oh_geol/97_Fall/ordovici. htm § The size and frequency of the largest explosive eruptions on Earth § Nature and Origin of Life on Planetary Bodies http: //www. fas. org/irp/imint/docs/rst/Sect 20/A 12. html

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