Snowball Earth:

Did Earth freeze over for 10 million years? Allday Lecturer Paul Hoffman of Harvard visits the Jackson School to explain his once controversial theory

As the 2006 Edwin Allday Lecturer in Geological Sciences, Paul Hoffman of Harvard University will make three presentations to members of the Jackson School community, discussing his world famous research which has led to wider acceptance of the paradigm-shifting theory known as "Snowball Earth."

The Snowball Earth hypothesis attempts to explain a number of phenomena noted in the geological record by proposing that an ice age that took place in the Neoproterozoic, about 600-700 million years ago, was so severe that the Earth's oceans froze over completely. The general hypothesis has been around for several decades. Joseph Kirschvink, professor of geology at the California Institute of Technology, coined the term "Snowball Earth" in 1992.

Hoffman and his colleague Daniel P. Schrag championed the theory and in 1999 co-authored the paper that propelled it toward wider acceptance in the scientific community.

According to the BBC, which produced a documentary on the theory in 2001, scientists across the world "are starting to believe that in the past the Earth froze over completely for ten million years, then warmed up rapidly about 600 million years ago. Almost all life was wiped out. But out of the freeze emerged the first complex creatures on Earth. Scientists now believe that the so-called Snowball Earth theory could hold the key to the evolution of complex life on this planet."

Members of the Jackson School community have the chance to hear Hoffman make three presentations on the theory: An overall exposition and defense ("Snowball Earth: Science or Snowjob?") and two talks on detailed aspects of the geological evidence ("Post-glacial cap-carbonate sequences: signatures of snowball earth?" and "The syn-glacial deposits of a snowball earth").

See the timetable at the top of this page for locations and details.

For more information contact J.B. Bird at the Jackson School, jbird@jsg.utexas.edu, 512-232-9623.