Dr Mark Duffett Research Fellow in Geophysics

Professor Paul Hoffman of Harvard University, proponent of the Snowball Earth hypothesis, will be giving a free public lecture in the Centenary Lecture Theatre, University of Tasmania (Sandy Bay campus) at 6 p.m. on Monday September 29. Prof. Hoffman, one of the world’s leading geologists, is visiting Hobart as part of an Australian tour that will include studying rocks critical to his ‘Snowball Earth’ theory.

Sedimentary and magnetic evidence suggests that most of the planet, including the equator, was covered under thick ice during the Neoproterozoic era, 750 million to 550 million years ago, when low levels of atmospheric carbon dioxide, fainter sunlight and runaway feedback effects caused the polar ice caps to expand and freeze the oceans to a depth of up to 1 km.

These extreme climate shifts, together with the appearance of early primitive organisms during the Ediacaran era, 600 million to 544 million years ago, make the Neoproterozoic era one of the most important episodes in Earth’s turbulent history.

“If all the land was covered in ice sheets and the oceans had no dissolved oxygen, there would have been no place for any organism to hide,” according to Professor Hoffman, a specialist in the first geologic time period of the earth or Precambrian era, 4.5 billion to 570 million years ago. “However, single-celled organisms probably survived the glaciation.”

Prof. Hoffman’s lecture will focus on evidence for major glacial changes he has collected over the past 15 years in what is now Namibia. It should be of interest to anyone interested in the science behind climate change.

Canadian-born Prof. Hoffman joined Harvard University in 1994 where he developed the Snowball Earth hypothesis. His trip to Australia is sponsored by the Harvard Club of Australia Foundation, and his Tasmanian sojourn by the Geological Society of Australia.

Dr Mark Duffett
Geological Society of Australia (Tasmania Division) executive committee

http://fcms.its.utas.edu.au/scieng/codes/index.asp

Background
Dr Hoffman: http://www.eps.harvard.edu/people/faculty/hoffman/
Snowball Earth: http://www.snowballearth.org/