oxygen New Scientist, #2746, 5 February 2010 by Nick Lane. Posits an earlier much longer snowball period, c. 2.4 – c. 2.0 Gya, triggered by the Great Oxygenation Event. 'Snowball Earth' theory melted BBC News online (2002-03-06) report on findings by geoscientists at the University of St Andrews, Scotland that casts doubt on the snowball Earth hypothesis due to evidence of sedimentary material, which could only have been derived from floating ice on open oceanic waters. Life may have survived 'snowball Earth' in ocean pockets BBC News online (2010-12-14) report on research presented in the journal Geology by Dr Dan Le Heron (et al.) of Royal Holloway, University of London who studied rock formations in Flinders Ranges in South Australia, formed from sediments dating to the Sturtian glaciation, which bear the unmistakable mark of turbulent oceans. Snowball Earth animated simulation by NASA and LDEO Ice ages Cryogenian Extinction events Proterozoic events Paleoclimatology Hypotheses Meteorological hypotheses