, a biomagnetist
at the Caifornia Institute of Technology in Pasadena, USA,
coined the name "snowball earth". He recognized its self-reversing
character (building on earlier work by atmospheric scientists James Walker, Hal
Marshall and Jim Kasting) and was the first to associate the runaway ice-albedo
concept to a known geological event, the Marinoan
. He proposed three
independent tests of his hypothesis: global synchroneity, ocean anoxia
and ultra-greenhouse aftermaths, each of which has been supported by new evidence.
hypothesis was first presented in 1989 to a think-tank called the Proterozoic
Paleobiology Research Group (PPRG) organized by Bill
at the University
of California Los Angeles. It was published in 1992 as an unrefereed, seven-paragraph-long,
article buried in a 1348-page book. The article
is a geological classic but fell
short of what was needed to convince a skeptical audience of a radical idea.
Initially and for several years afterwards, it was openly supported by only two
other geologists, Cees Klein at the University of New Mexico (USA) and Nic Beukes
at the Rand Afrikaans University in South Africa. Research activity ramped up
) after a 1998 paper in the
Harvard University and extensive lecture tours by its lead author Paul Hoffman.
They argued that the third of Kirschvink's predictions (ultra-greenhouse
aftermaths) could account for post-glacial 'cap carbonates
of the Marinoan snowball earth. Kirschvink's genius was to bring three
distinct disciplines to bear on the problem of apparent low-latitude glaciation:
climate physics (the ice-albedo feedback instability of Buyko and Sellers), geochemistry
(the silicate rock weathering
of James Walker and coauthors) and geology
(glacial sedimentology and Kirschvink's own discipline of paleomagnetism,
earlier combined by Brian Harland). Kirschvink originally set out to disprove
low-latitude glaciation but was compelled by his own data to support it.