Friday, 2 September 2011

Pumice Rafts Could Have Given Rise To Early Life

A team of scientists from Oxford and the University of Western Australia believe that life could have begun on rafts of a volcanic rock called pumice, which would have floated on the oceans. Pumice is a very porous rock and, because of its huge surface area to volume ratio, it is able to float in water. 'During its life cycle, pumice is potentially exposed to - among other things - lightning associated with volcanic eruptions, oily hydrocarbons and metals produced by hydrothermal vents and ultraviolet light from the sun'  explained Professor Martin Brasier from the University of Oxford.
Pumice rafts on the volcanic Greek island of Santorini

Incidentally, these conditions match exactly those in experiments designed to see how complex organic molecules such as DNA could have been synthesised on the early Earth. The tiny chambers inside the pumice would have acted like miniaturised flasks, test tubes and beakers, creating a vast and constantly replenished laboratory, building life molecule by molecule. We know that pumice rafts do exist today. Vast outcrops have been found on beaches of the volcanic Greek island Santorini.
Pumice from near the Strelley Pool

Life was thriving between sandstone grains in water pools in Western Australia around 3.4 billion years ago. The team believes that pumice rafts could contain micro fossils which could be over 3.5 billion years old. Samples of pumice were found near to the Strelley Pool where the oldest known fossils on Earth were found.

The team are going to conduct more research into ancient pumice rafts to investigate further this highly plausible theory.