Life on Earth: French team backs claim on age of microbes

29th January 2008, Comments 0 comments

Claims that microbial life began on Earth billions of years ago have been given support from a French team which drilled into mysterious layers of spongey rock

   PARIS, January 29, 2008 - Claims that microbial life began on Earth
billions of years ago have been given support from a French team which drilled
into mysterious layers of spongey rock in Western Australia.
   Researchers from the Institute for Global Physics in Paris used a technique
called nanospectroscopy to pore over cores drilled from an enigmatic rock
formation in the Pilbara region.
   Palaeo-geologists from around the world have been lured to Pilbara, famous
for rock layers in the shape of cones, waves and "egg carton" domes.
   One school of thought holds that these layers comprise the fossilised
remains of bacteria, called stromatolites, that seethed in shallow seas or
lake water, which washed over the area when the Earth was young.
   Others, though, dispute a microbial origin, and say the shapes were the
result of chemical weathering, a reaction between the rock and sea water, or
hydrothermal vents.
   The French investigators, led by Kevin Lepot, drilled a deep core of rock
from the Pilbara's Tubiana formation at Meentheena and took images of the
sample to a resolution of 10 nanometres, or 10 billionths of a metre.
   They found minute crystals of aragonite, a calcite residue from dead
micro-organisms.
   Previous research have dated the Tubiana rocks to 2.72 billion years.
   In 2006, Australian and Canadian researchers led by Abigail Allwood of
Sydney's Macquarie University dated microfossils in rocks from Pilbara's
Strelley Pool Chert formation at more than 3.4 billion years old, the earliest
evidence so far of life on Earth.
   Dating of early life on Earth could help determine whether life exists, or
has existed, on Mars, the best bet for microbial lifeforms in other planets of
the Solar System.
   Mars once had an atmosphere and was awash with water -- two ingredients
that, with warmth, comprise the essentials for bacterial life.
   The new study appears in the February issue of the journal Nature
Geoscience, published by Britain's Nature group.

AFP 

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