Mineral-filled 'microtubules' found in the glassy surfaces of ancient undersea lava may be some of the earliest evidence of microscopic life on Earth, an Indian origin Canadian geologist has said.
According to Professor Neil Banerjee from the University of Western Ontario, Canada, it may also be a clue to life on Mars.
Prof Banerjee and his team found that microbes seeking vital minerals in the volcanic glass, had drilled the tubules in the same way, they drill basalt lava, which squeezes out of the ocean floor in volcanic zones, today.
The team dated the palagonite filler using a new method called Laser Ablation Mass Spectrometry. It allowed the team to aim a 40-micron-wide laser at very specific patches in the microtubules, and vaporize them.
Identification of the ratio of lead and uranium isotopes in the vapour revealed the palagonite filler dated to 3.3 to 3.5 billion years ago.
According to Dr Banerjee, dating the palagonite filler is essential for dating the microbes, as the microbes could have colonized the pillow lava itself long after it had solidified on the sea floor.
"We have managed to date for the first time minerals that fill the microtubules. In this case, the palagonite filler dated to 3.3 to 3.5 billion years ago -- a range that neatly includes the 3.35 billion-year age of the Pilbara pillow lavas. That means the microbes drilled the tubules pretty soon after the rocks formed," said Prof Banerjee.
"To our knowledge, this is the first direct dating of Archean ichnofauna," he said.
He said their method might find use in Mars exploration projects as well.
"On Mars, the best place to look for signs of microbial life might be the lavas around impact craters, where there are also signs of ancient water. We do think we have something that could contribute to the exploration of Mars," he said.
The findings are scheduled for publication in the June issue of the journal Geology, reports Discovery News.
