Theoretical origin of life; ealiest possibly found (Introduction)

by David Turell , Wednesday, May 10, 2017, 00:56 (2758 days ago) @ David Turell

More evidence of early life from Australia:

https://phys.org/news/2017-05-oldest-evidence-life-billion-year-old-australian.html

"Fossil evidence of early life has been discovered by UNSW scientists in 3.48 billion year old hot spring deposits in the Pilbara of Western Australia - pushing back by 3 billion years the earliest known existence of inhabited terrestrial hot springs on Earth.

"Previously, the world's oldest evidence for microbial life on land came from 2.7- 2.9 billion year old deposits in South Africa containing organic matter-rich ancient soils.

"'Our exciting findings don't just extend back the record of life living in hot springs by 3 billion years, they indicate that life was inhabiting the land much earlier than previously thought, by up to about 580 million years," says study first author, UNSW PhD candidate, Tara Djokic.

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"The researchers studied exceptionally well-preserved deposits which are approximately 3.5 billion year old in the ancient Dresser Formation in the Pilbara Craton of Western Australia

"They interpreted the deposits were formed on land, not in the ocean, by identifying the presence of geyserite - a mineral deposit formed from near boiling-temperature, silica-rich, fluids that is only found in a terrestrial hot spring environment. Previously, the oldest known geyserite had been identified from rocks about 400 million years old.

"Within the Pilbara hotspring deposits, the researchers also discovered stromatolites - layered rock structures created by communities of ancient microbes. And there were other signs of early life in the deposits as well, including fossilised micro-stromatolites, microbial palisade texture and well preserved bubbles that are inferred to have been trapped in a sticky substance (microbial) to preserve the bubble shape.

"'This shows a diverse variety of life existed in fresh water, on land, very early in Earth's history," says Professor Van Kranendonk, Director of the Australian Centre for Astrobiology and head of the UNSW school of Biological, Earth and Environmental Sciences."

Comment: I think it is still more likely that life began in the oceans than on land. One reason is the concentration of salt in our blood is the same as the salt concentration in sea water