Scientists uncover oldest evidence of life on earth in Australia's Pilbara region
11 May 2017
Ancient hot spring deposits found in Australia's desert could provide clues to the origins of life on earth, and pointers for searching for its extraterrestrial existence, according to a new study.
The discovery of fossilised microbial deposits in the Pilbara region of Western Australia could extend the geological record of life in hot springs and have important implications for understanding the origins of life, according to researchers.
According to the scientists, the evidence suggests life may have evolved on land, rather than deep in the ocean.
''Prior to this work, the oldest evidence of life on land was 2.7 billion years old. That wasn't in hot springs, it was in South Africa in rich soils. Basically, that was an argument to say: 'We don't see life on land very early on, it must have adapted later,''' said lead author Tara Djokic of the University of New South Wales. ''Now, we are seeing life was already on land 3.5 billion years ago.''
Life is currently thought to have either evolved in deep sea hydrothermal vents or, as Charles Darwin theorised in his ''warm little pond scenario,'' it was sparked by the mixing of chemicals on land.
According to Djokic, the discovery of fossils in the Dresser Formation in the Pilbara Craton provided a new geological perspective that supported Darwin's theory.
''I don't think the Dresser Formation is anywhere close to the origin of life, but it does lend weight to that environment being available, which was previously not known,'' she said.
The findings hint that early life may have originated in springs on land, as opposed to deep inside ocean hydrothermal vents, as was commonly believed, Djokic told Live Science.
Life emerged on earth after it coalesced about 4.5 billion years ago, but exactly how soon after the planet's formation, remains a subject of debate. Ancient rocks in Greenland dating back to 3.7 billion years contained hints of microbial mats of cyanobacteria known as stromatolites, while another formation in Quebec might date back to 4.28 billion years.