Archaeology / Cultural Heritage

[Archaeology] [twocolumns]

Anthropology / Human Evolution

[Anthropology] [twocolumns]

Palaeontology / Earth Sciences

[Palaeontology] [twocolumns]

Evolution / Genetics


Life thrived on young Earth: Scientists discover 3.7-billion-year-old fossils

In an extraordinary find, a team of Australian researchers have uncovered the world's oldest fossils in a remote area of Greenland, capturing the earliest history of the planet and demonstrating that life on Earth emerged rapidly in the planet's early years.

Life thrived on young Earth: Scientists discover 3.7-billion-year-old fossils
The coast of Greenland [Credit: Mariusz Kluzniak/Flickr]
Led by the University of Wollongong's (UOW) Professor Allen Nutman, the team discovered 3.7-billion-year-old stromatolite fossils in the world's oldest sedimentary rocks, in the Isua Greenstone Belt along the edge of Greenland's icecap.

The findings are outlined in a study published in Nature, with co-authors Associate Professor Vickie Bennett from The Australian National University (ANU), the University of New South Wales' (UNSW) Professor Martin Van Kranendonk, and Professor Allan Chivas, from UOW.

The discovery of the Isua stromatolite fossils provides a greater understanding of early diversity of life on Earth and researchers said could have implications for our understanding of life on Mars. Professor Nutman, from UOW's School of Earth and Environmental Sciences, said the Isua stromatolite fossils predated the world's previous oldest stromatolite fossils -- which were found in Western Australia -- by 220 million years.

The discovery pushes back the fossil record to near the start of Earth's geological record and points to evidence of life on Earth very early in its history. The Isua stromatolites, which were exposed by the recent melting of a perennial snow patch, were laid down in shallow sea, providing the first evidence of an environment in which early life thrived.

Life thrived on young Earth: Scientists discover 3.7-billion-year-old fossils
Associate Professor Vickie Bennett (left), Professor Allen Nutman (centre), and Dr Clark Friend (right), 
examining the rocks in Greenland [Credit: Yuri Amelin]
For much of Earth's history, life was just single cells, and stromatolite fossils are mounds of carbonate constructed by these communities of microbes.

"The significance of stromatolites is that not only do they provide obvious evidence of ancient life that is visible with the naked eye, but that they are complex ecosystems," Professor Nutman said.

"This indicates that as long as 3.7 billion years ago microbial life was already diverse. This diversity shows that life emerged within the first few hundred millions years of Earth's existence, which is in keeping with biologists' calculations showing the great antiquity of life's genetic code."

Co-lead investigator Associate Professor Vickie Bennett, from ANU, said this study provided a new perspective into the history of Earth.

Life thrived on young Earth: Scientists discover 3.7-billion-year-old fossils
The stromatolites in figure a are from Greenland; those in c and d are younger stromatolites from 
Western Australia. Figure b shows the layers created by microbes as they formed the Greenland 
stromatolites (blue lines). ‘Stroms’ are several overlapping stromatolites
[Credit: Allen P. Nutman et al., Nature]
"This discovery turns the study of planetary habitability on its head," Associate Professor Bennett said.

"Rather than speculating about potential early environments, for the first time we have rocks that we know record the conditions and environments that sustained early life. Our research will provide new insights into chemical cycles and rock-water-microbe interactions on a young planet."

Professor Martin Van Kranendonk, Director of the Australian Centre for Astrobiology at UNSW, of which Professor Nutman is also an Associate Member, said it was a groundbreaking find that could point to similar life structures on Mars, which 3.7 billion years ago was a damp environment.

"The structures and geochemistry from newly exposed outcrops in Greenland display all of the features used in younger rocks to argue for a biological origin," Professor Van Kranendonk said.

"This discovery represents a new benchmark for the oldest preserved evidence of life on Earth. It points to a rapid emergence of life on Earth and supports the search for life in similarly ancient rocks on Mars."

Author: India Lloyd | Source: University of Wollongong [August 31, 2016]

Post A Comment
  • Blogger Comment using Blogger
  • Facebook Comment using Facebook
  • Disqus Comment using Disqus

No comments :

Exhibitions / Travel

[Exhibitions] [bsummary]

Natural Heritage / Environment / Wildlife

[Natural Heritage] [list]

Astronomy / Astrobiology / Space Exploration

[Universe] [list]