Armed with a clipboard, compass, tape and grid paper, UCLA professor Craig Manning and a team of geologists mapped the outcroppings of a peninsula on Akilia Island in West Greenland.
The geologists hoped to find evidence to support their theory that life existed on Earth far earlier than conventional wisdom teaches.
By studying rock on the Akilia Island, scientists can look for certain elements within the layers that would prove the existence of life at certain points throughout the planet’s history.And their discovery of evidence that life began 3.8 billion years ago – 300 million years earlier than previously thought – represents an advancement in their continuing research that began 10 years ago.
A decade ago, two of the scientists mapping Akilia Island and another UCLA geologist published a small discovery that existence of life began 3.8 billion years ago, but critics said the study lacked concrete evidence.
So this year, study authors Stephen Mojzsis, assistant professor of geological sciences at the University of Colorado at Boulder, and T. Mark Harrison, professor of geochemistry at UCLA and director of UCLA’s Institute of Geophysics and Planetary Physics, joined Manning to return to West Greenland and thoroughly re-examine their findings – for better or worse.
“It could have gone either way. We could have placed the claim on much firmer footing, or we could have proved ourselves wrong,” Harrison said.
Manning and the team of geologists worked for three weeks to map Akilia Island, meticulously taping off the area in grid format and then copying the measurements onto over 20 sheets of grid paper.
The area was roughly the size of two football fields. They camped in tents, used a small motorboat to transport them from island to island, and weathered one bad storm that delayed their return home.
After their expedition, Mojzsis, Harrison and Manning published stronger evidence for the age of the rocks on Akilia Island last month in the American Journal of Science. The study contained Manning’s detailed maps, making their claim that life on Earth originated more than 3.8 billion years ago stronger than ever.
The scientists were able to deduce that life was present in West Greenland 3.8 billion years ago by determining the age of ancient rocks on Akilia Island indirectly, measuring the age of cross-cutting rocks that had pushed up from the mantle below.
The geologists were able to work backward to get a picture of what Akilia Island looked like millions of years ago by unfolding each crease in Manning’s geological maps. The scientists then looked for evidence for life in carbon isotopic evidence from the rocks by analyzing carbon areas of the cross-cutting rocks at the NSF National Microprobe Facility, housed at UCLA.
“Our study strengthens quite significantly the idea that life was an early phenomenon on Earth,” said Mojzsis, who was a post-doctorate research fellow at UCLA.
The issue surrounding the date when life emerged on earth comes from the fact that the age of rocks is questionable. Rocks, which chart the passage of time with their internal rate of chemical decay, haven’t stayed the same since they originated. The minerals in older rocks have changed from their original condition, said Mojzsis.
“We don’t have a complete geological record for when life emerged on Earth. ... We have little pieces, hints,” said Kevin McKeegan, co-director of the NSF National Ion Microprobe Facility, a professor in the Department of Earth and Space Sciences at UCLA, and an author of the original 1996 study.
“We are trying to answer the questions of the earliest evidence for life on Earth ... and this is as far back as we can push it.”