Scientists have found the oldest piece of earth in the history of mankind. A zircon rock that dates back 4.4 billion years was found at a sheep ranch in the Jack Hills area of Australia, according to several news reports.
Researchers from the University of Wisconsin-Madison extracted the tiny piece of the crystal rock from a remote rock outcrop in Western Australia. The finding resolves several questions about early earth's atmosphere, its habitability and age.
"This, I believe, is the oldest zircon that's ever been dated on Earth," John Valley, a professor of the university who also led the study, said in a statement.
The findings have been published in the journal, Nature Geoscience.
The Jack Hills range in Australia is known to be the best source for early earth material. The researchers used a technique called atom-probe tomography to identify individual atoms of lead in the rock and determined their mass to confirm the rock's age.
"If there's a process by where lead can move from one part of the crystal to another place, then the place where lead is concentrated will have an older apparent age and the place from where it moves will have a younger apparent age," Valley told LiveScience.
It is believed that the earth formed 4.5 billion years ago and was a hot molten ball of fire then. The period is called Hadean eon after the Greek god of the underworld- Hades- for its hot and inhospitable atmosphere. The crust of the earth formed in the next 100 million years. Many experts believed that even after the crust formation, the atmosphere was too warm to sustain life.
However, the rock's properties show that early Earth was a lot cooler than previously believed and temperatures were low enough to nurture life.
"This confirms our view of how the Earth cooled and became habitable," Valley explained.
"The study reinforces our conclusion that Earth had a hydrosphere before 4.3 billion years ago," he added.
The oldest fossil before this find dates back 3.4 billion years, reports Reuters. However, the new find could mean life could have existed back then.
"We have no evidence that life existed then. We have no evidence that it didn't. But there is no reason why life could not have existed on Earth 4.3 billion years ago," Valley told Reuters.
Apart from serving as a 'window to early earth', Jack Hills is rich in iron ore. Currently, Crosslands Resources, a subsidiary of Mitsubishi, is developing certain areas of Jack Hills. The company has taken on an expansion project and proposes to build infrastructure in the area to maximize growth opportunities.
